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

base/gfx/convolver_unittest.cc

-// 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 "base/gfx/convolver.h"
-#include "testing/gtest/include/gtest/gtest.h"
-
-namespace gfx {
-
-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 gfx
-