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 | |||||||||||
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Canvas.EdgeType | |||||||||||
Canvas.VertexMode |
Constants | |||||||||||
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int | ALL_SAVE_FLAG | restore everything when restore() is called | |||||||||
int | CLIP_SAVE_FLAG | restore the current clip when restore() is called | |||||||||
int | CLIP_TO_LAYER_SAVE_FLAG | clip against the layer's bounds | |||||||||
int | FULL_COLOR_LAYER_SAVE_FLAG | the layer needs to 8-bits per color component | |||||||||
int | HAS_ALPHA_LAYER_SAVE_FLAG | the layer needs to per-pixel alpha | |||||||||
int | MATRIX_SAVE_FLAG | restore the current matrix when restore() is called |
Public Constructors | |||||||||||
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Construct an empty raster canvas.
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Construct a canvas with the specified bitmap to draw into.
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Public Methods | |||||||||||
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Intersect the current clip with the specified path.
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Modify the current clip with the specified path.
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Modify the current clip with the specified rectangle, which is
expressed in local coordinates.
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Modify the current clip with the specified rectangle.
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Intersect the current clip with the specified rectangle, which is
expressed in local coordinates.
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Intersect the current clip with the specified rectangle, which is
expressed in local coordinates.
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Intersect the current clip with the specified rectangle, which is
expressed in local coordinates.
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Modify the current clip with the specified rectangle, which is
expressed in local coordinates.
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Intersect the current clip with the specified rectangle, which is
expressed in local coordinates.
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Intersect the current clip with the specified region.
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Modify the current clip with the specified region.
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Preconcat the current matrix with the specified matrix.
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Fill the entire canvas' bitmap (restricted to the current clip) with the
specified ARGB color, using srcover porterduff mode.
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Draw the specified arc, which will be scaled to fit inside the specified oval. | |||||||||||
Treat the specified array of colors as a bitmap, and draw it.
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Draw the bitmap using the specified matrix.
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Legacy version of drawBitmap(int[] colors, ...) that took ints for x,y
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Draw the specified bitmap, scaling/translating automatically to fill
the destination rectangle.
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Draw the specified bitmap, with its top/left corner at (x,y), using
the specified paint, transformed by the current matrix.
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Draw the specified bitmap, scaling/translating automatically to fill
the destination rectangle.
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Draw the bitmap through the mesh, where mesh vertices are evenly
distributed across the bitmap.
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Draw the specified circle using the specified paint.
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Fill the entire canvas' bitmap (restricted to the current clip) with the
specified color, using srcover porterduff mode.
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Fill the entire canvas' bitmap (restricted to the current clip) with the
specified color and porter-duff xfermode.
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Draw a line segment with the specified start and stop x,y coordinates,
using the specified paint.
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Draw a series of lines.
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Draw the specified oval using the specified paint.
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Fill the entire canvas' bitmap (restricted to the current clip) with
the specified paint.
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Draw the specified path using the specified paint.
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Draw the picture, stretched to fit into the dst rectangle.
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Save the canvas state, draw the picture, and restore the canvas state.
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Draw the picture, stretched to fit into the dst rectangle.
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Helper for drawPoints() for drawing a single point.
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Draw a series of points.
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Helper for drawPoints() that assumes you want to draw the entire array
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Draw the text in the array, with each character's origin specified by
the pos array.
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Draw the text in the array, with each character's origin specified by
the pos array.
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Fill the entire canvas' bitmap (restricted to the current clip) with the
specified RGB color, using srcover porterduff mode.
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Draw the specified Rect using the specified paint.
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Draw the specified Rect using the specified paint.
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Draw the specified Rect using the specified Paint.
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Draw the specified round-rect using the specified paint.
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Draw the text, with origin at (x,y), using the specified paint.
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Draw the specified range of text, specified by start/end, with its
origin at (x,y), in the specified Paint.
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Draw the text, with origin at (x,y), using the specified paint.
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Draw the text, with origin at (x,y), using the specified paint.
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Draw the text, with origin at (x,y), using the specified paint, along
the specified path.
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Draw the text, with origin at (x,y), using the specified paint, along
the specified path.
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Draw the array of vertices, interpreted as triangles (based on mode).
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Retrieve the clip bounds.
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Retrieve the clip bounds, returning true if they are non-empty.
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Returns the target density of the canvas. | |||||||||||
Returns the height of the current drawing layer
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Return, in ctm, the current transformation matrix.
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Return a new matrix with a copy of the canvas' current transformation
matrix.
