[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/paint_vector_icon.h"
+#include "ui/gfx/skbitmap_operations.h"
+#include "ui/gfx/vector_icons_public.h"
+
+namespace media {
+
+scoped_refptr<VideoFrame> GetInterstitial(gfx::Size canvas_size,
+                                          SkCanvas* existing_frame_canvas,
+                                          bool isRemotingSuccessful) {
+  if (!existing_frame_canvas)
+    return nullptr;
+
+  // Initial bitmap to grab the existing frame image.
+  SkBitmap bitmap;
+  bitmap.setInfo(existing_frame_canvas->imageInfo());
+
+  // 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.drawBitmap(modified_bitmap, SkIntToScalar(0), SkIntToScalar(0));
+  canvas.restore();
+
+  // Write text over the image.
+  SkPaint paint_text;

[xjz, 2016/11/03 23:53:39]

nit: naming. This is used by both text and bitmap. Right? Maybe just "paint"?

[apacible, 2016/11/04 01:25:38]

Done.

+  int text_size = SkIntToScalar(30);
+  paint_text.setAntiAlias(true);
+  paint_text.setFilterQuality(kHigh_SkFilterQuality);
+  paint_text.setColor(SK_ColorLTGRAY);
+  paint_text.setTypeface(SkTypeface::MakeFromName(
+      "sans", SkFontStyle::FromOldStyle(SkTypeface::kNormal)));
+  paint_text.setTextSize(text_size);
+
+  // Center the text in the canvas.

[xjz, 2016/11/03 23:53:40]

We only center the text horizontally, not vertically. right?
And please move this comment down to before Line 67.

[apacible, 2016/11/04 01:25:38]

Done.

+  const std::string remote_playback_message =
+      isRemotingSuccessful
+          ? GetLocalizedStringUTF8(MEDIA_REMOTING_CASTING_VIDEO_TEXT)
+          : GetLocalizedStringUTF8(MEDIA_REMOTING_CAST_ERROR_TEXT);
+
+  SkScalar sk_vertical_text_margin = (canvas_size.height() / 2.0) + text_size;

[xjz, 2016/11/03 23:53:40]

nit: this is only the top margin. Is this actual the vertical offset to draw the
text? Maybe rename it something like |text_offset_y|? I am not good at naming
though. Feel free to suggest anything that sounds good to you. :)

[apacible, 2016/11/04 01:25:38]

Done.

+  size_t display_text_width = paint_text.measureText(
+      remote_playback_message.c_str(), remote_playback_message.size());
+  SkScalar sk_horizontal_text_margin =

[xjz, 2016/11/03 23:53:40]

nit: ditto naming.

[apacible, 2016/11/04 01:25:38]

Done.

+      (canvas_size.width() - display_text_width) / 2.0;
+  canvas.drawText(remote_playback_message.c_str(),
+                  remote_playback_message.size(), sk_horizontal_text_margin,
+                  sk_vertical_text_margin, paint_text);
+
+  // Draw the appropriate Cast icon.
+  gfx::VectorIconId current_icon = isRemotingSuccessful
+                                       ? gfx::VectorIconId::MEDIA_ROUTER_ACTIVE
+                                       : gfx::VectorIconId::MEDIA_ROUTER_ERROR;
+  // gfx::ImageSkia and SkBitmap have the same width.
+  gfx::ImageSkia icon_image =
+      gfx::CreateVectorIcon(current_icon, 65, SK_ColorLTGRAY);
+  const SkBitmap* icon_bitmap = icon_image.bitmap();
+  SkScalar sk_horizontal_image_margin =

[xjz, 2016/11/03 23:53:40]

nit: naming.

[apacible, 2016/11/04 01:25:38]

Done.

+      (canvas_size.width() - icon_image.width()) / 2.0;
+  SkScalar sk_vertical_image_margin =

[xjz, 2016/11/03 23:53:39]

nit: naming.

[apacible, 2016/11/04 01:25:38]

Done.

+      (canvas_size.height() / 2.0) - icon_image.height();
+  canvas.drawBitmap(*icon_bitmap, sk_horizontal_image_margin,
+                    sk_vertical_image_margin, &paint_text);
+
+  // Create a new VideoFrame, copy the bitmap, then return it.
+  const gfx::Rect region_in_frame =
+      gfx::Rect(modified_bitmap.width(), modified_bitmap.height());
+  scoped_refptr<media::VideoFrame> video_frame = media::VideoFrame::CreateFrame(
+      media::PIXEL_FORMAT_I420, canvas_size, gfx::Rect(canvas_size),
+      canvas_size, base::TimeDelta());
+  media::CopyRGBToVideoFrame(
+      reinterpret_cast<uint8_t*>(modified_bitmap.getPixels()),
+      modified_bitmap.rowBytes(), region_in_frame, video_frame.get());
+  return video_frame;
+}
+
+}  // namespace media