JavaFX 27 · com.sun.prism.j2d.paint.MultipleGradientPaintContext

Field Summary

Modifier and Type	Field and Description
protected float	a00 Elements of the inverse transform matrix.
protected float	a01 Elements of the inverse transform matrix.
protected float	a02 Elements of the inverse transform matrix.
protected float	a10 Elements of the inverse transform matrix.
protected float	a11 Elements of the inverse transform matrix.
protected float	a12 Elements of the inverse transform matrix.
protected static WeakReference<Raster>	cached The cached raster, which is reusable among instances.
protected static ColorModel	cachedModel The cached ColorModel.
protected MultipleGradientPaint.ColorSpaceType	colorSpace The ColorSpace in which to perform the interpolation
protected MultipleGradientPaint.CycleMethod	cycleMethod The method to use when painting out of the gradient bounds.
protected int	fastGradientArraySize Size of gradients array for scaling the 0-1 index when looking up colors the fast way.
private float[]	fractions Fractions array.
protected int[]	gradient Array which contains the interpolated color values for each interval, used by calculateSingleArrayGradient().
protected static final int	GRADIENT_SIZE Constant number of max colors between any 2 arbitrary colors.
protected static final int	GRADIENT_SIZE_INDEX
private int[][]	gradients Array of gradient arrays, one array for each interval.
protected boolean	isSimpleLookup This boolean specifies whether we are in simple lookup mode, where an input value between 0 and 1 may be used to directly index into a single array of gradient colors.
private static final int[]	LinearRGBtoSRGB
private static final int	MAX_GRADIENT_ARRAY_SIZE Maximum length of the fast single-array.
protected ColorModel	model The PaintContext's ColorModel.
private float[]	normalizedIntervals Normalized intervals array.
protected Raster	saved Raster is reused whenever possible.
private static final int[]	SRGBtoLinearRGB Color space conversion lookup tables.
private int	transparencyTest Used to determine if gradient colors are all opaque.
private static ColorModel	xrgbmodel Color model used if gradient colors are all opaque.

Constructor Summary

Access	Constructor and Description
protected	MultipleGradientPaintContext(MultipleGradientPaint mgp, ColorModel cm, Rectangle deviceBounds, Rectangle2D userBounds, AffineTransform t, RenderingHints hints, float[] fractions, Color[] colors, MultipleGradientPaint.CycleMethod cycleMethod, MultipleGradientPaint.ColorSpaceType colorSpace) Constructor for MultipleGradientPaintContext superclass.

Method Summary

Modifier and Type	Method and Description
private void	calculateLookupData(Color[] colors) This function is the meat of this class.
private void	calculateMultipleArrayGradient(Color[] colors) SLOW LOOKUP METHOD This method calculates the gradient color values for each interval and places each into its own 255 size array.
private void	calculateSingleArrayGradient(Color[] colors, float the size of the smallest interval Imin) FAST LOOKUP METHOD This method calculates the gradient color values and places them in a single int array, gradient[].
private int	convertEntireColorLinearRGBtoSRGB(int rgb) Yet another helper function.
private static int	convertLinearRGBtoSRGB(int color) Helper function to convert a color component in linear RGB space to SRGB space.
private static int	convertSRGBtoLinearRGB(int color) Helper function to convert a color component in sRGB space to linear RGB space.
public final void	dispose() Implements java.awt.PaintContext.dispose. Releases the resources allocated for the operation.
protected abstract void	fillRaster(int[] pixels, int off, int adjust, int x, int y, int w, int h)
private static synchronized Raster	getCachedRaster(ColorModel cm, int w, int h) Took this cacheRaster code from GradientPaint.
public final ColorModel	getColorModel() Implements java.awt.PaintContext.getColorModel. Returns the `ColorModel` of the output.
public final Raster	getRaster(int x, int y, int w, int h) Implements java.awt.PaintContext.getRaster. Returns a `Raster` containing the colors generated for the graphics operation.
protected final int	Returns: integer color to display indexIntoGradientsArrays(float the unmanipulated position, which will be mapped into the range 0 to 1 position) Helper function to index into the gradients array.
private void	interpolate(int the start color rgb1, int the end color rgb2, int[] the output array of colors; must not be null output) Yet another helper function.
private static synchronized void	putCachedRaster(ColorModel cm, Raster ras) Took this cacheRaster code from GradientPaint.

