Reland the combined 3 pass image blur with a fix to the bounds calculation
Use the old bounds calculation so that CPU and GPU agree. Adjust all the combined 3 pass code to use the new bounds. This reverts commit59f8f15487and fixes bound calculation. Original change's description: > Revert "Use combined three pass code for image blur." > > This reverts commitd4a0fc7383. > > Reason for revert: Too naive about bounds > > Original change's description: > > Use combined three pass code for image blur. > > > > This changes more closely matches the GL output, and the runtimes are similar or > > faster for the common cases. > > > > x86_64 times: > > benchmark old-Us new-Us old/new > > blur_image_filter_large_80.00_80.00 4842.04 2626.10 1.84381 > > blur_image_filter_small_80.00_80.00 3297.72 854.97 3.85712 > > blur_image_filter_large_10.00_10.00 930.44 720.50 1.29138 > > blur_image_filter_small_10.00_10.00 69.96 42.15 1.65979 > > blur_image_filter_large_1.00_1.00 682.66 521.78 1.30833 > > blur_image_filter_small_1.00_1.00 19.21 14.43 1.33125 > > blur_image_filter_large_0.50_0.50 696.17 64.14 10.8539 > > blur_image_filter_small_0.50_0.50 16.26 5.02 3.23904 > > > > arm64 times: > > benchmark old-Us new-Us old/new > > blur_image_filter_large_80.00_80.00 42144.53 14128.42 2.98296 > > blur_image_filter_small_80.00_80.00 24840.58 4392.58 5.65512 > > blur_image_filter_large_10.00_10.00 3556.40 3793.70 0.937449 > > blur_image_filter_small_10.00_10.00 282.53 220.62 1.28062 > > blur_image_filter_large_1.00_1.00 2502.20 2937.99 0.851671 > > blur_image_filter_small_1.00_1.00 83.32 81.93 1.01697 > > blur_image_filter_large_0.50_0.50 5643.80 272.83 20.6861 > > blur_image_filter_small_0.50_0.50 141.02 38.29 3.68295 > > > > Cq-Include-Trybots: skia.primary:Test-Debian9-Clang-GCE-CPU-AVX2-x86_64-Release-All-SKNX_NO_SIMD > > Change-Id: Ic53b3186607d5485477b92e4ca7b092bf1366c52 > > Reviewed-on: https://skia-review.googlesource.com/52771 > > Commit-Queue: Herb Derby <herb@google.com> > > Reviewed-by: Mike Klein <mtklein@google.com> > > TBR=mtklein@google.com,herb@google.com,senorblanco@chromium.org > > Change-Id: Idf679a8fc6d777625ad9527b843aa1614d878cba > No-Presubmit: true > No-Tree-Checks: true > No-Try: true > Cq-Include-Trybots: skia.primary:Test-Debian9-Clang-GCE-CPU-AVX2-x86_64-Release-All-SKNX_NO_SIMD > Reviewed-on: https://skia-review.googlesource.com/60900 > Reviewed-by: Herb Derby <herb@google.com> > Commit-Queue: Herb Derby <herb@google.com> Change-Id: Idda0d83b1e2f753c9c8e703f9506dd31b117ec55 Cq-Include-Trybots: skia.primary:Test-Debian9-Clang-GCE-CPU-AVX2-x86_64-Release-All-SKNX_NO_SIMD Reviewed-on: https://skia-review.googlesource.com/61320 Commit-Queue: Herb Derby <herb@google.com> Reviewed-by: Mike Klein <mtklein@google.com>
This commit is contained in:
Herb Derby
Skia Commit-Bot
parent
85f8536ca2
commit
0cc4824141
@ -7,11 +7,16 @@
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#include "SkBlurImageFilter.h"
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#include <algorithm>
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#include "SkArenaAlloc.h"
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#include "SkAutoPixmapStorage.h"
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#include "SkBitmap.h"
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#include "SkColorData.h"
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#include "SkColorSpaceXformer.h"
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#include "SkTFitsIn.h"
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#include "SkGpuBlurUtils.h"
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#include "SkNx.h"
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#include "SkOpts.h"
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#include "SkReadBuffer.h"
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#include "SkSpecialImage.h"
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@ -23,6 +28,11 @@
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#include "SkGr.h"
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#endif
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// The value where the three pass window calculation results in a zero window.
