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public
class
Canvas
extends Object
java.lang.Object | |
↳ | android.graphics.Canvas |
The Canvas class holds the "draw" calls. To draw something, you need 4 basic components: A Bitmap to hold the pixels, a Canvas to host the draw calls (writing into the bitmap), a drawing primitive (e.g. Rect, Path, text, Bitmap), and a paint (to describe the colors and styles for the drawing).
For more information about how to use Canvas, read the Canvas and Drawables developer guide.
Nested classes | |
---|---|
enum |
Canvas.EdgeType
This enum is deprecated. quickReject no longer uses this. |
enum |
Canvas.VertexMode
|
Constants | |
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int |
ALL_SAVE_FLAG
Restore everything when restore() is called (standard save flags). |
Public constructors | |
---|---|
Canvas()
Construct an empty raster canvas. |
|
Canvas(Bitmap bitmap)
Construct a canvas with the specified bitmap to draw into. |
Public methods | |
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boolean
|
clipOutPath(Path path)
Set the clip to the difference of the current clip and the specified path. |
boolean
|
clipOutRect(int left, int top, int right, int bottom)
Set the clip to the difference of the current clip and the specified rectangle, which is expressed in local coordinates. |
boolean
|
clipOutRect(Rect rect)
Set the clip to the difference of the current clip and the specified rectangle, which is expressed in local coordinates. |
boolean
|
clipOutRect(float left, float top, float right, float bottom)
Set the clip to the difference of the current clip and the specified rectangle, which is expressed in local coordinates. |
boolean
|
clipOutRect(RectF rect)
Set the clip to the difference of the current clip and the specified rectangle, which is expressed in local coordinates. |
boolean
|
clipPath(Path path, Region.Op op)
This method is deprecated.
Region.Op values other than |
boolean
|
clipPath(Path path)
Intersect the current clip with the specified path. |
boolean
|
clipRect(float left, float top, float right, float bottom, Region.Op op)
This method is deprecated.
Region.Op values other than |
boolean
|
clipRect(RectF rect)
Intersect the current clip with the specified rectangle, which is expressed in local coordinates. |
boolean
|
clipRect(Rect rect)
Intersect the current clip with the specified rectangle, which is expressed in local coordinates. |
boolean
|
clipRect(Rect rect, Region.Op op)
This method is deprecated.
Region.Op values other than |
boolean
|
clipRect(int left, int top, int right, int bottom)
Intersect the current clip with the specified rectangle, which is expressed in local coordinates. |
boolean
|
clipRect(float left, float top, float right, float bottom)
Intersect the current clip with the specified rectangle, which is expressed in local coordinates. |
boolean
|
clipRect(RectF rect, Region.Op op)
This method is deprecated.
Region.Op values other than |
void
|
concat(Matrix matrix)
Preconcat the current matrix with the specified matrix. |
void
|
disableZ()
Disables Z support, preventing any RenderNodes drawn after this point from being visually reordered or having shadows rendered. |
void
|
drawARGB(int a, int r, int g, int b)
Fill the entire canvas' bitmap (restricted to the current clip) with the specified ARGB color, using srcover porterduff mode. |
void
|
drawArc(float left, float top, float right, float bottom, float startAngle, float sweepAngle, boolean useCenter, Paint paint)
Draw the specified arc, which will be scaled to fit inside the specified oval. |
void
|
drawArc(RectF oval, float startAngle, float sweepAngle, boolean useCenter, Paint paint)
Draw the specified arc, which will be scaled to fit inside the specified oval. |
void
|
drawBitmap(Bitmap bitmap, Matrix matrix, Paint paint)
Draw the bitmap using the specified matrix. |
void
|
drawBitmap(int[] colors, int offset, int stride, float x, float y, int width, int height, boolean hasAlpha, Paint paint)
This method is deprecated.
Usage with a |
void
|
drawBitmap(int[] colors, int offset, int stride, int x, int y, int width, int height, boolean hasAlpha, Paint paint)
This method is deprecated.
Usage with a |
void
|
drawBitmap(Bitmap bitmap, Rect src, Rect dst, Paint paint)
Draw the specified bitmap, scaling/translating automatically to fill the destination rectangle. |
void
|
drawBitmap(Bitmap bitmap, Rect src, RectF dst, Paint paint)
Draw the specified bitmap, scaling/translating automatically to fill the destination rectangle. |
void
|
drawBitmap(Bitmap bitmap, float left, float top, Paint paint)
Draw the specified bitmap, with its top/left corner at (x,y), using the specified paint, transformed by the current matrix. |
void
|
drawBitmapMesh(Bitmap bitmap, int meshWidth, int meshHeight, float[] verts, int vertOffset, int[] colors, int colorOffset, Paint paint)
Draw the bitmap through the mesh, where mesh vertices are evenly distributed across the bitmap. |
void
|
drawCircle(float cx, float cy, float radius, Paint paint)
Draw the specified circle using the specified paint. |
void
|
drawColor(long color, BlendMode mode)
Fill the entire canvas' bitmap (restricted to the current clip) with the specified color and blendmode. |
void
|
drawColor(int color)
Fill the entire canvas' bitmap (restricted to the current clip) with the specified color, using srcover porterduff mode. |
void
|
drawColor(int color, BlendMode mode)
Fill the entire canvas' bitmap (restricted to the current clip) with the specified color and blendmode. |
void
|
drawColor(long color)
Fill the entire canvas' bitmap (restricted to the current clip) with the specified color, using srcover porterduff mode. |
void
|
drawColor(int color, PorterDuff.Mode mode)
Fill the entire canvas' bitmap (restricted to the current clip) with the specified color and porter-duff xfermode. |
void
|
drawDoubleRoundRect(RectF outer, float[] outerRadii, RectF inner, float[] innerRadii, Paint paint)
Draws a double rounded rectangle using the specified paint. |
void
|
drawDoubleRoundRect(RectF outer, float outerRx, float outerRy, RectF inner, float innerRx, float innerRy, Paint paint)
Draws a double rounded rectangle using the specified paint. |
void
|
drawLine(float startX, float startY, float stopX, float stopY, Paint paint)
Draw a line segment with the specified start and stop x,y coordinates, using the specified paint. |
void
|
drawLines(float[] pts, int offset, int count, Paint paint)
Draw a series of lines. |
void
|
drawLines(float[] pts, Paint paint)
|
void
|
drawOval(float left, float top, float right, float bottom, Paint paint)
Draw the specified oval using the specified paint. |
void
|
drawOval(RectF oval, Paint paint)
Draw the specified oval using the specified paint. |
void
|
drawPaint(Paint paint)
Fill the entire canvas' bitmap (restricted to the current clip) with the specified paint. |
void
|
drawPath(Path path, Paint paint)
Draw the specified path using the specified paint. |
void
|
drawPicture(Picture picture, RectF dst)
Draw the picture, stretched to fit into the dst rectangle. |
void
|
drawPicture(Picture picture)
Save the canvas state, draw the picture, and restore the canvas state. |
void
|
drawPicture(Picture picture, Rect dst)
Draw the picture, stretched to fit into the dst rectangle. |
void
|
drawPoint(float x, float y, Paint paint)
Helper for drawPoints() for drawing a single point. |
void
|
drawPoints(float[] pts, Paint paint)
Helper for drawPoints() that assumes you want to draw the entire array |
void
|
drawPoints(float[] pts, int offset, int count, Paint paint)
Draw a series of points. |
void
|
drawPosText(String text, float[] pos, Paint paint)
This method is deprecated. This method does not support glyph composition and decomposition and should therefore not be used to render complex scripts. It also doesn't handle supplementary characters (eg emoji). |
void
|
drawPosText(char[] text, int index, int count, float[] pos, Paint paint)
This method is deprecated. This method does not support glyph composition and decomposition and should therefore not be used to render complex scripts. It also doesn't handle supplementary characters (eg emoji). |
void
|
drawRGB(int r, int g, int b)
Fill the entire canvas' bitmap (restricted to the current clip) with the specified RGB color, using srcover porterduff mode. |
void
|
drawRect(float left, float top, float right, float bottom, Paint paint)
Draw the specified Rect using the specified paint. |
void
|
drawRect(Rect r, Paint paint)
Draw the specified Rect using the specified Paint. |
void
|
drawRect(RectF rect, Paint paint)
Draw the specified Rect using the specified paint. |
void
|
drawRenderNode(RenderNode renderNode)
Draws the given RenderNode. |
void
|
drawRoundRect(RectF rect, float rx, float ry, Paint paint)
Draw the specified round-rect using the specified paint. |
void
|
drawRoundRect(float left, float top, float right, float bottom, float rx, float ry, Paint paint)
Draw the specified round-rect using the specified paint. |
void
|
drawText(CharSequence text, int start, int end, float x, float y, Paint paint)
Draw the specified range of text, specified by start/end, with its origin at (x,y), in the specified Paint. |
void
|
drawText(String text, float x, float y, Paint paint)
Draw the text, with origin at (x,y), using the specified paint. |
void
|
drawText(char[] text, int index, int count, float x, float y, Paint paint)
Draw the text, with origin at (x,y), using the specified paint. |
void
|
drawText(String text, int start, int end, float x, float y, Paint paint)
Draw the text, with origin at (x,y), using the specified paint. |
void
|
drawTextOnPath(String text, Path path, float hOffset, float vOffset, Paint paint)
Draw the text, with origin at (x,y), using the specified paint, along the specified path. |
void
|
drawTextOnPath(char[] text, int index, int count, Path path, float hOffset, float vOffset, Paint paint)
Draw the text, with origin at (x,y), using the specified paint, along the specified path. |
void
|
drawTextRun(MeasuredText text, int start, int end, int contextStart, int contextEnd, float x, float y, boolean isRtl, Paint paint)
Draw a run of text, all in a single direction, with optional context for complex text shaping. |
void
|
drawTextRun(char[] text, int index, int count, int contextIndex, int contextCount, float x, float y, boolean isRtl, Paint paint)
Draw a run of text, all in a single direction, with optional context for complex text shaping. |
void
|
drawTextRun(CharSequence text, int start, int end, int contextStart, int contextEnd, float x, float y, boolean isRtl, Paint paint)
Draw a run of text, all in a single direction, with optional context for complex text shaping. |
void
|
drawVertices(Canvas.VertexMode mode, int vertexCount, float[] verts, int vertOffset, float[] texs, int texOffset, int[] colors, int colorOffset, short[] indices, int indexOffset, int indexCount, Paint paint)
Draw the array of vertices, interpreted as triangles (based on mode). |
void
|
enableZ()
Enables Z support which defaults to disabled. |
boolean
|
getClipBounds(Rect bounds)
Return the bounds of the current clip (in local coordinates) in the bounds parameter, and return true if it is non-empty. |
final
Rect
|
getClipBounds()
Retrieve the bounds of the current clip (in local coordinates). |
int
|
getDensity()
Returns the target density of the canvas. |
DrawFilter
|
getDrawFilter()
|
int
|
getHeight()
Returns the height of the current drawing layer |
void
|
getMatrix(Matrix ctm)
This method is deprecated.
