/* * Copyright 2006 The Android Open Source Project * * Use of this source code is governed by a BSD-style license that can be * found in the LICENSE file. */ #include "SkBlurMask.h" #include "SkMath.h" #include "SkTemplates.h" #include "SkEndian.h" SkScalar SkBlurMask::ConvertRadiusToSigma(SkScalar radius) { // This constant approximates the scaling done in the software path's // "high quality" mode, in SkBlurMask::Blur() (1 / sqrt(3)). // IMHO, it actually should be 1: we blur "less" than we should do // according to the CSS and canvas specs, simply because Safari does the same. // Firefox used to do the same too, until 4.0 where they fixed it. So at some // point we should probably get rid of these scaling constants and rebaseline // all the blur tests. static const SkScalar kBLUR_SIGMA_SCALE = 0.57735f; return radius ? kBLUR_SIGMA_SCALE * radius + 0.5f : 0.0f; } #define UNROLL_SEPARABLE_LOOPS /** * 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, bool transpose) { int diameter = leftRadius + rightRadius; int kernelSize = diameter + 1; int border = SkMin32(width, diameter); uint32_t scale = (1 << 24) / kernelSize; int new_width = width + SkMax32(leftRadius, rightRadius) * 2; int dst_x_stride = transpose ? height : 1; int dst_y_stride = transpose ? 1 : new_width; uint32_t half = 1 << 23; for (int y = 0; y < height; ++y) { 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; for (int x = 0; x < rightRadius - leftRadius; x++) { *dptr = 0; dptr += dst_x_stride; } #define LEFT_BORDER_ITER \ sum += *right++; \ *dptr = (sum * scale + half) >> 24; \ dptr += dst_x_stride; int x = 0; #ifdef UNROLL_SEPARABLE_LOOPS for (; x < border - 16; x += 16) { LEFT_BORDER_ITER LEFT_BORDER_ITER LEFT_BORDER_ITER LEFT_BORDER_ITER LEFT_BORDER_ITER LEFT_BORDER_ITER LEFT_BORDER_ITER LEFT_BORDER_ITER LEFT_BORDER_ITER LEFT_BORDER_ITER LEFT_BORDER_ITER LEFT_BORDER_ITER LEFT_BORDER_ITER LEFT_BORDER_ITER LEFT_BORDER_ITER LEFT_BORDER_ITER } #endif for (; x < border; ++x) { LEFT_BORDER_ITER } #undef LEFT_BORDER_ITER #define TRIVIAL_ITER \ *dptr = (sum * scale + half) >> 24; \ dptr += dst_x_stride; x = width; #ifdef UNROLL_SEPARABLE_LOOPS for (; x < diameter - 16; x += 16) { TRIVIAL_ITER TRIVIAL_ITER TRIVIAL_ITER TRIVIAL_ITER TRIVIAL_ITER TRIVIAL_ITER TRIVIAL_ITER TRIVIAL_ITER TRIVIAL_ITER TRIVIAL_ITER TRIVIAL_ITER TRIVIAL_ITER TRIVIAL_ITER TRIVIAL_ITER TRIVIAL_ITER TRIVIAL_ITER } #endif for (; x < diameter; ++x) { TRIVIAL_ITER } #undef TRIVIAL_ITER #define CENTER_ITER \ sum += *right++; \ *dptr = (sum * scale + half) >> 24; \ sum -= *left++; \ dptr += dst_x_stride; x = diameter; #ifdef UNROLL_SEPARABLE_LOOPS for (; x < width - 16; x += 16) { CENTER_ITER CENTER_ITER CENTER_ITER CENTER_ITER CENTER_ITER CENTER_ITER CENTER_ITER CENTER_ITER CENTER_ITER CENTER_ITER CENTER_ITER CENTER_ITER CENTER_ITER CENTER_ITER CENTER_ITER CENTER_ITER } #endif for (; x < width; ++x) { CENTER_ITER } #undef CENTER_ITER #define RIGHT_BORDER_ITER \ *dptr = (sum * scale + half) >> 24; \ sum -= *left++; \ dptr += dst_x_stride; x = 0; #ifdef UNROLL_SEPARABLE_LOOPS for (; x < border - 16; x += 16) { RIGHT_BORDER_ITER RIGHT_BORDER_ITER RIGHT_BORDER_ITER RIGHT_BORDER_ITER RIGHT_BORDER_ITER