Remove many unused files from //skia/ext

skia/ext/convolver.cc

Index: skia/ext/convolver.cc
diff --git a/skia/ext/convolver.cc b/skia/ext/convolver.cc
deleted file mode 100644
index 092fefaa9b6692914163a45743e0bc73bd40f0f0..0000000000000000000000000000000000000000
--- a/skia/ext/convolver.cc
+++ /dev/null
@@ -1,713 +0,0 @@
-// Copyright (c) 2011 The Chromium Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style license that can be
-// found in the LICENSE file.
-
-#include <algorithm>
-
-#include "base/logging.h"
-#include "skia/ext/convolver.h"
-#include "skia/ext/convolver_SSE2.h"
-#include "skia/ext/convolver_mips_dspr2.h"
-#include "third_party/skia/include/core/SkSize.h"
-#include "third_party/skia/include/core/SkTypes.h"
-
-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;
-}
-
-// Takes the value produced by accumulating element-wise product of image with
-// a kernel and brings it back into range.
-// All of the filter scaling factors are in fixed point with kShiftBits bits of
-// fractional part.
-inline unsigned char BringBackTo8(int a, bool take_absolute) {
-  a >>= ConvolutionFilter1D::kShiftBits;
-  if (take_absolute)
-    a = std::abs(a);
-  return ClampTo8(a);
-}
-
-// 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_;
-};
-
-// Convolves horizontally along a single row. The row data is given in
-// |src_data| and continues for the num_values() of the filter.
-template<bool has_alpha>
-void ConvolveHorizontally(const unsigned char* src_data,
-                          const ConvolutionFilter1D& filter,
-                          unsigned char* out_row) {
-  // Loop over each pixel on this row in the output image.
-  int num_values = filter.num_values();
-  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 + 0];
-      accum[1] += cur_filter * row_to_filter[filter_x * 4 + 1];
-      accum[2] += cur_filter * row_to_filter[filter_x * 4 + 2];
-      if (has_alpha)
-        accum[3] += cur_filter * row_to_filter[filter_x * 4 + 3];
-    }
-
-    // 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 + 0] = ClampTo8(accum[0]);
-    out_row[out_x * 4 + 1] = ClampTo8(accum[1]);
-    out_row[out_x * 4 + 2] = ClampTo8(accum[2]);
-    if (has_alpha)
-      out_row[out_x * 4 + 3] = 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 + 0];
-      accum[1] += cur_filter * source_data_rows[filter_y][byte_offset + 1];
-      accum[2] += cur_filter * source_data_rows[filter_y][byte_offset + 2];
-      if (has_alpha)
-        accum[3] += cur_filter * source_data_rows[filter_y][byte_offset + 3];
-    }
-
-    // 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 + 0] = ClampTo8(accum[0]);
-    out_row[byte_offset + 1] = ClampTo8(accum[1]);
-    out_row[byte_offset + 2] = 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 + 0],
-          std::max(out_row[byte_offset + 1], out_row[byte_offset + 2]));
-      if (alpha < max_color_channel)
-        out_row[byte_offset + 3] = max_color_channel;
-      else
-        out_row[byte_offset + 3] = alpha;
-    } else {
-      // No alpha channel, the image is opaque.