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// N[Solve[sigma*3*Sqrt[2 Pi]/4 == 1/2, sigma], 16]
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static constexpr double kZeroWindow = 0.26596152026762;
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static constexpr double kPi = 3.14159265358979323846264338327950288;
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class SkBlurImageFilterImpl final : public SkImageFilter {
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public:
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SkBlurImageFilterImpl(SkScalar sigmaX,
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@ -162,6 +172,367 @@ static void get_box3_params(SkScalar s, int *kernelSize, int* kernelSize3, int *
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}
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}
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#if !defined(SK_SUPPORT_LEGACY_BLUR_IMAGE)
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// This is defined by the SVG spec:
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// https://drafts.fxtf.org/filter-effects/#feGaussianBlurElement
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static int calculate_window(double sigma) {
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// NB 136 is the largest sigma that will not cause a buffer full of 255 mask values to overflow
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// using the Gauss filter. It also limits the size of buffers used hold intermediate values.
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// Explanation of maximums:
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// sum0 = window * 255
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// sum1 = window * sum0 -> window * window * 255
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// sum2 = window * sum1 -> window * window * window * 255 -> window^3 * 255
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//
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// The value window^3 * 255 must fit in a uint32_t. So,
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// window^3 < 2^32. window = 255.
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//
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// window = floor(sigma * 3 * sqrt(2 * kPi) / 4 + 0.5)
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// For window <= 255, the largest value for sigma is 136.
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sigma = SkTPin(sigma, 0.0, 136.0);
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auto possibleWindow = static_cast<int>(floor(sigma * 3 * sqrt(2 * kPi) / 4 + 0.5));
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return std::max(1, possibleWindow);
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}
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// Calculating the border is tricky. The border is the distance in pixels between the first dst
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// pixel and the first src pixel (or the last src pixel and the last dst pixel).
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// I will go through the odd case which is simpler, and then through the even case. Given a
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// stack of filters seven wide for the odd case of three passes.
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//
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// S
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// aaaAaaa
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// bbbBbbb
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// cccCccc
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// D
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//
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// The furthest changed pixel is when the filters are in the following configuration.
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//
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// S
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// aaaAaaa
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// bbbBbbb
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// cccCccc
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// D
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//
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// The A pixel is calculated using the value S, the B uses A, and the C uses B, and
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// finally D is C. So, with a window size of seven the border is nine. In the odd case, the
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// border is 3*((window - 1)/2).
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//
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// For even cases the filter stack is more complicated. The spec specifies two passes
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// of even filters and a final pass of odd filters. A stack for a width of six looks like
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// this.
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//
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// S
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// aaaAaa
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// bbBbbb
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// cccCccc
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// D
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//
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// The furthest pixel looks like this.
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//
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// S
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// aaaAaa
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// bbBbbb
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// cccCccc
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// D
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//
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// For a window of six, the border value is eight. In the even case the border is 3 *
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// (window/2) - 1.
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static int calculate_border(int window) {
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return (window & 1) == 1 ? 3 * ((window - 1) / 2) : 3 * (window / 2) - 1;
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}
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static int calculate_buffer(int window) {
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int bufferSize = window - 1;
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return (window & 1) == 1 ? 3 * bufferSize : 3 * bufferSize + 1;
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}
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// blur_one_direction implements the common three pass box filter approximation of Gaussian blur,
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// but combines all three passes into a single pass. This approach is facilitated by three circular
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// buffers the width of the window which track values for trailing edges of each of the three
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// passes. This allows the algorithm to use more precision in the calculation because the values
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// are not rounded each pass. And this implementation also avoids a trap that's easy to fall
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// into resulting in blending in too many zeroes near the edge.
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//
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// In general, a window sum has the form:
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// sum_n+1 = sum_n + leading_edge - trailing_edge.
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// If instead we do the subtraction at the end of the previous iteration, we can just
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// calculate the sums instead of having to do the subtractions too.
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//
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// In previous iteration:
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// sum_n+1 = sum_n - trailing_edge.
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//
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// In this iteration:
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// sum_n+1 = sum_n + leading_edge.
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//
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// Now we can stack all three sums and do them at once. Sum0 gets its leading edge from the
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// actual data. Sum1's leading edge is just Sum0, and Sum2's leading edge is Sum1. So, doing the
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// three passes at the same time has the form:
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//
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// sum0_n+1 = sum0_n + leading edge
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// sum1_n+1 = sum1_n + sum0_n+1
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// sum2_n+1 = sum2_n + sum1_n+1
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//
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// sum2_n+1 / window^3 is the new value of the destination pixel.
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//
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// Reduce the sums by the trailing edges which were stored in the circular buffers,
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// for the next go around. This is the case for odd sized windows, even windows the the third
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// circular buffer is one larger then the first two circular buffers.
