ui/gfx/image/image_util.cc

// Copyright (c) 2012 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 "ui/gfx/image/image_util.h"

#include <algorithm>

#include "base/memory/scoped_ptr.h"
#include "third_party/skia/include/core/SkBitmap.h"
#include "ui/gfx/codec/jpeg_codec.h"
#include "ui/gfx/image/image.h"
#include "ui/gfx/image/image_skia.h"

namespace gfx {

const uint32_t kMinimumVisibleOpacity = 12;

// The iOS implementations of the JPEG functions are in image_util_ios.mm.
#if !defined(OS_IOS)
Image ImageFrom1xJPEGEncodedData(const unsigned char* input,
                                 size_t input_size) {
  scoped_ptr<SkBitmap> bitmap(gfx::JPEGCodec::Decode(input, input_size));
  if (bitmap.get())
    return Image::CreateFrom1xBitmap(*bitmap);

  return Image();
}

bool JPEG1xEncodedDataFromImage(const Image& image, int quality,
                                std::vector<unsigned char>* dst) {
  const gfx::ImageSkiaRep& image_skia_rep =
      image.AsImageSkia().GetRepresentation(1.0f);
  if (image_skia_rep.scale() != 1.0f)
    return false;

  const SkBitmap& bitmap = image_skia_rep.sk_bitmap();
  SkAutoLockPixels bitmap_lock(bitmap);

  if (!bitmap.readyToDraw())
    return false;

  return gfx::JPEGCodec::Encode(
          reinterpret_cast<unsigned char*>(bitmap.getAddr32(0, 0)),
          gfx::JPEGCodec::FORMAT_SkBitmap, bitmap.width(),
          bitmap.height(),
          static_cast<int>(bitmap.rowBytes()), quality,
          dst);
}
#endif  // !defined(OS_IOS)

bool VisibleMargins(const ImageSkia& image, int* leading, int* trailing) {
  *leading = 0;
  *trailing = std::max(1, image.width()) - 1;
  if (!image.HasRepresentation(1.0))
    return false;

  const ImageSkiaRep& rep = image.GetRepresentation(1.0);
  if (rep.is_null())
    return false;

  const SkBitmap& bitmap = rep.sk_bitmap();
  if (bitmap.isNull() || bitmap.width() == 0)
    return false;

  if (bitmap.isOpaque())
    return true;

  SkAutoLockPixels l(bitmap);
  int inner_min = bitmap.width();
  for (int x = 0; x < bitmap.width(); ++x) {
    for (int y = 0; y < bitmap.height(); ++y) {
      if (SkColorGetA(bitmap.getColor(x, y)) > kMinimumVisibleOpacity) {
        inner_min = x;
        break;
      }
    }
    if (inner_min < bitmap.width())
      break;
  }

  int inner_max = -1;
  for (int x = bitmap.width() - 1; x > inner_min; --x) {
    for (int y = 0; y < bitmap.height(); ++y) {
      if (SkColorGetA(bitmap.getColor(x, y)) > kMinimumVisibleOpacity) {
        inner_max = x;
        break;
      }
    }
    if (inner_max > -1)
      break;
  }

  if (inner_min == bitmap.width()) {
    *leading = bitmap.width()/2;
    *trailing = bitmap.width()/2 + 1;
    return true;
  }

  *leading = inner_min;
  *trailing = inner_max;
  return true;
}

}  // namespace gfx