msarett | c573a40 | 2016-08-02 08:05:56 -0700 | [diff] [blame^] | 1 | /* |
| 2 | * Copyright 2015 Google Inc. |
| 3 | * |
| 4 | * Use of this source code is governed by a BSD-style license that can be |
| 5 | * found in the LICENSE file. |
| 6 | */ |
| 7 | |
| 8 | #include "SkLatticeIter.h" |
| 9 | #include "SkRect.h" |
| 10 | |
| 11 | /** |
| 12 | * Divs must be in increasing order with no duplicates. |
| 13 | */ |
| 14 | static bool valid_divs(const int* divs, int count, int len) { |
| 15 | if (count <= 0) { |
| 16 | return false; |
| 17 | } |
| 18 | |
| 19 | int prev = -1; |
| 20 | for (int i = 0; i < count; i++) { |
| 21 | if (prev >= divs[i] || divs[i] > len) { |
| 22 | return false; |
| 23 | } |
| 24 | } |
| 25 | |
| 26 | return true; |
| 27 | } |
| 28 | |
| 29 | bool SkLatticeIter::Valid(int width, int height, const SkCanvas::Lattice& lattice) { |
| 30 | return valid_divs(lattice.fXDivs, lattice.fXCount, width) && |
| 31 | valid_divs(lattice.fYDivs, lattice.fYCount, height); |
| 32 | } |
| 33 | |
| 34 | /** |
| 35 | * Count the number of pixels that are in "scalable" patches. |
| 36 | */ |
| 37 | static int count_scalable_pixels(const int32_t* divs, int numDivs, bool firstIsScalable, |
| 38 | int length) { |
| 39 | if (0 == numDivs) { |
| 40 | return firstIsScalable ? length : 0; |
| 41 | } |
| 42 | |
| 43 | int i; |
| 44 | int count; |
| 45 | if (firstIsScalable) { |
| 46 | count = divs[0]; |
| 47 | i = 1; |
| 48 | } else { |
| 49 | count = 0; |
| 50 | i = 0; |
| 51 | } |
| 52 | |
| 53 | for (; i < numDivs; i += 2) { |
| 54 | // Alternatively, we could use |top| and |bottom| as variable names, instead of |
| 55 | // |left| and |right|. |
| 56 | int left = divs[i]; |
| 57 | int right = (i + 1 < numDivs) ? divs[i + 1] : length; |
| 58 | count += right - left; |
| 59 | } |
| 60 | |
| 61 | return count; |
| 62 | } |
| 63 | |
| 64 | /** |
| 65 | * Set points for the src and dst rects on subsequent draw calls. |
| 66 | */ |
| 67 | static void set_points(float* dst, float* src, const int* divs, int divCount, int srcFixed, |
| 68 | int srcScalable, float dstStart, float dstStop, bool isScalable) { |
| 69 | |
| 70 | float dstLen = dstStop - dstStart; |
| 71 | int srcLen = srcFixed + srcScalable; |
| 72 | float scale; |
| 73 | if (srcFixed <= dstLen) { |
| 74 | // This is the "normal" case, where we scale the "scalable" patches and leave |
| 75 | // the other patches fixed. |
| 76 | scale = (dstLen - ((float) srcFixed)) / ((float) srcScalable); |
| 77 | } else { |
| 78 | // In this case, we eliminate the "scalable" patches and scale the "fixed" patches. |
| 79 | scale = dstLen / ((float) srcFixed); |
| 80 | } |
| 81 | |
| 82 | src[0] = 0.0f; |
| 83 | dst[0] = dstStart; |
| 84 | for (int i = 0; i < divCount; i++) { |