|
final
Matrix
|
getMatrix()
This method is deprecated.
|
int
|
getMaximumBitmapHeight()
Returns the maximum allowed height for bitmaps drawn with this canvas. |
int
|
getMaximumBitmapWidth()
Returns the maximum allowed width for bitmaps drawn with this canvas. |
int
|
getSaveCount()
Returns the number of matrix/clip states on the Canvas' private stack. |
int
|
getWidth()
Returns the width of the current drawing layer |
boolean
|
isHardwareAccelerated()
Indicates whether this Canvas uses hardware acceleration. |
boolean
|
isOpaque()
Return true if the device that the current layer draws into is opaque (i.e. |
boolean
|
quickReject(float left, float top, float right, float bottom, Canvas.EdgeType type)
This method is deprecated.
The EdgeType is ignored. Use |
boolean
|
quickReject(Path path)
Return true if the specified path, after being transformed by the current matrix, would lie completely outside of the current clip. |
boolean
|
quickReject(RectF rect)
Return true if the specified rectangle, after being transformed by the current matrix, would lie completely outside of the current clip. |
boolean
|
quickReject(RectF rect, Canvas.EdgeType type)
This method is deprecated.
The EdgeType is ignored. Use |
boolean
|
quickReject(Path path, Canvas.EdgeType type)
This method is deprecated.
The EdgeType is ignored. Use |
boolean
|
quickReject(float left, float top, float right, float bottom)
Return true if the specified rectangle, after being transformed by the current matrix, would lie completely outside of the current clip. |
void
|
restore()
This call balances a previous call to save(), and is used to remove all modifications to the matrix/clip state since the last save call. |
void
|
restoreToCount(int saveCount)
Efficient way to pop any calls to save() that happened after the save count reached saveCount. |
void
|
rotate(float degrees)
Preconcat the current matrix with the specified rotation. |
final
void
|
rotate(float degrees, float px, float py)
Preconcat the current matrix with the specified rotation. |
int
|
save()
Saves the current matrix and clip onto a private stack. |
int
|
saveLayer(RectF bounds, Paint paint, int saveFlags)
This method is deprecated.
Use |
int
|
saveLayer(RectF bounds, Paint paint)
This behaves the same as save(), but in addition it allocates and redirects drawing to an offscreen rendering target. |
int
|
saveLayer(float left, float top, float right, float bottom, Paint paint)
Convenience for |
int
|
saveLayer(float left, float top, float right, float bottom, Paint paint, int saveFlags)
This method is deprecated.
Use |
int
|
saveLayerAlpha(float left, float top, float right, float bottom, int alpha, int saveFlags)
This method is deprecated.
Use |
int
|
saveLayerAlpha(RectF bounds, int alpha)
Convenience for |
int
|
saveLayerAlpha(RectF bounds, int alpha, int saveFlags)
This method is deprecated.
Use |
int
|
saveLayerAlpha(float left, float top, float right, float bottom, int alpha)
Convenience for |
final
void
|
scale(float sx, float sy, float px, float py)
Preconcat the current matrix with the specified scale. |
void
|
scale(float sx, float sy)
Preconcat the current matrix with the specified scale. |
void
|
setBitmap(Bitmap bitmap)
Specify a bitmap for the canvas to draw into. |
void
|
setDensity(int density)
Specifies the density for this Canvas' backing bitmap. |
void
|
setDrawFilter(DrawFilter filter)
|
void
|
setMatrix(Matrix matrix)
Completely replace the current matrix with the specified matrix. |
void
|
skew(float sx, float sy)
Preconcat the current matrix with the specified skew. |
void
|
translate(float dx, float dy)
Preconcat the current matrix with the specified translation |
Inherited methods | |
---|---|
public static final int ALL_SAVE_FLAG
Restore everything when restore() is called (standard save flags).
Note: for performance reasons, it is
strongly recommended to pass this - the complete set of flags - to any
call to saveLayer()
and saveLayerAlpha()
variants.
Note: all methods that accept this flag have flagless versions that are equivalent to passing this flag.
Constant Value: 31 (0x0000001f)
public Canvas ()
Construct an empty raster canvas. Use setBitmap() to specify a bitmap to
draw into. The initial target density is Bitmap#DENSITY_NONE
;
this will typically be replaced when a target bitmap is set for the
canvas.
public Canvas (Bitmap bitmap)
Construct a canvas with the specified bitmap to draw into. The bitmap must be mutable.
The initial target density of the canvas is the same as the given bitmap's density.
Parameters | |
---|---|
bitmap |
Bitmap : Specifies a mutable bitmap for the canvas to draw into.
This value cannot be null . |
public boolean clipOutPath (Path path)
Set the clip to the difference of the current clip and the specified path.
Parameters | |
---|---|
path |
Path : The path used in the difference operation
This value cannot be null . |
Returns | |
---|---|
boolean |
true if the resulting clip is non-empty |
public boolean clipOutRect (int left, int top, int right, int bottom)
Set the clip to the difference of the current clip and the specified rectangle, which is expressed in local coordinates.
Parameters | |
---|---|
left |
int : The left side of the rectangle used in the difference operation |
top |
int : The top of the rectangle used in the difference operation |
right |
int : The right side of the rectangle used in the difference operation |
bottom |
int : The bottom of the rectangle used in the difference operation |
Returns | |
---|---|
boolean |
true if the resulting clip is non-empty |
public boolean clipOutRect (Rect rect)
Set the clip to the difference of the current clip and the specified rectangle, which is expressed in local coordinates.
Parameters | |
---|---|
rect |
Rect : The rectangle to perform a difference op with the current clip.
This value cannot be null . |
Returns | |
---|---|
boolean |
true if the resulting clip is non-empty |
public boolean clipOutRect (float left, float top, float right, float bottom)
Set the clip to the difference of the current clip and the specified rectangle, which is expressed in local coordinates.
Parameters | |
---|---|
left |
float : The left side of the rectangle used in the difference operation |
top |
float : The top of the rectangle used in the difference operation |
right |
float : The right side of the rectangle used in the difference operation |
bottom |
float : The bottom of the rectangle used in the difference operation |
Returns | |
---|---|
boolean |
true if the resulting clip is non-empty |
public boolean clipOutRect (RectF rect)
Set the clip to the difference of the current clip and the specified rectangle, which is expressed in local coordinates.
Parameters | |
---|---|
rect |
RectF : The rectangle to perform a difference op with the current clip.
This value cannot be null . |
Returns | |
---|---|
boolean |
true if the resulting clip is non-empty |
public boolean clipPath (Path path, Region.Op op)
This method is deprecated.
Region.Op values other than Region.Op#INTERSECT
and
Region.Op#DIFFERENCE
have the ability to expand the clip. The canvas clipping APIs
are intended to only expand the clip as a result of a restore operation. This enables a view
parent to clip a canvas to clearly define the maximal drawing area of its children. The
recommended alternative calls are clipPath(android.graphics.Path)
and
clipOutPath(android.graphics.Path)
;
As of API Level API level android.os.Build.VERSION_CODES.P Build.VERSION_CODES.P
only Region.Op#INTERSECT
and
Region.Op#DIFFERENCE
are valid Region.Op parameters.
Modify the current clip with the specified path.
Parameters | |
---|---|
path |
Path : The path to operate on the current clip
This value cannot be null . |
op |
Region.Op : How the clip is modified
This value cannot be null . |
Returns | |
---|---|
boolean |
true if the resulting is non-empty |
public boolean clipPath (Path path)
Intersect the current clip with the specified path.
