Functionality has been requested in the Extension API for Javascript to...

chrome/browser/extensions/extension_tabs_module.cc

 // Copyright (c) 2009 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/extensions/extension_tabs_module.h"
 
+#include "base/gfx/jpeg_codec.h"
 #include "base/string_util.h"
 #include "chrome/browser/browser.h"
 #include "chrome/browser/browser_list.h"
 #include "chrome/browser/browser_window.h"
 #include "chrome/browser/extensions/extension_function_dispatcher.h"
 #include "chrome/browser/extensions/extension_tabs_module_constants.h"
 #include "chrome/browser/extensions/extensions_service.h"
 #include "chrome/browser/profile.h"
+#include "chrome/browser/renderer_host/backing_store.h"
+#include "chrome/browser/renderer_host/render_view_host.h"
 #include "chrome/browser/renderer_host/render_view_host_delegate.h"
 #include "chrome/browser/tab_contents/navigation_entry.h"
 #include "chrome/browser/tab_contents/tab_contents.h"
 #include "chrome/browser/window_sizer.h"
 #include "chrome/common/extensions/extension.h"
 #include "chrome/common/extensions/extension_error_utils.h"
+#include "net/base/base64.h"
+#include "skia/ext/image_operations.h"
+#include "skia/ext/platform_canvas.h"
+#include "third_party/skia/include/core/SkBitmap.h"
 
 
 namespace keys = extension_tabs_module_constants;
 
 // Forward declare static helper functions defined below.
 static DictionaryValue* CreateWindowValue(Browser* browser, bool populate_tabs);
 static ListValue* CreateTabList(Browser* browser);
 
 // |error_message| can optionally be passed in a will be set with an appropriate
 // message if the window cannot be found by id.
@@ skipping 577 matching lines @@
 
   Browser* browser = NULL;
   TabContents* contents = NULL;
   if (!GetTabById(tab_id, profile(), &browser, NULL, &contents, NULL, &error_))
     return false;
 
   browser->CloseTabContents(contents);
   return true;
 }
 
+bool GetVisibleTabCaptureFunction::RunImpl() {
+  Browser* browser;
+  // windowId defaults to "current" window.
+  int window_id = -1;
+
+  if (!args_->IsType(Value::TYPE_NULL)) {
+    EXTENSION_FUNCTION_VALIDATE(args_->GetAsInteger(&window_id));
+    browser = GetBrowserInProfileWithId(profile(), window_id, &error_);
+  } else {
+    browser = dispatcher()->GetBrowser();
+  }
+
+  if (!browser) {
+    error_ = keys::kNoCurrentWindowError;
+    return false;
+  }
+
+  SkBitmap screen_capture;
+#if defined(OS_WIN)
+  TabContents* tab_contents = browser->GetSelectedTabContents();
+  RenderViewHost* render_view_host = tab_contents->render_view_host();
+  BackingStore* backing_store = render_view_host->GetBackingStore(true);
+  skia::PlatformCanvas temp_canvas;
+  if (!temp_canvas.initialize(backing_store->size().width(),
+                              backing_store->size().height(), true)) {
+    error_ = ExtensionErrorUtils::FormatErrorMessage(
+        keys::kInternalVisibleTabCaptureError, "");
+    return false;
+  }
+  HDC temp_dc = temp_canvas.beginPlatformPaint();
+  BitBlt(temp_dc,
+         0, 0, backing_store->size().width(), backing_store->size().height(),
+         backing_store->hdc(), 0, 0, SRCCOPY);
+  temp_canvas.endPlatformPaint();
+
+  screen_capture = temp_canvas.getTopPlatformDevice().accessBitmap(false);
+#else
+  // TODO(adamhunter): TODO(port): Write this for other platforms.

[Aaron Boodman, 2009/07/30 18:15:12]

What about the other platforms? What is the timeline for implementation? Do we
know how to do it?

+  NOTIMPLEMENTED();

[Aaron Boodman, 2009/07/30 18:15:12]

Also, I forget what the behavior of NOTIMPLEMENTED() is in Release. We should
not crash. I would prefer to just return an error in platforms we don't support.

+#endif
+  scoped_refptr<RefCountedBytes> jpeg_data(new RefCountedBytes);
+  SkAutoLockPixels screen_capture_lock(screen_capture);
+  bool encoded = JPEGCodec::Encode(
+      reinterpret_cast<unsigned char*>(screen_capture.getAddr32(0, 0)),
+      JPEGCodec::FORMAT_BGRA, screen_capture.width(),
+      screen_capture.height(),
+      static_cast<int>(screen_capture.rowBytes()), 90,
+      &jpeg_data->data);
+  if (!encoded) {
+    error_ = ExtensionErrorUtils::FormatErrorMessage(
+        keys::kInternalVisibleTabCaptureError, "");
+    return false;
+  }
+
+  std::string base64_result;
+  std::string stream_as_string;
+  stream_as_string.resize(jpeg_data->data.size());
+  memcpy(&stream_as_string[0],
+      reinterpret_cast<const char*>(&jpeg_data->data[0]),
+      jpeg_data->data.size());
+
+  net::Base64Encode(stream_as_string, &base64_result);
+  base64_result.insert(0, "data:image/jpg;base64,");
+  result_.reset(new StringValue(base64_result));
+  return true;
+}
+
 bool GetTabLanguageFunction::RunImpl() {
   int tab_id = 0;
   Browser* browser = NULL;
   TabContents* contents = NULL;
 
   // If |tab_id| is specified, look for it. Otherwise default to selected tab
   // in the current window.
   if (!args_->IsType(Value::TYPE_NULL)) {
     EXTENSION_FUNCTION_VALIDATE(args_->GetAsInteger(&tab_id));
     if (!GetTabById(tab_id, profile(), &browser, NULL, &contents, NULL,
@@ skipping 102 matching lines @@
   if (ExtensionTabUtil::GetTabById(tab_id, profile, browser, tab_strip,
                                    contents, tab_index))
     return true;
 
   if (error_message)
     *error_message = ExtensionErrorUtils::FormatErrorMessage(
         keys::kTabNotFoundError, IntToString(tab_id));
 
   return false;
 }