| 85 | src[i + 1] = (float) (divs[i]); |
| 86 | float srcDelta = src[i + 1] - src[i]; |
| 87 | float dstDelta; |
| 88 | if (srcFixed <= dstLen) { |
| 89 | dstDelta = isScalable ? scale * srcDelta : srcDelta; |
| 90 | } else { |
| 91 | dstDelta = isScalable ? 0.0f : scale * srcDelta; |
| 92 | } |
| 93 | dst[i + 1] = dst[i] + dstDelta; |
| 94 | |
| 95 | // Alternate between "scalable" and "fixed" patches. |
| 96 | isScalable = !isScalable; |
| 97 | } |
| 98 | |
| 99 | src[divCount + 1] = (float) srcLen; |
| 100 | dst[divCount + 1] = dstStop; |
| 101 | } |
| 102 | |
| 103 | SkLatticeIter::SkLatticeIter(int srcWidth, int srcHeight, const SkCanvas::Lattice& lattice, |
| 104 | const SkRect& dst) |
| 105 | { |
| 106 | const int* xDivs = lattice.fXDivs; |
| 107 | int xCount = lattice.fXCount; |
| 108 | const int* yDivs = lattice.fYDivs; |
| 109 | int yCount = lattice.fYCount; |
| 110 | |
| 111 | // In the x-dimension, the first rectangle always starts at x = 0 and is "scalable". |
| 112 | // If xDiv[0] is 0, it indicates that the first rectangle is degenerate, so the |
| 113 | // first real rectangle "scalable" in the x-direction. |
| 114 | // |
| 115 | // The same interpretation applies to the y-dimension. |
| 116 | // |
| 117 | // As we move left to right across the image, alternating patches will be "fixed" or |
| 118 | // "scalable" in the x-direction. Similarly, as move top to bottom, alternating |
| 119 | // patches will be "fixed" or "scalable" in the y-direction. |
| 120 | SkASSERT(xCount > 0 && yCount > 0); |
| 121 | bool xIsScalable = (0 == xDivs[0]); |
| 122 | if (xIsScalable) { |
| 123 | // Once we've decided that the first patch is "scalable", we don't need the |
| 124 | // xDiv. It is always implied that we start at zero. |
| 125 | xDivs++; |
| 126 | xCount--; |
| 127 | } |
| 128 | bool yIsScalable = (0 == yDivs[0]); |
| 129 | if (yIsScalable) { |
| 130 | // Once we've decided that the first patch is "scalable", we don't need the |
| 131 | // yDiv. It is always implied that we start at zero. |
| 132 | yDivs++; |
| 133 | yCount--; |
| 134 | } |
| 135 | |
| 136 | // We never need the final xDiv/yDiv if it is equal to the width/height. This is implied. |
| 137 | if (xCount > 0 && srcWidth == xDivs[xCount - 1]) { |
| 138 | xCount--; |
| 139 | } |
| 140 | if (yCount > 0 && srcHeight == yDivs[yCount - 1]) { |
| 141 | yCount--; |
| 142 | } |
| 143 | |
| 144 | // Count "scalable" and "fixed" pixels in each dimension. |
| 145 | int xCountScalable = count_scalable_pixels(xDivs, xCount, xIsScalable, srcWidth); |
| 146 | int xCountFixed = srcWidth - xCountScalable; |
| 147 | int yCountScalable = count_scalable_pixels(yDivs, yCount, yIsScalable, srcHeight); |
| 148 | int yCountFixed = srcHeight - yCountScalable; |
| 149 | |
| 150 | fSrcX.reset(xCount + 2); |