Parameters | |
---|---|
path |
Path : The path to intersect with the current clip
This value cannot be null . |
Returns | |
---|---|
boolean |
true if the resulting clip is non-empty |
public boolean clipRect (float left, float top, float right, float bottom, Region.Op op)
This method is deprecated.
Region.Op values other than Region.Op#INTERSECT
and
Region.Op#DIFFERENCE
have the ability to expand the clip. The canvas clipping APIs
are intended to only expand the clip as a result of a restore operation. This enables a view
parent to clip a canvas to clearly define the maximal drawing area of its children. The
recommended alternative calls are clipRect(float, float, float, float)
and
clipOutRect(float, float, float, float)
;
As of API Level API level android.os.Build.VERSION_CODES.P Build.VERSION_CODES.P
only Region.Op#INTERSECT
and
Region.Op#DIFFERENCE
are valid Region.Op parameters.
Modify the current clip with the specified rectangle, which is expressed in local coordinates.
Parameters | |
---|---|
left |
float : The left side of the rectangle to intersect with the
current clip |
top |
float : The top of the rectangle to intersect with the current
clip |
right |
float : The right side of the rectangle to intersect with the
current clip |
bottom |
float : The bottom of the rectangle to intersect with the current
clip |
op |
Region.Op : How the clip is modified
This value cannot be null . |
Returns | |
---|---|
boolean |
true if the resulting clip is non-empty |
public boolean clipRect (RectF rect)
Intersect the current clip with the specified rectangle, which is expressed in local coordinates.
Parameters | |
---|---|
rect |
RectF : The rectangle to intersect with the current clip.
This value cannot be null . |
Returns | |
---|---|
boolean |
true if the resulting clip is non-empty |
public boolean clipRect (Rect rect)
Intersect the current clip with the specified rectangle, which is expressed in local coordinates.
Parameters | |
---|---|
rect |
Rect : The rectangle to intersect with the current clip.
This value cannot be null . |
Returns | |
---|---|
boolean |
true if the resulting clip is non-empty |
public boolean clipRect (Rect rect, Region.Op op)
This method is deprecated.
Region.Op values other than Region.Op#INTERSECT
and
Region.Op#DIFFERENCE
have the ability to expand the clip. The canvas clipping APIs
are intended to only expand the clip as a result of a restore operation. This enables a view
parent to clip a canvas to clearly define the maximal drawing area of its children. The
recommended alternative calls are clipRect(android.graphics.Rect)
and clipOutRect(android.graphics.Rect)
;
As of API Level API level android.os.Build.VERSION_CODES.P Build.VERSION_CODES.P
only Region.Op#INTERSECT
and
Region.Op#DIFFERENCE
are valid Region.Op parameters.
Modify the current clip with the specified rectangle, which is expressed in local coordinates.
Parameters | |
---|---|
rect |
Rect : The rectangle to intersect with the current clip.
This value cannot be null . |
op |
Region.Op : How the clip is modified
This value cannot be null . |
Returns | |
---|---|
boolean |
true if the resulting clip is non-empty |
public boolean clipRect (int left, int top, int right, int bottom)
Intersect the current clip with the specified rectangle, which is expressed in local coordinates.
Parameters | |
---|---|
left |
int : The left side of the rectangle to intersect with the
current clip |
top |
int : The top of the rectangle to intersect with the current clip |
right |
int : The right side of the rectangle to intersect with the
current clip |
bottom |
int : The bottom of the rectangle to intersect with the current
clip |
Returns | |
---|---|
boolean |
true if the resulting clip is non-empty |
public boolean clipRect (float left, float top, float right, float bottom)
Intersect the current clip with the specified rectangle, which is expressed in local coordinates.
Parameters | |
---|---|
left |
float : The left side of the rectangle to intersect with the
current clip |
top |
float : The top of the rectangle to intersect with the current clip |
right |
float : The right side of the rectangle to intersect with the
current clip |
bottom |
float : The bottom of the rectangle to intersect with the current
clip |
Returns | |
---|---|
boolean |
true if the resulting clip is non-empty |
public boolean clipRect (RectF rect, Region.Op op)
This method is deprecated.
Region.Op values other than Region.Op#INTERSECT
and
Region.Op#DIFFERENCE
have the ability to expand the clip. The canvas clipping APIs
are intended to only expand the clip as a result of a restore operation. This enables a view
parent to clip a canvas to clearly define the maximal drawing area of its children. The
recommended alternative calls are clipRect(android.graphics.RectF)
and clipOutRect(android.graphics.RectF)
;
As of API Level API level android.os.Build.VERSION_CODES.P Build.VERSION_CODES.P
only Region.Op#INTERSECT
and
Region.Op#DIFFERENCE
are valid Region.Op parameters.
Modify the current clip with the specified rectangle.
Parameters | |
---|---|
rect |
RectF : The rect to intersect with the current clip
This value cannot be null . |
op |
Region.Op : How the clip is modified
This value cannot be null . |
Returns | |
---|---|
boolean |
true if the resulting clip is non-empty |
public void concat (Matrix matrix)
Preconcat the current matrix with the specified matrix. If the specified matrix is null, this method does nothing.
Parameters | |
---|---|
matrix |
Matrix : The matrix to preconcatenate with the current matrix
This value may be null . |
public void disableZ ()
Disables Z support, preventing any RenderNodes drawn after this point from being
visually reordered or having shadows rendered.
Note: This is not impacted by any save()
or restore()
calls as it is not
considered to be part of the current matrix or clip.
See enableZ()
public void drawARGB (int a, int r, int g, int b)
Fill the entire canvas' bitmap (restricted to the current clip) with the specified ARGB color, using srcover porterduff mode.
Parameters | |
---|---|
a |
int : alpha component (0..255) of the color to draw onto the canvas |
r |
int : red component (0..255) of the color to draw onto the canvas |
g |
int : green component (0..255) of the color to draw onto the canvas |
b |
int : blue component (0..255) of the color to draw onto the canvas |
public void drawArc (float left, float top, float right, float bottom, float startAngle, float sweepAngle, boolean useCenter, Paint paint)
Draw the specified arc, which will be scaled to fit inside the specified oval.
If the start angle is negative or >= 360, the start angle is treated as start angle modulo 360.
If the sweep angle is >= 360, then the oval is drawn completely. Note that this differs slightly from SkPath::arcTo, which treats the sweep angle modulo 360. If the sweep angle is negative, the sweep angle is treated as sweep angle modulo 360
The arc is drawn clockwise. An angle of 0 degrees correspond to the geometric angle of 0 degrees (3 o'clock on a watch.)
Parameters | |
---|---|
left |
float |
top |
float |
right |
float |
bottom |
float |
startAngle |
float : Starting angle (in degrees) where the arc begins |
sweepAngle |
float : Sweep angle (in degrees) measured clockwise |
useCenter |
boolean : If true, include the center of the oval in the arc, and close it if it is
being stroked. This will draw a wedge |
paint |
Paint : The paint used to draw the arc
This value cannot be null . |
public void drawArc (RectF oval, float startAngle, float sweepAngle, boolean useCenter, Paint paint)
Draw the specified arc, which will be scaled to fit inside the specified oval.
If the start angle is negative or >= 360, the start angle is treated as start angle modulo 360.
If the sweep angle is >= 360, then the oval is drawn completely. Note that this differs slightly from SkPath::arcTo, which treats the sweep angle modulo 360. If the sweep angle is negative, the sweep angle is treated as sweep angle modulo 360
The arc is drawn clockwise. An angle of 0 degrees correspond to the geometric angle of 0 degrees (3 o'clock on a watch.)
Parameters | |
---|---|
oval |
RectF : The bounds of oval used to define the shape and size of the arc
This value cannot be null . |
startAngle |
float : Starting angle (in degrees) where the arc begins |
sweepAngle |
float : Sweep angle (in degrees) measured clockwise |
useCenter |
boolean : If true, include the center of the oval in the arc, and close it if it is
being stroked. This will draw a wedge |
paint |
Paint : The paint used to draw the arc
This value cannot be null . |
public void drawBitmap (Bitmap bitmap, Matrix matrix, Paint paint)
Draw the bitmap using the specified matrix.
Parameters | |
---|---|
bitmap |
Bitmap : The bitmap to draw
This value cannot be null . |
matrix |
Matrix : The matrix used to transform the bitmap when it is drawn
This value cannot be null . |
paint |
Paint : May be null. The paint used to draw the bitmap
This value may be null . |
public void drawBitmap (int[] colors, int offset, int stride, float x, float y, int width, int height, boolean hasAlpha, Paint paint)
This method is deprecated.
Usage with a hardware accelerated
canvas
requires an internal copy of color buffer contents every time this method is
called. Using a Bitmap avoids this copy, and allows the application to more
explicitly control the lifetime and copies of pixel data.
Treat the specified array of colors as a bitmap, and draw it. This gives the same result as first creating a bitmap from the array, and then drawing it, but this method avoids explicitly creating a bitmap object which can be more efficient if the colors are changing often.
Parameters | |
---|---|
colors |
int : Array of colors representing the pixels of the bitmap
This value cannot be null . |
offset |
int : Offset into the array of colors for the first pixel |
stride |
int : The number of colors in the array between rows (must be >= width or <= -width). |
x |
float : The X coordinate for where to draw the bitmap |
y |
float : The Y coordinate for where to draw the bitmap |
width |
int : The width of the bitmap |
height |
int : The height of the bitmap |
hasAlpha |
boolean : True if the alpha channel of the colors contains valid values. If false, the
alpha byte is ignored (assumed to be 0xFF for every pixel). |
paint |
Paint : May be null. The paint used to draw the bitmap
This value may be null . |
public void drawBitmap (int[] colors, int offset, int stride, int x, int y, int width, int height, boolean hasAlpha, Paint paint)
This method is deprecated.
