Move BitmapPlatformDevice::makeOpaque into a shared file

skia/ext/bitmap_platform_device.cc

+// Copyright (c) 2010 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/bitmap_platform_device.h"
+
+#include "skia/ext/bitmap_platform_device_data.h"
+#include "third_party/skia/include/core/SkUtils.h"
+
+namespace {
+
+// Constrains position and size to fit within available_size. If |size| is -1,
+// all the available_size is used. Returns false if the position is out of
+// available_size.
+bool Constrain(int available_size, int* position, int *size) {
+  if (*size < -2)
+    return false;
+
+  if (*position < 0) {
+    if (*size != -1)
+      *size += *position;
+    *position = 0;
+  }
+  if (*size == 0 || *position >= available_size)
+    return false;
+
+  if (*size > 0) {
+    int overflow = (*position + *size) - available_size;
+    if (overflow > 0) {
+      *size -= overflow;
+    }
+  } else {
+    // Fill up available size.
+    *size = available_size - *position;
+  }
+  return true;
+}
+
+}  // namespace
+
+namespace skia {
+
+void BitmapPlatformDevice::makeOpaque(int x, int y, int width, int height) {
+  const SkBitmap& bitmap = accessBitmap(true);
+  SkASSERT(bitmap.config() == SkBitmap::kARGB_8888_Config);
+
+  // FIXME(brettw): This is kind of lame, we shouldn't be dealing with
+  // transforms at this level. Probably there should be a PlatformCanvas
+  // function that does the transform (using the actual transform not just the
+  // translation) and calls us with the transformed rect.
+  const SkMatrix& matrix = data_->transform();
+  int bitmap_start_x = SkScalarRound(matrix.getTranslateX()) + x;
+  int bitmap_start_y = SkScalarRound(matrix.getTranslateY()) + y;
+
+  if (Constrain(bitmap.width(), &bitmap_start_x, &width) &&
+      Constrain(bitmap.height(), &bitmap_start_y, &height)) {
+    SkAutoLockPixels lock(bitmap);
+    SkASSERT(bitmap.rowBytes() % sizeof(uint32_t) == 0u);
+    size_t row_words = bitmap.rowBytes() / sizeof(uint32_t);
+    // Set data to the first pixel to be modified.
+    uint32_t* data = bitmap.getAddr32(0, 0) + (bitmap_start_y * row_words) +
+                     bitmap_start_x;
+    for (int i = 0; i < height; i++) {
+      for (int j = 0; j < width; j++)
+        data[j] |= (0xFF << SK_A32_SHIFT);
+      data += row_words;
+    }
+  }
+}
+
+}