Move convolver, image_operations, and skia_utils from base/gfx to skia/ext.

This changes the namespace in those files from "gfx" to "skia".

I split skia_utils into two parts, the Windows specific part is now in a separate file called skia_utils_win.

There were several obsolete includes of these headers which I removed. I also removed img_resize_perftest which isn't used and has bitrotted.
Review URL: http://codereview.chromium.org/12842

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@6248 0039d316-1c4b-4281-b951-d872f2087c98

18 files changed, 1525 insertions, 5 deletions

diff --git a/skia/SConscript b/skia/SConscript
index 00b8e1b..fbafc92 100644
--- a/skia/SConscript
+++ b/skia/SConscript
@@ -152,6 +152,10 @@ input_files = [
   'sgl/SkUtils.cpp',
   'sgl/SkWriter32.cpp',
   'sgl/SkXfermode.cpp',
+
+  'ext/convolver.cc',
+  'ext/image_operations.cc',
+  'ext/skia_utils.cc',
 ]
 
 if env['PLATFORM'] == 'posix':
@@ -176,11 +180,13 @@ if env['PLATFORM'] == 'darwin':
   input_files.append('ext/bitmap_platform_device_mac.cc')
   input_files.append('ext/platform_canvas_mac.cc')
   input_files.append('ext/platform_device_mac.cc')
+  input_files.append('ext/skia_utils_mac.cc')
 
 if env['PLATFORM'] == 'win32':
   input_files.append('ext/bitmap_platform_device_win.cc')
   input_files.append('ext/platform_canvas_win.cc')
   input_files.append('ext/platform_device_win.cc')
+  input_files.append('ext/skia_utils_win.cc')
   input_files.append('ext/vector_canvas.cc')
   input_files.append('ext/vector_device.cc')
 
diff --git a/skia/ext/bitmap_platform_device_mac.cc b/skia/ext/bitmap_platform_device_mac.cc
index d4458d7..52ce586 100755
--- a/skia/ext/bitmap_platform_device_mac.cc
+++ b/skia/ext/bitmap_platform_device_mac.cc
@@ -10,8 +10,8 @@
 #include "SkRegion.h"
 #include "SkUtils.h"
 
-#include "base/gfx/skia_utils_mac.h"
 #include "base/logging.h"
+#include "skia/ext/skia_utils_mac.h"
 
