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Diffstat (limited to 'gfx/2d/convolver.cpp')
| -rw-r--r-- | gfx/2d/convolver.cpp | 562 |
1 files changed, 562 insertions, 0 deletions
diff --git a/gfx/2d/convolver.cpp b/gfx/2d/convolver.cpp new file mode 100644 index 000000000..0221f1563 --- /dev/null +++ b/gfx/2d/convolver.cpp @@ -0,0 +1,562 @@ +// Copyright (c) 2006-2011 The Chromium Authors. All rights reserved. +// +// Redistribution and use in source and binary forms, with or without +// modification, are permitted provided that the following conditions +// are met: +// * Redistributions of source code must retain the above copyright +// notice, this list of conditions and the following disclaimer. +// * Redistributions in binary form must reproduce the above copyright +// notice, this list of conditions and the following disclaimer in +// the documentation and/or other materials provided with the +// distribution. +// * Neither the name of Google, Inc. nor the names of its contributors +// may be used to endorse or promote products derived from this +// software without specific prior written permission. +// +// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS +// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT +// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS +// FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE +// COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, +// INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, +// BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS +// OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED +// AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, +// OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT +// OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF +// SUCH DAMAGE. + +#include "2D.h" +#include "convolver.h" + +#include <algorithm> + +#include "skia/include/core/SkTypes.h" + + +#if defined(USE_SSE2) +#include "convolverSSE2.h" +#endif + +#if defined(_MIPS_ARCH_LOONGSON3A) +#include "convolverLS3.h" +#endif + +using mozilla::gfx::Factory; + +#if defined(SK_CPU_LENDIAN) +#define R_OFFSET_IDX 0 +#define G_OFFSET_IDX 1 +#define B_OFFSET_IDX 2 +#define A_OFFSET_IDX 3 +#else +#define R_OFFSET_IDX 3 +#define G_OFFSET_IDX 2 +#define B_OFFSET_IDX 1 +#define A_OFFSET_IDX 0 +#endif + +#if defined(USE_SSE2) +#define ConvolveHorizontally4_SIMD ConvolveHorizontally4_SSE2 +#define ConvolveHorizontally_SIMD ConvolveHorizontally_SSE2 +#define ConvolveVertically_SIMD ConvolveVertically_SSE2 +#endif + +#if defined(_MIPS_ARCH_LOONGSON3A) +#define ConvolveHorizontally4_SIMD ConvolveHorizontally4_LS3 +#define ConvolveHorizontally_SIMD ConvolveHorizontally_LS3 +#define ConvolveVertically_SIMD ConvolveVertically_LS3 +#endif + +namespace skia { + +namespace { + +// Converts the argument to an 8-bit unsigned value by clamping to the range +// 0-255. +inline unsigned char ClampTo8(int a) { + if (static_cast<unsigned>(a) < 256) + return a; // Avoid the extra check in the common case. + if (a < 0) + return 0; + return 255; +} + +// Stores a list of rows in a circular buffer. The usage is you write into it +// by calling AdvanceRow. It will keep track of which row in the buffer it +// should use next, and the total number of rows added. +class CircularRowBuffer { + public: + // The number of pixels in each row is given in |source_row_pixel_width|. + // The maximum number of rows needed in the buffer is |max_y_filter_size| + // (we only need to store enough rows for the biggest filter). + // + // We use the |first_input_row| to compute the coordinates of all of the + // following rows returned by Advance(). + CircularRowBuffer(int dest_row_pixel_width, int max_y_filter_size, + int first_input_row) + : row_byte_width_(dest_row_pixel_width * 4), + num_rows_(max_y_filter_size), + next_row_(0), + next_row_coordinate_(first_input_row) { + buffer_.resize(row_byte_width_ * max_y_filter_size); + row_addresses_.resize(num_rows_); + } + + // Moves to the next row in the buffer, returning a pointer to the beginning + // of it. + unsigned char* AdvanceRow() { + unsigned