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//
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// sum2_n+2 = sum2_n+1 - buffer2[i];
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// buffer2[i] = sum1;
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// sum1_n+2 = sum1_n+1 - buffer1[i];
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// buffer1[i] = sum0;
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// sum0_n+2 = sum0_n+1 - buffer0[i];
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// buffer0[i] = leading edge
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//
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// This is all encapsulated in the processValue function below.
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//
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using Pass0And1 = Sk4u[2];
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// The would be dLeft parameter is assumed to be 0.
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static void blur_one_direction(Sk4u* buffer, int window,
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int srcLeft, int srcRight, int dstRight,
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const uint32_t* src, int srcXStride, int srcYStride, int srcH,
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uint32_t* dst, int dstXStride, int dstYStride) {
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// The circular buffers are one less than the window.
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auto pass0Count = window - 1,
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pass1Count = window - 1,
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pass2Count = (window & 1) == 1 ? window - 1 : window;
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Pass0And1* buffer01Start = (Pass0And1*)buffer;
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Sk4u* buffer2Start = buffer + pass0Count + pass1Count;
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Pass0And1* buffer01End = (Pass0And1*)buffer2Start;
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Sk4u* buffer2End = buffer2Start + pass2Count;
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// If the window is odd then the divisor is just window ^ 3 otherwise,
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// it is window * window * (window + 1) = window ^ 3 + window ^ 2;
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auto window2 = window * window;
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auto window3 = window2 * window;
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auto divisor = (window & 1) == 1 ? window3 : window3 + window2;
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// NB the sums in the blur code use the following technique to avoid
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// adding 1/2 to round the divide.
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//
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// Sum/d + 1/2 == (Sum + h) / d
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// Sum + d(1/2) == Sum + h
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// h == (1/2)d
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//
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// But the d/2 it self should be rounded.
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// h == d/2 + 1/2 == (d + 1) / 2
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//
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// weight = 1 / d * 2 ^ 32
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auto weight = static_cast<uint32_t>(round(1.0 / divisor * (1ull << 32)));
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auto half = static_cast<uint32_t>((divisor + 1) / 2);
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auto border = calculate_border(window);
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// Calculate the start and end of the source pixels with respect to the destination start.
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auto srcStart = srcLeft - border,
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srcEnd = srcRight - border,
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dstEnd = dstRight;
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for (auto y = 0; y < srcH; y++) {
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auto buffer01Cursor = buffer01Start;
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auto buffer2Cursor = buffer2Start;
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Sk4u sum0{0u};
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Sk4u sum1{0u};
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Sk4u sum2{half};
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sk_bzero(buffer01Start, (buffer2End - (Sk4u *) (buffer01Start)) * sizeof(*buffer2Start));
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// Given an expanded input pixel, move the window ahead using the leadingEdge value.
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auto processValue = [&](const Sk4u& leadingEdge) -> Sk4u {
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sum0 += leadingEdge;
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sum1 += sum0;
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sum2 += sum1;
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Sk4u value = sum2.mulHi(weight);
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sum2 -= *buffer2Cursor;
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*buffer2Cursor = sum1;
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buffer2Cursor = (buffer2Cursor + 1) < buffer2End ? buffer2Cursor + 1 : buffer2Start;
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sum1 -= (*buffer01Cursor)[1];
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(*buffer01Cursor)[1] = sum0;
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sum0 -= (*buffer01Cursor)[0];
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(*buffer01Cursor)[0] = leadingEdge;
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buffer01Cursor =
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(buffer01Cursor + 1) < buffer01End ? buffer01Cursor + 1 : buffer01Start;
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return value;
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};
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auto srcIdx = srcStart;
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auto dstIdx = 0;
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const uint32_t* srcCursor = src;
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uint32_t* dstCursor = dst;
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// The destination pixels are not effected by the src pixels,
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// change to zero as per the spec.
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// https://drafts.fxtf.org/filter-effects/#FilterPrimitivesOverviewIntro
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while (dstIdx < srcIdx) {
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*dstCursor = 0;
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dstCursor += dstXStride;
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SK_PREFETCH(dstCursor);
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dstIdx++;
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}
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// The edge of the source is before the edge of the destination. Calculate the sums for
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// the pixels before the start of the destination.
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while (dstIdx > srcIdx) {
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Sk4u leadingEdge = srcIdx < srcEnd ? SkNx_cast<uint32_t>(Sk4b::Load(srcCursor)) : 0;
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(void) processValue(leadingEdge);
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srcCursor += srcXStride;
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srcIdx++;
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}
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// The dstIdx and srcIdx are in sync now; the code just uses the dstIdx for both now.