 namespace gfx {
 
diff --git a/skia/ext/convolver.cc b/skia/ext/convolver.cc
new file mode 100644
index 0000000..c854019
--- /dev/null
+++ b/skia/ext/convolver.cc
@@ -0,0 +1,336 @@
+// Copyright (c) 2006-2008 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 "skia/ext/convolver.h"
+
+#include "base/basictypes.h"
+#include "base/logging.h"
+
+namespace skia {
+
+namespace {
+
+// Converts the argument to an 8-bit unsigned value by clamping to the range
+// 0-255.
+inline uint8 ClampTo8(int32 a) {
+  if (static_cast<uint32>(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.
+  uint8* AdvanceRow() {
+    uint8* 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).
+  uint8* 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<uint8> 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<uint8*> 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 uint8* src_data,
+                          const ConvolusionFilter1D& 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 int16* 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 uint8* row_to_filter = &src_data[filter_offset * 4];
+
+    // Apply the filter to the row to get the destination pixel in |accum|.
+    int32 accum[4] = {0};
+    for (int filter_x = 0; filter_x < filter_length; filter_x++) {
+      int16 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] >>= ConvolusionFilter1D::kShiftBits;
+    accum[1] >>= ConvolusionFilter1D::kShiftBits;
+    accum[2] >>= ConvolusionFilter1D::kShiftBits;
+    if (has_alpha)
+      accum[3] >>= ConvolusionFilter1D::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 convolusion 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 int16* filter_values,
+                        int filter_length,
+                        uint8* const* source_data_rows,
+                        int pixel_width,
+                        uint8* out_row) {
+  // We go through each column in the output and do a vertical convolusion,
+  // 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.
+    int32 accum[4] = {0};
+    for (int filter_y = 0; filter_y < filter_length; filter_y++) {
+      int16 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] >>= ConvolusionFilter1D::kShiftBits;
+    accum[1] >>= ConvolusionFilter1D::kShiftBits;
+    accum[2] >>= ConvolusionFilter1D::kShiftBits;
+    if (has_alpha)
+      accum[3] >>= ConvolusionFilter1D::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) {
+      uint8 alpha = ClampTo8(accum[3]);
+
+      // Make sure the alpha channel doesn't come out larger 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;
+    }
+  }
+}
+
+}  // namespace
+
+// ConvolusionFilter1D ---------------------------------------------------------
+
+void ConvolusionFilter1D::AddFilter(int filter_offset,
+                                    const float* filter_values,
+                                    int filter_length) {
+  FilterInstance instance;
+  instance.data_location = static_cast<int>(filter_values_.size());
+  instance.offset = filter_offset;
+  instance.length = filter_length;
+  filters_.push_back(instance);
+
+  DCHECK(filter_length > 0);
+  for (int i = 0; i < filter_length; i++)
+    filter_values_.push_back(FloatToFixed(filter_values[i]));
+
+  max_filter_ = std::max(max_filter_, filter_length);
+}
+
+void ConvolusionFilter1D::AddFilter(int filter_offset,
+                                    const int16* filter_values,
+                                    int filter_length) {
+  FilterInstance instance;
+  instance.data_location = static_cast<int>(filter_values_.size());
+  instance.offset = filter_offset;
+  instance.length = filter_length;
+  filters_.push_back(instance);
+
+  DCHECK(filter_length > 0);
+  for (int i = 0; i < filter_length; i++)
+    filter_values_.push_back(filter_values[i]);
+
+  max_filter_ = std::max(max_filter_, filter_length);
+}
+
+// BGRAConvolve2D -------------------------------------------------------------
+
+void BGRAConvolve2D(const uint8* source_data,
+                    int source_byte_row_stride,
+                    bool source_has_alpha,
+                    const ConvolusionFilter1D& filter_x,
+                    const ConvolusionFilter1D& filter_y,
+                    uint8* output) {
+  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 convolusion as the first pixel for the first vertical filter.
+  int filter_offset, filter_length;
+  const int16* 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 convolusion. This
+  // will result in a horizontally convolved image. We write the results into
+  // a circular buffer of convolved rows and do vertical convolusion as rows
+  // are available. This prevents us from having to store the entire
+  // intermediate image and helps cache coherency.
+  CircularRowBuffer row_buffer(filter_x.num_values(), max_y_filter_size,
+                               filter_offset);
+
+  // Loop over every possible output row, processing just enough horizontal
+  // convolusions to run each subsequent vertical convolusion.
+  int output_row_byte_width = filter_x.num_values() * 4;
+  int num_output_rows = filter_y.num_values();
+  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 (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.
+    uint8* cur_output_row = &output[out_y * output_row_byte_width];
+
+    // Get the list of rows that the circular buffer has, in order.
+    int first_row_in_circular_buffer;
+    uint8* 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.
+    uint8* const* first_row_for_filter =
+        &rows_to_convolve[filter_offset - first_row_in_circular_buffer];
+
+    if (source_has_alpha) {
+      ConvolveVertically<true>(filter_values, filter_length,
+                               first_row_for_filter,
+                               filter_x.num_values(), cur_output_row);
+    } else {
+      ConvolveVertically<false>(filter_values, filter_length,
+                                first_row_for_filter,
+                                filter_x.num_values(), cur_output_row);
+    }
+  }
+}
+
+}  // namespace skia
+
diff --git a/skia/ext/convolver.h b/skia/ext/convolver.h
new file mode 100644
index 0000000..62c1e30
--- /dev/null
+++ b/skia/ext/convolver.h
@@ -0,0 +1,137 @@
+// Copyright (c) 2006-2008 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.
+
+#ifndef SKIA_EXT_CONVOLVER_H_
+#define SKIA_EXT_CONVOLVER_H_
+
+#include <vector>
+
+#include "base/basictypes.h"
+
+// avoid confusion with Mac OS X's math library (Carbon)
+#if defined(OS_MACOSX)
+#undef FloatToFixed
+#endif
+
+namespace skia {
+
+// 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 convolusion by first convolving each row by one
+// ConvolusionFilter1D, then convolving each column by another one.
+//
+// Entries are stored in fixed point, shifted left by kShiftBits.
+class ConvolusionFilter1D {
+ public:
+  // The number of bits that fixed point values are shifted by.
+  enum { kShiftBits = 14 };
+
+  ConvolusionFilter1D() : max_filter_(0) {
+  }
+
+  // Convert between floating point and our fixed point representation.
+  static inline int16 FloatToFixed(float f) {
+    return static_cast<int16>(f * (1 << kShiftBits));
+  }
+  static inline unsigned char FixedToChar(int16 x) {
+    return static_cast<unsigned char>(x >> kShiftBits);
+  }
+
+  // Returns the maximum pixel span of a filter.
+  int max_filter() const { return max_filter_; }
+
+  // Returns the number of filters in this filter. This is the dimension of the
+  // output image.
+  int num_values() const { return static_cast<int>(filters_.size()); }
