diff options
| -rw-r--r-- | src/effects/SkBlurMask.cpp | 114 |
1 files changed, 104 insertions, 10 deletions
diff --git a/src/effects/SkBlurMask.cpp b/src/effects/SkBlurMask.cpp index 99bf2d5003..c97916bbb0 100644 --- a/src/effects/SkBlurMask.cpp +++ b/src/effects/SkBlurMask.cpp @@ -22,12 +22,51 @@ #define UNROLL_SEPARABLE_LOOPS +#define SK_DISABLE_BLUR_ROUNDING + /** * This function performs a box blur in X, of the given radius. If the * "transpose" parameter is true, it will transpose the pixels on write, * such that X and Y are swapped. Reads are always performed from contiguous * memory in X, for speed. The destination buffer (dst) must be at least * (width + leftRadius + rightRadius) * height bytes in size. + * + * This is what the inner loop looks like before unrolling, and with the two + * cases broken out separately (width < diameter, width >= diameter): + * + * if (width < diameter) { + * for (int x = 0; x < width; ++x) { + * sum += *right++; + * *dptr = (sum * scale + half) >> 24; + * dptr += dst_x_stride; + * } + * for (int x = width; x < diameter; ++x) { + * *dptr = (sum * scale + half) >> 24; + * dptr += dst_x_stride; + * } + * for (int x = 0; x < width; ++x) { + * *dptr = (sum * scale + half) >> 24; + * sum -= *left++; + * dptr += dst_x_stride; + * } + * } else { + * for (int x = 0; x < diameter; ++x) { + * sum += *right++; + * *dptr = (sum * scale + half) >> 24; + * dptr += dst_x_stride; + * } + * for (int x = diameter; x < width; ++x) { + * sum += *right++; + * *dptr = (sum * scale + half) >> 24; + * sum -= *left++; + * dptr += dst_x_stride; + * } + * for (int x = 0; x < diameter; ++x) { + * *dptr = (sum * scale + half) >> 24; + * sum -= *left++; + * dptr += dst_x_stride; + * } + * } */ static int boxBlur(const uint8_t* src, int src_y_stride, uint8_t* dst, int leftRadius, int rightRadius, int width, int height, @@ -40,8 +79,13 @@ static int boxBlur(const uint8_t* src, int src_y_stride, uint8_t* dst, int new_width = width + SkMax32(leftRadius, rightRadius) * 2; int dst_x_stride = transpose ? height : 1; int dst_y_stride = transpose ? 1 : new_width; +#ifndef SK_DISABLE_BLUR_ROUNDING + uint32_t half = 1 << 23; +#else + uint32_t half = 0; +#endif for (int y = 0; y < height; ++y) { - int sum = 0; + uint32_t sum = 0; uint8_t* dptr = dst + y * dst_y_stride; const uint8_t* right = src + y * src_y_stride; const uint8_t* left = right; @@ -51,7 +95,7 @@ static int boxBlur(const uint8_t* src, int src_y_stride, uint8_t* dst, } #define LEFT_BORDER_ITER \ sum += *right++; \ - *dptr = (sum * scale) >> 24; \ + *dptr = (sum * scale + half) >> 24; \ dptr += dst_x_stride; int x = 0; @@ -80,7 +124,7 @@ static int boxBlur(const uint8_t* src, int src_y_stride, uint8_t* dst, } #undef LEFT_BORDER_ITER #define TRIVIAL_ITER \ - *dptr = (sum * scale) >> 24; \ + *dptr = (sum * scale + half) >> 24; \ dptr += dst_x_stride; x = width; #ifdef UNROLL_SEPARABLE_LOOPS @@ -109,7 +153,7 @@ static int boxBlur(const uint8_t* src, int src_y_stride, uint8_t* dst, #undef TRIVIAL_ITER #define CENTER_ITER \ sum += *right++; \ - *dptr = (sum * scale) >> 24; \ + *dptr = (sum * scale + half) >> 24; \ sum -= *left++; \ dptr += dst_x_stride; @@ -139,7 +183,7 @@ static int boxBlur(const uint8_t* src, int src_y_stride, uint8_t* dst, } #undef CENTER_ITER #define RIGHT_BORDER_ITER \ - *dptr = (sum * scale) >> 24; \ + *dptr = (sum * scale + half) >> 24; \ sum -= *left++; \ dptr += dst_x_stride; @@ -184,7 +228,52 @@ static int boxBlur(const uint8_t* src, int src_y_stride, uint8_t* dst, * interpolates between them. In float this would be: * outer_weight * outer_sum / kernelSize + * (1.0 - outer_weight) * innerSum / (kernelSize - 2) + * + * This is what the inner loop looks like before