android.graphics
Class Picture

java.lang.Object
  android.graphics.Picture

public class Picture
extends Object

A picture records drawing calls (via the canvas returned by beginRecording) and can then play them back (via picture.draw(canvas) or canvas.drawPicture). The picture's contents can also be written to a stream, and then later restored to a new picture (via writeToStream / createFromStream). For most content (esp. text, lines, rectangles), drawing a sequence from a picture can be faster than the equivalent API calls, since the picture performs its playback without incurring any java-call overhead.

Constructor Summary

Picture()

Picture(Picture src)
Create a picture by making a copy of what has already been recorded in src.

Method Summary

Canvas	beginRecording(int width, int height) To record a picture, call beginRecording() and then draw into the Canvas that is returned.
static Picture	createFromStream(InputStream stream) Create a new picture (already recorded) from the data in the stream.
void	draw(Canvas canvas) Draw this picture on the canvas.
void	endRecording() Call endRecording when the picture is built.
protected void	finalize() Called by the virtual machine when there are no longer any (non-weak) references to the receiver.
int	getHeight() Get the height of the picture as passed to beginRecording.
int	getWidth() Get the width of the picture as passed to beginRecording.
(package private) int	ni()
void	writeToStream(OutputStream stream) Write the picture contents to a stream.

Methods inherited from class java.lang.Object

clone, equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

Picture

public Picture()

Picture

public Picture(Picture src)

Create a picture by making a copy of what has already been recorded in src. The contents of src are unchanged, and if src changes later, those changes will not be reflected in this picture.

Method Detail

beginRecording

public Canvas beginRecording(int width,
                             int height)

To record a picture, call beginRecording() and then draw into the Canvas that is returned. Nothing we appear on screen, but all of the draw commands (e.g. drawRect(...)) will be recorded. To stop recording, call endRecording(). At this point the Canvas that was returned must no longer be referenced, and nothing should be drawn into it.

endRecording

public void endRecording()

Call endRecording when the picture is built. After this call, the picture may be drawn, but the canvas that was returned by beginRecording must not be referenced anymore. This is automatically called if Picture.draw() or Canvas.drawPicture() is called.

getWidth

public int getWidth()

Get the width of the picture as passed to beginRecording. This does not reflect (per se) the content of the picture.

getHeight

public int getHeight()

Get the height of the picture as passed to beginRecording. This does not reflect (per se) the content of the picture.

draw

public void draw(Canvas canvas)

Draw this picture on the canvas. The picture may have the side effect of changing the matrix and clip of the canvas.

Parameters:

canvas - The picture is drawn to this canvas

createFromStream

public static Picture createFromStream(InputStream stream)

Create a new picture (already recorded) from the data in the stream. This data was generated by a previous call to writeToStream().

writeToStream

public void writeToStream(OutputStream stream)

Write the picture contents to a stream. The data can be used to recreate the picture in this or another process by calling createFromStream.

finalize

protected void finalize()
                 throws Throwable

Description copied from class: Object

Called by the virtual machine when there are no longer any (non-weak) references to the receiver. Subclasses can use this facility to guarantee that any associated resources are cleaned up before the receiver is garbage collected. Uncaught exceptions which are thrown during the running of the method cause it to terminate immediately, but are otherwise ignored.

Note: The virtual machine assumes that the implementation in class Object is empty.

Overrides:

finalize in class Object

Throws:

Throwable - The virtual machine ignores any exceptions which are thrown during finalization.

ni

final int ni()