Inherited from java.lang.Object:: clone equals finalize getClass hashCode notify notifyAll toString wait wait wait

Field Detail

a00	back to summary
protected float a00 Elements of the inverse transform matrix.

a01	back to summary
protected float a01 Elements of the inverse transform matrix.

a02	back to summary
protected float a02 Elements of the inverse transform matrix.

a10	back to summary
protected float a10 Elements of the inverse transform matrix.

a11	back to summary
protected float a11 Elements of the inverse transform matrix.

a12	back to summary
protected float a12 Elements of the inverse transform matrix.

cached	back to summary
protected static WeakReference<Raster> cached The cached raster, which is reusable among instances.

cachedModel	back to summary
protected static ColorModel cachedModel The cached ColorModel.

colorSpace	back to summary
protected MultipleGradientPaint.ColorSpaceType colorSpace The ColorSpace in which to perform the interpolation

cycleMethod	back to summary
protected MultipleGradientPaint.CycleMethod cycleMethod The method to use when painting out of the gradient bounds.

fastGradientArraySize	back to summary
protected int fastGradientArraySize Size of gradients array for scaling the 0-1 index when looking up colors the fast way.

fractions	back to summary
private float[] fractions Fractions array.

gradient	back to summary
protected int[] gradient Array which contains the interpolated color values for each interval, used by calculateSingleArrayGradient(). It is protected for possible direct access by subclasses.

GRADIENT_SIZE	back to summary
protected static final int GRADIENT_SIZE Constant number of max colors between any 2 arbitrary colors. Used for creating and indexing gradients arrays.

GRADIENT_SIZE_INDEX	back to summary
protected static final int GRADIENT_SIZE_INDEX

gradients	back to summary
private int[][] gradients Array of gradient arrays, one array for each interval. Used by calculateMultipleArrayGradient().

isSimpleLookup	back to summary
protected boolean isSimpleLookup This boolean specifies whether we are in simple lookup mode, where an input value between 0 and 1 may be used to directly index into a single array of gradient colors. If this boolean value is false, then we have to use a 2-step process where we have to determine which gradient array we fall into, then determine the index into that array.

LinearRGBtoSRGB	back to summary
private static final int[] LinearRGBtoSRGB

MAX_GRADIENT_ARRAY_SIZE	back to summary
private static final int MAX_GRADIENT_ARRAY_SIZE Maximum length of the fast single-array. If the estimated array size is greater than this, switch over to the slow lookup method. No particular reason for choosing this number, but it seems to provide satisfactory performance for the common case (fast lookup).

model	back to summary
protected ColorModel model The PaintContext's ColorModel. This is ARGB if colors are not all opaque, otherwise it is RGB.

normalizedIntervals	back to summary
private float[] normalizedIntervals Normalized intervals array.

saved	back to summary
protected Raster saved Raster is reused whenever possible.

SRGBtoLinearRGB	back to summary
private static final int[] SRGBtoLinearRGB Color space conversion lookup tables.

transparencyTest	back to summary
private int transparencyTest Used to determine if gradient colors are all opaque.

xrgbmodel	back to summary
private static ColorModel xrgbmodel Color model used if gradient colors are all opaque.

Constructor Detail

MultipleGradientPaintContext	back to summary
protected MultipleGradientPaintContext(MultipleGradientPaint mgp, ColorModel cm, Rectangle deviceBounds, Rectangle2D userBounds, AffineTransform t, RenderingHints hints, float[] fractions, Color[] colors, MultipleGradientPaint.CycleMethod cycleMethod, MultipleGradientPaint.ColorSpaceType colorSpace) Constructor for MultipleGradientPaintContext superclass.