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Returns the maximum allowed height for bitmaps drawn with this canvas.
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Returns the maximum allowed width for bitmaps drawn with this canvas.
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Returns the number of matrix/clip states on the Canvas' private stack.
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Returns the width of the current drawing layer
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Indicates whether this Canvas uses hardware acceleration.
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Return true if the device that the current layer draws into is opaque
(i.e.
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Return true if the specified path, after being transformed by the
current matrix, would lie completely outside of the current clip.
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Return true if the specified rectangle, after being transformed by the
current matrix, would lie completely outside of the current clip.
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Return true if the specified rectangle, after being transformed by the
current matrix, would lie completely outside of the current clip.
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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.
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Efficient way to pop any calls to save() that happened after the save
count reached saveCount.
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Preconcat the current matrix with the specified rotation.
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Preconcat the current matrix with the specified rotation.
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Saves the current matrix and clip onto a private stack.
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Based on saveFlags, can save the current matrix and clip onto a private
stack.
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This behaves the same as save(), but in addition it allocates an
offscreen bitmap.
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Helper version of saveLayer() that takes 4 values rather than a RectF.
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This behaves the same as save(), but in addition it allocates an
offscreen bitmap.
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Helper for saveLayerAlpha() that takes 4 values instead of a RectF.
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Preconcat the current matrix with the specified scale.
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Preconcat the current matrix with the specified scale.
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Specify a bitmap for the canvas to draw into.
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Specifies the density for this Canvas' backing bitmap. | |||||||||||
Completely replace the current matrix with the specified matrix.
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Preconcat the current matrix with the specified skew.
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Preconcat the current matrix with the specified translation
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[Expand]
Inherited Methods | |||||||||||
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From class
java.lang.Object
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restore everything when restore() is called
restore the current clip when restore() is called
clip against the layer's bounds
the layer needs to 8-bits per color component
the layer needs to per-pixel alpha
restore the current matrix when restore() is called
Construct an empty raster canvas. Use setBitmap() to specify a bitmap to
draw into. The initial target density is DENSITY_NONE
;
this will typically be replaced when a target bitmap is set for the
canvas.
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.
bitmap | Specifies a mutable bitmap for the canvas to draw into. |
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Intersect the current clip with the specified path.
path | The path to intersect with the current clip |
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Modify the current clip with the specified path.
path | The path to operate on the current clip |
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op | How the clip is modified |
Modify the current clip with the specified rectangle, which is expressed in local coordinates.
rect | The rectangle to intersect with the current clip. |
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op | How the clip is modified |
Modify the current clip with the specified rectangle.
rect | The rect to intersect with the current clip |
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op | How the clip is modified |
Intersect the current clip with the specified rectangle, which is expressed in local coordinates.
left | The left side of the rectangle to intersect with the current clip |
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top | The top of the rectangle to intersect with the current clip |
right | The right side of the rectangle to intersect with the current clip |
bottom | The bottom of the rectangle to intersect with the current clip |
Intersect the current clip with the specified rectangle, which is expressed in local coordinates.
left | The left side of the rectangle to intersect with the current clip |
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top | The top of the rectangle to intersect with the current clip |
right | The right side of the rectangle to intersect with the current clip |
bottom | The bottom of the rectangle to intersect with the current clip |
Intersect the current clip with the specified rectangle, which is expressed in local coordinates.
rect | The rectangle to intersect with the current clip. |
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Modify the current clip with the specified rectangle, which is expressed in local coordinates.
left | The left side of the rectangle to intersect with the current clip |
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top | The top of the rectangle to intersect with the current clip |
right | The right side of the rectangle to intersect with the current clip |
bottom | The bottom of the rectangle to intersect with the current clip |
op | How the clip is modified |
Intersect the current clip with the specified rectangle, which is expressed in local coordinates.
rect | The rectangle to intersect with the current clip. |
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Intersect the current clip with the specified region. Note that unlike clipRect() and clipPath() which transform their arguments by the current matrix, clipRegion() assumes its argument is already in the coordinate system of the current layer's bitmap, and so not transformation is performed.
region | The region to operate on the current clip, based on op |
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Modify the current clip with the specified region. Note that unlike clipRect() and clipPath() which transform their arguments by the current matrix, clipRegion() assumes its argument is already in the coordinate system of the current layer's bitmap, and so not transformation is performed.
region | The region to operate on the current clip, based on op |
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op | How the clip is modified |
Preconcat the current matrix with the specified matrix.