Usage with a hardware accelerated
canvas
requires an internal copy of color buffer contents every time this method is
called. Using a Bitmap avoids this copy, and allows the application to more
explicitly control the lifetime and copies of pixel data.
Legacy version of drawBitmap(int[] colors, ...) that took ints for x,y
Parameters | |
---|---|
colors |
int : This value cannot be null . |
offset |
int |
stride |
int |
x |
int |
y |
int |
width |
int |
height |
int |
hasAlpha |
boolean |
paint |
Paint : This value may be null . |
public void drawBitmap (Bitmap bitmap, Rect src, Rect dst, Paint paint)
Draw the specified bitmap, scaling/translating automatically to fill the destination rectangle. If the source rectangle is not null, it specifies the subset of the bitmap to draw.
Note: if the paint contains a maskfilter that generates a mask which extends beyond the bitmap's original width/height (e.g. BlurMaskFilter), then the bitmap will be drawn as if it were in a Shader with CLAMP mode. Thus the color outside of the original width/height will be the edge color replicated.
This function ignores the density associated with the bitmap. This is because the source and destination rectangle coordinate spaces are in their respective densities, so must already have the appropriate scaling factor applied.
Parameters | |
---|---|
bitmap |
Bitmap : The bitmap to be drawn
This value cannot be null . |
src |
Rect : May be null. The subset of the bitmap to be drawn
This value may be null . |
dst |
Rect : The rectangle that the bitmap will be scaled/translated to fit into
This value cannot be null . |
paint |
Paint : May be null. The paint used to draw the bitmap
This value may be null . |
public void drawBitmap (Bitmap bitmap, Rect src, RectF dst, Paint paint)
Draw the specified bitmap, scaling/translating automatically to fill the destination rectangle. If the source rectangle is not null, it specifies the subset of the bitmap to draw.
Note: if the paint contains a maskfilter that generates a mask which extends beyond the bitmap's original width/height (e.g. BlurMaskFilter), then the bitmap will be drawn as if it were in a Shader with CLAMP mode. Thus the color outside of the original width/height will be the edge color replicated.
This function ignores the density associated with the bitmap. This is because the source and destination rectangle coordinate spaces are in their respective densities, so must already have the appropriate scaling factor applied.
Parameters | |
---|---|
bitmap |
Bitmap : The bitmap to be drawn
This value cannot be null . |
src |
Rect : May be null. The subset of the bitmap to be drawn
This value may be null . |
dst |
RectF : The rectangle that the bitmap will be scaled/translated to fit into
This value cannot be null . |
paint |
Paint : May be null. The paint used to draw the bitmap
This value may be null . |
public void drawBitmap (Bitmap bitmap, float left, float top, Paint paint)
Draw the specified bitmap, with its top/left corner at (x,y), using the specified paint, transformed by the current matrix.
Note: if the paint contains a maskfilter that generates a mask which extends beyond the bitmap's original width/height (e.g. BlurMaskFilter), then the bitmap will be drawn as if it were in a Shader with CLAMP mode. Thus the color outside of the original width/height will be the edge color replicated.
If the bitmap and canvas have different densities, this function will take care of automatically scaling the bitmap to draw at the same density as the canvas.
Parameters | |
---|---|
bitmap |
Bitmap : The bitmap to be drawn
This value cannot be null . |
left |
float : The position of the left side of the bitmap being drawn |
top |
float : The position of the top side of the bitmap being drawn |
paint |
Paint : The paint used to draw the bitmap (may be null)
This value may be null . |
public void drawBitmapMesh (Bitmap bitmap, int meshWidth, int meshHeight, float[] verts, int vertOffset, int[] colors, int colorOffset, Paint paint)
Draw the bitmap through the mesh, where mesh vertices are evenly distributed across the
bitmap. There are meshWidth+1 vertices across, and meshHeight+1 vertices down. The verts
array is accessed in row-major order, so that the first meshWidth+1 vertices are distributed
across the top of the bitmap from left to right. A more general version of this method is
drawVertices().
Prior to API level android.os.Build.VERSION_CODES.P Build.VERSION_CODES.P
vertOffset and colorOffset were ignored,
effectively treating them as zeros. In API level android.os.Build.VERSION_CODES.P Build.VERSION_CODES.P
and above
these parameters will be respected.
Parameters | |
---|---|
bitmap |
Bitmap : The bitmap to draw using the mesh
This value cannot be null . |
meshWidth |
int : The number of columns in the mesh. Nothing is drawn if this is 0 |
meshHeight |
int : The number of rows in the mesh. Nothing is drawn if this is 0 |
verts |
float : Array of x,y pairs, specifying where the mesh should be drawn. There must be at
least (meshWidth+1) * (meshHeight+1) * 2 + vertOffset values in the array
This value cannot be null . |
vertOffset |
int : Number of verts elements to skip before drawing |
colors |
int : May be null. Specifies a color at each vertex, which is interpolated across the
cell, and whose values are multiplied by the corresponding bitmap colors. If not
null, there must be at least (meshWidth+1) * (meshHeight+1) + colorOffset values
in the array.
This value may be null . |
colorOffset |
int : Number of color elements to skip before drawing |
paint |
Paint : May be null. The paint used to draw the bitmap
This value may be null . |
public void drawCircle (float cx, float cy, float radius, Paint paint)
Draw the specified circle using the specified paint. If radius is <= 0, then nothing will be drawn. The circle will be filled or framed based on the Style in the paint.
Parameters | |
---|---|
cx |
float : The x-coordinate of the center of the circle to be drawn |
cy |
float : The y-coordinate of the center of the circle to be drawn |
radius |
float : The radius of the circle to be drawn |
paint |
Paint : The paint used to draw the circle
This value cannot be null . |
public void drawColor (long color, BlendMode mode)
Fill the entire canvas' bitmap (restricted to the current clip) with the specified color and blendmode.
Parameters | |
---|---|
color |
long : the ColorLong to draw onto the canvas. See the Color
class for details about ColorLong s. |
mode |
BlendMode : the blendmode to apply to the color
This value cannot be null . |
Throws | |
---|---|
IllegalArgumentException |
if the color space encoded in the ColorLong
is invalid or unknown. |
public void drawColor (int color)
Fill the entire canvas' bitmap (restricted to the current clip) with the specified color, using srcover porterduff mode.
Parameters | |
---|---|
color |
int : the color to draw onto the canvas |
public void drawColor (int color, BlendMode mode)
Fill the entire canvas' bitmap (restricted to the current clip) with the specified color and blendmode.
Parameters | |
---|---|
color |
int : the color to draw onto the canvas |
mode |
BlendMode : the blendmode to apply to the color
This value cannot be null . |
public void drawColor (long color)
Fill the entire canvas' bitmap (restricted to the current clip) with the specified color, using srcover porterduff mode.
Parameters | |
---|---|
color |
long : the ColorLong to draw onto the canvas. See the Color
class for details about ColorLong s. |
Throws | |
---|---|
IllegalArgumentException |
if the color space encoded in the ColorLong
is invalid or unknown. |
public void drawColor (int color, PorterDuff.Mode mode)
Fill the entire canvas' bitmap (restricted to the current clip) with the specified color and porter-duff xfermode.
Parameters | |
---|---|
color |
int : the color to draw onto the canvas |
mode |
PorterDuff.Mode : the porter-duff mode to apply to the color
This value cannot be null . |
public void drawDoubleRoundRect (RectF outer, float[] outerRadii, RectF inner, float[] innerRadii, Paint paint)
Draws a double rounded rectangle using the specified paint. The resultant round rect
will be filled in the area defined between the outer and inner rectangular bounds if
the Paint
configured with Paint.Style#FILL
.
Otherwise if Paint.Style#STROKE
is used, then 2 rounded rect strokes will
be drawn at the outer and inner rounded rectangles
Parameters | |
---|---|
outer |
RectF : The outer rectangular bounds of the roundRect to be drawn
This value cannot be null . |
outerRadii |
float : Array of 8 float representing the x, y corner radii for top left,
top right, bottom right, bottom left corners respectively on the outer
rounded rectangle
This value cannot be null . |
inner |
RectF : The inner rectangular bounds of the roundRect to be drawn
This value cannot be null . |
innerRadii |
float : Array of 8 float representing the x, y corner radii for top left,
top right, bottom right, bottom left corners respectively on the
outer rounded rectangle
This value cannot be null . |
paint |
Paint : The paint used to draw the double roundRect
This value cannot be null . |
public void drawDoubleRoundRect (RectF outer, float outerRx, float outerRy, RectF inner, float innerRx, float innerRy, Paint paint)
Draws a double rounded rectangle using the specified paint. The resultant round rect
will be filled in the area defined between the outer and inner rectangular bounds if
the Paint
configured with Paint.Style#FILL
.