char* row = &buffer_[next_row_ * row_byte_width_]; + next_row_coordinate_++; + + // Set the pointer to the next row to use, wrapping around if necessary. + next_row_++; + if (next_row_ == num_rows_) + next_row_ = 0; + return row; + } + + // Returns a pointer to an "unrolled" array of rows. These rows will start + // at the y coordinate placed into |*first_row_index| and will continue in + // order for the maximum number of rows in this circular buffer. + // + // The |first_row_index_| may be negative. This means the circular buffer + // starts before the top of the image (it hasn't been filled yet). + unsigned char* const* GetRowAddresses(int* first_row_index) { + // Example for a 4-element circular buffer holding coords 6-9. + // Row 0 Coord 8 + // Row 1 Coord 9 + // Row 2 Coord 6 <- next_row_ = 2, next_row_coordinate_ = 10. + // Row 3 Coord 7 + // + // The "next" row is also the first (lowest) coordinate. This computation + // may yield a negative value, but that's OK, the math will work out + // since the user of this buffer will compute the offset relative + // to the first_row_index and the negative rows will never be used. + *first_row_index = next_row_coordinate_ - num_rows_; + + int cur_row = next_row_; + for (int i = 0; i < num_rows_; i++) { + row_addresses_[i] = &buffer_[cur_row * row_byte_width_]; + + // Advance to the next row, wrapping if necessary. + cur_row++; + if (cur_row == num_rows_) + cur_row = 0; + } + return &row_addresses_[0]; + } + + private: + // The buffer storing the rows. They are packed, each one row_byte_width_. + std::vector<unsigned char> buffer_; + + // Number of bytes per row in the |buffer_|. + int row_byte_width_; + + // The number of rows available in the buffer. + int num_rows_; + + // The next row index we should write into. This wraps around as the + // circular buffer is used. + int next_row_; + + // The y coordinate of the |next_row_|. This is incremented each time a + // new row is appended and does not wrap. + int next_row_coordinate_; + + // Buffer used by GetRowAddresses(). + std::vector<unsigned char*> row_addresses_; +}; + +} // namespace + +// Convolves horizontally along a single row. The row data is given in +// |src_data| and continues for the [begin, end) of the filter. +template<bool has_alpha> +void ConvolveHorizontally(const unsigned char* src_data, + const ConvolutionFilter1D& filter, + unsigned char* out_row) { + int num_values = filter.num_values(); + // Loop over each pixel on this row in the output image. + for (int out_x = 0; out_x < num_values; out_x++) { + // Get the filter that determines the current output pixel. + int filter_offset, filter_length; + const ConvolutionFilter1D::Fixed* filter_values = + filter.FilterForValue(out_x, &filter_offset, &filter_length); + + // Compute the first pixel in this row that the filter affects. It will + // touch |filter_length| pixels (4 bytes each) after this. + const unsigned char* row_to_filter = &src_data[filter_offset * 4]; + + // Apply the filter to the row to get the destination pixel in |accum|. + int accum[4] = {0}; + for (int filter_x = 0; filter_x < filter_length; filter_x++) { + ConvolutionFilter1D::Fixed cur_filter = filter_values[filter_x]; + accum[0] += cur_filter * row_to_filter[filter_x * 4 + R_OFFSET_IDX]; + accum[1] += cur_filter * row_to_filter[filter_x * 4 + G_OFFSET_IDX]; + accum[2] += cur_filter * row_to_filter[filter_x * 4 + B_OFFSET_IDX]; + if (has_alpha) + accum[3] += cur_filter * row_to_filter[filter_x * 4 + A_OFFSET_IDX]; + } + + // Bring this value back in range. All of the filter scaling factors + // are in fixed point with kShiftBits bits of fractional part. + accum[0] >>= ConvolutionFilter1D::kShiftBits; + accum[1] >>= ConvolutionFilter1D::kShiftBits; + accum[2] >>= ConvolutionFilter1D::kShiftBits; + if (has_alpha) + accum[3] >>= ConvolutionFilter1D::kShiftBits; + + // Store the new pixel. + out_row[out_x * 4 + R_OFFSET_IDX] = ClampTo8(accum[0]); + out_row[out_x * 4 + G_OFFSET_IDX] = ClampTo8(accum[1]); + out_row[out_x * 4 + B_OFFSET_IDX] = ClampTo8(accum[2]); + if (has_alpha) + out_row[out_x * 4 + A_OFFSET_IDX] = ClampTo8(accum[3]); + } +} + +// Does vertical convolution to produce one output row. The filter values and +// length are given in the first two parameters. These are applied to each +// of the rows pointed to in the |source_data_rows| array, with each row +// being |pixel_width| wide. +// +// The output must have room for |pixel_width * 4| bytes. +template<bool has_alpha> +void ConvolveVertically(const ConvolutionFilter1D::Fixed* filter_values, + int filter_length, + unsigned char* const* source_data_rows, + int pixel_width, + unsigned char* out_row) { + // We go through each column in the output and do a vertical convolution, + // generating one output pixel each time. + for (int out_x = 0; out_x < pixel_width; out_x++) { + // Compute the number of bytes over in each row that the current column + // we're convolving starts at. The pixel will cover the next 4 bytes. + int byte_offset = out_x * 4; + + // Apply the filter to one column of pixels. + int accum[4] = {0}; + for (int filter_y = 0; filter_y < filter_length; filter_y++) { + ConvolutionFilter1D::Fixed cur_filter = filter_values[filter_y]; + accum[0] += cur_filter + * source_data_rows[filter_y][byte_offset + R_OFFSET_IDX]; + accum[1] += cur_filter + * source_data_rows[filter_y][byte_offset + G_OFFSET_IDX]; + accum[2] += cur_filter + * source_data_rows[filter_y][byte_offset + B_OFFSET_IDX]; + if (has_alpha) + accum[3] += cur_filter + * source_data_rows[filter_y][byte_offset + A_OFFSET_IDX]; + } + + // Bring this value back in range. All of the filter scaling factors + // are in fixed point with kShiftBits bits of precision. + accum[0] >>= ConvolutionFilter1D::kShiftBits; + accum[1] >>= ConvolutionFilter1D::kShiftBits; + accum[2] >>= ConvolutionFilter1D::kShiftBits; + if (has_alpha) + accum[3] >>= ConvolutionFilter1D::kShiftBits; + + // Store the new pixel. + out_row[byte_offset + R_OFFSET_IDX] = ClampTo8(accum[0]); + out_row[byte_offset + G_OFFSET_IDX] = ClampTo8(accum[1]); + out_row[byte_offset + B_OFFSET_IDX] = ClampTo8(accum[2]); + if (has_alpha) { + unsigned char alpha = ClampTo8(accum[3]); + + // Make sure the alpha channel doesn't come out smaller than any of the + // color channels. We use premultipled alpha channels, so this should + // never happen, but rounding errors will cause this from time to time. + // These "impossible" colors will cause overflows (and hence random pixel + // values) when the resulting bitmap is drawn to the screen. + // + // We only need to do this when generating the final output row (here). + int max_color_channel = std::max(out_row[byte_offset + R_OFFSET_IDX], + std::max(out_row[byte_offset + G_OFFSET_IDX], out_row[byte_offset + B_OFFSET_IDX])); + if (alpha < max_color_channel) + out_row[byte_offset + A_OFFSET_IDX] = max_color_channel; + else + out_row[byte_offset + A_OFFSET_IDX] = alpha; + } else { + // No alpha channel, the image is opaque. + out_row[byte_offset + A_OFFSET_IDX] = 0xff; + } + } +} + +void ConvolveVertically(const ConvolutionFilter1D::Fixed* filter_values, + int filter_length, + unsigned char* const* source_data_rows, + int pixel_width, unsigned char* out_row, + bool has_alpha, bool use_simd) { + +#if defined(USE_SSE2) || defined(_MIPS_ARCH_LOONGSON3A) + // If the binary was not built with SSE2 support, we had to fallback to C version. + if (use_simd) { + ConvolveVertically_SIMD(filter_values, filter_length, + source_data_rows, + pixel_width, + out_row, has_alpha); + } else +#endif + { + if (has_alpha) { + ConvolveVertically<true>(filter_values, filter_length, + source_data_rows, + pixel_width, + out_row); + } else { + ConvolveVertically<false>(filter_values, filter_length, + source_data_rows, + pixel_width, + out_row); + } + } +} + +void ConvolveHorizontally(const unsigned char* src_data, + const ConvolutionFilter1D& filter, + unsigned char* out_row, + bool has_alpha, bool use_simd) { + int width = filter.num_values(); + int processed = 0; +#if defined(USE_SSE2) || defined(_MIPS_ARCH_LOONGSON3A) + int simd_width = width & ~3; + if (use_simd && simd_width) { + // SIMD implementation works with 4 pixels at a