/*****************************************************************************
* Copyright (C) The Apache Software Foundation. All rights reserved. *
* ------------------------------------------------------------------------- *
* This software is published under the terms of the Apache Software License *
* version 1.1, a copy of which has been included with this distribution in *
* the LICENSE file. *
*****************************************************************************/
package com.kitfox.svg.batik;
import java.awt.Color;
import java.awt.Rectangle;
import java.awt.RenderingHints;
import java.awt.geom.AffineTransform;
import java.awt.geom.NoninvertibleTransformException;
import java.awt.geom.Point2D;
import java.awt.geom.Rectangle2D;
import java.awt.image.ColorModel;
/**
* Provides the actual implementation for the LinearGradientPaint This is where
* the pixel processing is done.
*
* @author Nicholas Talian, Vincent Hardy, Jim Graham, Jerry Evans
* @author <a href="mailto:vincent.hardy@eng.sun.com">Vincent Hardy</a>
* @version $Id: LinearGradientPaintContext.java,v 1.2 2007/02/04 01:28:05
* kitfox Exp $
* @see java.awt.PaintContext
* @see java.awt.Paint
* @see java.awt.GradientPaint
*/
final class LinearGradientPaintContext extends MultipleGradientPaintContext {
/**
* The following invariants are used to process the gradient value from a
* device space coordinate, (X, Y): g(X, Y) = dgdX*X + dgdY*Y + gc
*/
private float dgdX, dgdY, gc, pixSz;
private static final int DEFAULT_IMPL = 1;
private static final int ANTI_ALIAS_IMPL = 3;
private int fillMethod;
/**
* Constructor for LinearGradientPaintContext.
*
* @param cm
* {@link ColorModel} that receives the <code>Paint</code> data.
* This is used only as a hint.
*
* @param deviceBounds
* the device space bounding box of the graphics primitive being
* rendered
*
* @param userBounds
* the user space bounding box of the graphics primitive being
* rendered
*
* @param t
* the {@link AffineTransform} from user space into device space
* (gradientTransform should be concatenated with this)
*
* @param hints
* the hints that the context object uses to choose between
* rendering alternatives
*
* @param start
* gradient start point, in user space
*
* @param end
* gradient end point, in user space
*
* @param fractions
* the fractions specifying the gradient distribution
*
* @param colors
* the gradient colors
*
* @param cycleMethod
* either NO_CYCLE, REFLECT, or REPEAT
*
* @param colorSpace
* which colorspace to use for interpolation, either SRGB or
* LINEAR_RGB
*
*/
public LinearGradientPaintContext(ColorModel cm, Rectangle deviceBounds,
Rectangle2D userBounds, AffineTransform t, RenderingHints hints,
Point2D dStart, Point2D dEnd, float[] fractions, Color[] colors,
MultipleGradientPaint.CycleMethodEnum cycleMethod,
MultipleGradientPaint.ColorSpaceEnum colorSpace)
throws NoninvertibleTransformException {
super(cm, deviceBounds, userBounds, t, hints, fractions, colors,
cycleMethod, colorSpace);
// Use single precision floating points
Point2D.Float start = new Point2D.Float((float) dStart.getX(),
(float) dStart.getY());
Point2D.Float end = new Point2D.Float((float) dEnd.getX(),
(float) dEnd.getY());
// A given point in the raster should take on the same color as its
// projection onto the gradient vector.
// Thus, we want the projection of the current position vector
// onto the gradient vector, then normalized with respect to the
// length of the gradient vector, giving a value which can be mapped
// into
// the range 0-1.
