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| 1 | /* | ||
| 2 | * Copyright (c) 2006, 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.MultipleGradientPaint.CycleMethod; | ||
| 29 | import java.awt.MultipleGradientPaint.ColorSpaceType; | ||
| 30 | import java.awt.geom.AffineTransform; | ||
| 31 | import java.awt.geom.Rectangle2D; | ||
| 32 | import java.awt.image.ColorModel; | ||
| 33 | |||
| 34 | /** | ||
| 35 | * Provides the actual implementation for the RadialGradientPaint. | ||
| 36 | * This is where the pixel processing is done. A RadialGradienPaint | ||
| 37 | * only supports circular gradients, but it should be possible to scale | ||
| 38 | * the circle to look approximately elliptical, by means of a | ||
| 39 | * gradient transform passed into the RadialGradientPaint constructor. | ||
| 40 | * | ||
| 41 | * @author Nicholas Talian, Vincent Hardy, Jim Graham, Jerry Evans | ||
| 42 | */ | ||
| 43 | final class RadialGradientPaintContext extends MultipleGradientPaintContext { | ||
| 44 | |||
| 45 | /** True when (focus == center). */ | ||
| 46 | private boolean isSimpleFocus = false; | ||
| 47 | |||
| 48 | /** True when (cycleMethod == NO_CYCLE). */ | ||
| 49 | private boolean isNonCyclic = false; | ||
| 50 | |||
| 51 | /** Radius of the outermost circle defining the 100% gradient stop. */ | ||
| 52 | private float radius; | ||
| 53 | |||
| 54 | /** Variables representing center and focus points. */ | ||
| 55 | private float centerX, centerY, focusX, focusY; | ||
| 56 | |||
| 57 | /** Radius of the gradient circle squared. */ | ||
| 58 | private float radiusSq; | ||
| 59 | |||
| 60 | /** Constant part of X, Y user space coordinates. */ | ||
| 61 | private float constA, constB; | ||
| 62 | |||
| 63 | /** Constant second order delta for simple loop. */ | ||
| 64 | private float gDeltaDelta; | ||
| 65 | |||
| 66 | /** | ||
| 67 | * This value represents the solution when focusX == X. It is called | ||
| 68 | * trivial because it is easier to calculate than the general case. | ||
| 69 | */ | ||
| 70 | private float trivial; | ||
| 71 | |||
| 72 | /** Amount for offset when clamping focus. */ | ||
| 73 | private static final float SCALEBACK = .99f; | ||
| 74 | |||
| 75 | /** | ||
| 76 | * Constructor for RadialGradientPaintContext. | ||
| 77 | * | ||
| 78 | * @param paint the {@code RadialGradientPaint} from which this context | ||
| 79 | * is created | ||
| 80 | * @param cm the {@code ColorModel} that receives | ||
| 81 | * the {@code Paint} data (this is used only as a hint) | ||
| 82 | * @param deviceBounds the device space bounding box of the | ||
| 83 | * graphics primitive being rendered | ||
| 84 | * @param userBounds the user space bounding box of the | ||
| 85 | * graphics primitive being rendered | ||
| 86 | * @param t the {@code AffineTransform} from user | ||
| 87 | * space into device space (gradientTransform should be | ||
| 88 | * concatenated with this) | ||
| 89 | * @param hints the hints that the context object uses to choose | ||
| 90 | * between rendering alternatives | ||
| 91 | * @param cx the center X coordinate in user space of the circle defining | ||
| 92 | * the gradient. The last color of the gradient is mapped to | ||
| 93 | * the perimeter of this circle. | ||
| 94 | * @param cy the center Y coordinate in user space of the circle defining | ||
| 95 | * the gradient. The last color of the gradient is mapped to | ||
| 96 | * the perimeter of this circle. | ||
| 97 | * @param r the radius of the circle defining the extents of the | ||
| 98 | * color gradient | ||
| 99 | * @param fx the X coordinate in user space to which the first color | ||
