/*
* @(#)GradientPaintContext.java 1.24 05/11/17
*
* Copyright 2006 Sun Microsystems, Inc. All rights reserved.
* SUN PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
*/
package java.awt;
import java.awt.image.Raster;
import java.awt.image.WritableRaster;
import sun.awt.image.IntegerComponentRaster;
import java.awt.image.ColorModel;
import java.awt.image.DirectColorModel;
import java.awt.geom.Point2D;
import java.awt.geom.AffineTransform;
import java.awt.geom.NoninvertibleTransformException;
import java.lang.ref.WeakReference;
class GradientPaintContext implements PaintContext {
static ColorModel xrgbmodel =
new DirectColorModel(24, 0x00ff0000, 0x0000ff00, 0x000000ff);
static ColorModel xbgrmodel =
new DirectColorModel(24, 0x000000ff, 0x0000ff00, 0x00ff0000);
static ColorModel cachedModel;
static WeakReference cached;
static synchronized Raster getCachedRaster(ColorModel cm, int w, int h) {
if (cm == cachedModel) {
if (cached != null) {
Raster ras = (Raster) cached.get();
if (ras != null &&
ras.getWidth() >= w &&
ras.getHeight() >= h)
{
cached = null;
return ras;
}
}
}
return cm.createCompatibleWritableRaster(w, h);
}
static synchronized void putCachedRaster(ColorModel cm, Raster ras) {
if (cached != null) {
Raster cras = (Raster) cached.get();
if (cras != null) {
int cw = cras.getWidth();
int ch = cras.getHeight();
int iw = ras.getWidth();
int ih = ras.getHeight();
if (cw >= iw && ch >= ih) {
return;
}
if (cw * ch >= iw * ih) {
return;
}
}
}
cachedModel = cm;
cached = new WeakReference(ras);
}
double x1;
double y1;
double dx;
double dy;
boolean cyclic;
int interp[];
Raster saved;
ColorModel model;
public GradientPaintContext(ColorModel cm,
Point2D p1, Point2D p2, AffineTransform xform,
Color c1, Color c2, boolean cyclic) {
// First calculate the distance moved in user space when
// we move a single unit along the X & Y axes in device space.
Point2D xvec = new Point2D.Double(1, 0);
Point2D yvec = new Point2D.Double(0, 1);
try {
AffineTransform inverse = xform.createInverse();
inverse.deltaTransform(xvec, xvec);
inverse.deltaTransform(yvec, yvec);
} catch (NoninvertibleTransformException e) {
xvec.setLocation(0, 0);
yvec.setLocation(0, 0);
}
// Now calculate the (square of the) user space distance
// between the anchor points. This value equals:
// (UserVec . UserVec)
double udx = p2.getX() - p1.getX();
double udy = p2.getY() - p1.getY();
double ulenSq = udx * udx + udy * udy;
if (ulenSq <= Double.MIN_VALUE) {
dx = 0;
dy = 0;
} else {
// Now calculate the proportional distance moved along the
// vector from p1 to p2 when we move a unit along X & Y in
// device space.
//
// The length of the projection of the Device Axis Vector is
// its dot product with the Unit User Vector:
// (DevAxisVec . (UserVec / Len(UserVec))
//
// The "proportional" length is that length divided again
// by the length of the User Vector:
// (DevAxisVec . (UserVec / Len(UserVec))) / Len(UserVec)
// which simplifies to:
// ((DevAxisVec . UserVec) / Len(UserVec)) / Len(UserVec)
// which simplifies to:
// (DevAxisVec . UserVec) / LenSquared(UserVec)
dx = (xvec.getX() * udx + xvec.getY() * udy) / ulenSq;
dy = (yvec.getX() * udx + yvec.getY() * udy) / ulenSq;
if (cyclic) {
dx = dx % 1.0;
dy = dy % 1.0;
} else {
// We are acyclic
if (dx < 0) {
// If we are using the acyclic form below, we need
// dx to be non-negative for simplicity of scanning
// across the scan lines for the transition points.
// To ensure that constraint, we negate the dx/dy
// values and swap the points and colors.