+
+  // Appends the given list of scaling values for generating a given output
+  // pixel. |filter_offset| 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 |filter_length| pixels.
+  //
+  // You will probably want to make sure your input is normalized (that is,
+  // all entries in |filter_values| sub to one) to prevent affecting the overall
+  // brighness of the image.
+  //
+  // The filter_length must be > 0.
+  //
+  // This version will automatically convert your input to fixed point.
+  void AddFilter(int filter_offset,
+                 const float* filter_values,
+                 int filter_length);
+
+  // Same as the above version, but the input is already fixed point.
+  void AddFilter(int filter_offset,
+                 const int16* filter_values,
+                 int filter_length);
+
+  // Retrieves a filter for the given |value_offset|, 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 |filter_length| values in this array.
+  inline const int16* FilterForValue(int value_offset,
+                                     int* filter_offset,
+                                     int* filter_length) const {
+    const FilterInstance& filter = filters_[value_offset];
+    *filter_offset = filter.offset;
+    *filter_length = filter.length;
+    return &filter_values_[filter.data_location];
+  }
+
+ private:
+  struct FilterInstance {
+    // Offset within filter_values for this instance of the filter.
+    int data_location;
+
+    // Distance from the left of the filter to the center. IN PIXELS
+    int offset;
+
+    // Number of values in this filter instance.
+    int length;
+  };
+
+  // Stores the information for each filter added to this class.
+  std::vector<FilterInstance> filters_;
+
+  // 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<int16> filter_values_;
+
+  // The maximum size of any filter we've added.
+  int max_filter_;
+};
+
+// Does a two-dimensional convolusion on the given source image.
+//
+// It is assumed the source pixel offsets referenced in the input filters
+// reference only valid pixels, so the source image size is not required. Each
+// row of the source image starts |source_byte_row_stride| after the previous
+// one (this allows you to have rows with some padding at the end).
+//
+// The result will be put into the given output buffer. The destination image
+// size will be xfilter.num_values() * yfilter.num_values() pixels. It will be
+// in rows of exactly xfilter.num_values() * 4 bytes.
+//
+// |source_has_alpha| is a hint that allows us to avoid doing computations on
+// the alpha channel if the image is opaque. If you don't know, set this to
+// true and it will work properly, but setting this to false will be a few
+// percent faster if you know the image is opaque.
+//
+// The layout in memory is assumed to be 4-bytes per pixel in B-G-R-A order
+// (this is ARGB when loaded into 32-bit words on a little-endian machine).
+void BGRAConvolve2D(const uint8* source_data,
+                    int source_byte_row_stride,
+                    bool source_has_alpha,
+                    const ConvolusionFilter1D& xfilter,
+                    const ConvolusionFilter1D& yfilter,
+                    uint8* output);
+
+}  // namespace skia
+
+#endif  // SKIA_EXT_CONVOLVER_H_
+
diff --git a/skia/ext/convolver_unittest.cc b/skia/ext/convolver_unittest.cc
new file mode 100644
index 0000000..c0ae734
--- /dev/null
+++ b/skia/ext/convolver_unittest.cc
@@ -0,0 +1,128 @@
+// Copyright (c) 2006-2008 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 <string.h>
+#include <time.h>
+#include <vector>
+
+#include "skia/ext/convolver.h"
+
+#include "testing/gtest/include/gtest/gtest.h"
+
+namespace skia {
+
+namespace {
+
+// Fills the given filter with impulse functions for the range 0->num_entries.
+  void FillImpulseFilter(int num_entries, ConvolusionFilter1D* filter) {
+  float one = 1.0f;
+  for (int i = 0; i < num_entries; i++)
+    filter->AddFilter(i, &one, 1);
+}
+
+// Filters the given input with the impulse function, and verifies that it
+// does not change.
+void TestImpulseConvolusion(const unsigned char* data, int width, int height) {
+  int byte_count = width * height * 4;
+
+  ConvolusionFilter1D filter_x;
+  FillImpulseFilter(width, &filter_x);
+
+  ConvolusionFilter1D filter_y;
+  FillImpulseFilter(height, &filter_y);
+
+  std::vector<unsigned char> output;
+  output.resize(byte_count);
+  BGRAConvolve2D(data, width * 4, true, filter_x, filter_y, &output[0]);
+
+  // Output should exactly match input.
+  EXPECT_EQ(0, memcmp(data, &output[0], byte_count));
+}
+
+// Fills the destination filter with a box filter averaging every two pixels
+// to produce the output.
+void FillBoxFilter(int size, ConvolusionFilter1D* filter) {
+  const float box[2] = { 0.5, 0.5 };
+  for (int i = 0; i < size; i++)
+    filter->AddFilter(i * 2, box, 2);
+}
+
+}  // namespace
+
+// Tests that each pixel, when set and run through the impulse filter, does
+// not change.
+TEST(Convolver, Impulse) {
+  // We pick an "odd" size that is not likely to fit on any boundaries so that
+  // we can see if all the widths and paddings are handled properly.
+  int width = 15;
+  int height = 31;
+  int byte_count = width * height * 4;
+  std::vector<unsigned char> input;
+  input.resize(byte_count);
+
+  unsigned char* input_ptr = &input[0];
+  for (int y = 0; y < height; y++) {
+    for (int x = 0; x < width; x++) {
+      for (int channel = 0; channel < 3; channel++) {
+        memset(input_ptr, 0, byte_count);
+        input_ptr[(y * width + x) * 4 + channel] = 0xff;
+        // Always set the alpha channel or it will attempt to "fix" it for us.
+        input_ptr[(y * width + x) * 4 + 3] = 0xff;
+        TestImpulseConvolusion(input_ptr, width, height);
+      }
+    }
+  }
+}
+
+// Tests that using a box filter to halve an image results in every square of 4
+// pixels in the original get averaged to a pixel in the output.
+TEST(Convolver, Halve) {
+  static const int kSize = 16;
+
+  int src_width = kSize;
+  int src_height = kSize;
+  int src_row_stride = src_width * 4;
+  int src_byte_count = src_row_stride * src_height;
+  std::vector<unsigned char> input;
+  input.resize(src_byte_count);
+
+  int dest_width = src_width / 2;
+  int dest_height = src_height / 2;
+  int dest_byte_count = dest_width * dest_height * 4;
+  std::vector<unsigned char> output;
+  output.resize(dest_byte_count);
+
+  // First fill the array with a bunch of random data.
+  srand(static_cast<unsigned>(time(NULL)));
+  for (int i = 0; i < src_byte_count; i++)
+    input[i] = rand() * 255 / RAND_MAX;
+
+  // Compute the filters.
+  ConvolusionFilter1D filter_x, filter_y;
+  FillBoxFilter(dest_width, &filter_x);
+  FillBoxFilter(dest_height, &filter_y);
+
+  // Do the convolusion.
+  BGRAConvolve2D(&input[0], src_width, true, filter_x, filter_y, &output[0]);
+
+  // Compute the expected results and check, allowing for a small difference
+  // to account for rounding errors.
+  for (int y = 0; y < dest_height; y++) {
+    for (int x = 0; x < dest_width; x++) {
+      for (int channel = 0; channel < 4; channel++) {
+        int src_offset = (y * 2 * src_row_stride + x * 2 * 4) + channel;
+        int value = input[src_offset] +  // Top left source pixel.
+                    input[src_offset + 4] +  // Top right source pixel.
+                    input[src_offset + src_row_stride] +  // Lower left.
+                    input[src_offset + src_row_stride + 4];  // Lower right.
