Fixing transparent pixels appearing black when rendered for the context menu.

chrome/renderer/chrome_render_frame_observer.cc

 // Copyright 2013 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/renderer/chrome_render_frame_observer.h"
 
 #include <stddef.h>
 #include <string.h>
 
 #include <limits>
@@ skipping 27 matching lines @@
 #include "third_party/WebKit/public/platform/WebURLRequest.h"
 #include "third_party/WebKit/public/web/WebDataSource.h"
 #include "third_party/WebKit/public/web/WebDocument.h"
 #include "third_party/WebKit/public/web/WebElement.h"
 #include "third_party/WebKit/public/web/WebFrameContentDumper.h"
 #include "third_party/WebKit/public/web/WebLocalFrame.h"
 #include "third_party/WebKit/public/web/WebNode.h"
 #include "third_party/WebKit/public/web/WebSecurityPolicy.h"
 #include "third_party/skia/include/core/SkBitmap.h"
 #include "ui/gfx/codec/jpeg_codec.h"
+#include "ui/gfx/codec/png_codec.h"
 #include "ui/gfx/geometry/size_f.h"
 #include "url/gurl.h"
 
 #if BUILDFLAG(ENABLE_PRINTING)
 #include "components/printing/common/print_messages.h"
 #include "components/printing/renderer/print_web_view_helper.h"
 #endif
 
 using blink::WebDataSource;
 using blink::WebElement;
 using blink::WebFrameContentDumper;
 using blink::WebLocalFrame;
 using blink::WebNode;
 using blink::WebString;
 using content::RenderFrame;
 
 // Maximum number of characters in the document to index.
 // Any text beyond this point will be clipped.
 static const size_t kMaxIndexChars = 65535;
 
 // Constants for UMA statistic collection.
 static const char kTranslateCaptureText[] = "Translate.CaptureText";
 
 // For a page that auto-refreshes, we still show the bubble, if
 // the refresh delay is less than this value (in seconds).
 static const double kLocationChangeIntervalInSeconds = 10;
 
+// For the context menu, we want to keep transparency as is instead of
+// replacing transparent pixels with black ones
+static const bool kDiscardTransparencyForContextMenu = false;
+
 namespace {
 
 // If the source image is null or occupies less area than
 // |thumbnail_min_area_pixels|, we return the image unmodified.  Otherwise, we
 // scale down the image so that the width and height do not exceed
 // |thumbnail_max_size_pixels|, preserving the original aspect ratio.
 SkBitmap Downscale(const blink::WebImage& image,
                    int thumbnail_min_area_pixels,
                    const gfx::Size& thumbnail_max_size_pixels) {
   if (image.IsNull())
@@ skipping 102 matching lines @@
   // to investigate what it is doing and fix (http://crbug.com/606164).
   WebNode context_node = frame->ContextMenuNode();
   if (!context_node.IsNull() && context_node.IsElementNode()) {
     frame->ReloadImage(context_node);
   }
 }
 
 void ChromeRenderFrameObserver::RequestThumbnailForContextNode(
     int32_t thumbnail_min_area_pixels,
     const gfx::Size& thumbnail_max_size_pixels,
+    bool use_png_codec,
     const RequestThumbnailForContextNodeCallback& callback) {
   WebNode context_node = render_frame()->GetWebFrame()->ContextMenuNode();
   SkBitmap thumbnail;
   gfx::Size original_size;
   if (!context_node.IsNull() && context_node.IsElementNode()) {
     blink::WebImage image = context_node.To<WebElement>().ImageContents();
     original_size = image.Size();
     thumbnail = Downscale(image,
                           thumbnail_min_area_pixels,
                           thumbnail_max_size_pixels);
   }
 
   SkBitmap bitmap;
   if (thumbnail.colorType() == kN32_SkColorType) {
     bitmap = thumbnail;
   } else {
     SkImageInfo info = thumbnail.info().makeColorType(kN32_SkColorType);
     if (bitmap.tryAllocPixels(info)) {
       thumbnail.readPixels(info, bitmap.getPixels(), bitmap.rowBytes(), 0, 0);
     }
   }
 
   std::vector<uint8_t> thumbnail_data;
   constexpr int kDefaultQuality = 90;
   std::vector<unsigned char> data;
-  if (gfx::JPEGCodec::Encode(bitmap, kDefaultQuality, &data)) {
-    thumbnail_data.swap(data);
+
+  if (use_png_codec) {
+    if (gfx::PNGCodec::EncodeBGRASkBitmap(
+            bitmap, kDiscardTransparencyForContextMenu, &data)) {
+      thumbnail_data.swap(data);
+    }
+  } else {
+    if (gfx::JPEGCodec::Encode(bitmap, kDefaultQuality, &data)) {
+      thumbnail_data.swap(data);
+    }
   }
 
   callback.Run(thumbnail_data, original_size);
 }
 
 void ChromeRenderFrameObserver::OnPrintNodeUnderContextMenu() {
 #if BUILDFLAG(ENABLE_PRINTING)
   printing::PrintWebViewHelper* helper =
       printing::PrintWebViewHelper::Get(render_frame());
   if (helper)
@@ skipping 171 matching lines @@
     const service_manager::BindSourceInfo& source_info,
     chrome::mojom::ImageContextMenuRendererRequest request) {
   image_context_menu_renderer_bindings_.AddBinding(this, std::move(request));
 }
 
 void ChromeRenderFrameObserver::OnThumbnailCapturerRequest(
     const service_manager::BindSourceInfo& source_info,
     chrome::mojom::ThumbnailCapturerRequest request) {
   thumbnail_capturer_bindings_.AddBinding(this, std::move(request));
 }