matrix | The matrix to preconcatenate with the current matrix |
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Fill the entire canvas' bitmap (restricted to the current clip) with the specified ARGB color, using srcover porterduff mode.
a | alpha component (0..255) of the color to draw onto the canvas |
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r | red component (0..255) of the color to draw onto the canvas |
g | green component (0..255) of the color to draw onto the canvas |
b | blue component (0..255) of the color to draw onto the canvas |
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.)
oval | The bounds of oval used to define the shape and size of the arc |
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startAngle | Starting angle (in degrees) where the arc begins |
sweepAngle | Sweep angle (in degrees) measured clockwise |
useCenter | 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 | The paint used to draw the arc |
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.
colors | Array of colors representing the pixels of the bitmap |
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offset | Offset into the array of colors for the first pixel |
stride | The number of colors in the array between rows (must be >= width or <= -width). |
x | The X coordinate for where to draw the bitmap |
y | The Y coordinate for where to draw the bitmap |
width | The width of the bitmap |
height | The height of the bitmap |
hasAlpha | 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 | May be null. The paint used to draw the bitmap |
Draw the bitmap using the specified matrix.
bitmap | The bitmap to draw |
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matrix | The matrix used to transform the bitmap when it is drawn |
paint | May be null. The paint used to draw the bitmap |
Legacy version of drawBitmap(int[] colors, ...) that took ints for x,y
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.
bitmap | The bitmap to be drawn |
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src | May be null. The subset of the bitmap to be drawn |
dst | The rectangle that the bitmap will be scaled/translated to fit into |
paint | May be null. The paint used to draw the bitmap |
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.
bitmap | The bitmap to be drawn |
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left | The position of the left side of the bitmap being drawn |
top | The position of the top side of the bitmap being drawn |
paint | The paint used to draw the bitmap (may be null) |
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.
bitmap | The bitmap to be drawn |
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src | May be null. The subset of the bitmap to be drawn |
dst | The rectangle that the bitmap will be scaled/translated to fit into |
paint | May be null. The paint used to draw the bitmap |
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 methid is drawVertices().
bitmap | The bitmap to draw using the mesh |
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meshWidth | The number of columns in the mesh. Nothing is drawn if this is 0 |
meshHeight | The number of rows in the mesh. Nothing is drawn if this is 0 |
verts | Array of x,y pairs, specifying where the mesh should be drawn. There must be at least (meshWidth+1) * (meshHeight+1) * 2 + meshOffset values in the array |
vertOffset | Number of verts elements to skip before drawing |
colors | 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. |
colorOffset | Number of color elements to skip before drawing |
paint | May be null. The paint used to draw the bitmap |
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.
cx | The x-coordinate of the center of the cirle to be drawn |
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cy | The y-coordinate of the center of the cirle to be drawn |
radius | The radius of the cirle to be drawn |
paint | The paint used to draw the circle |
Fill the entire canvas' bitmap (restricted to the current clip) with the specified color, using srcover porterduff mode.
color | the color to draw onto the canvas |
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Fill the entire canvas' bitmap (restricted to the current clip) with the specified color and porter-duff xfermode.
color | the color to draw with |
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mode | the porter-duff mode to apply to the color |
Draw a line segment with the specified start and stop x,y coordinates, using the specified paint. NOTE: since a line is always "framed", the Style is ignored in the paint.
startX | The x-coordinate of the start point of the line |
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startY | The y-coordinate of the start point of the line |
paint | The paint used to draw the line |
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.
pts | Array of points to draw [x0 y0 x1 y1 x2 y2 ...] |
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offset | Number of values in the array to skip before drawing. |
count | 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 | The paint used to draw the points |
Draw the specified oval using the specified paint. The oval will be filled or framed based on the Style in the paint.
oval | The rectangle bounds of the oval to be drawn |
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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.
paint | The paint used to draw onto the canvas |
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Draw the specified path using the specified paint. The path will be filled or framed based on the Style in the paint.
path | The path to be drawn |
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paint | The paint used to draw the path |
Draw the picture, stretched to fit into the dst rectangle.
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.
picture | The picture to be drawn |
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Draw the picture, stretched to fit into the dst rectangle.
Helper for drawPoints() for drawing a single point.