Method Detail

calculateLookupData	back to summary
private void calculateLookupData(Color[] colors) This function is the meat of this class. It calculates an array of gradient colors based on an array of fractions and color values at those fractions.

calculateMultipleArrayGradient	back to summary
private void calculateMultipleArrayGradient(Color[] colors) SLOW LOOKUP METHOD This method calculates the gradient color values for each interval and places each into its own 255 size array. The arrays are stored in gradients[][]. (255 is used because this is the maximum number of unique colors between 2 arbitrary colors in a 24 bit color system.) This method uses the minimum amount of space (only 255 * number of intervals), but it aggravates the lookup procedure, because now we have to find out which interval to select, then calculate the index within that interval. This causes a significant performance hit, because it requires this calculation be done for every point in the rendering loop. For those of you who are interested, this is a classic example of the time-space tradeoff.

calculateMultipleArrayGradient

back to summary

private void calculateMultipleArrayGradient(Color[] colors)

SLOW LOOKUP METHOD This method calculates the gradient color values for each interval and places each into its own 255 size array. The arrays are stored in gradients[][]. (255 is used because this is the maximum number of unique colors between 2 arbitrary colors in a 24 bit color system.) This method uses the minimum amount of space (only 255 * number of intervals), but it aggravates the lookup procedure, because now we have to find out which interval to select, then calculate the index within that interval. This causes a significant performance hit, because it requires this calculation be done for every point in the rendering loop. For those of you who are interested, this is a classic example of the time-space tradeoff.

calculateSingleArrayGradient	back to summary
private void calculateSingleArrayGradient(Color[] colors, float Imin) FAST LOOKUP METHOD This method calculates the gradient color values and places them in a single int array, gradient[]. It does this by allocating space for each interval based on its size relative to the smallest interval in the array. The smallest interval is allocated 255 interpolated values (the maximum number of unique in-between colors in a 24 bit color system), and all other intervals are allocated size = (255 * the ratio of their size to the smallest interval). This scheme expedites a speedy retrieval because the colors are distributed along the array according to their user-specified distribution. All that is needed is a relative index from 0 to 1. The only problem with this method is that the possibility exists for the array size to balloon in the case where there is a disproportionately small gradient interval. In this case the other intervals will be allocated huge space, but much of that data is redundant. We thus need to use the space conserving scheme below. Parameters Imin:float the size of the smallest interval

calculateSingleArrayGradient

back to summary

private void calculateSingleArrayGradient(Color[] colors, float Imin)

FAST LOOKUP METHOD This method calculates the gradient color values and places them in a single int array, gradient[]. It does this by allocating space for each interval based on its size relative to the smallest interval in the array. The smallest interval is allocated 255 interpolated values (the maximum number of unique in-between colors in a 24 bit color system), and all other intervals are allocated size = (255 * the ratio of their size to the smallest interval). This scheme expedites a speedy retrieval because the colors are distributed along the array according to their user-specified distribution. All that is needed is a relative index from 0 to 1. The only problem with this method is that the possibility exists for the array size to balloon in the case where there is a disproportionately small gradient interval. In this case the other intervals will be allocated huge space, but much of that data is redundant. We thus need to use the space conserving scheme below.