Otherwise if Paint.Style#STROKE
is used, then 2 rounded rect strokes will
be drawn at the outer and inner rounded rectangles
Parameters | |
---|---|
outer |
RectF : The outer rectangular bounds of the roundRect to be drawn
This value cannot be null . |
outerRx |
float : The x-radius of the oval used to round the corners on the outer rectangle |
outerRy |
float : The y-radius of the oval used to round the corners on the outer rectangle |
inner |
RectF : The inner rectangular bounds of the roundRect to be drawn
This value cannot be null . |
innerRx |
float : The x-radius of the oval used to round the corners on the inner rectangle |
innerRy |
float : The y-radius of the oval used to round the corners on the outer rectangle |
paint |
Paint : The paint used to draw the double roundRect
This value cannot be null . |
public void drawLine (float startX, float startY, float stopX, float stopY, Paint paint)
Draw a line segment with the specified start and stop x,y coordinates, using the specified paint.
Note that since a line is always "framed", the Style is ignored in the paint.
Degenerate lines (length is 0) will not be drawn.
Parameters | |
---|---|
startX |
float : The x-coordinate of the start point of the line |
startY |
float : The y-coordinate of the start point of the line |
stopX |
float |
stopY |
float |
paint |
Paint : The paint used to draw the line
This value cannot be null . |
public void drawLines (float[] pts, int offset, int count, Paint paint)
Draw a series of lines. Each line is taken from 4 consecutive values in the pts array. Thus to draw 1 line, the array must contain at least 4 values. This is logically the same as drawing the array as follows: drawLine(pts[0], pts[1], pts[2], pts[3]) followed by drawLine(pts[4], pts[5], pts[6], pts[7]) and so on.
Parameters | |
---|---|
pts |
float : Array of points to draw [x0 y0 x1 y1 x2 y2 ...]
This value cannot be null . |
offset |
int : Number of values in the array to skip before drawing. |
count |
int : The number of values in the array to process, after skipping "offset" of them.
Since each line uses 4 values, the number of "lines" that are drawn is really
(count >> 2). |
paint |
Paint : The paint used to draw the points
This value cannot be null . |
public void drawLines (float[] pts, Paint paint)
Parameters | |
---|---|
pts |
float : This value cannot be null . |
paint |
Paint : This value cannot be null . |
public void drawOval (float left, float top, float right, float bottom, Paint paint)
Draw the specified oval using the specified paint. The oval will be filled or framed based on the Style in the paint.
Parameters | |
---|---|
left |
float |
top |
float |
right |
float |
bottom |
float |
paint |
Paint : This value cannot be null . |
public void drawOval (RectF oval, Paint paint)
Draw the specified oval using the specified paint. The oval will be filled or framed based on the Style in the paint.
Parameters | |
---|---|
oval |
RectF : The rectangle bounds of the oval to be drawn
This value cannot be null . |
paint |
Paint : This value cannot be null . |
public void drawPaint (Paint paint)
Fill the entire canvas' bitmap (restricted to the current clip) with the specified paint. This is equivalent (but faster) to drawing an infinitely large rectangle with the specified paint.
Parameters | |
---|---|
paint |
Paint : The paint used to draw onto the canvas
This value cannot be null . |
public void drawPath (Path path, Paint paint)
Draw the specified path using the specified paint. The path will be filled or framed based on the Style in the paint.
Parameters | |
---|---|
path |
Path : The path to be drawn
This value cannot be null . |
paint |
Paint : The paint used to draw the path
This value cannot be null . |
public void drawPicture (Picture picture, RectF dst)
Draw the picture, stretched to fit into the dst rectangle.
Parameters | |
---|---|
picture |
Picture : This value cannot be null . |
dst |
RectF : This value cannot be null . |
public void drawPicture (Picture picture)
Save the canvas state, draw the picture, and restore the canvas state. This differs from picture.draw(canvas), which does not perform any save/restore.
Note: This forces the picture to internally call
Picture#endRecording
in order to prepare for playback.
Parameters | |
---|---|
picture |
Picture : The picture to be drawn
This value cannot be null . |
public void drawPicture (Picture picture, Rect dst)
Draw the picture, stretched to fit into the dst rectangle.
Parameters | |
---|---|
picture |
Picture : This value cannot be null . |
dst |
Rect : This value cannot be null . |
public void drawPoint (float x, float y, Paint paint)
Helper for drawPoints() for drawing a single point.
Parameters | |
---|---|
x |
float |
y |
float |
paint |
Paint : This value cannot be null . |
public void drawPoints (float[] pts, Paint paint)
Helper for drawPoints() that assumes you want to draw the entire array
Parameters | |
---|---|
pts |
float : This value cannot be null . |
paint |
Paint : This value cannot be null . |
public void drawPoints (float[] pts, int offset, int count, Paint paint)
Draw a series of points. Each point is centered at the coordinate specified by pts[], and its diameter is specified by the paint's stroke width (as transformed by the canvas' CTM), with special treatment for a stroke width of 0, which always draws exactly 1 pixel (or at most 4 if antialiasing is enabled). The shape of the point is controlled by the paint's Cap type. The shape is a square, unless the cap type is Round, in which case the shape is a circle.
Parameters | |
---|---|
pts |
float : Array of points to draw [x0 y0 x1 y1 x2 y2 ...] |
offset |
int : Number of values to skip before starting to draw. |
count |
int : The number of values to process, after skipping offset of them. Since one point
uses two values, the number of "points" that are drawn is really (count >> 1). |
paint |
Paint : The paint used to draw the points
This value cannot be null . |
public void drawPosText (String text, float[] pos, Paint paint)
This method is deprecated.
This method does not support glyph composition and decomposition and should
therefore not be used to render complex scripts. It also doesn't handle
supplementary characters (eg emoji).
Draw the text in the array, with each character's origin specified by the pos array.
Parameters | |
---|---|
text |
String : The text to be drawn
This value cannot be null . |
pos |
float : Array of [x,y] positions, used to position each character
This value cannot be null . |
paint |
Paint : The paint used for the text (e.g. color, size, style)
This value cannot be null . |
public void drawPosText (char[] text, int index, int count, float[] pos, Paint paint)
This method is deprecated.
This method does not support glyph composition and decomposition and should
therefore not be used to render complex scripts. It also doesn't handle
supplementary characters (eg emoji).
Draw the text in the array, with each character's origin specified by the pos array.
Parameters | |
---|---|
text |
char : The text to be drawn
This value cannot be null . |
index |
int : The index of the first character to draw |
count |
int : The number of characters to draw, starting from index. |
pos |
float : Array of [x,y] positions, used to position each character
This value cannot be null . |
paint |
Paint : The paint used for the text (e.g. color, size, style)
This value cannot be null . |
public void drawRGB (int r, int g, int b)
Fill the entire canvas' bitmap (restricted to the current clip) with the specified RGB color, using srcover porterduff mode.
Parameters | |
---|---|
r |
int : red component (0..255) of the color to draw onto the canvas |
g |
int : green component (0..255) of the color to draw onto the canvas |
b |
int : blue component (0..255) of the color to draw onto the canvas |
public void drawRect (float left, float top, float right, float bottom, Paint paint)
Draw the specified Rect using the specified paint. The rectangle will be filled or framed based on the Style in the paint.
Parameters | |
---|---|
left |
float : The left side of the rectangle to be drawn |
top |
float : The top side of the rectangle to be drawn |
right |
float : The right side of the rectangle to be drawn |
bottom |
float : The bottom side of the rectangle to be drawn |
paint |
Paint : The paint used to draw the rect
This value cannot be null . |
public void drawRect (Rect r, Paint paint)
Draw the specified Rect using the specified Paint. The rectangle will be filled or framed based on the Style in the paint.
Parameters | |
---|---|
r |
Rect : The rectangle to be drawn.
This value cannot be null . |
paint |
Paint : The paint used to draw the rectangle
This value cannot be null . |
public void drawRect (RectF rect, Paint paint)
Draw the specified Rect using the specified paint. The rectangle will be filled or framed based on the Style in the paint.
Parameters | |
---|---|
rect |
RectF : The rect to be drawn
This value cannot be null . |
paint |
Paint : The paint used to draw the rect
This value cannot be null . |
public void drawRenderNode (RenderNode renderNode)
Draws the given RenderNode. This is only supported in hardware rendering, which can be
verified by asserting that isHardwareAccelerated()
is true. If
isHardwareAccelerated()
is false then this throws an exception.
See RenderNode
for more information on what a RenderNode is and how to use it.
Parameters | |
---|---|
renderNode |
RenderNode : The RenderNode to draw, must be non-null.
This value cannot be null . |
public void drawRoundRect (RectF rect, float rx, float ry, Paint paint)
Draw the specified round-rect using the specified paint. The roundrect will be filled or framed based on the Style in the paint.
Parameters | |
---|---|
rect |
RectF : The rectangular bounds of the roundRect to be drawn
This value cannot be null . |
rx |
float : The x-radius of the oval used to round the corners |
ry |
float : The y-radius of the oval used to round the corners |
paint |
Paint : The paint used to draw the roundRect
This value cannot be null . |
public void drawRoundRect (float left, float top, float right, float bottom, float rx, float ry, Paint paint)
Draw the specified round-rect using the specified paint. The roundrect will be filled or framed based on the Style in the paint.
Parameters | |
---|---|
left |
float |
top |
float |
right |
float |
bottom |
float |
rx |
float : The x-radius of the oval used to round the corners |
ry |
float : The y-radius of the oval used to round the corners |
paint |
Paint : The paint used to draw the roundRect
This value cannot be null . |
public void drawText (CharSequence text, int start, int end, float x, float y, Paint paint)
Draw the specified range of text, specified by start/end, with its origin at (x,y), in the specified Paint. The origin is interpreted based on the Align setting in the Paint.