Point2D p = p1; p1 = p2; p2 = p;
Color c = c1; c1 = c2; c2 = c;
dx = -dx;
dy = -dy;
}
}
}
Point2D dp1 = xform.transform(p1, null);
this.x1 = dp1.getX();
this.y1 = dp1.getY();
this.cyclic = cyclic;
int rgb1 = c1.getRGB();
int rgb2 = c2.getRGB();
int a1 = (rgb1 >> 24) & 0xff;
int r1 = (rgb1 >> 16) & 0xff;
int g1 = (rgb1 >> 8) & 0xff;
int b1 = (rgb1 ) & 0xff;
int da = ((rgb2 >> 24) & 0xff) - a1;
int dr = ((rgb2 >> 16) & 0xff) - r1;
int dg = ((rgb2 >> 8) & 0xff) - g1;
int db = ((rgb2 ) & 0xff) - b1;
if (a1 == 0xff && da == 0) {
model = xrgbmodel;
if (cm instanceof DirectColorModel) {
DirectColorModel dcm = (DirectColorModel) cm;
int tmp = dcm.getAlphaMask();
if ((tmp == 0 || tmp == 0xff) &&
dcm.getRedMask() == 0xff &&
dcm.getGreenMask() == 0xff00 &&
dcm.getBlueMask() == 0xff0000)
{
model = xbgrmodel;
tmp = r1; r1 = b1; b1 = tmp;
tmp = dr; dr = db; db = tmp;
}
}
} else {
model = ColorModel.getRGBdefault();
}
interp = new int[cyclic ? 513 : 257];
for (int i = 0; i <= 256; i++) {
float rel = i / 256.0f;
int rgb =
(((int) (a1 + da * rel)) << 24) |
(((int) (r1 + dr * rel)) << 16) |
(((int) (g1 + dg * rel)) << 8) |
(((int) (b1 + db * rel)) );
interp[i] = rgb;
if (cyclic) {
interp[512 - i] = rgb;
}
}
}
/**
* Release the resources allocated for the operation.
*/
public void dispose() {
if (saved != null) {
putCachedRaster(model, saved);
saved = null;
}
}
/**
* Return the ColorModel of the output.
*/
public ColorModel getColorModel() {
return model;
}
/**
* Return a Raster containing the colors generated for the graphics
* operation.
* @param x,y,w,h The area in device space for which colors are
* generated.
*/
public Raster getRaster(int x, int y, int w, int h) {
double rowrel = (x - x1) * dx + (y - y1) * dy;
Raster rast = saved;
if (rast == null || rast.getWidth() < w || rast.getHeight() < h) {
rast = getCachedRaster(model, w, h);
saved = rast;
}
IntegerComponentRaster irast = (IntegerComponentRaster) rast;
int off = irast.getDataOffset(0);
int adjust = irast.getScanlineStride() - w;
int[] pixels = irast.getDataStorage();
if (cyclic) {
cycleFillRaster(pixels, off, adjust, w, h, rowrel, dx, dy);
} else {
clipFillRaster(pixels, off, adjust, w, h, rowrel, dx, dy);
}
return rast;
}
void cycleFillRaster(int[] pixels, int off, int adjust, int w, int h,
double rowrel, double dx, double dy) {
rowrel = rowrel % 2.0;
int irowrel = ((int) (rowrel * (1 << 30))) << 1;
int idx = (int) (-dx * (1 << 31));
int idy = (int) (-dy * (1 << 31));
while (--h >= 0) {
int icolrel = irowrel;
for (int j = w; j > 0; j--) {
pixels[off++] = interp[icolrel >>> 23];
icolrel += idx;
}
off += adjust;
irowrel += idy;
}
}
void clipFillRaster(int[] pixels, int off, int adjust, int w, int h,
double rowrel, double dx, double dy) {
while (--h >= 0) {
double colrel = rowrel;
int j = w;
if (colrel <= 0.0) {
int rgb = interp[0];
do {
pixels[off++] = rgb;
colrel += dx;
} while (--j > 0 && colrel <= 0.0);
}
while (colrel < 1.0 && --j >= 0) {
pixels[off++] = interp[(int) (colrel * 256)];
colrel += dx;
}
if (j > 0) {
int rgb = interp[256];
do {
pixels[off++] = rgb;
} while (--j > 0);
}
off += adjust;
rowrel += dy;
}
}
}