// projection = currentVector dot gradientVector /
// length(gradientVector)
// normalized = projection / length(gradientVector)
float dx = end.x - start.x; // change in x from start to end
float dy = end.y - start.y; // change in y from start to end
float dSq = dx * dx + dy * dy; // total distance squared
// avoid repeated calculations by doing these divides once.
float constX = dx / dSq;
float constY = dy / dSq;
// incremental change along gradient for +x
dgdX = a00 * constX + a10 * constY;
// incremental change along gradient for +y
dgdY = a01 * constX + a11 * constY;
float dgdXAbs = Math.abs(dgdX);
float dgdYAbs = Math.abs(dgdY);
if (dgdXAbs > dgdYAbs) {
pixSz = dgdXAbs;
} else {
pixSz = dgdYAbs;
}
// constant, incorporates the translation components from the matrix
gc = (a02 - start.x) * constX + (a12 - start.y) * constY;
Object colorRend = hints == null
? RenderingHints.VALUE_COLOR_RENDER_SPEED
: hints.get(RenderingHints.KEY_COLOR_RENDERING);
Object rend = hints == null ? RenderingHints.VALUE_RENDER_SPEED
: hints.get(RenderingHints.KEY_RENDERING);
fillMethod = DEFAULT_IMPL;
if ((cycleMethod == MultipleGradientPaint.REPEAT) || hasDiscontinuity) {
if (rend == RenderingHints.VALUE_RENDER_QUALITY) {
fillMethod = ANTI_ALIAS_IMPL;
}
// ColorRend overrides rend.
if (colorRend == RenderingHints.VALUE_COLOR_RENDER_SPEED) {
fillMethod = DEFAULT_IMPL;
} else if (colorRend == RenderingHints.VALUE_COLOR_RENDER_QUALITY) {
fillMethod = ANTI_ALIAS_IMPL;
}
}
}
protected void fillHardNoCycle(int[] pixels, int off, int adjust, int x,
int y, int w, int h) {
// constant which can be pulled out of the inner loop
final float initConst = (dgdX * x) + gc;
for (int i = 0; i < h; i++) { // for every row
// initialize current value to be start.
float g = initConst + dgdY * (y + i);
final int rowLimit = off + w; // end of row iteration
if (dgdX == 0) {
// System.out.println("In fillHard: " + g);
final int val;
if (g <= 0) {
val = gradientUnderflow;
} else if (g >= 1) {
val = gradientOverflow;
} else {
// Could be a binary search...
int gradIdx = 0;
while (gradIdx < gradientsLength - 1) {
if (g < fractions[gradIdx + 1]) {
break;
}
gradIdx++;
}
float delta = (g - fractions[gradIdx]);
float idx = ((delta * GRADIENT_SIZE_INDEX)
/ normalizedIntervals[gradIdx]) + 0.5f;
val = gradients[gradIdx][(int) idx];
}
while (off < rowLimit) {
pixels[off++] = val;
}
} else {
// System.out.println("In fillHard2: " + g);
int gradSteps;
int preGradSteps;
final int preVal, postVal;
if (dgdX >= 0) {
gradSteps = (int) ((1 - g) / dgdX);
preGradSteps = (int) Math.ceil((0 - g) / dgdX);
preVal = gradientUnderflow;
postVal = gradientOverflow;
} else { // dgdX < 0
gradSteps = (int) ((0 - g) / dgdX);
preGradSteps = (int) Math.ceil((1 - g) / dgdX);
preVal = gradientOverflow;
postVal = gradientUnderflow;
}
if (gradSteps > w) {
gradSteps = w;
}
final int gradLimit = off + gradSteps;
if (preGradSteps > 0) {
if (preGradSteps > w) {
preGradSteps = w;
}
final int preGradLimit = off + preGradSteps;
while (off < preGradLimit) {
pixels[off++] = preVal;
}
g += dgdX * preGradSteps;
}
if (dgdX > 0) {
// Could be a binary search...
int gradIdx = 0;
while (gradIdx < gradientsLength - 1) {
if (g < fractions[gradIdx + 1]) {
break;
}
gradIdx++;
}
while (off < gradLimit) {
float delta = (g - fractions[gradIdx]);
final int[] grad = gradients[gradIdx];
int steps = (int) Math
.ceil((fractions[gradIdx + 1] - g) / dgdX);
int subGradLimit = off + steps;
if (subGradLimit > gradLimit) {
subGradLimit = gradLimit;
}
int idx = (int) (((delta * GRADIENT_SIZE_INDEX)
/ normalizedIntervals[gradIdx]) * (1 << 16))
+ (1 << 15);
int step = (int) (((dgdX * GRADIENT_SIZE_INDEX)
/ normalizedIntervals[gradIdx]) * (1 << 16));
while (off < subGradLimit) {
pixels[off++] = grad[idx >> 16];
idx += step;
}
g += dgdX * steps;
gradIdx++;
}
} else {
// Could be a binary search...