+        value /= 4;  // Average.
+        int difference = value - output[(y * dest_width + x) * 4 + channel];
+        EXPECT_TRUE(difference >= -1 || difference <= 1);
+      }
+    }
+  }
+}
+
+}  // namespace skia
+
diff --git a/skia/ext/image_operations.cc b/skia/ext/image_operations.cc
new file mode 100644
index 0000000..9eab6e5
--- /dev/null
+++ b/skia/ext/image_operations.cc
@@ -0,0 +1,366 @@
+// Copyright (c) 2006-2008 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.
+//
+#define _USE_MATH_DEFINES
+#include <cmath>
+#include <limits>
+#include <vector>
+
+#include "skia/ext/image_operations.h"
+
+#include "base/gfx/rect.h"
+#include "base/gfx/size.h"
+#include "base/logging.h"
+#include "base/stack_container.h"
+#include "skia/ext/convolver.h"
+#include "SkBitmap.h"
+
+// TODO(brettw) this should be removed when the base/gfx dependencies are
+// removed.
+using namespace gfx;
+
+namespace skia {
+
+namespace {
+
+// Returns the ceiling/floor as an integer.
+inline int CeilInt(float val) {
+  return static_cast<int>(ceil(val));
+}
+inline int FloorInt(float val) {
+  return static_cast<int>(floor(val));
+}
+
+// Filter function computation -------------------------------------------------
+
+// Evaluates the box filter, which goes from -0.5 to +0.5.
+float EvalBox(float x) {
+  return (x >= -0.5f && x < 0.5f) ? 1.0f : 0.0f;
+}
+
+// Evaluates the Lanczos filter of the given filter size window for the given
+// position.
+//
+// |filter_size| is the width of the filter (the "window"), outside of which
+// the value of the function is 0. Inside of the window, the value is the
+// normalized sinc function:
+//   lanczos(x) = sinc(x) * sinc(x / filter_size);
+// where
+//   sinc(x) = sin(pi*x) / (pi*x);
+float EvalLanczos(int filter_size, float x) {
+  if (x <= -filter_size || x >= filter_size)
+    return 0.0f;  // Outside of the window.
+  if (x > -std::numeric_limits<float>::epsilon() &&
+      x < std::numeric_limits<float>::epsilon())
+    return 1.0f;  // Special case the discontinuity at the origin.
+  float xpi = x * static_cast<float>(M_PI);
+  return (sin(xpi) / xpi) *  // sinc(x)
+          sin(xpi / filter_size) / (xpi / filter_size);  // sinc(x/filter_size)
+}
+
+// ResizeFilter ----------------------------------------------------------------
+
+// Encapsulates computation and storage of the filters required for one complete
+// resize operation.
+class ResizeFilter {
+ public:
+  ResizeFilter(ImageOperations::ResizeMethod method,
+               const Size& src_full_size,
+               const Size& dest_size,
+               const Rect& dest_subset);
+
+  // Returns the bounds in the input bitmap of data that is used in the output.
+  // The filter offsets are within this rectangle.
+  const Rect& src_depend() { return src_depend_; }
+
+  // Returns the filled filter values.
+  const ConvolusionFilter1D& x_filter() { return x_filter_; }
+  const ConvolusionFilter1D& y_filter() { return y_filter_; }
+
+ private:
+  // Returns the number of pixels that the filer spans, in filter space (the
+  // destination image).
+  float GetFilterSupport(float scale) {
+    switch (method_) {
+      case ImageOperations::RESIZE_BOX:
+        // The box filter just scales with the image scaling.
+        return 0.5f;  // Only want one side of the filter = /2.
+      case ImageOperations::RESIZE_LANCZOS3:
+        // The lanczos filter takes as much space in the source image in
+        // each direction as the size of the window = 3 for Lanczos3.
+        return 3.0f;
+      default:
+        NOTREACHED();
+        return 1.0f;
+    }
+  }
+
+  // Computes one set of filters either horizontally or vertically. The caller
+  // will specify the "min" and "max" rather than the bottom/top and
+  // right/bottom so that the same code can be re-used in each dimension.
+  //
+  // |src_depend_lo| and |src_depend_size| gives the range for the source
+  // depend rectangle (horizontally or vertically at the caller's discretion
+  // -- see above for what this means).
+  //
+  // Likewise, the range of destination values to compute and the scale factor
+  // for the transform is also specified.
+  void ComputeFilters(int src_size,
+                      int dest_subset_lo, int dest_subset_size,
+                      float scale, float src_support,
+                      ConvolusionFilter1D* output);
+
+  // Computes the filter value given the coordinate in filter space.
+  inline float ComputeFilter(float pos) {
+    switch (method_) {
+      case ImageOperations::RESIZE_BOX:
+        return EvalBox(pos);
+      case ImageOperations::RESIZE_LANCZOS3:
+        return EvalLanczos(2, pos);
+      default:
+        NOTREACHED();
+        return 0;
+    }
+  }
+
+  ImageOperations::ResizeMethod method_;
+
+  // Subset of source the filters will touch.
+  Rect src_depend_;
+
+  // Size of the filter support on one side only in the destination space.
+  // See GetFilterSupport.
+  float x_filter_support_;
+  float y_filter_support_;
+
+  // Subset of scaled destination bitmap to compute.
+  Rect out_bounds_;
+
+  ConvolusionFilter1D x_filter_;
+  ConvolusionFilter1D y_filter_;
+
+  DISALLOW_EVIL_CONSTRUCTORS(ResizeFilter);
+};
+
+ResizeFilter::ResizeFilter(ImageOperations::ResizeMethod method,
+                           const Size& src_full_size,
+                           const Size& dest_size,
+                           const Rect& dest_subset)
+    : method_(method),
+      out_bounds_(dest_subset) {
+  float scale_x = static_cast<float>(dest_size.width()) /
+                  static_cast<float>(src_full_size.width());
+  float scale_y = static_cast<float>(dest_size.height()) /
+                  static_cast<float>(src_full_size.height());
+
+  x_filter_support_ = GetFilterSupport(scale_x);
+  y_filter_support_ = GetFilterSupport(scale_y);
+
+  gfx::Rect src_full(0, 0, src_full_size.width(), src_full_size.height());
+  gfx::Rect dest_full(0, 0,
+                      static_cast<int>(src_full_size.width() * scale_x + 0.5),
+                      static_cast<int>(src_full_size.height() * scale_y + 0.5));
+
+  // Support of the filter in source space.
+  float src_x_support = x_filter_support_ / scale_x;
+  float src_y_support = y_filter_support_ / scale_y;
+
+  ComputeFilters(src_full_size.width(), dest_subset.x(), dest_subset.width(),
+                 scale_x, src_x_support, &x_filter_);
+  ComputeFilters(src_full_size.height(), dest_subset.y(), dest_subset.height(),
+                 scale_y, src_y_support, &y_filter_);
+}
+
+void ResizeFilter::ComputeFilters(int src_size,
+                                  int dest_subset_lo, int dest_subset_size,
+                                  float scale, float src_support,
+                                  ConvolusionFilter1D* output) {
+  int dest_subset_hi = dest_subset_lo + dest_subset_size;  // [lo, hi)
+
+  // When we're doing a magnification, the scale will be larger than one. This
+  // means the destination pixels are much smaller than the source pixels, and
+  // that the range covered by the filter won't necessarily cover any source
+  // pixel boundaries. Therefore, we use these clamped values (max of 1) for
+  // some computations.
+  float clamped_scale = std::min(1.0f, scale);
+
+  // Speed up the divisions below by turning them into multiplies.
+  float inv_scale = 1.0f / scale;
+
+  StackVector<float, 64> filter_values;
+  StackVector<int16, 64> fixed_filter_values;
+
+  // Loop over all pixels in the output range. We will generate one set of