time. + // Therefore we process as much as we can using SSE and then use + // C implementation for leftovers + ConvolveHorizontally_SIMD(src_data, filter, out_row); + processed = simd_width; + } +#endif + + if (width > processed) { +#if defined(_MIPS_ARCH_LOONGSON3A) + ConvolveHorizontally1_LS3(src_data, filter, out_row); +#else + if (has_alpha) { + ConvolveHorizontally<true>(src_data, filter, out_row); + } else { + ConvolveHorizontally<false>(src_data, filter, out_row); + } +#endif + } +} + +// ConvolutionFilter1D --------------------------------------------------------- + +ConvolutionFilter1D::ConvolutionFilter1D() + : max_filter_(0) { +} + +ConvolutionFilter1D::~ConvolutionFilter1D() { +} + +void ConvolutionFilter1D::AddFilter(int filter_offset, + const float* filter_values, + int filter_length) { + SkASSERT(filter_length > 0); + + std::vector<Fixed> fixed_values; + fixed_values.reserve(filter_length); + + for (int i = 0; i < filter_length; ++i) + fixed_values.push_back(FloatToFixed(filter_values[i])); + + AddFilter(filter_offset, &fixed_values[0], filter_length); +} + +void ConvolutionFilter1D::AddFilter(int filter_offset, + const Fixed* filter_values, + int filter_length) { + // It is common for leading/trailing filter values to be zeros. In such + // cases it is beneficial to only store the central factors. + // For a scaling to 1/4th in each dimension using a Lanczos-2 filter on + // a 1080p image this optimization gives a ~10% speed improvement. + int first_non_zero = 0; + while (first_non_zero < filter_length && filter_values[first_non_zero] == 0) + first_non_zero++; + + if (first_non_zero < filter_length) { + // Here we have at least one non-zero factor. + int last_non_zero = filter_length - 1; + while (last_non_zero >= 0 && filter_values[last_non_zero] == 0) + last_non_zero--; + + filter_offset += first_non_zero; + filter_length = last_non_zero + 1 - first_non_zero; + SkASSERT(filter_length > 0); + + for (int i = first_non_zero; i <= last_non_zero; i++) + filter_values_.push_back(filter_values[i]); + } else { + // Here all the factors were zeroes. + filter_length = 0; + } + + FilterInstance instance; + + // We pushed filter_length elements onto filter_values_ + instance.data_location = (static_cast<int>(filter_values_.size()) - + filter_length); + instance.offset = filter_offset; + instance.length = filter_length; + filters_.push_back(instance); + + max_filter_ = std::max(max_filter_, filter_length); +} + +void BGRAConvolve2D(const unsigned char* source_data, + int source_byte_row_stride, + bool source_has_alpha, + const ConvolutionFilter1D& filter_x, + const ConvolutionFilter1D& filter_y, + int output_byte_row_stride, + unsigned char* output) { + bool use_simd = Factory::HasSSE2(); + +#if !defined(USE_SSE2) + // Even we have runtime support for SSE2 instructions, since the binary + // was not built with SSE2 support, we had to fallback to C version. + use_simd = false; +#endif + +#if defined(_MIPS_ARCH_LOONGSON3A) + use_simd = true; +#endif + + + int max_y_filter_size = filter_y.max_filter(); + + // The next row in the input that we will generate a horizontally + // convolved row for. If the filter doesn't start at the beginning of the + // image (this is the case when we are only resizing a subset), then we + // don't want to generate any output rows before that. Compute the starting + // row for convolution as the first pixel for the first vertical filter. + int filter_offset, filter_length; + const ConvolutionFilter1D::Fixed* filter_values = + filter_y.FilterForValue(0, &filter_offset, &filter_length); + int next_x_row = filter_offset; + + // We loop over each row in the input doing a horizontal convolution. This + // will result in a horizontally convolved image. We write the results into + // a circular buffer of convolved rows and do vertical convolution as rows + // are available. This prevents us from having to store the entire + // intermediate image and helps cache coherency. + // We will need four extra rows to allow horizontal convolution could be done + // simultaneously. We also padding each row in row buffer to be aligned-up to + // 16 bytes. + // TODO(jiesun): We do not use aligned load from row buffer in vertical + // convolution pass yet. Somehow Windows does not like it. + int row_buffer_width = (filter_x.num_values() + 15) & ~0xF; + int row_buffer_height = max_y_filter_size + (use_simd ? 