diff options
Diffstat (limited to 'src/effects')
| -rw-r--r-- | src/effects/SkBlurMask.cpp | 134 |
1 files changed, 83 insertions, 51 deletions
diff --git a/src/effects/SkBlurMask.cpp b/src/effects/SkBlurMask.cpp index 4e46ab6..a6492c3 100644 --- a/src/effects/SkBlurMask.cpp +++ b/src/effects/SkBlurMask.cpp @@ -18,33 +18,65 @@ #include "SkBlurMask.h" #include "SkTemplates.h" -static void build_sum_buffer(uint32_t dst[], int w, int h, const uint8_t src[], int srcRB) -{ - SkASSERT(srcRB >= w); +#if 0 +static void dump_sum_buffer(const uint32_t sum[], const int w, const int h) { + printf("---- sum buffer\n"); + for (int y = 0; y <= h; y++) { + for (int x = 0; x <= w; x++) { + printf(" %5d", sum[x]); + } + printf("\n"); + sum += w+1; + } +} +#else +#define dump_sum_buffer(sum, w, h) +#endif + +/** The sum buffer is an array of u32 to hold the accumulated sum of all of the + src values at their position, plus all values above and to the left. + When we sample into this buffer, we need an initial row and column of 0s, + so we have an index correspondence as follows: + + src[i, j] == sum[i+1, j+1] + sum[0, j] == sum[i, 0] == 0 + + We assume that the sum buffer's stride == its width + */ +static void build_sum_buffer(uint32_t sum[], int srcW, int srcH, const uint8_t src[], int srcRB) { + int sumW = srcW + 1; + + SkASSERT(srcRB >= srcW); // mod srcRB so we can apply it after each row - srcRB -= w; + srcRB -= srcW; int x, y; + // zero out the top row and column + memset(sum, 0, sumW * sizeof(sum[0])); + sum += sumW; + // special case first row uint32_t X = 0; - for (x = w - 1; x >= 0; --x) + *sum++ = 0; // initialze the first column to 0 + for (x = srcW - 1; x >= 0; --x) { X = *src++ + X; - *dst++ = X; + *sum++ = X; } src += srcRB; // now do the rest of the rows - for (y = h - 1; y > 0; --y) + for (y = srcH - 1; y > 0; --y) { uint32_t L = 0; uint32_t C = 0; - for (x = w - 1; x >= 0; --x) + *sum++ = 0; // initialze the first column to 0 + for (x = srcW - 1; x >= 0; --x) { - uint32_t T = dst[-w]; + uint32_t T = sum[-sumW]; X = *src++ + L + T - C; - *dst++ = X; + *sum++ = X; L = X; C = T; } @@ -52,36 +84,36 @@ static void build_sum_buffer(uint32_t dst[], int w, int h, const uint8_t src[], } } -static void apply_kernel(uint8_t dst[], int rx, int ry, const uint32_t src[], int sw, int sh) -{ +/* sw and sh are the width and height of the src. Since the sum buffer + matches that, but has an extra row and col at the beginning (with zeros), + we can just use sw and sh as our "max" values for pinning coordinates + when sampling into sum[][] + */ +static void apply_kernel(uint8_t dst[], int rx, int ry, const uint32_t sum[], + int sw, int sh) { uint32_t scale = (1 << 24) / ((2*rx + 1)*(2*ry + 1)); - int rowBytes = sw; + int sumStride = sw + 1; int dw = sw + 2*rx; int dh = sh + 2*ry; - sw -= 1; // now it is max_x - sh -= 1; // now it is max_y + int prev_y = -2*ry; + int next_y = 1; - int prev_y = -ry - 1 -ry; - int next_y = ry -ry; + for (int y = 0; y < dh; y++) { + int py = SkClampPos(prev_y) * sumStride; + int ny = SkFastMin32(next_y, sh) * sumStride; - for (int y = 0; y < dh; y++) - { - int py = SkClampPos(prev_y) * rowBytes; - int ny = SkFastMin32(next_y, sh) * rowBytes; - - int prev_x = -rx - 1 -rx; - int next_x = rx -rx; + int prev_x = -2*rx; + int next_x = 1; - for (int x = 0; x < dw; x++) - { + for (int x = 0; x < dw; x++) { int px = SkClampPos(prev_x); int nx = SkFastMin32(next_x, sw); - uint32_t sum = src[px+py] + src[nx+ny] - src[nx+py] - src[px+ny]; - *dst++ = SkToU8(sum * scale >> 24); + uint32_t tmp = sum[px+py] + sum[nx+ny] - sum[nx+py] - sum[px+ny]; + *dst++ = SkToU8(tmp * scale >> 24); prev_x += 1; next_x += 1; @@ -91,8 +123,13 @@ static void apply_kernel(uint8_t dst[], int rx, int ry, const uint32_t src[], in } } -static void apply_kernel_interp(uint8_t dst[], int rx, int ry, const uint32_t src[], int sw, int sh, U8CPU outer_weight) -{ +/* sw and sh are the width and height of the src. Since the sum buffer + matches that, but has an extra row and col at the beginning (with zeros), + we can just use sw and sh as our "max" values for pinning coordinates + when sampling into sum[][] + */ +static void apply_kernel_interp(uint8_t dst[], int rx, int ry, + const uint32_t sum[], int sw, int sh, U8CPU outer_weight) { SkASSERT(rx > 0 && ry > 0); SkASSERT(outer_weight <= 255); @@ -105,38 +142,33 @@ static void apply_kernel_interp(uint8_t dst[], int rx, int ry, const uint32_t sr uint32_t outer_scale = (outer_weight << 16) / ((2*rx + 1)*(2*ry + 1)); uint32_t inner_scale = (inner_weight << 16) / ((2*rx - 1)*(2*ry - 1)); - int rowBytes = sw; + int sumStride = sw + 1; int dw = sw + 2*rx; int dh = sh + 2*ry; - sw -= 1; // now it is max_x - sh -= 1; // now it is max_y + int prev_y = -2*ry; + int next_y = 1; - int prev_y = -ry - 1 -ry; - int next_y = ry -ry; + for (int y = 0; y < dh; y++) { + int py = SkClampPos(prev_y) * sumStride; + int ny = SkFastMin32(next_y, sh) * sumStride; - for (int y = 0; y < dh; y++) - { - int py = SkClampPos(prev_y) * rowBytes; - int ny = SkFastMin32(next_y, sh) * rowBytes; - - int ipy = SkClampPos(prev_y + 1) * rowBytes; - int iny = SkClampMax(next_y - 1, sh) * rowBytes; + int ipy = SkClampPos(prev_y + 1) * sumStride; + int iny = SkClampMax(next_y - 1, sh) * sumStride; - int prev_x = -rx - 1 -rx; - int next_x = rx -rx; + int prev_x = -2*rx; + int next_x = 1; - for (int x = 0; x < dw; x++) - { + for (int x = 0; x < dw; x++) { int px = SkClampPos(prev_x); int nx = SkFastMin32(next_x, sw); int ipx = SkClampPos(prev_x + 1); int inx = SkClampMax(next_x - 1, sw); - uint32_t outer_sum = src[px+py] + src[nx+ny] - src[nx+py] - src[px+ny]; - uint32_t inner_sum = src[ipx+ipy] + src[inx+iny] - src[inx+ipy] - src[ipx+iny]; + uint32_t outer_sum = sum[px+py] + sum[nx+ny] - sum[nx+py] - sum[px+ny]; + uint32_t inner_sum = sum[ipx+ipy] + sum[inx+iny] - sum[inx+ipy] - sum[ipx+iny]; *dst++ = SkToU8((outer_sum * outer_scale + inner_sum * inner_scale) >> 24); prev_x += 1; @@ -172,8 +204,7 @@ static void merge_src_with_blur(uint8_t dst[], int dstRB, static void clamp_with_orig(uint8_t dst[], int dstRowBytes, const uint8_t src[], int srcRowBytes, int sw, int sh, - SkBlurMask::Style style) -{ + SkBlurMask::Style style) { int x; while (--sh >= 0) { switch (style) { @@ -252,10 +283,11 @@ bool SkBlurMask::Blur(SkMask* dst, const SkMask& src, // build the blurry destination { - SkAutoTMalloc<uint32_t> storage(sw * sh); + SkAutoTMalloc<uint32_t> storage((sw + 1) * (sh + 1)); uint32_t* sumBuffer = storage.get(); build_sum_buffer(sumBuffer, sw, sh, sp, src.fRowBytes); + dump_sum_buffer(sumBuffer, sw, sh); if (outer_weight == 255) apply_kernel(dp, rx, ry, sumBuffer, sw, sh); else |