RIGHT_BORDER_ITER RIGHT_BORDER_ITER RIGHT_BORDER_ITER RIGHT_BORDER_ITER RIGHT_BORDER_ITER RIGHT_BORDER_ITER RIGHT_BORDER_ITER RIGHT_BORDER_ITER RIGHT_BORDER_ITER RIGHT_BORDER_ITER RIGHT_BORDER_ITER } #endif for (; x < border; ++x) { RIGHT_BORDER_ITER } #undef RIGHT_BORDER_ITER for (int x = 0; x < leftRadius - rightRadius; ++x) { *dptr = 0; dptr += dst_x_stride; } SkASSERT(sum == 0); } return new_width; } /** * This variant of the box blur handles blurring of non-integer radii. It * keeps two running sums: an outer sum for the rounded-up kernel radius, and * an inner sum for the rounded-down kernel radius. For each pixel, it linearly * 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) { int diameter = radius * 2; int kernelSize = diameter + 1; int border = SkMin32(width, diameter); int inner_weight = 255 - outer_weight; outer_weight += outer_weight >> 7; inner_weight += inner_weight >> 7; uint32_t outer_scale = (outer_weight << 16) / kernelSize; uint32_t inner_scale = (inner_weight << 16) / (kernelSize - 2); uint32_t half = 1 << 23; 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) { 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; int x = 0; #define LEFT_BORDER_ITER \ inner_sum = outer_sum; \ outer_sum += *right++; \ *dptr = (outer_sum * outer_scale + inner_sum * inner_scale + half) >> 24; \ dptr += dst_x_stride; #ifdef UNROLL_SEPARABLE_LOOPS for (;x < border - 16; x += 16) { LEFT_BORDER_ITER LEFT_BORDER_ITER LEFT_BORDER_ITER LEFT_BORDER_ITER LEFT_BORDER_ITER LEFT_BORDER_ITER LEFT_BORDER_ITER LEFT_BORDER_ITER LEFT_BORDER_ITER LEFT_BORDER_ITER LEFT_BORDER_ITER LEFT_BORDER_ITER LEFT_BORDER_ITER LEFT_BORDER_ITER LEFT_BORDER_ITER LEFT_BORDER_ITER } #endif for (;x < border; ++x) { LEFT_BORDER_ITER } #undef LEFT_BORDER_ITER for (int x = width; x < diameter; ++x) { *dptr = (outer_sum * outer_scale + inner_sum * inner_scale + half) >> 24; dptr += dst_x_stride; } x = diameter; #define CENTER_ITER \ 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++; #ifdef UNROLL_SEPARABLE_LOOPS for (; x < width - 16; x += 16) { CENTER_ITER CENTER_ITER CENTER_ITER CENTER_ITER CENTER_ITER CENTER_ITER CENTER_ITER CENTER_ITER CENTER_ITER CENTER_ITER CENTER_ITER CENTER_ITER CENTER_ITER CENTER_ITER CENTER_ITER CENTER_ITER } #endif for (; x < width; ++x) { CENTER_ITER } #undef CENTER_ITER #define RIGHT_BORDER_ITER \ inner_sum = outer_sum - *left++; \ *dptr = (outer_sum * outer_scale + inner_sum * inner_scale + half) >> 24; \ dptr += dst_x_stride; \ outer_sum = inner_sum; x = 0; #ifdef UNROLL_SEPARABLE_LOOPS for (; x < border - 16; x += 16) { RIGHT_BORDER_ITER RIGHT_BORDER_ITER RIGHT_BORDER_ITER RIGHT_BORDER_ITER RIGHT_BORDER_ITER RIGHT_BORDER_ITER RIGHT_BORDER_ITER RIGHT_BORDER_ITER RIGHT_BORDER_ITER RIGHT_BORDER_ITER RIGHT_BORDER_ITER RIGHT_BORDER_ITER RIGHT_BORDER_ITER RIGHT_BORDER_ITER RIGHT_BORDER_ITER RIGHT_BORDER_ITER } #endif for (; x < border; ++x) { RIGHT_BORDER_ITER } #undef RIGHT_BORDER_ITER SkASSERT(outer_sum == 0 && inner_sum == 0); } return new_width; } static void get_adjusted_radii(SkScalar passRadius, int *loRadius, int *hiRadius) { *loRadius = *hiRadius = SkScalarCeilToInt(passRadius); if (SkIntToScalar(*hiRadius) - passRadius > 0.5f) { *loRadius = *hiRadius - 1; } } #include "SkColorPriv.h" static void merge_src_with_blur(uint8_t dst[], int dstRB, const uint8_t src[], int srcRB, const uint8_t blur[], int blurRB, int sw, int sh) { dstRB -= sw; srcRB -= sw; blurRB -= sw; while (--sh >= 0) { for (int x = sw - 1; x >= 0; --x) { *dst = SkToU8(SkAlphaMul(*blur, SkAlpha255To256(*src))); dst += 1; src += 1; blur += 1; } dst += dstRB; src += srcRB; blur += blurRB; } } static void clamp_with_orig(uint8_t dst[], int dstRowBytes, const uint8_t src[], int srcRowBytes, int sw, int sh, SkBlurMask::Style style) { int x; while (--sh >= 0) { switch (style) { case SkBlurMask::kSolid_Style: for (x = sw - 1; x >= 0; --x) { int s = *src; int d = *dst; *dst = SkToU8(s + d - SkMulDiv255Round(s, d)); dst += 1; src += 1; } break; case SkBlurMask::kOuter_Style: for (x = sw - 1; x >= 0; --x) { if (*src) { *dst = SkToU8(SkAlphaMul(*dst, SkAlpha255To256(255 - *src))); } dst += 1; src += 1; } break; default: SkDEBUGFAIL("Unexpected blur style here"); break; } dst += dstRowBytes - sw; src += srcRowBytes - sw; } } /////////////////////////////////////////////////////////////////////////////// // we use a local function to wrap the class static method to work around // a bug in gcc98 void SkMask_FreeImage(uint8_t* image); void SkMask_FreeImage(uint8_t* image) { SkMask::FreeImage(image); } bool SkBlurMask::BoxBlur(SkMask* dst, const SkMask& src, SkScalar sigma, Style style, Quality quality, SkIPoint* margin) { if (src.fFormat != SkMask::kA8_Format) { return false; } // Force high quality off for small radii (performance) if (sigma <= SkIntToScalar(2)) { quality = kLow_Quality; } SkScalar passRadius; if (kHigh_Quality == quality) { // For the high quality path the 3 pass box blur kernel width is // 6*rad+1 while the full Gaussian width is 6*sigma. passRadius = sigma - (1/6.0f); } else { // For the low quality path we only attempt to cover 3*sigma of the // Gaussian blur area (1.5*sigma on each side). The single pass box // blur's kernel size is 2*rad+1. passRadius = 1.5f*sigma - 0.5f; } // highQuality: use three box blur passes as a cheap way // to approximate a Gaussian blur int passCount = (kHigh_Quality == quality) ? 3 : 1; int rx = SkScalarCeilToInt(passRadius); int outerWeight = 255 - SkScalarRoundToInt((SkIntToScalar(rx) - passRadius) * 255); SkASSERT(rx >= 0); SkASSERT((unsigned)outerWeight <= 255); if (rx <= 0) { return false; } int ry = rx; // only do square blur for now int padx = passCount * rx; int pady = passCount * ry; if (margin) { margin->set(padx, pady); } dst->fBounds.set(src.fBounds.fLeft - padx, src.fBounds.fTop - pady, src.fBounds.fRight + padx, src.fBounds.fBottom + pady); dst->fRowBytes = dst->fBounds.width(); dst->fFormat = SkMask::kA8_Format; dst->fImage = NULL; if (src.fImage) { size_t dstSize = dst->computeImageSize(); if (0 == dstSize) { return false; // too big to allocate, abort } int sw = src.fBounds.width(); int sh = src.fBounds.height(); const uint8_t* sp = src.fImage; uint8_t* dp = SkMask::AllocImage(dstSize); SkAutoTCallVProc autoCall(dp); // build the blurry destination SkAutoTMalloc tmpBuffer(dstSize); uint8_t* tp = tmpBuffer.get(); int w = sw, h = sh; if (outerWeight == 255) { int