Parameters | |
---|---|
text |
CharSequence : The text to be drawn
This value cannot be null . |
start |
int : The index of the first character in text to draw |
end |
int : (end - 1) is the index of the last character in text to draw |
x |
float : The x-coordinate of origin for where to draw the text |
y |
float : The y-coordinate of origin for where to draw the text |
paint |
Paint : The paint used for the text (e.g. color, size, style)
This value cannot be null . |
public void drawText (String text, float x, float y, Paint paint)
Draw the text, with origin at (x,y), using the specified paint. The origin is interpreted based on the Align setting in the paint.
Parameters | |
---|---|
text |
String : The text to be drawn
This value cannot be null . |
x |
float : The x-coordinate of the origin of the text being drawn |
y |
float : The y-coordinate of the baseline of the text being drawn |
paint |
Paint : The paint used for the text (e.g. color, size, style)
This value cannot be null . |
public void drawText (char[] text, int index, int count, float x, float y, Paint paint)
Draw the text, with origin at (x,y), using the specified paint. The origin is interpreted based on the Align setting in the paint.
Parameters | |
---|---|
text |
char : The text to be drawn
This value cannot be null . |
index |
int |
count |
int |
x |
float : The x-coordinate of the origin of the text being drawn |
y |
float : The y-coordinate of the baseline of the text being drawn |
paint |
Paint : The paint used for the text (e.g. color, size, style)
This value cannot be null . |
public void drawText (String text, int start, int end, float x, float y, Paint paint)
Draw the text, with origin at (x,y), using the specified paint. The origin is interpreted based on the Align setting in the paint.
Parameters | |
---|---|
text |
String : The text to be drawn
This value cannot be null . |
start |
int : The index of the first character in text to draw |
end |
int : (end - 1) is the index of the last character in text to draw |
x |
float : The x-coordinate of the origin of the text being drawn |
y |
float : The y-coordinate of the baseline of the text being drawn |
paint |
Paint : The paint used for the text (e.g. color, size, style)
This value cannot be null . |
public void drawTextOnPath (String text, Path path, float hOffset, float vOffset, Paint paint)
Draw the text, with origin at (x,y), using the specified paint, along the specified path. The paint's Align setting determines where along the path to start the text.
Parameters | |
---|---|
text |
String : The text to be drawn
This value cannot be null . |
path |
Path : The path the text should follow for its baseline
This value cannot be null . |
hOffset |
float : The distance along the path to add to the text's starting position |
vOffset |
float : The distance above(-) or below(+) the path to position the text |
paint |
Paint : The paint used for the text (e.g. color, size, style)
This value cannot be null . |
public void drawTextOnPath (char[] text, int index, int count, Path path, float hOffset, float vOffset, Paint paint)
Draw the text, with origin at (x,y), using the specified paint, along the specified path. The paint's Align setting determines where along the path to start the text.
Parameters | |
---|---|
text |
char : The text to be drawn
This value cannot be null . |
index |
int : The starting index within the text to be drawn |
count |
int : Starting from index, the number of characters to draw |
path |
Path : The path the text should follow for its baseline
This value cannot be null . |
hOffset |
float : The distance along the path to add to the text's starting position |
vOffset |
float : The distance above(-) or below(+) the path to position the text |
paint |
Paint : The paint used for the text (e.g. color, size, style)
This value cannot be null . |
public void drawTextRun (MeasuredText text, int start, int end, int contextStart, int contextEnd, float x, float y, boolean isRtl, Paint paint)
Draw a run of text, all in a single direction, with optional context for complex text shaping.
See drawTextRun(java.lang.CharSequence, int, int, int, int, float, float, boolean, android.graphics.Paint)
for
more details. This method uses a MeasuredText
rather than CharSequence to represent
the string.
Parameters | |
---|---|
text |
MeasuredText : the text to render
This value cannot be null . |
start |
int : the start of the text to render. Data before this position can be used for
shaping context. |
end |
int : the end of the text to render. Data at or after this position can be used for
shaping context. |
contextStart |
int : the index of the start of the shaping context |
contextEnd |
int : the index of the end of the shaping context |
x |
float : the x position at which to draw the text |
y |
float : the y position at which to draw the text |
isRtl |
boolean : whether the run is in RTL direction |
paint |
Paint : the paint
This value cannot be null . |
public void drawTextRun (char[] text, int index, int count, int contextIndex, int contextCount, float x, float y, boolean isRtl, Paint paint)
Draw a run of text, all in a single direction, with optional context for complex text shaping.
See drawTextRun(java.lang.CharSequence, int, int, int, int, float, float, boolean, android.graphics.Paint)
for
more details. This method uses a character array rather than CharSequence to represent the
string. Also, to be consistent with the pattern established in drawText(char[], int, int, float, float, Paint)
, in this
method count
and contextCount
are used rather than offsets of the end
position; count = end - start, contextCount = contextEnd -
contextStart
.
Parameters | |
---|---|
text |
char : the text to render
This value cannot be null . |
index |
int : the start of the text to render |
count |
int : the count of chars to render |
contextIndex |
int : the start of the context for shaping. Must be no greater than index. |
contextCount |
int : the number of characters in the context for shaping. contexIndex +
contextCount must be no less than index + count. |
x |
float : the x position at which to draw the text |
y |
float : the y position at which to draw the text |
isRtl |
boolean : whether the run is in RTL direction |
paint |
Paint : the paint
This value cannot be null . |
public void drawTextRun (CharSequence text, int start, int end, int contextStart, int contextEnd, float x, float y, boolean isRtl, Paint paint)
Draw a run of text, all in a single direction, with optional context for complex text shaping.
The run of text includes the characters from start
to end
in the text. In
addition, the range contextStart
to contextEnd
is used as context for the
purpose of complex text shaping, such as Arabic text potentially shaped differently based on
the text next to it.
All text outside the range contextStart..contextEnd
is ignored. The text between
start
and end
will be laid out and drawn. The context range is useful for
contextual shaping, e.g. Kerning, Arabic contextural form.
The direction of the run is explicitly specified by isRtl
. Thus, this method is
suitable only for runs of a single direction. Alignment of the text is as determined by the
Paint's TextAlign value. Further, 0 <= contextStart <= start <= end <= contextEnd
<= text.length
must hold on entry.
Also see Paint.getRunAdvance(char[], int, int, int, int, boolean, int)
for a corresponding method to measure
the text; the advance width of the text drawn matches the value obtained from that method.
Parameters | |
---|---|
text |
CharSequence : the text to render
This value cannot be null . |
start |
int : the start of the text to render. Data before this position can be used for
shaping context. |
end |
int : the end of the text to render. Data at or after this position can be used for
shaping context. |
contextStart |
int : the index of the start of the shaping context |
contextEnd |
int : the index of the end of the shaping context |
x |
float : the x position at which to draw the text |
y |
float : the y position at which to draw the text |
isRtl |
boolean : whether the run is in RTL direction |
paint |
Paint : the paint
This value cannot be null . |
public void drawVertices (Canvas.VertexMode mode, int vertexCount, float[] verts, int vertOffset, float[] texs, int texOffset, int[] colors, int colorOffset, short[] indices, int indexOffset, int indexCount, Paint paint)
Draw the array of vertices, interpreted as triangles (based on mode). The verts array is required, and specifies the x,y pairs for each vertex. If texs is non-null, then it is used to specify the coordinate in shader coordinates to use at each vertex (the paint must have a shader in this case). If there is no texs array, but there is a color array, then each color is interpolated across its corresponding triangle in a gradient. If both texs and colors arrays are present, then they behave as before, but the resulting color at each pixels is the result of multiplying the colors from the shader and the color-gradient together. The indices array is optional, but if it is present, then it is used to specify the index of each triangle, rather than just walking through the arrays in order.
Parameters | |
---|---|
mode |
Canvas.VertexMode : How to interpret the array of vertices
This value cannot be null . |
vertexCount |
int : The number of values in the vertices array (and corresponding texs and
colors arrays if non-null). Each logical vertex is two values (x, y), vertexCount
must be a multiple of 2. |
verts |
float : Array of vertices for the mesh
This value cannot be null . |
vertOffset |
int : Number of values in the verts to skip before drawing. |
texs |
float : May be null. If not null, specifies the coordinates to sample into the current
shader (e.g. bitmap tile or gradient)
This value may be null . |
texOffset |
int : Number of values in texs to skip before drawing. |
colors |
int : May be null. If not null, specifies a color for each vertex, to be interpolated
across the triangle.
This value may be null . |
colorOffset |
int : Number of values in colors to skip before drawing. |
indices |
short : If not null, array of indices to reference into the vertex (texs, colors)
array.
This value may be null . |
indexOffset |
int |
indexCount |
int : number of entries in the indices array (if not null). |
paint |
Paint : Specifies the shader to use if the texs array is non-null.
This value cannot be null . |
public void enableZ ()
Enables Z support which defaults to disabled. This allows for RenderNodes drawn with
drawRenderNode(android.graphics.RenderNode)
to be re-arranged based off of their
RenderNode#getElevation()
and RenderNode#getTranslationZ()
values. It also enables rendering of shadows for RenderNodes with an elevation or
translationZ.