unrolling, and with the two + * cases broken out separately (width < diameter, width >= diameter): + * + * if (width < diameter) { + * for (int x = 0; x < width; x++) { + * inner_sum = outer_sum; + * outer_sum += *right++; + * *dptr = (outer_sum * outer_scale + inner_sum * inner_scale + half) >> 24; + * dptr += dst_x_stride; + * } + * for (int x = width; x < diameter; ++x) { + * *dptr = (outer_sum * outer_scale + inner_sum * inner_scale + half) >> 24; + * dptr += dst_x_stride; + * } + * for (int x = 0; x < width; x++) { + * inner_sum = outer_sum - *left++; + * *dptr = (outer_sum * outer_scale + inner_sum * inner_scale + half) >> 24; + * dptr += dst_x_stride; + * outer_sum = inner_sum; + * } + * } else { + * for (int x = 0; x < diameter; x++) { + * inner_sum = outer_sum; + * outer_sum += *right++; + * *dptr = (outer_sum * outer_scale + inner_sum * inner_scale + half) >> 24; + * dptr += dst_x_stride; + * } + * for (int x = diameter; x < width; ++x) { + * inner_sum = outer_sum - *left; + * outer_sum += *right++; + * *dptr = (outer_sum * outer_scale + inner_sum * inner_scale + half) >> 24; + * dptr += dst_x_stride; + * outer_sum -= *left++; + * } + * for (int x = 0; x < diameter; x++) { + * inner_sum = outer_sum - *left++; + * *dptr = (outer_sum * outer_scale + inner_sum * inner_scale + half) >> 24; + * dptr += dst_x_stride; + * outer_sum = inner_sum; + * } + * } + * } + * return new_width; */ + static int boxBlurInterp(const uint8_t* src, int src_y_stride, uint8_t* dst, int radius, int width, int height, bool transpose, uint8_t outer_weight) @@ -197,11 +286,16 @@ static int boxBlurInterp(const uint8_t* src, int src_y_stride, uint8_t* dst, inner_weight += inner_weight >> 7; uint32_t outer_scale = (outer_weight << 16) / kernelSize; uint32_t inner_scale = (inner_weight << 16) / (kernelSize - 2); +#ifndef SK_DISABLE_BLUR_ROUNDING + uint32_t half = 1 << 23; +#else + uint32_t half = 0; +#endif int new_width = width + diameter; int dst_x_stride = transpose ? height : 1; int dst_y_stride = transpose ? 1 : new_width; for (int y = 0; y < height; ++y) { - int outer_sum = 0, inner_sum = 0; + uint32_t outer_sum = 0, inner_sum = 0; uint8_t* dptr = dst + y * dst_y_stride; const uint8_t* right = src + y * src_y_stride; const uint8_t* left = right; @@ -210,7 +304,7 @@ static int boxBlurInterp(const uint8_t* src, int src_y_stride, uint8_t* dst, #define LEFT_BORDER_ITER \ inner_sum = outer_sum; \ outer_sum += *right++; \ - *dptr = (outer_sum * outer_scale + inner_sum * inner_scale) >> 24; \ + *dptr = (outer_sum * outer_scale + inner_sum * inner_scale + half) >> 24; \ dptr += dst_x_stride; #ifdef UNROLL_SEPARABLE_LOOPS @@ -239,7 +333,7 @@ static int boxBlurInterp(const uint8_t* src, int src_y_stride, uint8_t* dst, } #undef LEFT_BORDER_ITER for (int x = width; x < diameter; ++x) { - *dptr = (outer_sum * outer_scale + inner_sum * inner_scale) >> 24; + *dptr = (outer_sum * outer_scale + inner_sum * inner_scale + half) >> 24; dptr += dst_x_stride; } x = diameter; @@ -247,7 +341,7 @@ static int boxBlurInterp(const uint8_t* src, int src_y_stride, uint8_t* dst, #define CENTER_ITER \ inner_sum = outer_sum - *left; \ outer_sum += *right++; \ - *dptr = (outer_sum * outer_scale + inner_sum * inner_scale) >> 24; \ + *dptr = (outer_sum * outer_scale + inner_sum * inner_scale + half) >> 24; \ dptr += dst_x_stride; \ outer_sum -= *left++; @@ -278,7 +372,7 @@ static int boxBlurInterp(const uint8_t* src, int src_y_stride, uint8_t* dst, #define RIGHT_BORDER_ITER \ inner_sum = outer_sum - *left++; \ - *dptr = (outer_sum * outer_scale + inner_sum * inner_scale) >> 24; \ + *dptr = (outer_sum * outer_scale + inner_sum * inner_scale + half) >> 24; \ dptr += dst_x_stride; \ outer_sum = inner_sum; |