Parameters

Imin:float: the size of the smallest interval

convertEntireColorLinearRGBtoSRGB	back to summary
private int convertEntireColorLinearRGBtoSRGB(int rgb) Yet another helper function. This one extracts the color components of an integer RGB triple, converts them from LinearRGB to SRGB, then recompacts them into an int.

convertLinearRGBtoSRGB	back to summary
private static int convertLinearRGBtoSRGB(int color) Helper function to convert a color component in linear RGB space to SRGB space. Used to build a static lookup table.

convertSRGBtoLinearRGB	back to summary
private static int convertSRGBtoLinearRGB(int color) Helper function to convert a color component in sRGB space to linear RGB space. Used to build a static lookup table.

dispose	back to summary
public final void dispose() Implements java.awt.PaintContext.dispose. Doc from java.awt.PaintContext.dispose. Releases the resources allocated for the operation. Annotations @Override

dispose

back to summary

public final void dispose()

Implements java.awt.PaintContext.dispose.

Doc from java.awt.PaintContext.dispose.

Releases the resources allocated for the operation.

Annotations

@Override

fillRaster	back to summary
protected abstract void fillRaster(int[] pixels, int off, int adjust, int x, int y, int w, int h)

getCachedRaster	back to summary
private static synchronized Raster getCachedRaster(ColorModel cm, int w, int h) Took this cacheRaster code from GradientPaint. It appears to recycle rasters for use by any other instance, as long as they are sufficiently large.

getColorModel back to summary

getColorModel	back to summary
public final ColorModel getColorModel() Implements java.awt.PaintContext.getColorModel. Doc from java.awt.PaintContext.getColorModel. Returns the `ColorModel` of the output. Note that this `ColorModel` might be different from the hint specified in the `createContext` method of `Paint`. Not all `PaintContext` objects are capable of generating color patterns in an arbitrary `ColorModel`. Annotations @Override

public final ColorModel getColorModel()

Implements java.awt.PaintContext.getColorModel.

Doc from java.awt.PaintContext.getColorModel.

Returns the ColorModel of the output. Note that this ColorModel might be different from the hint specified in the createContext method of Paint. Not all PaintContext objects are capable of generating color patterns in an arbitrary ColorModel.

Annotations

@Override

getRaster back to summary

getRaster	back to summary
public final Raster getRaster(int x, int y, int w, int h) Implements java.awt.PaintContext.getRaster. Doc from java.awt.PaintContext.getRaster. Returns a `Raster` containing the colors generated for the graphics operation. Annotations @Override

public final Raster getRaster(int x, int y, int w, int h)

Implements java.awt.PaintContext.getRaster.

Doc from java.awt.PaintContext.getRaster.

Returns a Raster containing the colors generated for the graphics operation.

Annotations

@Override

indexIntoGradientsArrays	back to summary
protected final int indexIntoGradientsArrays(float position) Helper function to index into the gradients array. This is necessary because each interval has an array of colors with uniform size 255. However, the color intervals are not necessarily of uniform length, so a conversion is required. Parameters position:float the unmanipulated position, which will be mapped into the range 0 to 1 Returns:int integer color to display

indexIntoGradientsArrays

back to summary

protected final int indexIntoGradientsArrays(float position)

Helper function to index into the gradients array. This is necessary because each interval has an array of colors with uniform size 255. However, the color intervals are not necessarily of uniform length, so a conversion is required.

Parameters

position:float: the unmanipulated position, which will be mapped into the range 0 to 1

Returns:int

integer color to display

interpolate	back to summary
private void interpolate(int rgb1, int rgb2, int[] output) Yet another helper function. This one linearly interpolates between 2 colors, filling up the output array. Parameters rgb1:int the start color rgb2:int the end color output:int[] the output array of colors; must not be null

interpolate

back to summary

private void interpolate(int rgb1, int rgb2, int[] output)

Yet another helper function. This one linearly interpolates between 2 colors, filling up the output array.

Parameters

rgb1:int: the start color
rgb2:int: the end color
output:int[]: the output array of colors; must not be null

putCachedRaster	back to summary
private static synchronized void putCachedRaster(ColorModel cm, Raster ras) Took this cacheRaster code from GradientPaint. It appears to recycle rasters for use by any other instance, as long as they are sufficiently large.

pack-priv abstract Class MultipleGradientPaintContext

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