int gradIdx = gradientsLength - 1;
while (gradIdx > 0) {
if (g > fractions[gradIdx]) {
break;
}
gradIdx--;
}
while (off < gradLimit) {
float delta = (g - fractions[gradIdx]);
final int[] grad = gradients[gradIdx];
int steps = (int) Math.ceil(delta / -dgdX);
int subGradLimit = off + steps;
if (subGradLimit > gradLimit) {
subGradLimit = gradLimit;
}
int idx = (int) (((delta * GRADIENT_SIZE_INDEX)
/ normalizedIntervals[gradIdx]) * (1 << 16))
+ (1 << 15);
int step = (int) (((dgdX * GRADIENT_SIZE_INDEX)
/ normalizedIntervals[gradIdx]) * (1 << 16));
while (off < subGradLimit) {
pixels[off++] = grad[idx >> 16];
idx += step;
}
g += dgdX * steps;
gradIdx--;
}
}
while (off < rowLimit) {
pixels[off++] = postVal;
}
}
off += adjust; // change in off from row to row
}
}
protected void fillSimpleNoCycle(int[] pixels, int off, int adjust, int x,
int y, int w, int h) {
// constant which can be pulled out of the inner loop
final float initConst = (dgdX * x) + gc;
final float step = dgdX * fastGradientArraySize;
final int fpStep = (int) (step * (1 << 16)); // fix point step
final int[] grad = gradient;
for (int i = 0; i < h; i++) { // for every row
// initialize current value to be start.
float g = initConst + dgdY * (y + i);
g *= fastGradientArraySize;
g += 0.5; // rounding factor...
final int rowLimit = off + w; // end of row iteration
if (dgdX == 0) {
// System.out.println("In fillSimpleNC: " + g);
final int val;
if (g <= 0) {
val = gradientUnderflow;
} else if (g >= fastGradientArraySize) {
val = gradientOverflow;
} else {
val = grad[(int) g];
}
while (off < rowLimit) {
pixels[off++] = val;
}
} else {
// System.out.println("In fillSimpleNC2: " + g);
int gradSteps;
int preGradSteps;
final int preVal, postVal;
if (dgdX > 0) {
gradSteps = (int) ((fastGradientArraySize - g) / step);
preGradSteps = (int) Math.ceil(0 - g / step);
preVal = gradientUnderflow;
postVal = gradientOverflow;
} else { // dgdX < 0
gradSteps = (int) ((0 - g) / step);
preGradSteps = (int) Math
.ceil((fastGradientArraySize - g) / step);
preVal = gradientOverflow;
postVal = gradientUnderflow;
}
if (gradSteps > w) {
gradSteps = w;
}
final int gradLimit = off + gradSteps;
if (preGradSteps > 0) {
if (preGradSteps > w) {
preGradSteps = w;
}
final int preGradLimit = off + preGradSteps;
while (off < preGradLimit) {
pixels[off++] = preVal;
}
g += step * preGradSteps;
}
int fpG = (int) (g * (1 << 16));
while (off < gradLimit) {
pixels[off++] = grad[fpG >> 16];
fpG += fpStep;
}
while (off < rowLimit) {
pixels[off++] = postVal;
}
}
off += adjust; // change in off from row to row
}
}
protected void fillSimpleRepeat(int[] pixels, int off, int adjust, int x,
int y, int w, int h) {
final float initConst = (dgdX * x) + gc;
// Limit step to fractional part of
// fastGradientArraySize (the non fractional part has
// no affect anyways, and would mess up lots of stuff
// below).
float step = (dgdX - (int) dgdX) * fastGradientArraySize;
// Make it a Positive step (a small negative step is
// the same as a positive step slightly less than
// fastGradientArraySize.