Any draw reordering will not be moved before this call. A typical usage of this might look something like:
void draw(Canvas canvas) { // Draw any background content canvas.drawColor(backgroundColor); // Begin drawing that may be reordered based off of Z canvas.enableZ(); for (RenderNode child : children) { canvas.drawRenderNode(child); } // End drawing that may be reordered based off of Z canvas.disableZ(); // Draw any overlays canvas.drawText("I'm on top of everything!", 0, 0, paint); }Note: This is not impacted by any
save()
or restore()
calls as it is not
considered to be part of the current matrix or clip.
See disableZ()
public boolean getClipBounds (Rect bounds)
Return the bounds of the current clip (in local coordinates) in the bounds parameter, and return true if it is non-empty. This can be useful in a way similar to quickReject, in that it tells you that drawing outside of these bounds will be clipped out.
Parameters | |
---|---|
bounds |
Rect : Return the clip bounds here. If it is null, ignore it but
still return true if the current clip is non-empty.
This value may be null . |
Returns | |
---|---|
boolean |
true if the current clip is non-empty. |
public final Rect getClipBounds ()
Retrieve the bounds of the current clip (in local coordinates).
Returns | |
---|---|
Rect |
the clip bounds, or [0, 0, 0, 0] if the clip is empty.
This value cannot be null . |
public int getDensity ()
Returns the target density of the canvas. The default density is
derived from the density of its backing bitmap, or
Bitmap#DENSITY_NONE
if there is not one.
Returns | |
---|---|
int |
Returns the current target density of the canvas, which is used to determine the scaling factor when drawing a bitmap into it. |
See also:
public int getHeight ()
Returns the height of the current drawing layer
Returns | |
---|---|
int |
the height of the current drawing layer |
public void getMatrix (Matrix ctm)
This method is deprecated.
Hardware accelerated
canvases may have any
matrix when passed to a View or Drawable, as it is implementation defined where in the
hierarchy such canvases are created. It is recommended in such cases to either draw contents
irrespective of the current matrix, or to track relevant transform state outside of the
canvas.
Return, in ctm, the current transformation matrix. This does not alter the matrix in the canvas, but just returns a copy of it.
Parameters | |
---|---|
ctm |
Matrix : This value cannot be null . |
public final Matrix getMatrix ()
This method is deprecated.
Hardware accelerated
canvases may have any
matrix when passed to a View or Drawable, as it is implementation defined where in the
hierarchy such canvases are created. It is recommended in such cases to either draw contents
irrespective of the current matrix, or to track relevant transform state outside of the
canvas.
Return a new matrix with a copy of the canvas' current transformation matrix.
Returns | |
---|---|
Matrix |
This value cannot be null . |
public int getMaximumBitmapHeight ()
Returns the maximum allowed height for bitmaps drawn with this canvas. Attempting to draw with a bitmap taller than this value will result in an error.
Returns | |
---|---|
int |
See also:
public int getMaximumBitmapWidth ()
Returns the maximum allowed width for bitmaps drawn with this canvas. Attempting to draw with a bitmap wider than this value will result in an error.
Returns | |
---|---|
int |
See also:
public int getSaveCount ()
Returns the number of matrix/clip states on the Canvas' private stack. This will equal # save() calls - # restore() calls.
Returns | |
---|---|
int |
public int getWidth ()
Returns the width of the current drawing layer
Returns | |
---|---|
int |
the width of the current drawing layer |
public boolean isHardwareAccelerated ()
Indicates whether this Canvas uses hardware acceleration. Note that this method does not define what type of hardware acceleration may or may not be used.
Returns | |
---|---|
boolean |
True if drawing operations are hardware accelerated, false otherwise. |
public boolean isOpaque ()
Return true if the device that the current layer draws into is opaque (i.e. does not support per-pixel alpha).
Returns | |
---|---|
boolean |
true if the device that the current layer draws into is opaque |
public boolean quickReject (float left, float top, float right, float bottom, Canvas.EdgeType type)
This method is deprecated.
The EdgeType is ignored. Use quickReject(float, float, float, float)
instead.
Return true if the specified rectangle, after being transformed by the current matrix, would lie completely outside of the current clip. Call this to check if an area you intend to draw into is clipped out (and therefore you can skip making the draw calls).
Parameters | |
---|---|
left |
float : The left side of the rectangle to compare with the
current clip |
top |
float : The top of the rectangle to compare with the current
clip |
right |
float : The right side of the rectangle to compare with the
current clip |
bottom |
float : The bottom of the rectangle to compare with the
current clip |
type |
Canvas.EdgeType : Canvas.EdgeType#AA if the path should be considered antialiased,
since that means it may affect a larger area (more pixels) than
non-antialiased (Canvas.EdgeType#BW ).
This value cannot be null . |
Returns | |
---|---|
boolean |
true if the rect (transformed by the canvas' matrix) does not intersect with the canvas' clip |
public boolean quickReject (Path path)
Return true if the specified path, after being transformed by the current matrix, would lie completely outside of the current clip. Call this to check if an area you intend to draw into is clipped out (and therefore you can skip making the draw calls). Note: for speed it may return false even if the path itself might not intersect the clip (i.e. the bounds of the path intersects, but the path does not).
Parameters | |
---|---|
path |
Path : The path to compare with the current clip
This value cannot be null . |
Returns | |
---|---|
boolean |
true if the path (transformed by the canvas' matrix) does not intersect with the canvas' clip |
public boolean quickReject (RectF rect)
Return true if the specified rectangle, after being transformed by the current matrix, would lie completely outside of the current clip. Call this to check if an area you intend to draw into is clipped out (and therefore you can skip making the draw calls).
Parameters | |
---|---|
rect |
RectF : the rect to compare with the current clip
This value cannot be null . |
Returns | |
---|---|
boolean |
true if the rect (transformed by the canvas' matrix) does not intersect with the canvas' clip |
public boolean quickReject (RectF rect, Canvas.EdgeType type)
This method is deprecated.
The EdgeType is ignored. Use quickReject(android.graphics.RectF)
instead.
Return true if the specified rectangle, after being transformed by the current matrix, would lie completely outside of the current clip. Call this to check if an area you intend to draw into is clipped out (and therefore you can skip making the draw calls).
Parameters | |
---|---|
rect |
RectF : the rect to compare with the current clip
This value cannot be null . |
type |
Canvas.EdgeType : Canvas.EdgeType#AA if the path should be considered antialiased,
since that means it may affect a larger area (more pixels) than
non-antialiased (Canvas.EdgeType#BW ).
This value cannot be null . |
Returns | |
---|---|
boolean |
true if the rect (transformed by the canvas' matrix) does not intersect with the canvas' clip |
public boolean quickReject (Path path, Canvas.EdgeType type)
This method is deprecated.
The EdgeType is ignored. Use quickReject(android.graphics.Path)
instead.
Return true if the specified path, after being transformed by the current matrix, would lie completely outside of the current clip. Call this to check if an area you intend to draw into is clipped out (and therefore you can skip making the draw calls). Note: for speed it may return false even if the path itself might not intersect the clip (i.e. the bounds of the path intersects, but the path does not).
Parameters | |
---|---|
path |
Path : The path to compare with the current clip
This value cannot be null . |
type |
Canvas.EdgeType : Canvas.EdgeType#AA if the path should be considered antialiased,
since that means it may affect a larger area (more pixels) than
non-antialiased (Canvas.EdgeType#BW ).
This value cannot be null . |
Returns | |
---|---|
boolean |
true if the path (transformed by the canvas' matrix) does not intersect with the canvas' clip |
public boolean quickReject (float left, float top, float right, float bottom)
Return true if the specified rectangle, after being transformed by the current matrix, would lie completely outside of the current clip. Call this to check if an area you intend to draw into is clipped out (and therefore you can skip making the draw calls).
Parameters | |
---|---|
left |
float : The left side of the rectangle to compare with the
current clip |
top |
float : The top of the rectangle to compare with the current
clip |
right |
float : The right side of the rectangle to compare with the
current clip |
bottom |
float : The bottom of the rectangle to compare with the
current clip |
Returns | |
---|---|
boolean |
true if the rect (transformed by the canvas' matrix) does not intersect with the canvas' clip |
public void restore ()
This call balances a previous call to save(), and is used to remove all modifications to the matrix/clip state since the last save call. It is an error to call restore() more times than save() was called.
public void restoreToCount (int saveCount)
Efficient way to pop any calls to save() that happened after the save count reached saveCount. It is an error for saveCount to be less than 1. Example: int count = canvas.save(); ... // more calls potentially to save() canvas.restoreToCount(count); // now the canvas is back in the same state it was before the initial // call to save().
Parameters | |
---|---|
saveCount |
int : The save level to restore to. |
public void rotate (float degrees)
Preconcat the current matrix with the specified rotation.
Parameters | |
---|---|
degrees |
float : The amount to rotate, in degrees |
public final void rotate (float degrees, float px, float py)
Preconcat the current matrix with the specified rotation.
Parameters | |
---|---|
degrees |
float : The amount to rotate, in degrees |
px |
float : The x-coord for the pivot point (unchanged by the rotation) |
py |
float : The y-coord for the pivot point (unchanged by the rotation) |
public int save ()
Saves the current matrix and clip onto a private stack.