4 : 0); + CircularRowBuffer row_buffer(row_buffer_width, + row_buffer_height, + filter_offset); + + // Loop over every possible output row, processing just enough horizontal + // convolutions to run each subsequent vertical convolution. + SkASSERT(output_byte_row_stride >= filter_x.num_values() * 4); + int num_output_rows = filter_y.num_values(); + int pixel_width = filter_x.num_values(); + + + // We need to check which is the last line to convolve before we advance 4 + // lines in one iteration. + int last_filter_offset, last_filter_length; + // SSE2 can access up to 3 extra pixels past the end of the + // buffer. At the bottom of the image, we have to be careful + // not to access data past the end of the buffer. Normally + // we fall back to the C++ implementation for the last row. + // If the last row is less than 3 pixels wide, we may have to fall + // back to the C++ version for more rows. Compute how many + // rows we need to avoid the SSE implementation for here. + filter_x.FilterForValue(filter_x.num_values() - 1, &last_filter_offset, + &last_filter_length); +#if defined(USE_SSE2) || defined(_MIPS_ARCH_LOONGSON3A) + int avoid_simd_rows = 1 + 3 / + (last_filter_offset + last_filter_length); +#endif + filter_y.FilterForValue(num_output_rows - 1, &last_filter_offset, + &last_filter_length); + + for (int out_y = 0; out_y < num_output_rows; out_y++) { + filter_values = filter_y.FilterForValue(out_y, + &filter_offset, &filter_length); + + // Generate output rows until we have enough to run the current filter. + if (use_simd) { +#if defined(USE_SSE2) || defined(_MIPS_ARCH_LOONGSON3A) + // We don't want to process too much rows in batches of 4 because + // we can go out-of-bounds at the end + while (next_x_row < filter_offset + filter_length) { + if (next_x_row + 3 < last_filter_offset + last_filter_length - + avoid_simd_rows) { + const unsigned char* src[4]; + unsigned char* out_row[4]; + for (int i = 0; i < 4; ++i) { + src[i] = &source_data[(next_x_row + i) * source_byte_row_stride]; + out_row[i] = row_buffer.AdvanceRow(); + } + ConvolveHorizontally4_SIMD(src, filter_x, out_row); + next_x_row += 4; + } else { + // Check if we need to avoid SSE2 for this row. + if (next_x_row < last_filter_offset + last_filter_length - + avoid_simd_rows) { + ConvolveHorizontally_SIMD( + &source_data[next_x_row * source_byte_row_stride], + filter_x, row_buffer.AdvanceRow()); + } else { + if (source_has_alpha) { + ConvolveHorizontally<true>( + &source_data[next_x_row * source_byte_row_stride], + filter_x, row_buffer.AdvanceRow()); + } else { + ConvolveHorizontally<false>( + &source_data[next_x_row * source_byte_row_stride], + filter_x, row_buffer.AdvanceRow()); + } + } + next_x_row++; + } + } +#endif + } else { + while (next_x_row < filter_offset + filter_length) { + if (source_has_alpha) { + ConvolveHorizontally<true>( + &source_data[next_x_row * source_byte_row_stride], + filter_x, row_buffer.AdvanceRow()); + } else { + ConvolveHorizontally<false>( + &source_data[next_x_row * source_byte_row_stride], + filter_x, row_buffer.AdvanceRow()); + } + next_x_row++; + } + } + + // Compute where in the output image this row of final data will go. + unsigned char* cur_output_row = &output[out_y * output_byte_row_stride]; + + // Get the list of rows that the circular buffer has, in order. + int first_row_in_circular_buffer; + unsigned char* const* rows_to_convolve = + row_buffer.GetRowAddresses(&first_row_in_circular_buffer); + + // Now compute the start of the subset of those rows that the filter + // needs. + unsigned char* const* first_row_for_filter = + &rows_to_convolve[filter_offset - first_row_in_circular_buffer]; + + ConvolveVertically(filter_values, filter_length, + first_row_for_filter, pixel_width, + cur_output_row, source_has_alpha, use_simd); + } +} + +} // namespace skia |