-      out_row[byte_offset + 3] = 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 source_has_alpha) {
-  if (source_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);
-  }
-}
-
-}  // namespace
-
-// 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 filter_size = filter_length;
-  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.trimmed_length = filter_length;
-  instance.length = filter_size;
-  filters_.push_back(instance);
-
-  max_filter_ = std::max(max_filter_, filter_length);
-}
-
-const ConvolutionFilter1D::Fixed* ConvolutionFilter1D::GetSingleFilter(
-    int* specified_filter_length,
-    int* filter_offset,
-    int* filter_length) const {
-  const FilterInstance& filter = filters_[0];
-  *filter_offset = filter.offset;
-  *filter_length = filter.trimmed_length;
-  *specified_filter_length = filter.length;
-  if (filter.trimmed_length == 0)
-    return NULL;
-
-  return &filter_values_[filter.data_location];
-}
-
-typedef void (*ConvolveVertically_pointer)(
-    const ConvolutionFilter1D::Fixed* filter_values,
-    int filter_length,
-    unsigned char* const* source_data_rows,
-    int pixel_width,
-    unsigned char* out_row,
-    bool has_alpha);
-typedef void (*Convolve4RowsHorizontally_pointer)(
-    const unsigned char* src_data[4],
-    const ConvolutionFilter1D& filter,
-    unsigned char* out_row[4]);
-typedef void (*ConvolveHorizontally_pointer)(
-    const unsigned char* src_data,
-    const ConvolutionFilter1D& filter,
-    unsigned char* out_row,
-    bool has_alpha);
-
-struct ConvolveProcs {
-  // This is how many extra pixels may be read by the
-  // conolve*horizontally functions.
-  int extra_horizontal_reads;
-  ConvolveVertically_pointer convolve_vertically;
-  Convolve4RowsHorizontally_pointer convolve_4rows_horizontally;
-  ConvolveHorizontally_pointer convolve_horizontally;
-};
-
-void SetupSIMD(ConvolveProcs *procs) {
-#ifdef SIMD_SSE2
-  procs->extra_horizontal_reads = 3;
-  procs->convolve_vertically = &ConvolveVertically_SSE2;
-  procs->convolve_4rows_horizontally = &Convolve4RowsHorizontally_SSE2;
-  procs->convolve_horizontally = &ConvolveHorizontally_SSE2;
-#elif defined SIMD_MIPS_DSPR2
-  procs->extra_horizontal_reads = 3;
-  procs->convolve_vertically = &ConvolveVertically_mips_dspr2;
-  procs->convolve_horizontally = &ConvolveHorizontally_mips_dspr2;
-#endif
-}
-
-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_if_possible) {
-  ConvolveProcs simd;
-  simd.extra_horizontal_reads = 0;
-  simd.convolve_vertically = NULL;
-  simd.convolve_4rows_horizontally = NULL;
-  simd.convolve_horizontally = NULL;
-  if (use_simd_if_possible) {
-    SetupSIMD(&simd);
-  }
-
-  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 +
-      (simd.convolve_4rows_horizontally ? 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();
-
-  // 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);
-  int avoid_simd_rows = 1 + simd.extra_horizontal_reads /
-      (last_filter_offset + last_filter_length);
-
-  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.
-    while (next_x_row < filter_offset + filter_length) {
-      if (simd.convolve_4rows_horizontally &&
-          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();
-        }
-        simd.convolve_4rows_horizontally(src, filter_x, out_row);
-        next_x_row += 4;
-      } else {
-        // Check if we need to avoid SSE2 for this row.
-        if (simd.convolve_horizontally &&
-            next_x_row < last_filter_offset + last_filter_length -
-            avoid_simd_rows) {
-          simd.convolve_horizontally(
-              &source_data[next_x_row * source_byte_row_stride],
-              filter_x, row_buffer.AdvanceRow(), source_has_alpha);
-        } 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++;
-      }
-    }
-
-    // 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];
-
-    if (simd.convolve_vertically) {
-      simd.convolve_vertically(filter_values, filter_length,
-                               first_row_for_filter,
-                               filter_x.num_values(), cur_output_row,
-                               source_has_alpha);
-    } else {
-      ConvolveVertically(filter_values, filter_length,
-                         first_row_for_filter,
-                         filter_x.num_values(), cur_output_row,
-                         source_has_alpha);
-    }
-  }
-}
-
-void SingleChannelConvolveX1D(const unsigned char* source_data,
-                              int source_byte_row_stride,
-                              int input_channel_index,
-                              int input_channel_count,
-                              const ConvolutionFilter1D& filter,
-                              const SkISize& image_size,
-                              unsigned char* output,
-                              int output_byte_row_stride,
-                              int output_channel_index,
-                              int output_channel_count,
-                              bool absolute_values) {
-  int filter_offset, filter_length, filter_size;
-  // Very much unlike BGRAConvolve2D, here we expect to have the same filter
-  // for all pixels.