+  // filter values for each one. Those values will tell us how to blend the
+  // source pixels to compute the destination pixel.
+  for (int dest_subset_i = dest_subset_lo; dest_subset_i < dest_subset_hi;
+       dest_subset_i++) {
+    // Reset the arrays. We don't declare them inside so they can re-use the
+    // same malloc-ed buffer.
+    filter_values->clear();
+    fixed_filter_values->clear();
+
+    // This is the pixel in the source directly under the pixel in the dest.
+    float src_pixel = dest_subset_i * inv_scale;
+
+    // Compute the (inclusive) range of source pixels the filter covers.
+    int src_begin = std::max(0, FloorInt(src_pixel - src_support));
+    int src_end = std::min(src_size - 1, CeilInt(src_pixel + src_support));
+
+    // Compute the unnormalized filter value at each location of the source
+    // it covers.
+    float filter_sum = 0.0f;  // Sub of the filter values for normalizing.
+    for (int cur_filter_pixel = src_begin; cur_filter_pixel <= src_end;
+         cur_filter_pixel++) {
+      // Distance from the center of the filter, this is the filter coordinate
+      // in source space.
+      float src_filter_pos = cur_filter_pixel - src_pixel;
+
+      // Since the filter really exists in dest space, map it there.
+      float dest_filter_pos = src_filter_pos * clamped_scale;
+
+      // Compute the filter value at that location.
+      float filter_value = ComputeFilter(dest_filter_pos);
+      filter_values->push_back(filter_value);
+
+      filter_sum += filter_value;
+    }
+    DCHECK(!filter_values->empty()) << "We should always get a filter!";
+
+    // The filter must be normalized so that we don't affect the brightness of
+    // the image. Convert to normalized fixed point.
+    int16 fixed_sum = 0;
+    for (size_t i = 0; i < filter_values->size(); i++) {
+      int16 cur_fixed = output->FloatToFixed(filter_values[i] / filter_sum);
+      fixed_sum += cur_fixed;
+      fixed_filter_values->push_back(cur_fixed);
+    }
+
+    // The conversion to fixed point will leave some rounding errors, which
+    // we add back in to avoid affecting the brightness of the image. We
+    // arbitrarily add this to the center of the filter array (this won't always
+    // be the center of the filter function since it could get clipped on the
+    // edges, but it doesn't matter enough to worry about that case).
+    int16 leftovers = output->FloatToFixed(1.0f) - fixed_sum;
+    fixed_filter_values[fixed_filter_values->size() / 2] += leftovers;
+
+    // Now it's ready to go.
+    output->AddFilter(src_begin, &fixed_filter_values[0],
+                      static_cast<int>(fixed_filter_values->size()));
+  }
+}
+
+}  // namespace
+
+// Resize ----------------------------------------------------------------------
+
+// static
+SkBitmap ImageOperations::Resize(const SkBitmap& source,
+                                 ResizeMethod method,
+                                 const Size& dest_size,
+                                 const Rect& dest_subset) {
+  DCHECK(Rect(dest_size.width(), dest_size.height()).Contains(dest_subset)) <<
+      "The supplied subset does not fall within the destination image.";
+
+  // If the size of source or destination is 0, i.e. 0x0, 0xN or Nx0, just
+  // return empty
+  if (source.width() < 1 || source.height() < 1 ||
+      dest_size.width() < 1 || dest_size.height() < 1)
+      return SkBitmap();
+
+  SkAutoLockPixels locker(source);
+
+  ResizeFilter filter(method, Size(source.width(), source.height()),
+                      dest_size, dest_subset);
+
+  // Get a source bitmap encompassing this touched area. We construct the
+  // offsets and row strides such that it looks like a new bitmap, while
+  // referring to the old data.
+  const uint8* source_subset =
+      reinterpret_cast<const uint8*>(source.getPixels());
+
+  // Convolve into the result.
+  SkBitmap result;
+  result.setConfig(SkBitmap::kARGB_8888_Config,
+                   dest_subset.width(), dest_subset.height());
+  result.allocPixels();
+  BGRAConvolve2D(source_subset, static_cast<int>(source.rowBytes()),
+                 !source.isOpaque(), filter.x_filter(), filter.y_filter(),
+                 static_cast<unsigned char*>(result.getPixels()));
+
+  // Preserve the "opaque" flag for use as an optimization later.
+  result.setIsOpaque(source.isOpaque());
+
+  return result;
+}
+
+// static
+SkBitmap ImageOperations::Resize(const SkBitmap& source,
+                                 ResizeMethod method,
+                                 const Size& dest_size) {
+  Rect dest_subset(0, 0, dest_size.width(), dest_size.height());
+  return Resize(source, method, dest_size, dest_subset);
+}
+
+// static
+SkBitmap ImageOperations::CreateBlendedBitmap(const SkBitmap& first,
+                                              const SkBitmap& second,
+                                              double alpha) {
+  DCHECK(alpha <= 1 && alpha >= 0);
+  DCHECK(first.width() == second.width());
+  DCHECK(first.height() == second.height());
+  DCHECK(first.bytesPerPixel() == second.bytesPerPixel());
+  DCHECK(first.config() == SkBitmap::kARGB_8888_Config);
+
+  // Optimize for case where we won't need to blend anything.
+  static const double alpha_min = 1.0 / 255;
+  static const double alpha_max = 254.0 / 255;
+  if (alpha < alpha_min) {
+    return first;
+  } else if (alpha > alpha_max) {
+    return second;
+  }
+
+  SkAutoLockPixels lock_first(first);
+  SkAutoLockPixels lock_second(second);
+
+  SkBitmap blended;
+  blended.setConfig(SkBitmap::kARGB_8888_Config, first.width(),
+                    first.height(), 0);
+  blended.allocPixels();
+  blended.eraseARGB(0, 0, 0, 0);
+
+  double first_alpha = 1 - alpha;
+
+  for (int y = 0; y < first.height(); y++) {
+    uint32* first_row = first.getAddr32(0, y);
+    uint32* second_row = second.getAddr32(0, y);
+    uint32* dst_row = blended.getAddr32(0, y);
+
+    for (int x = 0; x < first.width(); x++) {
+      uint32 first_pixel = first_row[x];
+      uint32 second_pixel = second_row[x];
+
+      int a = static_cast<int>(
+          SkColorGetA(first_pixel) * first_alpha +
+          SkColorGetA(second_pixel) * alpha);
+      int r = static_cast<int>(
+          SkColorGetR(first_pixel) * first_alpha +
+          SkColorGetR(second_pixel) * alpha);
+      int g = static_cast<int>(
+          SkColorGetG(first_pixel) * first_alpha +
+          SkColorGetG(second_pixel) * alpha);
+      int b = static_cast<int>(
+          SkColorGetB(first_pixel) * first_alpha +
+          SkColorGetB(second_pixel) * alpha);
+
+      dst_row[x] = SkColorSetARGB(a, r, g, b);
+    }
+  }
+
+  return blended;
+}
+
+}  // namespace skia
+
diff --git a/skia/ext/image_operations.h b/skia/ext/image_operations.h
new file mode 100644
index 0000000..60a8da7c
--- /dev/null
+++ b/skia/ext/image_operations.h
@@ -0,0 +1,63 @@
+// Copyright (c) 2006-2008 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.
+
+#ifndef SKIA_EXT_IMAGE_OPERATIONS_H_
+#define SKIA_EXT_IMAGE_OPERATIONS_H_
+
+#include "base/basictypes.h"
+#include "base/gfx/rect.h"
+
+class SkBitmap;
+
+namespace skia {
+
+class ImageOperations {
+ public:
+  enum ResizeMethod {
+    // Box filter. This is a weighted average of all of the pixels touching
+    // the destination pixel. For enlargement, this is nearest neighbor.
+    //
+    // You probably don't want this, it is here for testing since it is easy to
+    // compute. Use RESIZE_LANCZOS3 instead.
+    RESIZE_BOX,
+
+    // 3-cycle Lanczos filter. This is tall in the middle, goes negative on