| 100 | * is mapped | ||
| 101 | * @param fy the Y coordinate in user space to which the first color | ||
| 102 | * is mapped | ||
| 103 | * @param fractions the fractions specifying the gradient distribution | ||
| 104 | * @param colors the gradient colors | ||
| 105 | * @param cycleMethod either NO_CYCLE, REFLECT, or REPEAT | ||
| 106 | * @param colorSpace which colorspace to use for interpolation, | ||
| 107 | * either SRGB or LINEAR_RGB | ||
| 108 | */ | ||
| 109 | RadialGradientPaintContext(RadialGradientPaint paint, | ||
| 110 | ColorModel cm, | ||
| 111 | Rectangle deviceBounds, | ||
| 112 | Rectangle2D userBounds, | ||
| 113 | AffineTransform t, | ||
| 114 | RenderingHints hints, | ||
| 115 | float cx, float cy, | ||
| 116 | float r, | ||
| 117 | float fx, float fy, | ||
| 118 | float[] fractions, | ||
| 119 | Color[] colors, | ||
| 120 | CycleMethod cycleMethod, | ||
| 121 | ColorSpaceType colorSpace) | ||
| 122 | { | ||
| 123 | super(paint, cm, deviceBounds, userBounds, t, hints, | ||
| 124 | fractions, colors, cycleMethod, colorSpace); | ||
| 125 | |||
| 126 | // copy some parameters | ||
| 127 | centerX = cx; | ||
| 128 | centerY = cy; | ||
| 129 | focusX = fx; | ||
| 130 | focusY = fy; | ||
| 131 | radius = r; | ||
| 132 | |||
| 133 | this.isSimpleFocus = (focusX == centerX) && (focusY == centerY); | ||
| 134 | this.isNonCyclic = (cycleMethod == CycleMethod.NO_CYCLE); | ||
| 135 | |||
| 136 | // for use in the quadractic equation | ||
| 137 | radiusSq = radius * radius; | ||
| 138 | |||
| 139 | float dX = focusX - centerX; | ||
| 140 | float dY = focusY - centerY; | ||
| 141 | |||
| 142 | double distSq = (dX * dX) + (dY * dY); | ||
| 143 | |||
| 144 | // test if distance from focus to center is greater than the radius | ||
| 145 | if (distSq > radiusSq * SCALEBACK) { | ||
| 146 | // clamp focus to radius | ||
| 147 | float scalefactor = (float)Math.sqrt(radiusSq * SCALEBACK / distSq); | ||
| 148 | dX = dX * scalefactor; | ||
| 149 | dY = dY * scalefactor; | ||
| 150 | focusX = centerX + dX; | ||
| 151 | focusY = centerY + dY; | ||
| 152 | } | ||
| 153 | |||
| 154 | // calculate the solution to be used in the case where X == focusX | ||
| 155 | // in cyclicCircularGradientFillRaster() | ||
| 156 | trivial = (float)Math.sqrt(radiusSq - (dX * dX)); | ||
| 157 | |||
| 158 | // constant parts of X, Y user space coordinates | ||
| 159 | constA = a02 - centerX; | ||
| 160 | constB = a12 - centerY; | ||
| 161 | |||
| 162 | // constant second order delta for simple loop | ||
| 163 | gDeltaDelta = 2 * ( a00 * a00 + a10 * a10) / radiusSq; | ||
| 164 | } | ||
| 165 | |||
| 166 | /** | ||
| 167 | * Return a Raster containing the colors generated for the graphics | ||
| 168 | * operation. | ||
| 169 | * | ||
| 170 | * @param x,y,w,h the area in device space for which colors are | ||
| 171 | * generated. | ||
| 172 | */ | ||
| 173 | protected void fillRaster(int pixels[], int off, int adjust, | ||
| 174 | int x, int y, int w, int h) | ||
| 175 | { | ||
| 176 | if (isSimpleFocus && isNonCyclic && isSimpleLookup) { | ||
| 177 | simpleNonCyclicFillRaster(pixels, off, adjust, x, y, w, h); | ||
| 178 | } else { | ||
| 179 | cyclicCircularGradientFillRaster(pixels, off, adjust, x, y, w, h); | ||
| 180 | } | ||
| 181 | } | ||
| 182 | |||
| 183 | /** | ||
| 184 | * This code works in the simplest of cases, where the focus == center | ||
| 185 | * point, the gradient is noncyclic, and the gradient lookup method is | ||
| 186 | * fast (single array index, no conversion necessary). | ||
| 187 | */ | ||
