+void Gfx::doFunctionShFill(GfxFunctionShading *shading) {
+ double x0, y0, x1, y1;
+ GfxColor colors[4];
+
+ shading->getDomain(&x0, &y0, &x1, &y1);
+ shading->getColor(x0, y0, &colors[0]);
+ shading->getColor(x0, y1, &colors[1]);
+ shading->getColor(x1, y0, &colors[2]);
+ shading->getColor(x1, y1, &colors[3]);
+ doFunctionShFill1(shading, x0, y0, x1, y1, colors, 0);
+}
+
+void Gfx::doFunctionShFill1(GfxFunctionShading *shading,
+ double x0, double y0,
+ double x1, double y1,
+ GfxColor *colors, int depth) {
+ GfxColor fillColor;
+ GfxColor color0M, color1M, colorM0, colorM1, colorMM;
+ GfxColor colors2[4];
+ double *matrix;
+ double xM, yM;
+ int nComps, i, j;
+
+ nComps = shading->getColorSpace()->getNComps();
+ matrix = shading->getMatrix();
+
+ // compare the four corner colors
+ for (i = 0; i < 4; ++i) {
+ for (j = 0; j < nComps; ++j) {
+ if (fabs(colors[i].c[j] - colors[(i+1)&3].c[j]) > functionColorDelta) {
+ break;
+ }
+ }
+ if (j < nComps) {
+ break;
+ }
+ }
+
+ // center of the rectangle
+ xM = 0.5 * (x0 + x1);
+ yM = 0.5 * (y0 + y1);
+
+ // the four corner colors are close (or we hit the recursive limit)
+ // -- fill the rectangle; but require at least one subdivision
+ // (depth==0) to avoid problems when the four outer corners of the
+ // shaded region are the same color
+ if ((i == 4 && depth > 0) || depth == functionMaxDepth) {
+
+ // use the center color
+ shading->getColor(xM, yM, &fillColor);
+ state->setFillColor(&fillColor);
+ out->updateFillColor(state);
+
+ // fill the rectangle
+ state->moveTo(x0 * matrix[0] + y0 * matrix[2] + matrix[4],
+ x0 * matrix[1] + y0 * matrix[3] + matrix[5]);
+ state->lineTo(x1 * matrix[0] + y0 * matrix[2] + matrix[4],
+ x1 * matrix[1] + y0 * matrix[3] + matrix[5]);
+ state->lineTo(x1 * matrix[0] + y1 * matrix[2] + matrix[4],
+ x1 * matrix[1] + y1 * matrix[3] + matrix[5]);
+ state->lineTo(x0 * matrix[0] + y1 * matrix[2] + matrix[4],
+ x0 * matrix[1] + y1 * matrix[3] + matrix[5]);
+ state->closePath();
+ out->fill(state);
+ state->clearPath();
+
+ // the four corner colors are not close enough -- subdivide the
+ // rectangle
+ } else {
+
+ // colors[0] colorM0 colors[2]
+ // (x0,y0) (xM,y0) (x1,y0)
+ // +----------+----------+
+ // | | |
+ // | UL | UR |
+ // color0M | colorMM | color1M
+ // (x0,yM) +----------+----------+ (x1,yM)
+ // | (xM,yM) |
+ // | LL | LR |
+ // | | |
+ // +----------+----------+
+ // colors[1] colorM1 colors[3]
+ // (x0,y1) (xM,y1) (x1,y1)
+
+ shading->getColor(x0, yM, &color0M);
+ shading->getColor(x1, yM, &color1M);
+ shading->getColor(xM, y0, &colorM0);
+ shading->getColor(xM, y1, &colorM1);
+ shading->getColor(xM, yM, &colorMM);
+
+ // upper-left sub-rectangle
+ colors2[0] = colors[0];
+ colors2[1] = color0M;
+ colors2[2] = colorM0;
+ colors2[3] = colorMM;
+ doFunctionShFill1(shading, x0, y0, xM, yM, colors2, depth + 1);
+
+ // lower-left sub-rectangle
+ colors2[0] = color0M;
+ colors2[1] = colors[1];
+ colors2[2] = colorMM;
+ colors2[3] = colorM1;
+ doFunctionShFill1(shading, x0, yM, xM, y1, colors2, depth + 1);
+
+ // upper-right sub-rectangle
+ colors2[0] = colorM0;
+ colors2[1] = colorMM;
+ colors2[2] = colors[2];
+ colors2[3] = color1M;
+ doFunctionShFill1(shading, xM, y0, x1, yM, colors2, depth + 1);
+
+ // lower-right sub-rectangle
+ colors2[0] = colorMM;
+ colors2[1] = colorM1;
+ colors2[2] = color1M;
+ colors2[3] = colors[3];
+ doFunctionShFill1(shading, xM, yM, x1, y1, colors2, depth + 1);
+ }
+}
+