if (step < 0) {
step += fastGradientArraySize;
}
final int[] grad = gradient;
for (int i = 0; i < h; i++) { // for every row
// initialize current value to be start.
float g = initConst + dgdY * (y + i);
// now Limited between -1 and 1.
g = g - (int) g;
// put in the positive side.
if (g < 0) {
g += 1;
}
// scale for gradient array...
g *= fastGradientArraySize;
g += 0.5; // rounding factor
final int rowLimit = off + w; // end of row iteration
while (off < rowLimit) {
int idx = (int) g;
if (idx >= fastGradientArraySize) {
g -= fastGradientArraySize;
idx -= fastGradientArraySize;
}
pixels[off++] = grad[idx];
g += step;
}
off += adjust; // change in off from row to row
}
}
protected void fillSimpleReflect(int[] pixels, int off, int adjust, int x,
int y, int w, int h) {
final float initConst = (dgdX * x) + gc;
final int[] grad = gradient;
for (int i = 0; i < h; i++) { // for every row
// initialize current value to be start.
float g = initConst + dgdY * (y + i);
// now limited g to -2<->2
g = g - 2 * ((int) (g / 2.0f));
float step = dgdX;
// Pull it into the positive half
if (g < 0) {
g = -g; // take absolute value
step = -step; // Change direction..
}
// Now do the same for dgdX. This is safe because
// any step that is a multiple of 2.0 has no
// affect, hence we can remove it which the first
// part does. The second part simply adds 2.0
// (which has no affect due to the cylcle) to move
// all negative step values into the positive
// side.
step = step - 2 * ((int) step / 2.0f);
if (step < 0) {
step += 2.0;
}
final int reflectMax = 2 * fastGradientArraySize;
// Scale for gradient array.
g *= fastGradientArraySize;
g += 0.5;
step *= fastGradientArraySize;
final int rowLimit = off + w; // end of row iteration
while (off < rowLimit) {
int idx = (int) g;
if (idx >= reflectMax) {
g -= reflectMax;
idx -= reflectMax;
}
if (idx <= fastGradientArraySize) {
pixels[off++] = grad[idx];
} else {
pixels[off++] = grad[reflectMax - idx];
}
g += step;
}
off += adjust; // change in off from row to row
}
}
/**
* Return a Raster containing the colors generated for the graphics
* operation. This is where the area is filled with colors distributed
* linearly.
*
* @param x,y,w,h
* The area in device space for which colors are generated.
*
*/
@Override
protected void fillRaster(int[] pixels, int off, int adjust, int x, int y,
int w, int h) {
// constant which can be pulled out of the inner loop
final float initConst = (dgdX * x) + gc;
if (fillMethod == ANTI_ALIAS_IMPL) {
// initialize current value to be start.
for (int i = 0; i < h; i++) { // for every row
float g = initConst + dgdY * (y + i);
final int rowLimit = off + w; // end of row iteration
while (off < rowLimit) { // for every pixel in this row.
// get the color
pixels[off++] = indexGradientAntiAlias(g, pixSz);
g += dgdX; // incremental change in g
}
off += adjust; // change in off from row to row
}
} else if (!isSimpleLookup) {
if (cycleMethod == MultipleGradientPaint.NO_CYCLE) {
fillHardNoCycle(pixels, off, adjust, x, y, w, h);
} else {
// initialize current value to be start.
for (int i = 0; i < h; i++) { // for every row
float g = initConst + dgdY * (y + i);
final int rowLimit = off + w; // end of row iteration
while (off < rowLimit) { // for every pixel in this row.
// get the color
pixels[off++] = indexIntoGradientsArrays(g);
g += dgdX; // incremental change in g
}
off += adjust; // change in off from row to row
}
}
} else {
// Simple implementations: just scale index by array size
if (cycleMethod == MultipleGradientPaint.NO_CYCLE) {
fillSimpleNoCycle(pixels, off, adjust, x, y, w, h);
} else if (cycleMethod == MultipleGradientPaint.REPEAT) {
fillSimpleRepeat(pixels, off, adjust, x, y, w, h);
} else {
fillSimpleReflect(pixels, off, adjust, x, y, w, h);
}
}
}
}