| 188 | private void simpleNonCyclicFillRaster(int pixels[], int off, int adjust, | ||
| 189 | int x, int y, int w, int h) | ||
| 190 | { | ||
| 191 | /* We calculate sqrt(X^2 + Y^2) relative to the radius | ||
| 192 | * size to get the fraction for the color to use. | ||
| 193 | * | ||
| 194 | * Each step along the scanline adds (a00, a10) to (X, Y). | ||
| 195 | * If we precalculate: | ||
| 196 | * gRel = X^2+Y^2 | ||
| 197 | * for the start of the row, then for each step we need to | ||
| 198 | * calculate: | ||
| 199 | * gRel' = (X+a00)^2 + (Y+a10)^2 | ||
| 200 | * = X^2 + 2*X*a00 + a00^2 + Y^2 + 2*Y*a10 + a10^2 | ||
| 201 | * = (X^2+Y^2) + 2*(X*a00+Y*a10) + (a00^2+a10^2) | ||
| 202 | * = gRel + 2*(X*a00+Y*a10) + (a00^2+a10^2) | ||
| 203 | * = gRel + 2*DP + SD | ||
| 204 | * (where DP = dot product between X,Y and a00,a10 | ||
| 205 | * and SD = dot product square of the delta vector) | ||
| 206 | * For the step after that we get: | ||
| 207 | * gRel'' = (X+2*a00)^2 + (Y+2*a10)^2 | ||
| 208 | * = X^2 + 4*X*a00 + 4*a00^2 + Y^2 + 4*Y*a10 + 4*a10^2 | ||
| 209 | * = (X^2+Y^2) + 4*(X*a00+Y*a10) + 4*(a00^2+a10^2) | ||
| 210 | * = gRel + 4*DP + 4*SD | ||
| 211 | * = gRel' + 2*DP + 3*SD | ||
| 212 | * The increment changed by: | ||
| 213 | * (gRel'' - gRel') - (gRel' - gRel) | ||
| 214 | * = (2*DP + 3*SD) - (2*DP + SD) | ||
| 215 | * = 2*SD | ||
| 216 | * Note that this value depends only on the (inverse of the) | ||
| 217 | * transformation matrix and so is a constant for the loop. | ||
| 218 | * To make this all relative to the unit circle, we need to | ||
| 219 | * divide all values as follows: | ||
| 220 | * [XY] /= radius | ||
| 221 | * gRel /= radiusSq | ||
| 222 | * DP /= radiusSq | ||
| 223 | * SD /= radiusSq | ||
| 224 | */ | ||
| 225 | // coordinates of UL corner in "user space" relative to center | ||
| 226 | float rowX = (a00*x) + (a01*y) + constA; | ||
| 227 | float rowY = (a10*x) + (a11*y) + constB; | ||
| 228 | |||
| 229 | // second order delta calculated in constructor | ||
| 230 | float gDeltaDelta = this.gDeltaDelta; | ||
| 231 | |||
| 232 | // adjust is (scan-w) of pixels array, we need (scan) | ||
| 233 | adjust += w; | ||
| 234 | |||
| 235 | // rgb of the 1.0 color used when the distance exceeds gradient radius | ||
| 236 | int rgbclip = gradient[fastGradientArraySize]; | ||
| 237 | |||
| 238 | for (int j = 0; j < h; j++) { | ||
| 239 | // these values depend on the coordinates of the start of the row | ||
| 240 | float gRel = (rowX * rowX + rowY * rowY) / radiusSq; | ||
| 241 | float gDelta = (2 * ( a00 * rowX + a10 * rowY) / radiusSq + | ||
| 242 | gDeltaDelta/2); | ||
| 243 | |||
| 244 | /* Use optimized loops for any cases where gRel >= 1. | ||
| 245 | * We do not need to calculate sqrt(gRel) for these | ||
| 246 | * values since sqrt(N>=1) == (M>=1). | ||
| 247 | * Note that gRel follows a parabola which can only be < 1 | ||
| 248 | * for a small region around the center on each scanline. In | ||
| 249 | * particular: | ||
| 250 | * gDeltaDelta is always positive | ||
| 251 | * gDelta is <0 until it crosses the midpoint, then >0 | ||
| 252 | * To the left and right of that region, it will always be | ||
| 253 | * >=1 out to infinity, so we can process the line in 3 | ||
| 254 | * regions: | ||
| 255 | * out to the left - quick fill until gRel < 1, updating gRel | ||
| 256 | * in the heart - slow fraction=sqrt fill while gRel < 1 | ||
| 257 | * out to the right - quick fill rest of scanline, ignore gRel | ||
| 258 | */ | ||
| 259 | int i = 0; | ||
| 260 | // Quick fill for "out to the left" | ||
| 261 | while (i < w && gRel >= 1.0f) { | ||
