1 /*
2 * Copyright (c) 1997, 2014, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation. Oracle designates this
8 * particular file as subject to the "Classpath" exception as provided
9 * by Oracle in the LICENSE file that accompanied this code.
10 *
11 * This code is distributed in the hope that it will be useful, but WITHOUT
12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
14 * version 2 for more details (a copy is included in the LICENSE file that
15 * accompanied this code).
16 *
17 * You should have received a copy of the GNU General Public License version
18 * 2 along with this work; if not, write to the Free Software Foundation,
19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
20 *
21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
22 * or visit www.oracle.com if you need additional information or have any
23 * questions.
24 */
25
26 package java.awt;
27
28 import java.awt.image.Raster;
29 import sun.awt.image.IntegerComponentRaster;
30 import java.awt.image.ColorModel;
31 import java.awt.image.DirectColorModel;
32 import java.awt.geom.Point2D;
33 import java.awt.geom.AffineTransform;
34 import java.awt.geom.NoninvertibleTransformException;
35 import java.lang.ref.WeakReference;
36
37 class GradientPaintContext implements PaintContext {
38 static ColorModel xrgbmodel =
39 new DirectColorModel(24, 0x00ff0000, 0x0000ff00, 0x000000ff);
40 static ColorModel xbgrmodel =
41 new DirectColorModel(24, 0x000000ff, 0x0000ff00, 0x00ff0000);
42
43 static ColorModel cachedModel;
44 static WeakReference<Raster> cached;
45
46 static synchronized Raster getCachedRaster(ColorModel cm, int w, int h) {
47 if (cm == cachedModel) {
48 if (cached != null) {
49 Raster ras = cached.get();
50 if (ras != null &&
51 ras.getWidth() >= w &&
52 ras.getHeight() >= h)
53 {
54 cached = null;
55 return ras;
56 }
57 }
58 }
59 return cm.createCompatibleWritableRaster(w, h);
60 }
61
62 static synchronized void putCachedRaster(ColorModel cm, Raster ras) {
63 if (cached != null) {
64 Raster cras = cached.get();
65 if (cras != null) {
66 int cw = cras.getWidth();
67 int ch = cras.getHeight();
68 int iw = ras.getWidth();
69 int ih = ras.getHeight();
70 if (cw >= iw && ch >= ih) {
71 return;
72 }
73 if (cw * ch >= iw * ih) {
74 return;
75 }
76 }
77 }
78 cachedModel = cm;
79 cached = new WeakReference<>(ras);
80 }
81
82 double x1;
83 double y1;
84 double dx;
85 double dy;
86 boolean cyclic;
87 int interp[];
88 Raster saved;
89 ColorModel model;
90
91 public GradientPaintContext(ColorModel cm,
92 Point2D p1, Point2D p2, AffineTransform xform,
93 Color c1, Color c2, boolean cyclic) {
94 // First calculate the distance moved in user space when
95 // we move a single unit along the X & Y axes in device space.
96 Point2D xvec = new Point2D.Double(1, 0);
97 Point2D yvec = new Point2D.Double(0, 1);
98 try {
99 AffineTransform inverse = xform.createInverse();
100 inverse.deltaTransform(xvec, xvec);
101 inverse.deltaTransform(yvec, yvec);
102 } catch (NoninvertibleTransformException e) {
103 xvec.setLocation(0, 0);
104 yvec.setLocation(0, 0);
105 }
106
107 // Now calculate the (square of the) user space distance
108 // between the anchor points. This value equals:
109 // (UserVec . UserVec)
110 double udx = p2.getX() - p1.getX();
111 double udy = p2.getY() - p1.getY();
112 double ulenSq = udx * udx + udy * udy;
113
114 if (ulenSq <= Double.MIN_VALUE) {
115 dx = 0;
116 dy = 0;
117 } else {
118 // Now calculate the proportional distance moved along the
119 // vector from p1 to p2 when we move a unit along X & Y in
120 // device space.
121 //
122 // The length of the projection of the Device Axis Vector is
123 // its dot product with the Unit User Vector:
124 // (DevAxisVec . (UserVec / Len(UserVec))
125 //
126 // The "proportional" length is that length divided again
127 // by the length of the User Vector:
128 // (DevAxisVec . (UserVec / Len(UserVec))) / Len(UserVec)
129 // which simplifies to:
130 // ((DevAxisVec . UserVec) / Len(UserVec)) / Len(UserVec)
131 // which simplifies to:
132 // (DevAxisVec . UserVec) / LenSquared(UserVec)
133 dx = (xvec.getX() * udx + xvec.getY() * udy) / ulenSq;
134 dy = (yvec.getX() * udx + yvec.getY() * udy) / ulenSq;
135
136 if (cyclic) {
137 dx = dx % 1.0;
138 dy = dy % 1.0;
139 } else {
140 // We are acyclic
141 if (dx < 0) {
142 // If we are using the acyclic form below, we need
143 // dx to be non-negative for simplicity of scanning
144 // across the scan lines for the transition points.
145 // To ensure that constraint, we negate the dx/dy
146 // values and swap the points and colors.
