Blend background with existing content

Source/web/tests/WebViewTest.cpp

 /*
  * Copyright (C) 2011, 2012 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 40 matching lines @@
 #include "WebWidget.h"
 #include "core/dom/Document.h"
 #include "core/dom/Element.h"
 #include "core/html/HTMLDocument.h"
 #include "core/html/HTMLInputElement.h"
 #include "core/loader/FrameLoadRequest.h"
 #include "core/frame/FrameView.h"
 #include "core/page/Chrome.h"
 #include "core/page/Settings.h"
 #include "core/platform/chromium/KeyboardCodes.h"
+#include "platform/graphics/Color.h"
 #include "public/platform/Platform.h"
 #include "public/platform/WebSize.h"
 #include "public/platform/WebThread.h"
 #include "public/platform/WebUnitTestSupport.h"
 #include "public/web/WebWidgetClient.h"
+#include "third_party/skia/include/core/SkBitmap.h"
+#include "third_party/skia/include/core/SkBitmapDevice.h"
+#include "third_party/skia/include/core/SkCanvas.h"
 
 using namespace blink;
 using blink::FrameTestHelpers::runPendingTasks;
 using blink::URLTestHelpers::toKURL;
 
 namespace {
 
 enum HorizontalScrollbarState {
     NoHorizontalScrollbar,
     VisibleHorizontalScrollbar,
@@ skipping 202 matching lines @@
 TEST_F(WebViewTest, SetBaseBackgroundColorBeforeMainFrame)
 {
     const WebColor kBlue = 0xFF0000FF;
     WebView* webView = WebViewImpl::create(0);
     EXPECT_NE(kBlue, webView->backgroundColor());
     // webView does not have a frame yet, but we should still be able to set the background color.
     webView->setBaseBackgroundColor(kBlue);
     EXPECT_EQ(kBlue, webView->backgroundColor());
 }
 
+TEST_F(WebViewTest, SetBaseBackgroundColorAndBlendWithExistingContent)
+{
+    const WebColor kAlphaRed = 0x80FF0000;
+    const WebColor kAlphaGreen = 0x8000FF00;
+    const int kWidth = 100;
+    const int kHeight = 100;
+
+    // Set WebView background to green with alpha.
+    WebView* webView = m_webViewHelper.initialize();
+    webView->setBaseBackgroundColor(kAlphaGreen);
+    webView->settings()->setShouldClearDocumentBackground(false);
+    webView->resize(WebSize(kWidth, kHeight));
+    webView->layout();
+
+    // Set canvas background to red with alpha.
+    SkBitmap bitmap;
+    bitmap.setConfig(SkBitmap::kARGB_8888_Config, kWidth, kHeight);
+    bitmap.allocPixels();
+    SkBitmapDevice device(bitmap);
+    SkCanvas canvas(&device);
+    canvas.clear(kAlphaRed);
+    webView->paint(&canvas, WebRect(0, 0, kWidth, kHeight));
+
+    // The result should be a blend of red and green.
+    SkColor color = bitmap.getColor(kWidth / 2, kHeight / 2);
+    EXPECT_TRUE(WebCore::redChannel(color));
+    EXPECT_TRUE(WebCore::greenChannel(color));
+}
+
 TEST_F(WebViewTest, FocusIsInactive)
 {
     URLTestHelpers::registerMockedURLFromBaseURL(WebString::fromUTF8(m_baseURL.c_str()), "visible_iframe.html");
     WebView* webView = m_webViewHelper.initializeAndLoad(m_baseURL + "visible_iframe.html");
 
     webView->setFocus(true);
     webView->setIsActive(true);
     WebFrameImpl* frame = toWebFrameImpl(webView->mainFrame());
     EXPECT_TRUE(frame->frame()->document()->isHTMLDocument());
 
@@ skipping 1071 matching lines @@
     EXPECT_STREQ("1970-W01", inputElement->value().utf8().data());
 
     openDateTimeChooser(webViewImpl, inputElement);
     client.chooserCompletion()->didChooseValue(std::numeric_limits<double>::quiet_NaN());
     client.clearChooserCompletion();
     EXPECT_STREQ("", inputElement->value().utf8().data());
 }
 #endif
 
 }