JavaFX 27 · com.sun.prism.impl.paint.MultipleGradientContext

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 int	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	MAX_GRADIENT_ARRAY_SIZE Maximum length of the fast single-array.
private float[]	normalizedIntervals Normalized intervals array.
private int	transparencyTest Used to determine if gradient colors are all opaque.

Constructor Summary

Access	Constructor and Description
protected	MultipleGradientContext(Gradient mgp, BaseTransform t, float[] fractions, Color[] colors, int cycleMethod) Constructor for MultipleGradientContext 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[].
protected abstract void	fillRaster(int[] pixels, int off, int adjust, int x, int y, int w, int h)
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.

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.

cycleMethod	back to summary
protected int 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.

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).

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

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

Constructor Detail

MultipleGradientContext	back to summary
protected MultipleGradientContext(Gradient mgp, BaseTransform t, float[] fractions, Color[] colors, int cycleMethod) Constructor for MultipleGradientContext 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

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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

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

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

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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

pack-priv abstract Class MultipleGradientContext

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