chrome/browser/media/webrtc/window_icon_util_x11.cc

// Copyright 2016 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 "chrome/browser/media/webrtc/window_icon_util.h"

#include "ui/base/x/x11_util.h"
#include "ui/gfx/x/x11_atom_cache.h"
#include "ui/gfx/x/xproto_util.h"

gfx::ImageSkia GetWindowIcon(content::DesktopMediaID id) {
  DCHECK(id.type == content::DesktopMediaID::TYPE_WINDOW);

  std::vector<uint32_t> data;
  if (!GetArrayProperty(static_cast<x11::Window>(id.id),
                        x11::GetAtom("_NET_WM_ICON"), &data)) {
    return gfx::ImageSkia();
  }

  // The format of |data| is concatenation of sections like
  // [width, height, pixel data of size width * height], and the total bytes
  // number of |data| is |size|. And here we are picking the largest icon.
  int width = 0;
  int height = 0;
  int start = 0;
  size_t i = 0;
  while (i + 1 < data.size()) {
    if ((i == 0 || static_cast<int>(data[i] * data[i + 1]) > width * height) &&
        (i + 1 + data[i] * data[i + 1] < data.size())) {
      width = static_cast<int>(data[i]);
      height = static_cast<int>(data[i + 1]);
      start = i + 2;
    }
    i = i + 2 + static_cast<int>(data[i] * data[i + 1]);
  }

  SkBitmap result;
  SkImageInfo info = SkImageInfo::MakeN32(width, height, kUnpremul_SkAlphaType);
  result.allocPixels(info);

  uint32_t* pixels_data = reinterpret_cast<uint32_t*>(result.getPixels());

  for (long y = 0; y < height; ++y) {
    for (long x = 0; x < width; ++x) {
      pixels_data[result.rowBytesAsPixels() * y + x] =
          static_cast<uint32_t>(data[start + width * y + x]);
    }
  }

  return gfx::ImageSkia::CreateFrom1xBitmap(result);
}