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* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
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* published by the Free Software Foundation. Oracle designates this
* particular file as subject to the "Classpath" exception as provided
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*
* This code is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
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* 2 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*
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package java.awt;
import java.awt.geom.AffineTransform;
import java.awt.image.ColorModel;
import java.lang.ref.SoftReference;
import java.util.Arrays;
/**
* This is the superclass for Paints which use a multiple color
* gradient to fill in their raster. It provides storage for variables and
* enumerated values common to
* {@code LinearGradientPaint} and {@code RadialGradientPaint}.
*
* @author Nicholas Talian, Vincent Hardy, Jim Graham, Jerry Evans
* @since 1.6
*/
public abstract class MultipleGradientPaint implements Paint {
/** The method to use when painting outside the gradient bounds.
* @since 1.6
*/
public static enum CycleMethod {
/**
* Use the terminal colors to fill the remaining area.
*/
NO_CYCLE,
/**
* Cycle the gradient colors start-to-end, end-to-start
* to fill the remaining area.
*/
REFLECT,
/**
* Cycle the gradient colors start-to-end, start-to-end
* to fill the remaining area.
*/
REPEAT
}
/** The color space in which to perform the gradient interpolation.
* @since 1.6
*/
public static enum ColorSpaceType {
/**
* Indicates that the color interpolation should occur in sRGB space.
*/
SRGB,
/**
* Indicates that the color interpolation should occur in linearized
* RGB space.
*/
LINEAR_RGB
}
/** The transparency of this paint object. */
final int transparency;
/** Gradient keyframe values in the range 0 to 1. */
final float[] fractions;
/** Gradient colors. */
final Color[] colors;
/** Transform to apply to gradient. */
final AffineTransform gradientTransform;
/** The method to use when painting outside the gradient bounds. */
final CycleMethod cycleMethod;
/** The color space in which to perform the gradient interpolation. */
final ColorSpaceType colorSpace;
/**
* The following fields are used only by MultipleGradientPaintContext
* to cache certain values that remain constant and do not need to be
* recalculated for each context created from this paint instance.
*/
ColorModel model;
float[] normalizedIntervals;
boolean isSimpleLookup;
SoftReference<int[][]> gradients;
SoftReference<int[]> gradient;
int fastGradientArraySize;
/**
* Package-private constructor.
*
* @param fractions numbers ranging from 0.0 to 1.0 specifying the
* distribution of colors along the gradient
* @param colors array of colors corresponding to each fractional value
* @param cycleMethod either {@code NO_CYCLE}, {@code REFLECT},
* or {@code REPEAT}
* @param colorSpace which color space to use for interpolation,
* either {@code SRGB} or {@code LINEAR_RGB}
* @param gradientTransform transform to apply to the gradient
*
* @throws NullPointerException
* if {@code fractions} array is null,
* or {@code colors} array is null,
* or {@code gradientTransform} is null,
* or {@code cycleMethod} is null,
* or {@code colorSpace} is null
* @throws IllegalArgumentException
* if {@code fractions.length != colors.length},
* or {@code colors} is less than 2 in size,
* or a {@code fractions} value is less than 0.0 or greater than 1.0,
* or the {@code fractions} are not provided in strictly increasing order
*/
MultipleGradientPaint(float[] fractions,
Color[] colors,
CycleMethod cycleMethod,
ColorSpaceType colorSpace,
AffineTransform gradientTransform)
{
if (fractions == null) {
throw new NullPointerException("Fractions array cannot be null");
}
if (colors == null) {
throw new NullPointerException("Colors array cannot be null");
}
if (cycleMethod == null) {
throw new NullPointerException("Cycle method cannot be null");
}
if (colorSpace == null) {
throw new NullPointerException("Color space cannot be null");
}
if (gradientTransform == null) {
throw new NullPointerException("Gradient transform cannot be "+
"null");
}
if (fractions.length != colors.length) {
throw new IllegalArgumentException("Colors and fractions must " +
"have equal size");
}
if (colors.length < 2) {
throw new IllegalArgumentException("User must specify at least " +
"2 colors");
}
// check that values are in the proper range and progress
// in increasing order from 0 to 1
float previousFraction = -1.0f;
for (float currentFraction : fractions) {
if (currentFraction < 0f || currentFraction > 1f) {
throw new IllegalArgumentException("Fraction values must " +
"be in the range 0 to 1: " +
currentFraction);
}
if (currentFraction <= previousFraction) {
throw new IllegalArgumentException("Keyframe fractions " +
"must be increasing: " +
currentFraction);
}
previousFraction = currentFraction;
}
// We have to deal with the cases where the first gradient stop is not
// equal to 0 and/or the last gradient stop is not equal to 1.
// In both cases, create a new point and replicate the previous
// extreme point's color.
boolean fixFirst = false;
boolean fixLast = false;
int len = fractions.length;
int off = 0;
if (fractions[0] != 0f) {
// first stop is not equal to zero, fix this condition
fixFirst = true;
len++;
off++;
}
if (fractions[fractions.length-1] != 1f) {
// last stop is not equal to one, fix this condition
fixLast = true;
len++;
}
this.fractions = new float[len];
System.arraycopy(fractions, 0, this.fractions, off, fractions.length);
this.colors = new Color[len];
System.arraycopy(colors, 0, this.colors, off, colors.length);
if (fixFirst) {
this.fractions[0] = 0f;
this.colors[0] = colors[0];
}
if (fixLast) {
this.fractions[len-1] = 1f;
this.colors[len-1] = colors[colors.length - 1];
}
// copy some flags
this.colorSpace = colorSpace;
this.cycleMethod = cycleMethod;
// copy the gradient transform
this.gradientTransform = new AffineTransform(gradientTransform);
// determine transparency
boolean opaque = true;
for (int i = 0; i < colors.length; i++){
opaque = opaque && (colors[i].getAlpha() == 0xff);
}
this.transparency = opaque ? OPAQUE : TRANSLUCENT;
}
/**
* Returns a copy of the array of floats used by this gradient
* to calculate color distribution.
* The returned array always has 0 as its first value and 1 as its
* last value, with increasing values in between.
*
* @return a copy of the array of floats used by this gradient to
* calculate color distribution
*/
public final float[] getFractions() {
return Arrays.copyOf(fractions, fractions.length);
}
/**
* Returns a copy of the array of colors used by this gradient.
* The first color maps to the first value in the fractions array,
* and the last color maps to the last value in the fractions array.
*
* @return a copy of the array of colors used by this gradient
*/
public final Color[] getColors() {
return Arrays.copyOf(colors, colors.length);
}
/**
* Returns the enumerated type which specifies cycling behavior.
*
* @return the enumerated type which specifies cycling behavior
*/
public final CycleMethod getCycleMethod() {
return cycleMethod;
}
/**
* Returns the enumerated type which specifies color space for
* interpolation.
*
* @return the enumerated type which specifies color space for
* interpolation
*/
public final ColorSpaceType getColorSpace() {
return colorSpace;
}
/**
* Returns a copy of the transform applied to the gradient.
*
* <p>
* Note that if no transform is applied to the gradient
* when it is created, the identity transform is used.
*
* @return a copy of the transform applied to the gradient
*/
public final AffineTransform getTransform() {
return new AffineTransform(gradientTransform);
}
/**
* Returns the transparency mode for this {@code Paint} object.
*
* @return {@code OPAQUE} if all colors used by this
* {@code Paint} object are opaque,
* {@code TRANSLUCENT} if at least one of the
* colors used by this {@code Paint} object is not opaque.
* @see java.awt.Transparency
*/
public final int getTransparency() {
return transparency;
}
}