| 262 | pixels[off + i] = rgbclip; | ||
| 263 | gRel += gDelta; | ||
| 264 | gDelta += gDeltaDelta; | ||
| 265 | i++; | ||
| 266 | } | ||
| 267 | // Slow fill for "in the heart" | ||
| 268 | while (i < w && gRel < 1.0f) { | ||
| 269 | int gIndex; | ||
| 270 | |||
| 271 | if (gRel <= 0) { | ||
| 272 | gIndex = 0; | ||
| 273 | } else { | ||
| 274 | float fIndex = gRel * SQRT_LUT_SIZE; | ||
| 275 | int iIndex = (int) (fIndex); | ||
| 276 | float s0 = sqrtLut[iIndex]; | ||
| 277 | float s1 = sqrtLut[iIndex+1] - s0; | ||
| 278 | fIndex = s0 + (fIndex - iIndex) * s1; | ||
| 279 | gIndex = (int) (fIndex * fastGradientArraySize); | ||
| 280 | } | ||
| 281 | |||
| 282 | // store the color at this point | ||
| 283 | pixels[off + i] = gradient[gIndex]; | ||
| 284 | |||
| 285 | // incremental calculation | ||
| 286 | gRel += gDelta; | ||
| 287 | gDelta += gDeltaDelta; | ||
| 288 | i++; | ||
| 289 | } | ||
| 290 | // Quick fill to end of line for "out to the right" | ||
| 291 | while (i < w) { | ||
| 292 | pixels[off + i] = rgbclip; | ||
| 293 | i++; | ||
| 294 | } | ||
| 295 | |||
| 296 | off += adjust; | ||
| 297 | rowX += a01; | ||
| 298 | rowY += a11; | ||
| 299 | } | ||
| 300 | } | ||
| 301 | |||
| 302 | // SQRT_LUT_SIZE must be a power of 2 for the test above to work. | ||
| 303 | private static final int SQRT_LUT_SIZE = (1 << 11); | ||
| 304 | private static float sqrtLut[] = new float[SQRT_LUT_SIZE+1]; | ||
| 305 | static { | ||
| 306 | for (int i = 0; i < sqrtLut.length; i++) { | ||
| 307 | sqrtLut[i] = (float) Math.sqrt(i / ((float) SQRT_LUT_SIZE)); | ||
| 308 | } | ||
| 309 | } | ||
| 310 | |||
| 311 | /** | ||
| 312 | * Fill the raster, cycling the gradient colors when a point falls outside | ||
| 313 | * of the perimeter of the 100% stop circle. | ||
| 314 | * | ||
| 315 | * This calculation first computes the intersection point of the line | ||
| 316 | * from the focus through the current point in the raster, and the | ||
| 317 | * perimeter of the gradient circle. | ||
| 318 | * | ||
| 319 | * Then it determines the percentage distance of the current point along | ||
| 320 | * that line (focus is 0%, perimeter is 100%). | ||
| 321 | * | ||
| 322 | * Equation of a circle centered at (a,b) with radius r: | ||
| 323 | * (x-a)^2 + (y-b)^2 = r^2 | ||
| 324 | * Equation of a line with slope m and y-intercept b: | ||
| 325 | * y = mx + b | ||
| 326 | * Replacing y in the circle equation and solving using the quadratic | ||
| 327 | * formula produces the following set of equations. Constant factors have | ||
| 328 | * been extracted out of the inner loop. | ||
| 329 | */ | ||
| 330 | private void cyclicCircularGradientFillRaster(int pixels[], int off, | ||
| 331 | int adjust, | ||
| 332 | int x, int y, | ||
| 333 | int w, int h) | ||
| 334 | { | ||
| 335 | // constant part of the C factor of the quadratic equation | ||
| 336 | final double constC = | ||
| 337 | -radiusSq + (centerX * centerX) + (centerY * centerY); | ||
| 338 | |||
| 339 | // coefficients of the quadratic equation (Ax^2 + Bx + C = 0) | ||
| 340 | double A, B, C; | ||
| 341 | |||
| 342 | // slope and y-intercept of the focus-perimeter line | ||
| 343 | double slope, yintcpt; | ||
| 344 | |||
| 345 | // intersection with circle X,Y coordinate | ||
| 346 | double solutionX, solutionY; | ||
| 347 | |||
| 348 | // constant parts of X, Y coordinates | ||
| 349 | final float constX = (a00*x) + (a01*y) + a02; | ||
| 350 | final float constY = (a10*x) + (a11*y) + a12; | ||
| 351 | |||
| 352 | // constants in inner loop quadratic formula | ||
| 353 | final float precalc2 = 2 * centerY; | ||
| 354 | final float precalc3 = -2 * centerX; | ||