-  const ConvolutionFilter1D::Fixed* filter_values =
-      filter.GetSingleFilter(&filter_size, &filter_offset, &filter_length);
-
-  if (filter_values == NULL || image_size.width() < filter_size) {
-    NOTREACHED();
-    return;
-  }
-
-  int centrepoint = filter_length / 2;
-  if (filter_size - filter_offset != 2 * filter_offset) {
-    // This means the original filter was not symmetrical AND
-    // got clipped from one side more than from the other.
-    centrepoint = filter_size / 2 - filter_offset;
-  }
-
-  const unsigned char* source_data_row = source_data;
-  unsigned char* output_row = output;
-
-  for (int r = 0; r < image_size.height(); ++r) {
-    unsigned char* target_byte = output_row + output_channel_index;
-    // Process the lead part, padding image to the left with the first pixel.
-    int c = 0;
-    for (; c < centrepoint; ++c, target_byte += output_channel_count) {
-      int accval = 0;
-      int i = 0;
-      int pixel_byte_index = input_channel_index;
-      for (; i < centrepoint - c; ++i)  // Padding part.
-        accval += filter_values[i] * source_data_row[pixel_byte_index];
-
-      for (; i < filter_length; ++i, pixel_byte_index += input_channel_count)
-        accval += filter_values[i] * source_data_row[pixel_byte_index];
-
-      *target_byte = BringBackTo8(accval, absolute_values);
-    }
-
-    // Now for the main event.
-    for (; c < image_size.width() - centrepoint;
-         ++c, target_byte += output_channel_count) {
-      int accval = 0;
-      int pixel_byte_index = (c - centrepoint) * input_channel_count +
-          input_channel_index;
-
-      for (int i = 0; i < filter_length;
-           ++i, pixel_byte_index += input_channel_count) {
-        accval += filter_values[i] * source_data_row[pixel_byte_index];
-      }
-
-      *target_byte = BringBackTo8(accval, absolute_values);
-    }
-
-    for (; c < image_size.width(); ++c, target_byte += output_channel_count) {
-      int accval = 0;
-      int overlap_taps = image_size.width() - c + centrepoint;
-      int pixel_byte_index = (c - centrepoint) * input_channel_count +
-          input_channel_index;
-      int i = 0;
-      for (; i < overlap_taps - 1; ++i, pixel_byte_index += input_channel_count)
-        accval += filter_values[i] * source_data_row[pixel_byte_index];
-
-      for (; i < filter_length; ++i)
-        accval += filter_values[i] * source_data_row[pixel_byte_index];
-
-      *target_byte = BringBackTo8(accval, absolute_values);
-    }
-
-    source_data_row += source_byte_row_stride;
-    output_row += output_byte_row_stride;
-  }
-}
-
-void SingleChannelConvolveY1D(const unsigned char* source_data,
-                              int source_byte_row_stride,
-                              int input_channel_index,
-                              int input_channel_count,
-                              const ConvolutionFilter1D& filter,
-                              const SkISize& image_size,
-                              unsigned char* output,
-                              int output_byte_row_stride,
-                              int output_channel_index,
-                              int output_channel_count,
-                              bool absolute_values) {
-  int filter_offset, filter_length, filter_size;
-  // Very much unlike BGRAConvolve2D, here we expect to have the same filter
-  // for all pixels.
-  const ConvolutionFilter1D::Fixed* filter_values =
-      filter.GetSingleFilter(&filter_size, &filter_offset, &filter_length);
-
-  if (filter_values == NULL || image_size.height() < filter_size) {
-    NOTREACHED();
-    return;
-  }
-
-  int centrepoint = filter_length / 2;
-  if (filter_size - filter_offset != 2 * filter_offset) {
-    // This means the original filter was not symmetrical AND
-    // got clipped from one side more than from the other.
