[Media Remoting] Add function to create interstitial.

media/remoting/remoting_interstitial_ui.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 "media/remoting/remoting_interstitial_ui.h"
+
+#include "media/base/media_resources.h"
+#include "media/base/video_util.h"
+#include "third_party/skia/include/core/SkTypeface.h"
+#include "third_party/skia/include/effects/SkBlurImageFilter.h"
+#include "ui/gfx/color_palette.h"
+#include "ui/gfx/geometry/size.h"
+#include "ui/gfx/paint_vector_icon.h"
+#include "ui/gfx/skbitmap_operations.h"
+#include "ui/gfx/vector_icons_public.h"
+
+namespace media {
+
+scoped_refptr<VideoFrame> GetInterstitial(SkCanvas* existing_frame_canvas,

[miu, 2016/11/05 04:09:52]

BTW--Is it ever legal to call this function with a nullptr? If not, put the
null-checking burden on the caller, and make this a "documentative" argument by
using:

  const SkCanvas& existing_frame_canvas

(unless the methods you call on it are not const)

[apacible, 2016/11/07 17:57:43]

readPixels() isn't const.

+                                          bool is_remoting_successful) {
+  if (!existing_frame_canvas)
+    return nullptr;
+
+  // Initial bitmap to grab the existing frame image.
+  SkBitmap bitmap;
+  bitmap.setInfo(existing_frame_canvas->imageInfo());
+  const SkISize frame_size = existing_frame_canvas->getBaseLayerSize();
+  const gfx::Size canvas_size =
+      gfx::Size(frame_size.width(), frame_size.height());
+
+  // Second bitmap for manipulation.
+  SkBitmap modified_bitmap;
+
+  // Reads the pixels from the current frame into |modified_bitmap|. In the
+  // case this failed, create and use a blank bitmap.
+  if (existing_frame_canvas->readPixels(&bitmap, 0, 0)) {
+    // Make monochromatic.
+    color_utils::HSL shift = {-1, 0, 0.2};
+    modified_bitmap = SkBitmapOperations::CreateHSLShiftedBitmap(bitmap, shift);
+  } else {
+    modified_bitmap.allocN32Pixels(canvas_size.width(), canvas_size.height());
+  }
+
+  SkCanvas canvas(modified_bitmap);
+
+  // Blur the background image.
+  SkScalar sigma = SkDoubleToScalar(10);
+  SkPaint paint_blur;
+  paint_blur.setImageFilter(SkBlurImageFilter::Make(sigma, sigma, nullptr));
+  canvas.saveLayer(0, &paint_blur);
+  canvas.restore();
+
+  // Create SkPaint for text and icon bitmap.
+  // After |paint| draws, the new canvas should look like this:
+  //       _________________________________
+  //       |                                |
+  //       |                                |
+  //       |             [   ]              |
+  //       |        Casting Video...        |
+  //       |                                |
+  //       |________________________________|
+  //
+  // Both text and icon are centered horizontally. Together, they are

[miu, 2016/11/05 04:09:52]

Nice! :)

+  // centered vertically.
+  SkPaint paint;
+  int text_size = SkIntToScalar(30);
+  paint.setAntiAlias(true);
+  paint.setFilterQuality(kHigh_SkFilterQuality);
+  paint.setColor(SK_ColorLTGRAY);
+  paint.setTypeface(SkTypeface::MakeFromName(
+      "sans", SkFontStyle::FromOldStyle(SkTypeface::kNormal)));
+  paint.setTextSize(text_size);
+
+  // Draw the appropriate text.
+  const std::string remote_playback_message =
+      is_remoting_successful
+          ? GetLocalizedStringUTF8(MEDIA_REMOTING_CASTING_VIDEO_TEXT)
+          : GetLocalizedStringUTF8(MEDIA_REMOTING_CAST_ERROR_TEXT);
+  size_t display_text_width = paint.measureText(remote_playback_message.data(),
+                                                remote_playback_message.size());
+  SkScalar sk_text_offset_x = (canvas_size.width() - display_text_width) / 2.0;
+  SkScalar sk_text_offset_y = (canvas_size.height() / 2.0) + text_size;
+  canvas.drawText(remote_playback_message.data(),
+                  remote_playback_message.size(), sk_text_offset_x,
+                  sk_text_offset_y, paint);
+
+  // Draw the appropriate Cast icon.
+  gfx::VectorIconId current_icon = is_remoting_successful
+                                       ? gfx::VectorIconId::MEDIA_ROUTER_ACTIVE
+                                       : gfx::VectorIconId::MEDIA_ROUTER_ERROR;
+  gfx::ImageSkia icon_image =
+      gfx::CreateVectorIcon(current_icon, 65, SK_ColorLTGRAY);
+  const SkBitmap* icon_bitmap = icon_image.bitmap();
+  SkScalar sk_image_offset_x = (canvas_size.width() - icon_image.width()) / 2.0;
+  SkScalar sk_image_offset_y =
+      (canvas_size.height() / 2.0) - icon_image.height();
+  canvas.drawBitmap(*icon_bitmap, sk_image_offset_x, sk_image_offset_y, &paint);
+
+  // Create a new VideoFrame, copy the bitmap, then return it.
+  scoped_refptr<media::VideoFrame> video_frame = media::VideoFrame::CreateFrame(
+      media::PIXEL_FORMAT_I420, canvas_size, gfx::Rect(canvas_size),
+      canvas_size, base::TimeDelta());
+  modified_bitmap.lockPixels();
+  media::CopyRGBToVideoFrame(
+      reinterpret_cast<uint8_t*>(modified_bitmap.getPixels()),
+      modified_bitmap.rowBytes(),
+      gfx::Rect(canvas_size.width(), canvas_size.height()), video_frame.get());
+  modified_bitmap.unlockPixels();
+  return video_frame;
+}
+
+}  // namespace media