loRadius, hiRadius; get_adjusted_radii(passRadius, &loRadius, &hiRadius); if (kHigh_Quality == quality) { // Do three X blurs, with a transpose on the final one. w = boxBlur(sp, src.fRowBytes, tp, loRadius, hiRadius, w, h, false); w = boxBlur(tp, w, dp, hiRadius, loRadius, w, h, false); w = boxBlur(dp, w, tp, hiRadius, hiRadius, w, h, true); // Do three Y blurs, with a transpose on the final one. h = boxBlur(tp, h, dp, loRadius, hiRadius, h, w, false); h = boxBlur(dp, h, tp, hiRadius, loRadius, h, w, false); h = boxBlur(tp, h, dp, hiRadius, hiRadius, h, w, true); } else { w = boxBlur(sp, src.fRowBytes, tp, rx, rx, w, h, true); h = boxBlur(tp, h, dp, ry, ry, h, w, true); } } else { if (kHigh_Quality == quality) { // Do three X blurs, with a transpose on the final one. w = boxBlurInterp(sp, src.fRowBytes, tp, rx, w, h, false, outerWeight); w = boxBlurInterp(tp, w, dp, rx, w, h, false, outerWeight); w = boxBlurInterp(dp, w, tp, rx, w, h, true, outerWeight); // Do three Y blurs, with a transpose on the final one. h = boxBlurInterp(tp, h, dp, ry, h, w, false, outerWeight); h = boxBlurInterp(dp, h, tp, ry, h, w, false, outerWeight); h = boxBlurInterp(tp, h, dp, ry, h, w, true, outerWeight); } else { w = boxBlurInterp(sp, src.fRowBytes, tp, rx, w, h, true, outerWeight); h = boxBlurInterp(tp, h, dp, ry, h, w, true, outerWeight); } } dst->fImage = dp; // if need be, alloc the "real" dst (same size as src) and copy/merge // the blur into it (applying the src) if (style == kInner_Style) { // now we allocate the "real" dst, mirror the size of src size_t srcSize = src.computeImageSize(); if (0 == srcSize) { return false; // too big to allocate, abort } dst->fImage = SkMask::AllocImage(srcSize); merge_src_with_blur(dst->fImage, src.fRowBytes, sp, src.fRowBytes, dp + passCount * (rx + ry * dst->fRowBytes), dst->fRowBytes, sw, sh); SkMask::FreeImage(dp); } else if (style != kNormal_Style) { clamp_with_orig(dp + passCount * (rx + ry * dst->fRowBytes), dst->fRowBytes, sp, src.fRowBytes, sw, sh, style); } (void)autoCall.detach(); } if (style == kInner_Style) { dst->fBounds = src.fBounds; // restore trimmed bounds dst->fRowBytes = src.fRowBytes; } return true; } /* Convolving a box with itself three times results in a piecewise quadratic function: 0 x <= -1.5 9/8 + 3/2 x + 1/2 x^2 -1.5 < x <= -.5 3/4 - x^2 -.5 < x <= .5 9/8 - 3/2 x + 1/2 x^2 0.5 < x <= 1.5 0 1.5 < x Mathematica: g[x_] := Piecewise [ { {9/8 + 3/2 x + 1/2 x^2 , -1.5 < x <= -.5}, {3/4 - x^2 , -.5 < x <= .5}, {9/8 - 3/2 x + 1/2 x^2 , 0.5 < x <= 1.5} }, 0] To get the profile curve of the blurred step function at the rectangle edge, we evaluate the indefinite integral, which is piecewise cubic: 0 x <= -1.5 9/16 + 9/8 x + 3/4 x^2 + 1/6 x^3 -1.5 < x <= -0.5 1/2 + 3/4 x - 1/3 x^3 -.5 < x <= .5 7/16 + 9/8 x - 3/4 x^2 + 1/6 x^3 .5 < x <= 1.5 1 1.5 < x in Mathematica code: gi[x_] := Piecewise[ { { 0 , x <= -1.5 }, { 9/16 + 9/8 x + 3/4 x^2 + 1/6 x^3, -1.5 < x <= -0.5 }, { 1/2 + 3/4 x - 1/3 x^3 , -.5 < x <= .5}, { 7/16 + 9/8 x - 3/4 x^2 + 1/6 x^3, .5 < x <= 1.5} },1] */ static float gaussianIntegral(float x) { if (x > 1.5f) { return 0.0f; } if (x < -1.5f) { return 1.0f; } float x2 = x*x; float x3 = x2*x; if ( x > 0.5f ) { return 0.5625f - (x3 / 6.0f - 3.0f * x2 * 0.25f + 1.125f * x); } if ( x > -0.5f ) { return 0.5f - (0.75f * x - x3 / 3.0f); } return 0.4375f + (-x3 / 6.0f - 3.0f * x2 * 0.25f - 1.125f * x); } /* ComputeBlurProfile allocates and fills in an array of floating point values between 0 and 255 for the profile signature of a blurred half-plane with the given blur radius. Since we're going to be doing screened multiplications (i.e., 1 - (1-x)(1-y)) all the time, we actually fill in the profile pre-inverted (already done 255-x). It's the responsibility of the caller to delete the memory returned in profile_out. */ void SkBlurMask::ComputeBlurProfile(SkScalar sigma, uint8_t **profile_out) { int size = SkScalarCeilToInt(6*sigma); int center = size >> 1; uint8_t *profile = SkNEW_ARRAY(uint8_t, size); float invr = 1.f/(2*sigma); profile[0] = 255; for (int x = 1 ; x < size ; ++x) { float scaled_x = (center - x - .5f) * invr; float gi = gaussianIntegral(scaled_x); profile[x] = 255 - (uint8_t) (255.f * gi); } *profile_out = profile; } // TODO MAYBE: Maintain a profile cache to avoid recomputing this for // commonly used radii. Consider baking some of the most common blur radii // directly in as static data? // Implementation adapted from Michael Herf's approach: // http://stereopsis.com/shadowrect/ uint8_t SkBlurMask::ProfileLookup(const uint8_t *profile, int loc, int blurred_width, int sharp_width) { int dx = SkAbs32(((loc << 1) + 1) - blurred_width) - sharp_width; // how far are we from the original edge? int ox = dx >> 1; if (ox < 0) { ox = 0; } return profile[ox]; } void SkBlurMask::ComputeBlurredScanline(uint8_t *pixels, const uint8_t *profile, unsigned int width, SkScalar sigma) { unsigned int profile_size = SkScalarCeilToInt(6*sigma); SkAutoTMalloc horizontalScanline(width); unsigned int sw = width - profile_size; // nearest odd number less than the profile size represents the center // of the (2x scaled) profile int center = ( profile_size & ~1 ) - 1; int w = sw - center; for (unsigned int x = 0 ; x < width ; ++x) { if (profile_size <= sw) { pixels[x] = ProfileLookup(profile, x, width, w); } else { float span = float(sw)/(2*sigma); float giX = 1.5f - (x+.5f)/(2*sigma); pixels[x] = (uint8_t) (255 * (gaussianIntegral(giX) - gaussianIntegral(giX + span))); } } } bool SkBlurMask::BlurRect(SkScalar sigma, SkMask *dst, const SkRect &src, Style style, SkIPoint *margin, SkMask::CreateMode createMode) { int profile_size = SkScalarCeilToInt(6*sigma); int pad = profile_size/2; if (margin) { margin->set( pad, pad ); } dst->fBounds.set(SkScalarRoundToInt(src.fLeft - pad), SkScalarRoundToInt(src.fTop - pad), SkScalarRoundToInt(src.fRight + pad), SkScalarRoundToInt(src.fBottom + pad)); dst->fRowBytes = dst->fBounds.width(); dst->fFormat = SkMask::kA8_Format; dst->fImage = NULL; int sw = SkScalarFloorToInt(src.width()); int sh = SkScalarFloorToInt(src.height()); if (createMode == SkMask::kJustComputeBounds_CreateMode) { if (style == kInner_Style) { dst->fBounds.set(SkScalarRoundToInt(src.fLeft), SkScalarRoundToInt(src.fTop), SkScalarRoundToInt(src.fRight), SkScalarRoundToInt(src.fBottom)); // restore trimmed bounds dst->fRowBytes = sw; } return true; } uint8_t *profile = NULL; ComputeBlurProfile(sigma, &profile); SkAutoTDeleteArray ada(profile); size_t dstSize = dst->computeImageSize(); if (0 == dstSize) { return false; // too big to allocate, abort } uint8_t* dp = SkMask::AllocImage(dstSize); dst->fImage = dp; int dstHeight = dst->fBounds.height(); int dstWidth = dst->fBounds.width(); uint8_t *outptr = dp; SkAutoTMalloc horizontalScanline(dstWidth); SkAutoTMalloc verticalScanline(dstHeight); ComputeBlurredScanline(horizontalScanline, profile, dstWidth, sigma); ComputeBlurredScanline(verticalScanline, profile, dstHeight, sigma); for (int y = 0 ; y < dstHeight ; ++y) { for (int x = 0 ; x < dstWidth ; x++) { unsigned int maskval = SkMulDiv255Round(horizontalScanline[x], verticalScanline[y]); *(outptr++) = maskval; } } if (style == kInner_Style) { // now we allocate the "real" dst, mirror the size of src size_t srcSize = (size_t)(src.width() * src.height()); if (0 == srcSize) { return false; // too big to allocate, abort } dst->fImage = SkMask::AllocImage(srcSize); for (int y = 0 ; y < sh ; y++) { uint8_t *blur_scanline = dp + (y+pad)*dstWidth + pad; uint8_t *inner_scanline = dst->fImage + y*sw; memcpy(inner_scanline, blur_scanline, sw); } SkMask::FreeImage(dp); dst->fBounds.set(SkScalarRoundToInt(src.fLeft), SkScalarRoundToInt(src.fTop), SkScalarRoundToInt(src.fRight), SkScalarRoundToInt(src.fBottom)); // restore trimmed bounds dst->fRowBytes = sw; } else if (style == kOuter_Style) { for (int y = pad ; y < dstHeight-pad ; y++) { uint8_t *dst_scanline = dp + y*dstWidth + pad; memset(dst_scanline, 0, sw); } } else if (style == kSolid_Style) { for (int y = pad ; y < dstHeight-pad ; y++) { uint8_t *dst_scanline = dp + y*dstWidth + pad; memset(dst_scanline, 0xff, sw); } } // normal and solid styles are the same for analytic rect blurs, so don't // need to handle solid specially. return true; } bool SkBlurMask::BlurRRect(SkScalar sigma, SkMask *dst, const SkRRect &src, Style style, SkIPoint *margin, SkMask::CreateMode createMode) { // Temporary for now -- always fail, should cause caller to fall back // to old path. Plumbing just to land API and parallelize effort. return false; } // The "simple" blur is a direct implementation of separable convolution with a discrete // gaussian kernel. It's "ground truth" in a sense; too slow to be used, but very // useful for correctness comparisons. bool SkBlurMask::BlurGroundTruth(SkScalar sigma, SkMask* dst, const SkMask& src, Style style, SkIPoint* margin) { if (src.fFormat != SkMask::kA8_Format) { return false; } float variance = sigma * sigma; int windowSize = SkScalarCeilToInt(sigma*6); // round window size up to nearest odd number windowSize |= 1; SkAutoTMalloc gaussWindow(windowSize); int halfWindow = windowSize >> 1; gaussWindow[halfWindow] = 1; float windowSum = 1; for (int x = 1 ; x <= halfWindow ; ++x) { float gaussian = expf(-x*x / (2*variance)); gaussWindow[halfWindow + x] = gaussWindow[halfWindow-x] = gaussian; windowSum += 2*gaussian; } // leave the filter un-normalized for now; we will divide by the normalization // sum later; int pad = halfWindow; if (margin) { margin->set( pad, pad ); } dst->fBounds = src.fBounds; dst->fBounds.outset(pad, pad); dst->fRowBytes = dst->fBounds.width(); dst->fFormat = SkMask::kA8_Format; dst->fImage = NULL; if (src.fImage) { size_t dstSize = dst->computeImageSize(); if (0 == dstSize) { return false; // too big to allocate, abort } int srcWidth = src.fBounds.width(); int srcHeight = src.fBounds.height(); int dstWidth = dst->fBounds.width(); const uint8_t* srcPixels = src.fImage; uint8_t* dstPixels = SkMask::AllocImage(dstSize); SkAutoTCallVProc autoCall(dstPixels); // do the actual blur. First, make a padded copy of the source. // use double pad so we never have to check if we're outside anything int padWidth = srcWidth + 4*pad; int padHeight = srcHeight; int padSize = padWidth * padHeight; SkAutoTMalloc padPixels(padSize); memset(padPixels, 0, padSize); for (int y = 0 ; y < srcHeight; ++y) { uint8_t* padptr = padPixels + y * padWidth + 2*pad; const uint8_t* srcptr = srcPixels + y * srcWidth; memcpy(padptr, srcptr, srcWidth); } // blur in X, transposing the result into a temporary floating point buffer. // also double-pad the intermediate result so that the second blur doesn't // have to do extra conditionals. int tmpWidth = padHeight + 4*pad; int tmpHeight = padWidth - 2*pad; int tmpSize = tmpWidth * tmpHeight; SkAutoTMalloc tmpImage(tmpSize); memset(tmpImage, 0, tmpSize*sizeof(tmpImage[0])); for (int y = 0 ; y < padHeight ; ++y) { uint8_t *srcScanline = padPixels + y*padWidth; for (int x = pad ; x < padWidth - pad ; ++x) { float *outPixel = tmpImage + (x-pad)*tmpWidth + y + 2*pad; // transposed output uint8_t *windowCenter = srcScanline + x; for (int i = -pad ; i <= pad ; ++i) { *outPixel += gaussWindow[pad+i]*windowCenter[i]; } *outPixel /= windowSum; } } // blur in Y; now filling in the actual desired destination. We have to do // the transpose again; these transposes guarantee that we read memory in // linear order. for (int y = 0 ; y < tmpHeight ; ++y) { float *srcScanline = tmpImage + y*tmpWidth; for (int x = pad ; x < tmpWidth - pad ; ++x) { float *windowCenter = srcScanline + x; float finalValue = 0; for (int i = -pad ; i <= pad ; ++i) { finalValue += gaussWindow[pad+i]*windowCenter[i]; } finalValue /= windowSum; uint8_t *outPixel = dstPixels + (x-pad)*dstWidth + y; // transposed output int integerPixel = int(finalValue + 0.5f); *outPixel = SkClampMax( SkClampPos(integerPixel), 255 ); } } dst->fImage = dstPixels; // if need be, alloc the "real" dst (same size as src) and copy/merge // the blur into it (applying the src) if (style == kInner_Style) { // now we allocate the "real" dst, mirror the size of src size_t srcSize = src.computeImageSize(); if (0 == srcSize) { return false; // too big to allocate, abort } dst->fImage = SkMask::AllocImage(srcSize); merge_src_with_blur(dst->fImage, src.fRowBytes, srcPixels, src.fRowBytes, dstPixels + pad*dst->fRowBytes + pad, dst->fRowBytes, srcWidth, srcHeight); SkMask::FreeImage(dstPixels); } else if (style != kNormal_Style) { clamp_with_orig(dstPixels + pad*dst->fRowBytes + pad, dst->fRowBytes, srcPixels, src.fRowBytes, srcWidth, srcHeight, style); } (void)autoCall.detach(); } if (style == kInner_Style) { dst->fBounds = src.fBounds; // restore trimmed bounds dst->fRowBytes = src.fRowBytes; } return true; }