-    centrepoint = filter_size / 2 - filter_offset;
-  }
-
-  for (int c = 0; c < image_size.width(); ++c) {
-    unsigned char* target_byte = output + c * output_channel_count +
-        output_channel_index;
-    int r = 0;
-
-    for (; r < centrepoint; ++r, target_byte += output_byte_row_stride) {
-      int accval = 0;
-      int i = 0;
-      int pixel_byte_index = c * input_channel_count + input_channel_index;
-
-      for (; i < centrepoint - r; ++i)  // Padding part.
-        accval += filter_values[i] * source_data[pixel_byte_index];
-
-      for (; i < filter_length; ++i, pixel_byte_index += source_byte_row_stride)
-        accval += filter_values[i] * source_data[pixel_byte_index];
-
-      *target_byte = BringBackTo8(accval, absolute_values);
-    }
-
-    for (; r < image_size.height() - centrepoint;
-         ++r, target_byte += output_byte_row_stride) {
-      int accval = 0;
-      int pixel_byte_index = (r - centrepoint) * source_byte_row_stride +
-          c * input_channel_count + input_channel_index;
-      for (int i = 0; i < filter_length;
-           ++i, pixel_byte_index += source_byte_row_stride) {
-        accval += filter_values[i] * source_data[pixel_byte_index];
-      }
-
-      *target_byte = BringBackTo8(accval, absolute_values);
-    }
-
-    for (; r < image_size.height();
-         ++r, target_byte += output_byte_row_stride) {
-      int accval = 0;
-      int overlap_taps = image_size.height() - r + centrepoint;
-      int pixel_byte_index = (r - centrepoint) * source_byte_row_stride +
-          c * input_channel_count + input_channel_index;
-      int i = 0;
-      for (; i < overlap_taps - 1;
-           ++i, pixel_byte_index += source_byte_row_stride) {
-        accval += filter_values[i] * source_data[pixel_byte_index];
-      }
-
-      for (; i < filter_length; ++i)
-        accval += filter_values[i] * source_data[pixel_byte_index];
-
-      *target_byte = BringBackTo8(accval, absolute_values);
-    }
-  }
-}
-
-void SetUpGaussianConvolutionKernel(ConvolutionFilter1D* filter,
-                                    float kernel_sigma,
-                                    bool derivative) {
-  DCHECK(filter != NULL);
-  DCHECK_GT(kernel_sigma, 0.0);
-  const int tail_length = static_cast<int>(4.0f * kernel_sigma + 0.5f);
-  const int kernel_size = tail_length * 2 + 1;
-  const float sigmasq = kernel_sigma * kernel_sigma;
-  std::vector<float> kernel_weights(kernel_size, 0.0);
-  float kernel_sum = 1.0f;
-
-  kernel_weights[tail_length] = 1.0f;
-
-  for (int ii = 1; ii <= tail_length; ++ii) {
-    float v = std::exp(-0.5f * ii * ii / sigmasq);
-    kernel_weights[tail_length + ii] = v;
-    kernel_weights[tail_length - ii] = v;
-    kernel_sum += 2.0f * v;
-  }
-
-  for (int i = 0; i < kernel_size; ++i)
-    kernel_weights[i] /= kernel_sum;
-
-  if (derivative) {
-    kernel_weights[tail_length] = 0.0;
-    for (int ii = 1; ii <= tail_length; ++ii) {
-      float v = sigmasq * kernel_weights[tail_length + ii] / ii;
-      kernel_weights[tail_length + ii] = v;
-      kernel_weights[tail_length - ii] = -v;
-    }
-  }
-
-  filter->AddFilter(0, &kernel_weights[0], kernel_weights.size());
-}
-
-}  // namespace skia