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// Consume the source generating pixels to dst.
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auto loopEnd = std::min(dstEnd, srcEnd);
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while (dstIdx < loopEnd) {
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Sk4u leadingEdge = SkNx_cast<uint32_t>(Sk4b::Load(srcCursor));
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SkNx_cast<uint8_t>(processValue(leadingEdge)).store(dstCursor);
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srcCursor += srcXStride;
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dstCursor += dstXStride;
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SK_PREFETCH(dstCursor);
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dstIdx++;
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}
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// The leading edge is beyond the end of the source. Assume that the pixels
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// are now 0x0000 until the end of the destination.
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loopEnd = dstEnd;
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while (dstIdx < loopEnd) {
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SkNx_cast<uint8_t>(processValue(0u)).store(dstCursor);
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dstCursor += dstXStride;
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SK_PREFETCH(dstCursor);
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dstIdx++;
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}
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src += srcYStride;
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dst += dstYStride;
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}
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}
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static sk_sp<SkSpecialImage> combined_pass_blur(
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SkVector sigma,
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SkSpecialImage* source, const sk_sp<SkSpecialImage>& input,
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SkIRect srcBounds, SkIRect dstBounds) {
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SkBitmap inputBM;
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if (!input->getROPixels(&inputBM)) {
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return nullptr;
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}
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if (inputBM.colorType() != kN32_SkColorType) {
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return nullptr;
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}
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auto windowW = calculate_window(sigma.x()),
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windowH = calculate_window(sigma.y());
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SkBitmap src;
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inputBM.extractSubset(&src, srcBounds);
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// Make everything relative to the destination bounds.
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srcBounds.offset(-dstBounds.x(), -dstBounds.y());
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dstBounds.offset(-dstBounds.x(), -dstBounds.y());
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auto srcW = srcBounds.width(),
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srcH = srcBounds.height(),
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dstW = dstBounds.width(),
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dstH = dstBounds.height();
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SkImageInfo dstInfo = SkImageInfo::Make(dstW, dstH, inputBM.colorType(), inputBM.alphaType());
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SkBitmap dst;
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if (!dst.tryAllocPixels(dstInfo)) {
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return nullptr;
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}
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auto bufferSizeW = calculate_buffer(windowW),
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bufferSizeH = calculate_buffer(windowH);
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// The amount 1024 is enough for buffers up to 10 sigma. The tmp bitmap will be
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// allocated on the heap.
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SkSTArenaAlloc<1024> alloc;
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Sk4u* buffer = alloc.makeArrayDefault<Sk4u>(std::max(bufferSizeW, bufferSizeH));
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if (windowW > 1 && windowH > 1) {
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// Blur both directions.
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auto tmpW = srcH,
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tmpH = dstW;
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auto tmp = alloc.makeArrayDefault<uint32_t>(tmpW * tmpH);
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// Blur horizontally, and transpose.
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blur_one_direction(
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buffer, windowW,
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srcBounds.left(), srcBounds.right(), dstBounds.right(),
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static_cast<uint32_t*>(src.getPixels()), 1, src.rowBytesAsPixels(), srcH,
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tmp, tmpW, 1);
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// Blur vertically (scan in memory order because of the transposition),
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// and transpose back to the original orientation.
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blur_one_direction(
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buffer, windowH,
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srcBounds.top(), srcBounds.bottom(), dstBounds.bottom(),
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tmp, 1, tmpW, tmpH,
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static_cast<uint32_t*>(dst.getPixels()), dst.rowBytesAsPixels(), 1);
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} else if (windowW > 1) {
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// Blur only horizontally.
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blur_one_direction(
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buffer, windowW,
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srcBounds.left(), srcBounds.right(), dstBounds.right(),
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static_cast<uint32_t*>(src.getPixels()), 1, src.rowBytesAsPixels(), srcH,
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static_cast<uint32_t*>(dst.getPixels()), 1, dst.rowBytesAsPixels());
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} else if (windowH > 1) {
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// Blur only vertically.
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blur_one_direction(
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buffer, windowH,
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srcBounds.top(), srcBounds.bottom(), dstBounds.bottom(),
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static_cast<uint32_t*>(src.getPixels()), src.rowBytesAsPixels(), 1, srcW,
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static_cast<uint32_t*>(dst.getPixels()), dst.rowBytesAsPixels(), 1);
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} else {
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// There is no blurring to do, but we still need to copy the source while accounting for the
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// dstBounds. Remember that the src was intersected with the dst.