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.
pts | Array of points to draw [x0 y0 x1 y1 x2 y2 ...] |
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offset | Number of values to skip before starting to draw. |
count | 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 | The paint used to draw the points |
Helper for drawPoints() that assumes you want to draw the entire array
Draw the text in the array, with each character's origin specified by the pos array. This method does not support glyph composition and decomposition and should therefore not be used to render complex scripts.
text | The text to be drawn |
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index | The index of the first character to draw |
count | The number of characters to draw, starting from index. |
pos | Array of [x,y] positions, used to position each character |
paint | The paint used for the text (e.g. color, size, style) |
Draw the text in the array, with each character's origin specified by the pos array. This method does not support glyph composition and decomposition and should therefore not be used to render complex scripts.
text | The text to be drawn |
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pos | Array of [x,y] positions, used to position each character |
paint | The paint used for the text (e.g. color, size, style) |
Fill the entire canvas' bitmap (restricted to the current clip) with the specified RGB color, using srcover porterduff mode.
r | red component (0..255) of the color to draw onto the canvas |
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g | green component (0..255) of the color to draw onto the canvas |
b | blue component (0..255) of the color to draw onto the canvas |
Draw the specified Rect using the specified paint. The rectangle will be filled or framed based on the Style in the paint.
left | The left side of the rectangle to be drawn |
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top | The top side of the rectangle to be drawn |
right | The right side of the rectangle to be drawn |
bottom | The bottom side of the rectangle to be drawn |
paint | The paint used to draw the rect |
Draw the specified Rect using the specified paint. The rectangle will be filled or framed based on the Style in the paint.
rect | The rect to be drawn |
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paint | The paint used to draw the rect |
Draw the specified Rect using the specified Paint. The rectangle will be filled or framed based on the Style in the paint.
r | The rectangle to be drawn. |
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paint | The paint used to draw the rectangle |
Draw the specified round-rect using the specified paint. The roundrect will be filled or framed based on the Style in the paint.
rect | The rectangular bounds of the roundRect to be drawn |
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rx | The x-radius of the oval used to round the corners |
ry | The y-radius of the oval used to round the corners |
paint | The paint used to draw the roundRect |
Draw the text, with origin at (x,y), using the specified paint. The origin is interpreted based on the Align setting in the paint.
text | The text to be drawn |
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x | The x-coordinate of the origin of the text being drawn |
y | The y-coordinate of the origin of the text being drawn |
paint | The paint used for the text (e.g. color, size, style) |
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.
text | The text to be drawn |
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start | The index of the first character in text to draw |
end | (end - 1) is the index of the last character in text to draw |
x | The x-coordinate of origin for where to draw the text |
y | The y-coordinate of origin for where to draw the text |
paint | The paint used for the text (e.g. color, size, style) |
Draw the text, with origin at (x,y), using the specified paint. The origin is interpreted based on the Align setting in the paint.
text | The text to be drawn |
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x | The x-coordinate of the origin of the text being drawn |
y | The y-coordinate of the origin of the text being drawn |
paint | The paint used for the text (e.g. color, size, style) |
Draw the text, with origin at (x,y), using the specified paint. The origin is interpreted based on the Align setting in the paint.
text | The text to be drawn |
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start | The index of the first character in text to draw |
end | (end - 1) is the index of the last character in text to draw |
x | The x-coordinate of the origin of the text being drawn |
y | The y-coordinate of the origin of the text being drawn |
paint | The paint used for the text (e.g. color, size, style) |
Draw the text, with origin at (x,y), using the specified paint, along the specified path. The paint's Align setting determins where along the path to start the text.
text | The text to be drawn |
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path | The path the text should follow for its baseline |
hOffset | The distance along the path to add to the text's starting position |
vOffset | The distance above(-) or below(+) the path to position the text |
paint | The paint used for the text (e.g. color, size, style) |
Draw the text, with origin at (x,y), using the specified paint, along the specified path. The paint's Align setting determins where along the path to start the text.
text | The text to be drawn |
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path | The path the text should follow for its baseline |
hOffset | The distance along the path to add to the text's starting position |
vOffset | The distance above(-) or below(+) the path to position the text |
paint | The paint used for the text (e.g. color, size, style) |
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.
mode | How to interpret the array of vertices |
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vertexCount | 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 | Array of vertices for the mesh |
vertOffset | Number of values in the verts to skip before drawing. |
texs | May be null. If not null, specifies the coordinates to sample into the current shader (e.g. bitmap tile or gradient) |
texOffset | Number of values in texs to skip before drawing. |
colors | May be null. If not null, specifies a color for each vertex, to be interpolated across the triangle. |
colorOffset | Number of values in colors to skip before drawing. |
indices | If not null, array of indices to reference into the vertex (texs, colors) array. |
indexCount | number of entries in the indices array (if not null). |
paint | Specifies the shader to use if the texs array is non-null. |
Retrieve the clip bounds.