147 Point2D p = p1; p1 = p2; p2 = p;
148 Color c = c1; c1 = c2; c2 = c;
149 dx = -dx;
150 dy = -dy;
151 }
152 }
153 }
154
155 Point2D dp1 = xform.transform(p1, null);
156 this.x1 = dp1.getX();
157 this.y1 = dp1.getY();
158
159 this.cyclic = cyclic;
160 int rgb1 = c1.getRGB();
161 int rgb2 = c2.getRGB();
162 int a1 = (rgb1 >> 24) & 0xff;
163 int r1 = (rgb1 >> 16) & 0xff;
164 int g1 = (rgb1 >> 8) & 0xff;
165 int b1 = (rgb1 ) & 0xff;
166 int da = ((rgb2 >> 24) & 0xff) - a1;
167 int dr = ((rgb2 >> 16) & 0xff) - r1;
168 int dg = ((rgb2 >> 8) & 0xff) - g1;
169 int db = ((rgb2 ) & 0xff) - b1;
170 if (a1 == 0xff && da == 0) {
171 model = xrgbmodel;
172 if (cm instanceof DirectColorModel) {
173 DirectColorModel dcm = (DirectColorModel) cm;
174 int tmp = dcm.getAlphaMask();
175 if ((tmp == 0 || tmp == 0xff) &&
176 dcm.getRedMask() == 0xff &&
177 dcm.getGreenMask() == 0xff00 &&
178 dcm.getBlueMask() == 0xff0000)
179 {
180 model = xbgrmodel;
181 tmp = r1; r1 = b1; b1 = tmp;
182 tmp = dr; dr = db; db = tmp;
183 }
184 }
185 } else {
186 model = ColorModel.getRGBdefault();
187 }
188 interp = new int[cyclic ? 513 : 257];
189 for (int i = 0; i <= 256; i++) {
190 float rel = i / 256.0f;
191 int rgb =
192 (((int) (a1 + da * rel)) << 24) |
193 (((int) (r1 + dr * rel)) << 16) |
194 (((int) (g1 + dg * rel)) << 8) |
195 (((int) (b1 + db * rel)) );
196 interp[i] = rgb;
197 if (cyclic) {
198 interp[512 - i] = rgb;
199 }
200 }
201 }
202
203 /**
204 * Release the resources allocated for the operation.
205 */
206 public void dispose() {
207 if (saved != null) {
208 putCachedRaster(model, saved);
209 saved = null;
210 }
211 }
212
213 /**
214 * Return the ColorModel of the output.
215 */
216 public ColorModel getColorModel() {
217 return model;
218 }
219
220 /**
221 * Return a Raster containing the colors generated for the graphics
222 * operation.
223 * @param x,y,w,h The area in device space for which colors are
224 * generated.
225 */
226 public Raster getRaster(int x, int y, int w, int h) {
227 double rowrel = (x - x1) * dx + (y - y1) * dy;
228
229 Raster rast = saved;
230 if (rast == null || rast.getWidth() < w || rast.getHeight() < h) {
231 rast = getCachedRaster(model, w, h);
232 saved = rast;
233 }
234 IntegerComponentRaster irast = (IntegerComponentRaster) rast;
235 int off = irast.getDataOffset(0);
236 int adjust = irast.getScanlineStride() - w;
237 int[] pixels = irast.getDataStorage();
238
239 if (cyclic) {
240 cycleFillRaster(pixels, off, adjust, w, h, rowrel, dx, dy);
241 } else {
242 clipFillRaster(pixels, off, adjust, w, h, rowrel, dx, dy);
243 }
244
245 irast.markDirty();
246
247 return rast;
248 }
249
250 void cycleFillRaster(int[] pixels, int off, int adjust, int w, int h,
251 double rowrel, double dx, double dy) {
252 rowrel = rowrel % 2.0;
253 int irowrel = ((int) (rowrel * (1 << 30))) << 1;
254 int idx = (int) (-dx * (1 << 31));
255 int idy = (int) (-dy * (1 << 31));
256 while (--h >= 0) {
257 int icolrel = irowrel;
258 for (int j = w; j > 0; j--) {
259 pixels[off++] = interp[icolrel >>> 23];
260 icolrel += idx;
261 }
262
263 off += adjust;
264 irowrel += idy;
265 }
266 }
267
268 void clipFillRaster(int[] pixels, int off, int adjust, int w, int h,
269 double rowrel, double dx, double dy) {
270 while (--h >= 0) {
271 double colrel = rowrel;
272 int j = w;
273 if (colrel <= 0.0) {
274 int rgb = interp[0];
275 do {
276 pixels[off++] = rgb;
277 colrel += dx;
278 } while (--j > 0 && colrel <= 0.0);
279 }
280 while (colrel < 1.0 && --j >= 0) {
281 pixels[off++] = interp[(int) (colrel * 256)];
282 colrel += dx;
283 }
284 if (j > 0) {
285 int rgb = interp[256];
286 do {
287 pixels[off++] = rgb;
288 } while (--j > 0);
289 }
290
291 off += adjust;
292 rowrel += dy;
293 }
294 }
295 }