+    // each side, then oscillates 2 more times. It gives nice sharp edges.
+    RESIZE_LANCZOS3,
+  };
+
+  // Resizes the given source bitmap using the specified resize method, so that
+  // the entire image is (dest_size) big. The dest_subset is the rectangle in
+  // this destination image that should actually be returned.
+  //
+  // The output image will be (dest_subset.width(), dest_subset.height()). This
+  // will save work if you do not need the entire bitmap.
+  //
+  // The destination subset must be smaller than the destination image.
+  static SkBitmap Resize(const SkBitmap& source,
+                         ResizeMethod method,
+                         const gfx::Size& dest_size,
+                         const gfx::Rect& dest_subset);
+
+  // Alternate version for resizing and returning the entire bitmap rather than
+  // a subset.
+  static SkBitmap Resize(const SkBitmap& source,
+                         ResizeMethod method,
+                         const gfx::Size& dest_size);
+
+
+  // Create a bitmap that is a blend of two others. The alpha argument
+  // specifies the opacity of the second bitmap. The provided bitmaps must
+  // use have the kARGB_8888_Config config and be of equal dimensions.
+  static SkBitmap CreateBlendedBitmap(const SkBitmap& first,
+                                      const SkBitmap& second,
+                                      double alpha);
+ private:
+  ImageOperations();  // Class for scoping only.
+};
+
+}  // namespace skia
+
+#endif  // SKIA_EXT_IMAGE_OPERATIONS_H_
+
diff --git a/skia/ext/image_operations_unittest.cc b/skia/ext/image_operations_unittest.cc
new file mode 100644
index 0000000..7a52d1f
--- /dev/null
+++ b/skia/ext/image_operations_unittest.cc
@@ -0,0 +1,149 @@
+// Copyright (c) 2006-2008 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 <stdlib.h>
+
+#include "skia/ext/image_operations.h"
+
+#include "testing/gtest/include/gtest/gtest.h"
+#include "SkBitmap.h"
+
+namespace {
+
+// Computes the average pixel value for the given range, inclusive.
+uint32_t AveragePixel(const SkBitmap& bmp,
+                      int x_min, int x_max,
+                      int y_min, int y_max) {
+  float accum[4] = {0, 0, 0, 0};
+  int count = 0;
+  for (int y = y_min; y <= y_max; y++) {
+    for (int x = x_min; x <= x_max; x++) {
+      uint32_t cur = *bmp.getAddr32(x, y);
+      accum[0] += SkColorGetB(cur);
+      accum[1] += SkColorGetG(cur);
+      accum[2] += SkColorGetR(cur);
+      accum[3] += SkColorGetA(cur);
+      count++;
+    }
+  }
+
+  return SkColorSetARGB(static_cast<unsigned char>(accum[3] / count),
+                        static_cast<unsigned char>(accum[2] / count),
+                        static_cast<unsigned char>(accum[1] / count),
+                        static_cast<unsigned char>(accum[0] / count));
+}
+
+// Returns true if each channel of the given two colors are "close." This is
+// used for comparing colors where rounding errors may cause off-by-one.
+bool ColorsClose(uint32_t a, uint32_t b) {
+  return abs(static_cast<int>(SkColorGetB(a) - SkColorGetB(b))) < 2 &&
+         abs(static_cast<int>(SkColorGetG(a) - SkColorGetG(b))) < 2 &&
+         abs(static_cast<int>(SkColorGetR(a) - SkColorGetR(b))) < 2 &&
+         abs(static_cast<int>(SkColorGetA(a) - SkColorGetA(b))) < 2;
+}
+
+void FillDataToBitmap(int w, int h, SkBitmap* bmp) {
+  bmp->setConfig(SkBitmap::kARGB_8888_Config, w, h);
+  bmp->allocPixels();
+
+  unsigned char* src_data =
+      reinterpret_cast<unsigned char*>(bmp->getAddr32(0, 0));
+  for (int i = 0; i < w * h; i++) {
+    src_data[i * 4 + 0] = static_cast<unsigned char>(i % 255);
+    src_data[i * 4 + 1] = static_cast<unsigned char>(i % 255);
+    src_data[i * 4 + 2] = static_cast<unsigned char>(i % 255);
+    src_data[i * 4 + 3] = static_cast<unsigned char>(i % 255);
+  }
+}
+
+}  // namespace
+
+// Makes the bitmap 50% the size as the original using a box filter. This is
+// an easy operation that we can check the results for manually.
+TEST(ImageOperations, Halve) {
+  // Make our source bitmap.
+  int src_w = 30, src_h = 38;
+  SkBitmap src;
+  FillDataToBitmap(src_w, src_h, &src);
+
+  // Do a halving of the full bitmap.
+  SkBitmap actual_results = skia::ImageOperations::Resize(
+      src, skia::ImageOperations::RESIZE_BOX, gfx::Size(src_w / 2, src_h / 2));
+  ASSERT_EQ(src_w / 2, actual_results.width());
+  ASSERT_EQ(src_h / 2, actual_results.height());
+
+  // Compute the expected values & compare.
+  SkAutoLockPixels lock(actual_results);
+  for (int y = 0; y < actual_results.height(); y++) {
+    for (int x = 0; x < actual_results.width(); x++) {
+      int first_x = std::max(0, x * 2 - 1);
+      int last_x = std::min(src_w - 1, x * 2);
+
+      int first_y = std::max(0, y * 2 - 1);
+      int last_y = std::min(src_h - 1, y * 2);
+
+      uint32_t expected_color = AveragePixel(src,
+                                             first_x, last_x, first_y, last_y);
+      EXPECT_TRUE(ColorsClose(expected_color, *actual_results.getAddr32(x, y)));
+    }
+  }
+}
+
+TEST(ImageOperations, HalveSubset) {
+  // Make our source bitmap.
+  int src_w = 16, src_h = 34;
+  SkBitmap src;
+  FillDataToBitmap(src_w, src_h, &src);
+
+  // Do a halving of the full bitmap.
+  SkBitmap full_results = skia::ImageOperations::Resize(
+      src, skia::ImageOperations::RESIZE_BOX, gfx::Size(src_w / 2, src_h / 2));
+  ASSERT_EQ(src_w / 2, full_results.width());
+  ASSERT_EQ(src_h / 2, full_results.height());
+
+  // Now do a halving of a a subset, recall the destination subset is in the
+  // destination coordinate system (max = half of the original image size).
+  gfx::Rect subset_rect(2, 3, 3, 6);
+  SkBitmap subset_results = skia::ImageOperations::Resize(
+      src, skia::ImageOperations::RESIZE_BOX,
+      gfx::Size(src_w / 2, src_h / 2), subset_rect);
+  ASSERT_EQ(subset_rect.width(), subset_results.width());
+  ASSERT_EQ(subset_rect.height(), subset_results.height());
+
+  // The computed subset and the corresponding subset of the original image
+  // should be the same.
+  SkAutoLockPixels full_lock(full_results);
+  SkAutoLockPixels subset_lock(subset_results);
+  for (int y = 0; y < subset_rect.height(); y++) {
+    for (int x = 0; x < subset_rect.width(); x++) {
+      ASSERT_EQ(
+          *full_results.getAddr32(x + subset_rect.x(), y + subset_rect.y()),
+          *subset_results.getAddr32(x, y));
+    }
+  }
+}
+
+// Resamples an iamge to the same image, it should give almost the same result.
+TEST(ImageOperations, ResampleToSame) {
+  // Make our source bitmap.
+  int src_w = 16, src_h = 34;
+  SkBitmap src;
+  FillDataToBitmap(src_w, src_h, &src);
+
+  // Do a resize of the full bitmap to the same size. The lanczos filter is good
+  // enough that we should get exactly the same image for output.
+  SkBitmap results = skia::ImageOperations::Resize(
+      src, skia::ImageOperations::RESIZE_LANCZOS3, gfx::Size(src_w, src_h));
+  ASSERT_EQ(src_w, results.width());
+  ASSERT_EQ(src_h, results.height());
+
+  SkAutoLockPixels src_lock(src);
+  SkAutoLockPixels results_lock(results);
+  for (int y = 0; y < src_h; y++) {
+    for (int x = 0; x < src_w; x++) {
+      EXPECT_EQ(*src.getAddr32(x, y), *results.getAddr32(x, y));
+    }
+  }
+}
+
diff --git a/skia/ext/platform_device_mac.cc b/skia/ext/platform_device_mac.cc
index 9539e0f..3cc6fb4 100755
--- a/skia/ext/platform_device_mac.cc
+++ b/skia/ext/platform_device_mac.cc
@@ -5,7 +5,7 @@
 #include "skia/ext/bitmap_platform_device_mac.h"
 