| 355 | |||
| 356 | // value between 0 and 1 specifying position in the gradient | ||
| 357 | float g; | ||
| 358 | |||
| 359 | // determinant of quadratic formula (should always be > 0) | ||
| 360 | float det; | ||
| 361 | |||
| 362 | // sq distance from the current point to focus | ||
| 363 | float currentToFocusSq; | ||
| 364 | |||
| 365 | // sq distance from the intersect point to focus | ||
| 366 | float intersectToFocusSq; | ||
| 367 | |||
| 368 | // temp variables for change in X,Y squared | ||
| 369 | float deltaXSq, deltaYSq; | ||
| 370 | |||
| 371 | // used to index pixels array | ||
| 372 | int indexer = off; | ||
| 373 | |||
| 374 | // incremental index change for pixels array | ||
| 375 | int pixInc = w+adjust; | ||
| 376 | |||
| 377 | // for every row | ||
| 378 | for (int j = 0; j < h; j++) { | ||
| 379 | |||
| 380 | // user space point; these are constant from column to column | ||
| 381 | float X = (a01*j) + constX; | ||
| 382 | float Y = (a11*j) + constY; | ||
| 383 | |||
| 384 | // for every column (inner loop begins here) | ||
| 385 | for (int i = 0; i < w; i++) { | ||
| 386 | |||
| 387 | if (X == focusX) { | ||
| 388 | // special case to avoid divide by zero | ||
| 389 | solutionX = focusX; | ||
| 390 | solutionY = centerY; | ||
| 391 | solutionY += (Y > focusY) ? trivial : -trivial; | ||
| 392 | } else { | ||
| 393 | // slope and y-intercept of the focus-perimeter line | ||
| 394 | slope = (Y - focusY) / (X - focusX); | ||
| 395 | yintcpt = Y - (slope * X); | ||
| 396 | |||
| 397 | // use the quadratic formula to calculate the | ||
| 398 | // intersection point | ||
| 399 | A = (slope * slope) + 1; | ||
| 400 | B = precalc3 + (-2 * slope * (centerY - yintcpt)); | ||
| 401 | C = constC + (yintcpt* (yintcpt - precalc2)); | ||
| 402 | |||
| 403 | det = (float)Math.sqrt((B * B) - (4 * A * C)); | ||
| 404 | solutionX = -B; | ||
| 405 | |||
| 406 | // choose the positive or negative root depending | ||
| 407 | // on where the X coord lies with respect to the focus | ||
| 408 | solutionX += (X < focusX)? -det : det; | ||
| 409 | solutionX = solutionX / (2 * A); // divisor | ||
| 410 | solutionY = (slope * solutionX) + yintcpt; | ||
| 411 | } | ||
| 412 | |||
| 413 | // Calculate the square of the distance from the current point | ||
| 414 | // to the focus and the square of the distance from the | ||
| 415 | // intersection point to the focus. Want the squares so we can | ||
| 416 | // do 1 square root after division instead of 2 before. | ||
| 417 | |||
| 418 | deltaXSq = X - focusX; | ||
| 419 | deltaXSq = deltaXSq * deltaXSq; | ||
| 420 | |||
| 421 | deltaYSq = Y - focusY; | ||
| 422 | deltaYSq = deltaYSq * deltaYSq; | ||
| 423 | |||
| 424 | currentToFocusSq = deltaXSq + deltaYSq; | ||
| 425 | |||
| 426 | deltaXSq = (float)solutionX - focusX; | ||
| 427 | deltaXSq = deltaXSq * deltaXSq; | ||
| 428 | |||
| 429 | deltaYSq = (float)solutionY - focusY; | ||
| 430 | deltaYSq = deltaYSq * deltaYSq; | ||
| 431 | |||
| 432 | intersectToFocusSq = deltaXSq + deltaYSq; | ||
| 433 | |||
| 434 | // get the percentage (0-1) of the current point along the | ||
| 435 | // focus-circumference line | ||
| 436 | g = (float)Math.sqrt(currentToFocusSq / intersectToFocusSq); | ||
| 437 | |||
| 438 | // store the color at this point | ||
| 439 | pixels[indexer + i] = indexIntoGradientsArrays(g); | ||
| 440 | |||
| 441 | // incremental change in X, Y | ||
| 442 | X += a00; | ||
| 443 | Y += a10; | ||
| 444 | } //end inner loop | ||
| 445 | |||
| 446 | indexer += pixInc; | ||
| 447 | } //end outer loop | ||
| 448 | } | ||
| 449 | } | ||