- All Superinterfaces:
GraphicsCreator
- All Known Implementing Classes:
OSGBufferedImage
,OutputStreamGraphics
,OutputStreamGraphics.Surrogate
,PanelGraphics
,PrinterGraphics
,ThreadedOSGraphics
Basic operations for output stream graphics.
This interface represents common operations that classes
such as
Graph
use.-
Method Summary
Modifier and TypeMethodDescriptionboolean
canReset()
Test if the methodreset()
is supported.void
close()
Close resources.Get a graphics context for drawing.void
flush()
Flush the output.Get the color model for the image that will be produced.int
Get the image height parameter in user space.int
getWidth()
Get the image width parameter in user space.void
Final processing for writing an image file to the output stream.boolean
Determine if this instance is requesting an alpha channel.void
reset()
Reset this graphics output stream.
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Method Details
-
requestsAlpha
boolean requestsAlpha()Determine if this instance is requesting an alpha channel. The value may be changed from that provided in the constructor due to the capabilities of a particular image format.- Returns:
- true if an alpha channel is requested; false otherwise
-
getWidth
int getWidth()Get the image width parameter in user space. Unless a graphics context is modified, this value represents an upper bound on the X coordinate of points that will appear in the image in the coordinate system used by the graphics context independent of the orientation.The parameter typically refers to some object such as a buffered image so that the value returned by this method is constant.
- Returns:
- the width in user-space coordinates
-
getHeight
int getHeight()Get the image height parameter in user space. Unless a graphics context is modified, this value represents an upper bound on the Y coordinate of points that will appear in the image in the coordinate system used by the graphics context independent of the orientation.The parameter typically refers to some object such as a buffered image so that the value returned by this method is constant.
- Returns:
- the height in user-space coordinates
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close
Close resources. Typically this method will perform some action when a class that implements this interface has an associated output stream or a resource that can be closed. If there are no such resources, this method should simply return. Classes that implement this method should document what they actually do.- Throws:
IOException
- if an IO error occurred
-
flush
Flush the output. This method will provide a partial image or partial graphics if possible or feasible. After this method is called, the user must not use graphics contexts that were previously created. Whether this method performs any action depends on the implementation of each class or subclass implementing this interface.- Throws:
IOException
- - if an IO exception occurred- See Also:
-
getColorModel
ColorModel getColorModel()Get the color model for the image that will be produced.- Returns:
- the color model
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createGraphics
Get a graphics context for drawing. The graphics context created is not valid afterflush()
orreset()
is called.- Specified by:
createGraphics
in interfaceGraphicsCreator
- Returns:
- a new graphics context.
- Throws:
UnsupportedOperationException
- this operation is not supported, typically because the implementation can only create an instance of Graphics, not Graphics2D (something that would rarely, if ever, occur in practice)
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canReset
boolean canReset()Test if the methodreset()
is supported.- Returns:
- true if
reset()
is supported; false otherwise
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reset
Reset this graphics output stream. This is an optional operation as it is appropriate for some graphics output streams but not others- Throws:
UnsupportedOperationException
- an instance does not support resets
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imageComplete
Final processing for writing an image file to the output stream. This method does not close an IO stream, but will flush it.Subclasses should implement this method so that it throws an exception if called multiple times without a successful intervening call to
reset()
. The methodcanReset()
can be called to test if resets are allowed.- Throws:
IOException
- IO failure, or a PrintException (which will be provided as the cause of the IOException), or an indication that this method was called multiple times
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