 #include "base/logging.h"
-#include "base/gfx/skia_utils_mac.h"
+#include "skia/ext/skia_utils_mac.h"
 #include "SkMatrix.h"
 #include "SkPath.h"
 #include "SkUtils.h"
diff --git a/skia/ext/platform_device_win.cc b/skia/ext/platform_device_win.cc
index 15201c0..1e8301d 100644
--- a/skia/ext/platform_device_win.cc
+++ b/skia/ext/platform_device_win.cc
@@ -5,11 +5,14 @@
 #include "skia/ext/platform_device_win.h"
 
 #include "base/logging.h"
-#include "base/gfx/skia_utils.h"
 #include "SkMatrix.h"
 #include "SkPath.h"
 #include "SkRegion.h"
 #include "SkUtils.h"
+#include "skia/ext/skia_utils_win.h"
+
+// TODO(brettw) remove this when this file is converted to namespace skia.
+using namespace skia;
 
 namespace gfx {
 
diff --git a/skia/ext/skia_utils.cc b/skia/ext/skia_utils.cc
new file mode 100644
index 0000000..651670e
--- /dev/null
+++ b/skia/ext/skia_utils.cc
@@ -0,0 +1,26 @@
+// Copyright (c) 2006-2008 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 "skia/ext/skia_utils_win.h"
+
+#include "SkRect.h"
+#include "SkGradientShader.h"
+
+namespace skia {
+
+SkShader* CreateGradientShader(int start_point,
+                               int end_point,
+                               SkColor start_color,
+                               SkColor end_color) {
+  SkColor grad_colors[2] = { start_color, end_color};
+  SkPoint grad_points[2];
+  grad_points[0].set(SkIntToScalar(0), SkIntToScalar(start_point));
+  grad_points[1].set(SkIntToScalar(0), SkIntToScalar(end_point));
+
+  return SkGradientShader::CreateLinear(
+      grad_points, grad_colors, NULL, 2, SkShader::kRepeat_TileMode);
+}
+
+}  // namespace skia
+
diff --git a/skia/ext/skia_utils.h b/skia/ext/skia_utils.h
new file mode 100644
index 0000000..acfab28
--- /dev/null
+++ b/skia/ext/skia_utils.h
@@ -0,0 +1,23 @@
+// Copyright (c) 2006-2008 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.
+
+// This file contains cross-platform Skia helper routines.
+
+#ifndef SKIA_EXT_SKIA_UTILS_H_
+#define SKIA_EXT_SKIA_UTILS_H_
+
+#include "SkShader.h"
+
+namespace skia {
+
+// Creates a vertical gradient shader. The caller owns the shader.
+SkShader* CreateGradientShader(int start_point,
+                               int end_point,
+                               SkColor start_color,
+                               SkColor end_color);
+
+}  // namespace skia
+
+#endif  // SKIA_EXT_SKIA_UTILS_H_
+
diff --git a/skia/ext/skia_utils_mac.cc b/skia/ext/skia_utils_mac.cc
new file mode 100644
index 0000000..a7610aa
--- /dev/null
+++ b/skia/ext/skia_utils_mac.cc
@@ -0,0 +1,83 @@
+// Copyright (c) 2006-2008 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 "skia/ext/skia_utils_mac.h"
+
+#include "base/logging.h"
+#include "SkMatrix.h"
+#include "SkRect.h"
+
+namespace gfx {
+
+CGAffineTransform SkMatrixToCGAffineTransform(const SkMatrix& matrix) {
+  // CGAffineTransforms don't support perspective transforms, so make sure
+  // we don't get those.
+  DCHECK(matrix[SkMatrix::kMPersp0] == 0.0f);
+  DCHECK(matrix[SkMatrix::kMPersp1] == 0.0f);
+  DCHECK(matrix[SkMatrix::kMPersp2] == 1.0f);
+  
+  return CGAffineTransformMake(matrix[SkMatrix::kMScaleX],
+                               matrix[SkMatrix::kMSkewY],
+                               matrix[SkMatrix::kMSkewX],
+                               matrix[SkMatrix::kMScaleY],
+                               matrix[SkMatrix::kMTransX],
+                               matrix[SkMatrix::kMTransY]);
+}
+  
+SkIRect CGRectToSkIRect(const CGRect& rect) {
+  SkIRect sk_rect = {
+    SkScalarRound(rect.origin.x),
+    SkScalarRound(rect.origin.y),
+    SkScalarRound(rect.origin.x + rect.size.width),
+    SkScalarRound(rect.origin.y + rect.size.height)
+  };
+  return sk_rect;
+}
+
+SkRect CGRectToSkRect(const CGRect& rect) {
+  SkRect sk_rect = {
+    rect.origin.x,
+    rect.origin.y,
+    rect.origin.x + rect.size.width,
+    rect.origin.y + rect.size.height,
+  };
+  return sk_rect;
+}
+  
+CGRect SkIRectToCGRect(const SkIRect& rect) {
+  CGRect cg_rect = {
+    { rect.fLeft, rect.fTop },
+    { rect.fRight - rect.fLeft, rect.fBottom - rect.fTop }
+  };
+  return cg_rect;
+} 
+
+CGRect SkRectToCGRect(const SkRect& rect) {
+  CGRect cg_rect = {
+    { rect.fLeft, rect.fTop },
+    { rect.fRight - rect.fLeft, rect.fBottom - rect.fTop }
+  };
+  return cg_rect;
+}
+
+// Converts CGColorRef to the ARGB layout Skia expects.
+SkColor CGColorRefToSkColor(CGColorRef color) {
+  DCHECK(CGColorGetNumberOfComponents(color) == 4);
+  const CGFloat *components = CGColorGetComponents(color);
+  return SkColorSetARGB(SkScalarRound(255.0 * components[3]), // alpha
+                        SkScalarRound(255.0 * components[0]), // red
+                        SkScalarRound(255.0 * components[1]), // green
+                        SkScalarRound(255.0 * components[2])); // blue
+}
+
+// Converts ARGB to CGColorRef.
+CGColorRef SkColorToCGColorRef(SkColor color) {
+  return CGColorCreateGenericRGB(SkColorGetR(color) / 255.0,
+                                 SkColorGetG(color) / 255.0,
+                                 SkColorGetB(color) / 255.0,
+                                 SkColorGetA(color) / 255.0);
+}
+
+}  // namespace gfx
+
diff --git a/skia/ext/skia_utils_mac.h b/skia/ext/skia_utils_mac.h
new file mode 100644
index 0000000..a99905f
--- /dev/null
+++ b/skia/ext/skia_utils_mac.h
@@ -0,0 +1,51 @@
+// Copyright (c) 2006-2008 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.
+
+
+#ifndef BASE_GFX_SKIA_UTILS_MAC_H__
+#define BASE_GFX_SKIA_UTILS_MAC_H__
+
+#include "SkColor.h"
+#include <CoreGraphics/CGColor.h>
+
+struct SkMatrix;
+struct SkIRect;
+struct SkPoint;
+struct SkRect;
+
+namespace gfx {
+
+// Converts a Skia point to a CoreGraphics CGPoint.
+// Both use same in-memory format.
+inline const CGPoint& SkPointToCGPoint(const SkPoint& point) {
+  return reinterpret_cast<const CGPoint&>(point);
+}
+
+// Converts a CoreGraphics point to a Skia CGPoint.
+// Both use same in-memory format.
+inline const SkPoint& CGPointToSkPoint(const CGPoint& point) {
+  return reinterpret_cast<const SkPoint&>(point);
+}
+
+// Matrix converters.
+CGAffineTransform SkMatrixToCGAffineTransform(const SkMatrix& matrix);
+  
+// Rectangle converters.
+SkRect CGRectToSkRect(const CGRect& rect);
+SkIRect CGRectToSkIRect(const CGRect& rect);
+
+// Converts a Skia rect to a CoreGraphics CGRect.
+CGRect SkIRectToCGRect(const SkIRect& rect);
+CGRect SkRectToCGRect(const SkRect& rect);
+
+// Converts CGColorRef to the ARGB layout Skia expects.
+SkColor CGColorRefToSkColor(CGColorRef color);
+
+// Converts ARGB to CGColorRef.
+CGColorRef SkColorToCGColorRef(SkColor color);
+
+}  // namespace gfx
+
+#endif
+
diff --git a/skia/ext/skia_utils_win.cc b/skia/ext/skia_utils_win.cc
new file mode 100644
index 0000000..f695a63
--- /dev/null
+++ b/skia/ext/skia_utils_win.cc
@@ -0,0 +1,59 @@
+// Copyright (c) 2006-2008 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 <windows.h>
+
+#include "skia/ext/skia_utils_win.h"
+
+#include "SkRect.h"
+#include "SkGradientShader.h"
+
+namespace {
+
+// Compiler assert from base/logging.h
+template <bool>
+struct CompileAssert {
+};
+#undef COMPILE_ASSERT
+#define COMPILE_ASSERT(expr, msg) \
+  typedef CompileAssert<(bool(expr))> msg[bool(expr) ? 1 : -1]
+
+COMPILE_ASSERT(SK_OFFSETOF(RECT, left) == SK_OFFSETOF(SkIRect, fLeft), o1);
+COMPILE_ASSERT(SK_OFFSETOF(RECT, top) == SK_OFFSETOF(SkIRect, fTop), o2);
+COMPILE_ASSERT(SK_OFFSETOF(RECT, right) == SK_OFFSETOF(SkIRect, fRight), o3);
+COMPILE_ASSERT(SK_OFFSETOF(RECT, bottom) == SK_OFFSETOF(SkIRect, fBottom), o4);
+COMPILE_ASSERT(sizeof(RECT().left) == sizeof(SkIRect().fLeft), o5);
+COMPILE_ASSERT(sizeof(RECT().top) == sizeof(SkIRect().fTop), o6);
+COMPILE_ASSERT(sizeof(RECT().right) == sizeof(SkIRect().fRight), o7);
+COMPILE_ASSERT(sizeof(RECT().bottom) == sizeof(SkIRect().fBottom), o8);
+COMPILE_ASSERT(sizeof(RECT) == sizeof(SkIRect), o9);
+
+}  // namespace
+
+namespace skia {
+
+POINT SkPointToPOINT(const SkPoint& point) {
+  POINT win_point = { SkScalarRound(point.fX), SkScalarRound(point.fY) };
+  return win_point;
+}
+
+SkRect RECTToSkRect(const RECT& rect) {
+  SkRect sk_rect = { SkIntToScalar(rect.left), SkIntToScalar(rect.top),
+                     SkIntToScalar(rect.right), SkIntToScalar(rect.bottom) };
+  return sk_rect;
+}
+
+SkColor COLORREFToSkColor(COLORREF color) {
+  return SkColorSetRGB(GetRValue(color), GetGValue(color), GetBValue(color));
+}
+
+COLORREF SkColorToCOLORREF(SkColor color) {
+  // Currently, Alpha is always 255 or the color is 0 so there is no need to
+  // demultiply the channels. If this is needed, (SkColorGetX(color) * 255 / a)
+  // will have to be added in the conversion.
+  return RGB(SkColorGetR(color), SkColorGetG(color), SkColorGetB(color));
+}
+
+}  // namespace skia
+
diff --git a/skia/ext/skia_utils_win.h b/skia/ext/skia_utils_win.h
new file mode 100644
index 0000000..297608a
--- /dev/null
+++ b/skia/ext/skia_utils_win.h
@@ -0,0 +1,56 @@
+// Copyright (c) 2006-2008 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.
+
+#ifndef SKIA_EXT_SKIA_UTILS_WIN_H_
+#define SKIA_EXT_SKIA_UTILS_WIN_H_
+
+#include "SkColor.h"
+#include "SkShader.h"
+
+struct SkIRect;
+struct SkPoint;
+struct SkRect;
+typedef unsigned long DWORD;
+typedef DWORD COLORREF;
+typedef struct tagPOINT POINT;
+typedef struct tagRECT RECT;
+
+namespace skia {
+
+// Converts a Skia point to a Windows POINT.
+POINT SkPointToPOINT(const SkPoint& point);
+
+// Converts a Windows RECT to a Skia rect.
+SkRect RECTToSkRect(const RECT& rect);
+
+// Converts a Windows RECT to a Skia rect.
+// Both use same in-memory format. Verified by COMPILE_ASSERT() in
+// skia_utils.cc.
+inline const SkIRect& RECTToSkIRect(const RECT& rect) {
+  return reinterpret_cast<const SkIRect&>(rect);
+}
+
+// Converts a Skia rect to a Windows RECT.
+// Both use same in-memory format. Verified by COMPILE_ASSERT() in
+// skia_utils.cc.
+inline const RECT& SkIRectToRECT(const SkIRect& rect) {
+  return reinterpret_cast<const RECT&>(rect);
+}
+
+// Creates a vertical gradient shader. The caller owns the shader.
+SkShader* CreateGradientShader(int start_point,
+                               int end_point,
+                               SkColor start_color,
+                               SkColor end_color);
+
+// Converts COLORREFs (0BGR) to the ARGB layout Skia expects.
+SkColor COLORREFToSkColor(COLORREF color);
+
+// Converts ARGB to COLORREFs (0BGR).
+COLORREF SkColorToCOLORREF(SkColor color);
+
+}  // namespace skia
+
+#endif  // SKIA_EXT_SKIA_UTILS_WIN_H_
+
diff --git a/skia/ext/vector_device.cc b/skia/ext/vector_device.cc
index a587e0c..2dc0c30 100644
--- a/skia/ext/vector_device.cc
+++ b/skia/ext/vector_device.cc
@@ -5,12 +5,14 @@
 #include "skia/ext/vector_device.h"
 