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int y = 0;
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size_t dstWBytes = dstW * sizeof(uint32_t);
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for (;y < srcBounds.top(); y++) {
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sk_bzero(dst.getAddr32(0, y), dstWBytes);
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}
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for (;y < srcBounds.bottom(); y++) {
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int x = 0;
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uint32_t* dstPtr = dst.getAddr32(0, y);
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for (;x < srcBounds.left(); x++) {
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*dstPtr++ = 0;
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}
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memcpy(dstPtr,
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src.getAddr32(x - srcBounds.left(), y - srcBounds.top()),
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srcW * sizeof(uint32_t));
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dstPtr += srcW;
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x += srcW;
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for (;x < dstBounds.right(); x++) {
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*dstPtr++ = 0;
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}
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}
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for (;y < dstBounds.bottom(); y++) {
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sk_bzero(dst.getAddr32(0, y), dstWBytes);
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}
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}
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return SkSpecialImage::MakeFromRaster(SkIRect::MakeWH(dstBounds.width(),
|
||||
dstBounds.height()),
|
||||
dst, &source->props());
|
||||
}
|
||||
#endif
|
||||
|
||||
sk_sp<SkSpecialImage> SkBlurImageFilterImpl::onFilterImage(SkSpecialImage* source,
|
||||
const Context& ctx,
|
||||
SkIPoint* offset) const {
|
||||
@ -207,13 +578,17 @@ sk_sp<SkSpecialImage> SkBlurImageFilterImpl::onFilterImage(SkSpecialImage* sourc
|
||||
} else
|
||||
#endif
|
||||
{
|
||||
// If both sigmas will result in a zero width window, there is nothing to do.
|
||||
if (sigma.x() < kZeroWindow && sigma.y() < kZeroWindow) {
|
||||
result = input->makeSubset(inputBounds);
|
||||
} else {
|
||||
#if defined(SK_SUPPORT_LEGACY_BLUR_IMAGE)
|
||||
result = this->cpuFilter(source, sigma, input, inputBounds, dstBounds);
|
||||
#else
|
||||
// The new code will go here.
|
||||
result = this->cpuFilter(source, sigma, input, inputBounds, dstBounds);
|
||||
result = combined_pass_blur(sigma, source, input, inputBounds, dstBounds);
|
||||
#endif
|
||||
}
|
||||
}
|
||||
|
||||
// Return the resultOffset if the blur succeeded.
|
||||
if (result != nullptr) {
|
||||
@ -235,8 +610,8 @@ sk_sp<SkSpecialImage> SkBlurImageFilterImpl::gpuFilter(
|
||||
// The raw cross arm value c = E^-s
|
||||
// The normalized cross arm value = c/n
|
||||
// N[Solve[{c/n == 1/2048, sigma > 0}, sigma], 16]
|
||||
static constexpr double kCrossTooSmall = 0.2561130112451658;
|
||||
if (sigma.x() < kCrossTooSmall && sigma.y() < kCrossTooSmall) {
|
||||
static constexpr double kZeroWindowGPU = 0.2561130112451658;
|
||||
if (sigma.x() < kZeroWindowGPU && sigma.y() < kZeroWindowGPU) {
|
||||
return input->makeSubset(inputBounds);
|
||||
}
|
||||
|
||||
@ -280,13 +655,6 @@ sk_sp<SkSpecialImage> SkBlurImageFilterImpl::cpuFilter(
|
||||
SkVector sigma, const sk_sp<SkSpecialImage> &input,
|
||||
SkIRect inputBounds, SkIRect dstBounds) const
|
||||
{
|
||||
// If both sigmas will result in a zero width window, there is nothing to do.
|
||||
// N[Solve[sigma*3*Sqrt[2 Pi]/4 == 1/2, sigma], 16]
|
||||
static constexpr double kZeroWindow = 0.2659615202676218;
|
||||
if (sigma.x() < kZeroWindow && sigma.y() < kZeroWindow) {
|
||||
return input->makeSubset(inputBounds);
|
||||
}
|
||||
|
||||
int kernelSizeX, kernelSizeX3, lowOffsetX, highOffsetX;
|
||||
int kernelSizeY, kernelSizeY3, lowOffsetY, highOffsetY;
|
||||
get_box3_params(sigma.x(), &kernelSizeX, &kernelSizeX3, &lowOffsetX, &highOffsetX);
|
||||
|
||||
Loading…
Reference in New Issue
Block a user