Subsequent calls to translate,scale,rotate,skew,concat or clipRect, clipPath will all operate as usual, but when the balancing call to restore() is made, those calls will be forgotten, and the settings that existed before the save() will be reinstated.
Returns | |
---|---|
int |
The value to pass to restoreToCount() to balance this save() |
public int saveLayer (RectF bounds, Paint paint, int saveFlags)
This method is deprecated.
Use saveLayer(android.graphics.RectF, android.graphics.Paint)
instead.
This behaves the same as save(), but in addition it allocates and redirects drawing to an offscreen bitmap.
Note: this method is very expensive,
incurring more than double rendering cost for contained content. Avoid
using this method, especially if the bounds provided are large. It is
recommended to use a hardware layer
on a View
to apply an xfermode, color filter, or alpha, as it will perform much
better than this method.
All drawing calls are directed to a newly allocated offscreen bitmap. Only when the balancing call to restore() is made, is that offscreen buffer drawn back to the current target of the Canvas (either the screen, it's target Bitmap, or the previous layer).
Attributes of the Paint - Paint#getAlpha()
,
Paint#getXfermode()
, and
Paint#getColorFilter()
are applied when the
offscreen bitmap is drawn back when restore() is called.
As of API Level API level android.os.Build.VERSION_CODES.P Build.VERSION_CODES.P
the only valid
saveFlags
is ALL_SAVE_FLAG
. All other flags are ignored.
Parameters | |
---|---|
bounds |
RectF : May be null. The maximum size the offscreen bitmap
needs to be (in local coordinates)
This value may be null . |
paint |
Paint : This is copied, and is applied to the offscreen when
restore() is called.
This value may be null . |
saveFlags |
int : see _SAVE_FLAG constants, generally ALL_SAVE_FLAG is recommended
for performance reasons.
Value is either 0 or ALL_SAVE_FLAG |
Returns | |
---|---|
int |
value to pass to restoreToCount() to balance this save() |
public int saveLayer (RectF bounds, Paint paint)
This behaves the same as save(), but in addition it allocates and redirects drawing to an offscreen rendering target.
Note: this method is very expensive,
incurring more than double rendering cost for contained content. Avoid
using this method when possible and instead use a
hardware layer
on a View
to apply an xfermode, color filter, or alpha, as it will perform much
better than this method.
All drawing calls are directed to a newly allocated offscreen rendering target. Only when the balancing call to restore() is made, is that offscreen buffer drawn back to the current target of the Canvas (which can potentially be a previous layer if these calls are nested).
Attributes of the Paint - Paint#getAlpha()
,
Paint#getXfermode()
, and
Paint#getColorFilter()
are applied when the
offscreen rendering target is drawn back when restore() is called.
Parameters | |
---|---|
bounds |
RectF : May be null. The maximum size the offscreen render target
needs to be (in local coordinates)
This value may be null . |
paint |
Paint : This is copied, and is applied to the offscreen when
restore() is called.
This value may be null . |
Returns | |
---|---|
int |
value to pass to restoreToCount() to balance this save() |
public int saveLayer (float left, float top, float right, float bottom, Paint paint)
Convenience for saveLayer(android.graphics.RectF, android.graphics.Paint)
that takes the four float coordinates of the
bounds rectangle.
Parameters | |
---|---|
left |
float |
top |
float |
right |
float |
bottom |
float |
paint |
Paint : This value may be null . |
Returns | |
---|---|
int |
public int saveLayer (float left, float top, float right, float bottom, Paint paint, int saveFlags)
This method is deprecated.
Use saveLayer(float, float, float, float, android.graphics.Paint)
instead.
Helper version of saveLayer() that takes 4 values rather than a RectF.
As of API Level API level android.os.Build.VERSION_CODES.P Build.VERSION_CODES.P
the only valid
saveFlags
is ALL_SAVE_FLAG
. All other flags are ignored.
Parameters | |
---|---|
left |
float |
top |
float |
right |
float |
bottom |
float |
paint |
Paint : This value may be null . |
saveFlags |
int : Value is either 0 or ALL_SAVE_FLAG |
Returns | |
---|---|
int |
public int saveLayerAlpha (float left, float top, float right, float bottom, int alpha, int saveFlags)
This method is deprecated.
Use saveLayerAlpha(float, float, float, float, int)
instead.
Helper for saveLayerAlpha() that takes 4 values instead of a RectF.
As of API Level API level android.os.Build.VERSION_CODES.P Build.VERSION_CODES.P
the only valid
saveFlags
is ALL_SAVE_FLAG
. All other flags are ignored.
Parameters | |
---|---|
left |
float |
top |
float |
right |
float |
bottom |
float |
alpha |
int |
saveFlags |
int : Value is either 0 or ALL_SAVE_FLAG |
Returns | |
---|---|
int |
public int saveLayerAlpha (RectF bounds, int alpha)
Convenience for saveLayer(android.graphics.RectF, android.graphics.Paint)
but instead of taking a entire Paint object
it takes only the alpha
parameter.
Parameters | |
---|---|
bounds |
RectF : The maximum size the offscreen bitmap needs to be
(in local coordinates)
This value may be null . |
alpha |
int : The alpha to apply to the offscreen when it is
drawn during restore() |
Returns | |
---|---|
int |
public int saveLayerAlpha (RectF bounds, int alpha, int saveFlags)
This method is deprecated.
Use saveLayerAlpha(android.graphics.RectF, int)
instead.
This behaves the same as save(), but in addition it allocates and redirects drawing to an offscreen bitmap.
Note: this method is very expensive,
incurring more than double rendering cost for contained content. Avoid
using this method, especially if the bounds provided are large. It is
recommended to use a hardware layer
on a View
to apply an xfermode, color filter, or alpha, as it will perform much
better than this method.
All drawing calls are directed to a newly allocated offscreen bitmap. Only when the balancing call to restore() is made, is that offscreen buffer drawn back to the current target of the Canvas (either the screen, it's target Bitmap, or the previous layer).
The alpha
parameter is applied when the offscreen bitmap is
drawn back when restore() is called.
As of API Level API level android.os.Build.VERSION_CODES.P Build.VERSION_CODES.P
the only valid
saveFlags
is ALL_SAVE_FLAG
. All other flags are ignored.
Parameters | |
---|---|
bounds |
RectF : The maximum size the offscreen bitmap needs to be
(in local coordinates)
This value may be null . |
alpha |
int : The alpha to apply to the offscreen when it is
drawn during restore() |
saveFlags |
int : see _SAVE_FLAG constants, generally ALL_SAVE_FLAG is recommended
for performance reasons.
Value is either 0 or ALL_SAVE_FLAG |
Returns | |
---|---|
int |
value to pass to restoreToCount() to balance this call |
public int saveLayerAlpha (float left, float top, float right, float bottom, int alpha)
Convenience for saveLayerAlpha(android.graphics.RectF, int)
that takes the four float coordinates of
the bounds rectangle.
Parameters | |
---|---|
left |
float |
top |
float |
right |
float |
bottom |
float |
alpha |
int |
Returns | |
---|---|
int |
public final void scale (float sx, float sy, float px, float py)
Preconcat the current matrix with the specified scale.
Parameters | |
---|---|
sx |
float : The amount to scale in X |
sy |
float : The amount to scale in Y |
px |
float : The x-coord for the pivot point (unchanged by the scale) |
py |
float : The y-coord for the pivot point (unchanged by the scale) |
public void scale (float sx, float sy)
Preconcat the current matrix with the specified scale.
Parameters | |
---|---|
sx |
float : The amount to scale in X |
sy |
float : The amount to scale in Y |
public void setBitmap (Bitmap bitmap)
Specify a bitmap for the canvas to draw into. All canvas state such as
layers, filters, and the save/restore stack are reset. Additionally,
the canvas' target density is updated to match that of the bitmap.
Prior to API level android.os.Build.VERSION_CODES.O Build.VERSION_CODES.O
the current matrix and
clip stack were preserved.
Parameters | |
---|---|
bitmap |
Bitmap : Specifies a mutable bitmap for the canvas to draw into.
This value may be null . |
See also:
public void setDensity (int density)
Specifies the density for this Canvas' backing bitmap. This modifies
the target density of the canvas itself, as well as the density of its
backing bitmap via Bitmap#setDensity(int)
.
Parameters | |
---|---|
density |
int : The new target density of the canvas, which is used
to determine the scaling factor when drawing a bitmap into it. Use
Bitmap#DENSITY_NONE to disable bitmap scaling. |
See also:
public void setDrawFilter (DrawFilter filter)
Parameters | |
---|---|
filter |
DrawFilter : This value may be null . |
public void setMatrix (Matrix matrix)
Completely replace the current matrix with the specified matrix. If the
matrix parameter is null, then the current matrix is reset to identity.
Note: it is recommended to use concat(android.graphics.Matrix)
,
scale(float, float)
, translate(float, float)
and
rotate(float)
instead of this method.
Parameters | |
---|---|
matrix |
Matrix : The matrix to replace the current matrix with. If it is
null, set the current matrix to identity.
This value may be null . |
See also:
public void skew (float sx, float sy)
Preconcat the current matrix with the specified skew.
Parameters | |
---|---|
sx |
float : The amount to skew in X |
sy |
float : The amount to skew in Y |
public void translate (float dx, float dy)
Preconcat the current matrix with the specified translation
Parameters | |
---|---|
dx |
float : The distance to translate in X |
dy |
float : The distance to translate in Y |