| 151 | fDstX.reset(xCount + 2); |
| 152 | set_points(fDstX.begin(), fSrcX.begin(), xDivs, xCount, xCountFixed, xCountScalable, |
| 153 | dst.fLeft, dst.fRight, xIsScalable); |
| 154 | |
| 155 | fSrcY.reset(yCount + 2); |
| 156 | fDstY.reset(yCount + 2); |
| 157 | set_points(fDstY.begin(), fSrcY.begin(), yDivs, yCount, yCountFixed, yCountScalable, |
| 158 | dst.fTop, dst.fBottom, yIsScalable); |
| 159 | |
| 160 | fCurrX = fCurrY = 0; |
| 161 | fDone = false; |
| 162 | } |
| 163 | |
| 164 | bool SkLatticeIter::Valid(int width, int height, const SkIRect& center) { |
| 165 | return !center.isEmpty() && SkIRect::MakeWH(width, height).contains(center); |
| 166 | } |
| 167 | |
| 168 | SkLatticeIter::SkLatticeIter(int w, int h, const SkIRect& c, const SkRect& dst) { |
| 169 | SkASSERT(SkIRect::MakeWH(w, h).contains(c)); |
| 170 | |
| 171 | fSrcX.reset(4); |
| 172 | fSrcY.reset(4); |
| 173 | fDstX.reset(4); |
| 174 | fDstY.reset(4); |
| 175 | |
| 176 | fSrcX[0] = 0; |
| 177 | fSrcX[1] = SkIntToScalar(c.fLeft); |
| 178 | fSrcX[2] = SkIntToScalar(c.fRight); |
| 179 | fSrcX[3] = SkIntToScalar(w); |
| 180 | |
| 181 | fSrcY[0] = 0; |
| 182 | fSrcY[1] = SkIntToScalar(c.fTop); |
| 183 | fSrcY[2] = SkIntToScalar(c.fBottom); |
| 184 | fSrcY[3] = SkIntToScalar(h); |
| 185 | |
| 186 | fDstX[0] = dst.fLeft; |
| 187 | fDstX[1] = dst.fLeft + SkIntToScalar(c.fLeft); |
| 188 | fDstX[2] = dst.fRight - SkIntToScalar(w - c.fRight); |
| 189 | fDstX[3] = dst.fRight; |
| 190 | |
| 191 | fDstY[0] = dst.fTop; |
| 192 | fDstY[1] = dst.fTop + SkIntToScalar(c.fTop); |
| 193 | fDstY[2] = dst.fBottom - SkIntToScalar(h - c.fBottom); |
| 194 | fDstY[3] = dst.fBottom; |
| 195 | |
| 196 | if (fDstX[1] > fDstX[2]) { |
| 197 | fDstX[1] = fDstX[0] + (fDstX[3] - fDstX[0]) * c.fLeft / (w - c.width()); |
| 198 | fDstX[2] = fDstX[1]; |
| 199 | } |
| 200 | |
| 201 | if (fDstY[1] > fDstY[2]) { |
| 202 | fDstY[1] = fDstY[0] + (fDstY[3] - fDstY[0]) * c.fTop / (h - c.height()); |
| 203 | fDstY[2] = fDstY[1]; |
| 204 | } |
| 205 | |
| 206 | fCurrX = fCurrY = 0; |
| 207 | fDone = false; |
| 208 | } |
| 209 | |
| 210 | bool SkLatticeIter::next(SkRect* src, SkRect* dst) { |
| 211 | if (fDone) { |
| 212 | return false; |
| 213 | } |
| 214 | |
| 215 | const int x = fCurrX; |
| 216 | const int y = fCurrY; |
| 217 | SkASSERT(x >= 0 && x < fSrcX.count() - 1); |
| 218 | SkASSERT(y >= 0 && y < fSrcY.count() - 1); |
| 219 | |
| 220 | src->set(fSrcX[x], fSrcY[y], fSrcX[x + 1], fSrcY[y + 1]); |
| 221 | dst->set(fDstX[x], fDstY[y], fDstX[x + 1], fDstY[y + 1]); |
| 222 | if (fSrcX.count() - 1 == ++fCurrX) { |
| 223 | fCurrX = 0; |
| 224 | fCurrY += 1; |
| 225 | if (fCurrY >= fSrcY.count() - 1) { |
| 226 | fDone = true; |
| 227 | } |
| 228 | } |
| 229 | return true; |
| 230 | } |