Retrieve the clip bounds, returning true if they are non-empty.
bounds | Return the clip bounds here. If it is null, ignore it but still return true if the current clip is non-empty. |
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Returns the target density of the canvas. The default density is
derived from the density of its backing bitmap, or
DENSITY_NONE
if there is not one.
Returns the height of the current drawing layer
Return, in ctm, the current transformation matrix. This does not alter the matrix in the canvas, but just returns a copy of it.
Return a new matrix with a copy of the canvas' current transformation matrix.
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 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 the number of matrix/clip states on the Canvas' private stack. This will equal # save() calls - # restore() calls.
Returns the width of the current drawing layer
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.
Return true if the device that the current layer draws into is opaque (i.e. does not support per-pixel alpha).
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).
path | The path to compare with the current clip |
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type | true if the path should be considered antialiased, since that means it may affect a larger area (more pixels) than non-antialiased. |
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).
left | The left side of the rectangle to compare with the current clip |
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top | The top of the rectangle to compare with the current clip |
right | The right side of the rectangle to compare with the current clip |
bottom | The bottom of the rectangle to compare with the current clip |
type | true if the rect should be considered antialiased, since that means it may affect a larger area (more pixels) than non-antialiased. |
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).
rect | the rect to compare with the current clip |
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type | specifies how to treat the edges (BW or antialiased) |
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.
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().
saveCount | The save level to restore to. |
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Preconcat the current matrix with the specified rotation.
degrees | The amount to rotate, in degrees |
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Preconcat the current matrix with the specified rotation.
degrees | The amount to rotate, in degrees |
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px | The x-coord for the pivot point (unchanged by the rotation) |
py | The y-coord for the pivot point (unchanged by the rotation) |
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.
Based on saveFlags, can save 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.
saveFlags | flag bits that specify which parts of the Canvas state to save/restore |
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This behaves the same as save(), but in addition it allocates an offscreen bitmap. All drawing calls are directed there, and only when the balancing call to restore() is made is that offscreen transfered to the canvas (or the previous layer). Subsequent calls to translate, scale, rotate, skew, concat or clipRect, clipPath all operate on this copy. When the balancing call to restore() is made, this copy is deleted and the previous matrix/clip state is restored.
bounds | May be null. The maximum size the offscreen bitmap needs to be (in local coordinates) |
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paint | This is copied, and is applied to the offscreen when restore() is called. |
saveFlags | see _SAVE_FLAG constants |
Helper version of saveLayer() that takes 4 values rather than a RectF.
This behaves the same as save(), but in addition it allocates an offscreen bitmap. All drawing calls are directed there, and only when the balancing call to restore() is made is that offscreen transfered to the canvas (or the previous layer). Subsequent calls to translate, scale, rotate, skew, concat or clipRect, clipPath all operate on this copy. When the balancing call to restore() is made, this copy is deleted and the previous matrix/clip state is restored.
bounds | The maximum size the offscreen bitmap needs to be (in local coordinates) |
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alpha | The alpha to apply to the offscreen when when it is drawn during restore() |
saveFlags | see _SAVE_FLAG constants |
Helper for saveLayerAlpha() that takes 4 values instead of a RectF.
Preconcat the current matrix with the specified scale.
sx | The amount to scale in X |
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sy | The amount to scale in Y |
Preconcat the current matrix with the specified scale.
sx | The amount to scale in X |
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sy | The amount to scale in Y |
px | The x-coord for the pivot point (unchanged by the scale) |
py | The y-coord for the pivot point (unchanged by the scale) |
Specify a bitmap for the canvas to draw into. As a side-effect, also updates the canvas's target density to match that of the bitmap.
bitmap | Specifies a mutable bitmap for the canvas to draw into. |
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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)
.
density | The new target density of the canvas, which is used
to determine the scaling factor when drawing a bitmap into it. Use
DENSITY_NONE to disable bitmap scaling. |
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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(Matrix)
,
scale(float, float)
, translate(float, float)
and
rotate(float)
instead of this method.
matrix | The matrix to replace the current matrix with. If it is null, set the current matrix to identity. |
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Preconcat the current matrix with the specified skew.
sx | The amount to skew in X |
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sy | The amount to skew in Y |
Preconcat the current matrix with the specified translation
dx | The distance to translate in X |
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dy | The distance to translate in Y |