 #include "base/gfx/gdi_util.h"
-#include "base/gfx/skia_utils.h"
 #include "base/logging.h"
 #include "base/scoped_handle.h"
-
+#include "skia/ext/skia_utils_win.h"
 #include "SkUtils.h"
 
+// TOOD(brettw) remove this when this file is changed over to namespace skia.
+using namespace skia;
+
 namespace gfx {
 
 VectorDevice* VectorDevice::create(HDC dc, int width, int height) {
diff --git a/skia/skia.vcproj b/skia/skia.vcproj
index 5e06d73..65453c1 100644
--- a/skia/skia.vcproj
+++ b/skia/skia.vcproj
@@ -1321,6 +1321,22 @@
 				>
 			</File>
 			<File
+				RelativePath=".\ext\convolver.cc"
+				>
+			</File>
+			<File
+				RelativePath=".\ext\convolver.h"
+				>
+			</File>
+			<File
+				RelativePath=".\ext\image_operations.cc"
+				>
+			</File>
+			<File
+				RelativePath=".\ext\image_operations.h"
+				>
+			</File>
+			<File
 				RelativePath=".\ext\platform_canvas.h"
 				>
 			</File>
@@ -1345,6 +1361,22 @@
 				>
 			</File>
 			<File
+				RelativePath=".\ext\skia_utils.cc"
+				>
+			</File>
+			<File
+				RelativePath=".\ext\skia_utils.h"
+				>
+			</File>
+			<File
+				RelativePath=".\ext\skia_utils_win.cc"
+				>
+			</File>
+			<File
+				RelativePath=".\ext\skia_utils_win.h"
+				>
+			</File>
+			<File
 				RelativePath=".\ext\vector_canvas.cc"
 				>
 			</File>