From 26a029d407be480d791972afb5975cf62c9360a6 Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Fri, 19 Apr 2024 02:47:55 +0200 Subject: Adding upstream version 124.0.1. Signed-off-by: Daniel Baumann --- gfx/2d/SkConvolver.h | 169 +++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 169 insertions(+) create mode 100644 gfx/2d/SkConvolver.h (limited to 'gfx/2d/SkConvolver.h') diff --git a/gfx/2d/SkConvolver.h b/gfx/2d/SkConvolver.h new file mode 100644 index 0000000000..5ea8ab9b5d --- /dev/null +++ b/gfx/2d/SkConvolver.h @@ -0,0 +1,169 @@ +/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */ +/* vim: set ts=8 sts=2 et sw=2 tw=80: */ +// Copyright (c) 2011-2016 Google Inc. +// Use of this source code is governed by a BSD-style license that can be +// found in the gfx/skia/LICENSE file. + +#ifndef MOZILLA_GFX_SKCONVOLVER_H_ +#define MOZILLA_GFX_SKCONVOLVER_H_ + +#include "mozilla/Assertions.h" +#include +#include +#include + +namespace skia { + +class SkBitmapFilter { + public: + explicit SkBitmapFilter(float width) : fWidth(width) {} + virtual ~SkBitmapFilter() = default; + + float width() const { return fWidth; } + virtual float evaluate(float x) const = 0; + + protected: + float fWidth; +}; + +class SkBoxFilter final : public SkBitmapFilter { + public: + explicit SkBoxFilter(float width = 0.5f) : SkBitmapFilter(width) {} + + float evaluate(float x) const override { + return (x >= -fWidth && x < fWidth) ? 1.0f : 0.0f; + } +}; + +class SkLanczosFilter final : public SkBitmapFilter { + public: + explicit SkLanczosFilter(float width = 3.0f) : SkBitmapFilter(width) {} + + float evaluate(float x) const override { + if (x <= -fWidth || x >= fWidth) { + return 0.0f; // Outside of the window. + } + if (x > -FLT_EPSILON && x < FLT_EPSILON) { + return 1.0f; // Special case the discontinuity at the origin. + } + float xpi = x * float(M_PI); + return (sinf(xpi) / xpi) * // sinc(x) + sinf(xpi / fWidth) / (xpi / fWidth); // sinc(x/fWidth) + } +}; + +// Represents a filter in one dimension. Each output pixel has one entry in this +// object for the filter values contributing to it. You build up the filter +// list by calling AddFilter for each output pixel (in order). +// +// We do 2-dimensional convolution by first convolving each row by one +// SkConvolutionFilter1D, then convolving each column by another one. +// +// Entries are stored in ConvolutionFixed point, shifted left by kShiftBits. +class SkConvolutionFilter1D { + public: + using ConvolutionFixed = short; + + // The number of bits that ConvolutionFixed point values are shifted by. + enum { kShiftBits = 14 }; + + SkConvolutionFilter1D(); + ~SkConvolutionFilter1D(); + + // Convert between floating point and our ConvolutionFixed point + // representation. + static ConvolutionFixed ToFixed(float f) { + return static_cast(f * (1 << kShiftBits)); + } + + // Returns the maximum pixel span of a filter. + int maxFilter() const { return fMaxFilter; } + + // Returns the number of filters in this filter. This is the dimension of the + // output image. + int numValues() const { return static_cast(fFilters.size()); } + + void reserveAdditional(int filterCount, int filterValueCount) { + fFilters.reserve(fFilters.size() + filterCount); + fFilterValues.reserve(fFilterValues.size() + filterValueCount); + } + + // Appends the given list of scaling values for generating a given output + // pixel. |filterOffset| is the distance from the edge of the image to where + // the scaling factors start. The scaling factors apply to the source pixels + // starting from this position, and going for the next |filterLength| pixels. + // + // You will probably want to make sure your input is normalized (that is, + // all entries in |filterValuesg| sub to one) to prevent affecting the overall + // brighness of the image. + // + // The filterLength must be > 0. + void AddFilter(int filterOffset, const ConvolutionFixed* filterValues, + int filterLength); + + // Retrieves a filter for the given |valueOffset|, a position in the output + // image in the direction we're convolving. The offset and length of the + // filter values are put into the corresponding out arguments (see AddFilter + // above for what these mean), and a pointer to the first scaling factor is + // returned. There will be |filterLength| values in this array. + inline const ConvolutionFixed* FilterForValue(int valueOffset, + int* filterOffset, + int* filterLength) const { + const FilterInstance& filter = fFilters[valueOffset]; + *filterOffset = filter.fOffset; + *filterLength = filter.fTrimmedLength; + if (filter.fTrimmedLength == 0) { + return nullptr; + } + return &fFilterValues[filter.fDataLocation]; + } + + bool ComputeFilterValues(const SkBitmapFilter& aBitmapFilter, + int32_t aSrcSize, int32_t aDstSize); + + private: + struct FilterInstance { + // Offset within filterValues for this instance of the filter. + int fDataLocation; + + // Distance from the left of the filter to the center. IN PIXELS + int fOffset; + + // Number of values in this filter instance. + int fTrimmedLength; + + // Filter length as specified. Note that this may be different from + // 'trimmed_length' if leading/trailing zeros of the original floating + // point form were clipped differently on each tail. + int fLength; + }; + + // Stores the information for each filter added to this class. + std::vector fFilters; + + // We store all the filter values in this flat list, indexed by + // |FilterInstance.data_location| to avoid the mallocs required for storing + // each one separately. + std::vector fFilterValues; + + // The maximum size of any filter we've added. + int fMaxFilter; +}; + +void convolve_horizontally(const unsigned char* srcData, + const SkConvolutionFilter1D& filter, + unsigned char* outRow, bool hasAlpha); + +void convolve_vertically( + const SkConvolutionFilter1D::ConvolutionFixed* filterValues, + int filterLength, unsigned char* const* sourceDataRows, int pixelWidth, + unsigned char* outRow, bool hasAlpha); + +bool BGRAConvolve2D(const unsigned char* sourceData, int sourceByteRowStride, + bool sourceHasAlpha, const SkConvolutionFilter1D& filterX, + const SkConvolutionFilter1D& filterY, + int outputByteRowStride, unsigned char* output); + +} // namespace skia + +#endif /* MOZILLA_GFX_SKCONVOLVER_H_ */ -- cgit v1.2.3