src/extensions/browser/api/capture_web_contents_function.cc

   1 // Copyright 2013 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #include "extensions/browser/api/capture_web_contents_function.h"
   6
   7 #include "base/base64.h"
   8 #include "base/strings/stringprintf.h"
   9 #include "content/public/browser/render_widget_host.h"
  10 #include "content/public/browser/render_widget_host_view.h"
  11 #include "content/public/browser/web_contents.h"
  12 #include "extensions/browser/extension_function.h"
  13 #include "extensions/common/constants.h"
  14 #include "ui/gfx/codec/jpeg_codec.h"
  15 #include "ui/gfx/codec/png_codec.h"
  16 #include "ui/gfx/display.h"
  17 #include "ui/gfx/geometry/size_conversions.h"
  18 #include "ui/gfx/screen.h"
  19
  20 using content::RenderWidgetHost;
  21 using content::RenderWidgetHostView;
  22 using content::WebContents;
  23
  24 namespace extensions {
  25
  26 bool CaptureWebContentsFunction::HasPermission() {
  27   return true;
  28 }
  29
  30 bool CaptureWebContentsFunction::RunAsync() {
  31   EXTENSION_FUNCTION_VALIDATE(args_);
  32
  33   context_id_ = extension_misc::kCurrentWindowId;
  34   args_->GetInteger(0, &context_id_);
  35
  36   scoped_ptr<ImageDetails> image_details;
  37   if (args_->GetSize() > 1) {
  38     base::Value* spec = NULL;
  39     EXTENSION_FUNCTION_VALIDATE(args_->Get(1, &spec) && spec);
  40     image_details = ImageDetails::FromValue(*spec);
  41   }
  42
  43   if (!IsScreenshotEnabled())
  44     return false;
  45
  46   WebContents* contents = GetWebContentsForID(context_id_);
  47   if (!contents)
  48     return false;
  49
  50   // The default format and quality setting used when encoding jpegs.
  51   const ImageDetails::Format kDefaultFormat = ImageDetails::FORMAT_JPEG;
  52   const int kDefaultQuality = 90;
  53
  54   image_format_ = kDefaultFormat;
  55   image_quality_ = kDefaultQuality;
  56
  57   if (image_details) {
  58     if (image_details->format != ImageDetails::FORMAT_NONE)
  59       image_format_ = image_details->format;
  60     if (image_details->quality.get())
  61       image_quality_ = *image_details->quality;
  62   }
  63
  64   // TODO(miu): Account for fullscreen render widget?  http://crbug.com/419878
  65   RenderWidgetHostView* const view = contents->GetRenderWidgetHostView();
  66   RenderWidgetHost* const host = view ? view->GetRenderWidgetHost() : nullptr;
  67   if (!view || !host) {
  68     OnCaptureFailure(FAILURE_REASON_VIEW_INVISIBLE);
  69     return false;
  70   }
  71
  72   // By default, the requested bitmap size is the view size in screen
  73   // coordinates.  However, if there's more pixel detail available on the
  74   // current system, increase the requested bitmap size to capture it all.
  75   const gfx::Size view_size = view->GetViewBounds().size();
  76   gfx::Size bitmap_size = view_size;
  77   const gfx::NativeView native_view = view->GetNativeView();
  78   gfx::Screen* const screen = gfx::Screen::GetScreenFor(native_view);
  79   const float scale =
  80       screen->GetDisplayNearestWindow(native_view).device_scale_factor();
  81   if (scale > 1.0f)
  82     bitmap_size = gfx::ToCeiledSize(gfx::ScaleSize(view_size, scale));
  83
  84   host->CopyFromBackingStore(
  85       gfx::Rect(view_size),
  86       bitmap_size,
  87       base::Bind(&CaptureWebContentsFunction::CopyFromBackingStoreComplete,
  88                  this),
  89       kN32_SkColorType);
  90   return true;
  91 }
  92
  93 void CaptureWebContentsFunction::CopyFromBackingStoreComplete(
  94     bool succeeded,
  95     const SkBitmap& bitmap) {
  96   if (succeeded) {
  97     OnCaptureSuccess(bitmap);
  98     return;
  99   }
 100   OnCaptureFailure(FAILURE_REASON_UNKNOWN);
 101 }
 102
 103 void CaptureWebContentsFunction::OnCaptureSuccess(const SkBitmap& bitmap) {
 104   std::vector<unsigned char> data;
 105   SkAutoLockPixels screen_capture_lock(bitmap);
 106   bool encoded = false;
 107   std::string mime_type;
 108   switch (image_format_) {
 109     case ImageDetails::FORMAT_JPEG:
 110       encoded = gfx::JPEGCodec::Encode(
 111           reinterpret_cast<unsigned char*>(bitmap.getAddr32(0, 0)),
 112           gfx::JPEGCodec::FORMAT_SkBitmap,
 113           bitmap.width(),
 114           bitmap.height(),
 115           static_cast<int>(bitmap.rowBytes()),
 116           image_quality_,
 117           &data);
 118       mime_type = kMimeTypeJpeg;
 119       break;
 120     case ImageDetails::FORMAT_PNG:
 121       encoded =
 122           gfx::PNGCodec::EncodeBGRASkBitmap(bitmap,
 123                                             true,  // Discard transparency.
 124                                             &data);
 125       mime_type = kMimeTypePng;
 126       break;
 127     default:
 128       NOTREACHED() << "Invalid image format.";
 129   }
 130
 131   if (!encoded) {
 132     OnCaptureFailure(FAILURE_REASON_ENCODING_FAILED);
 133     return;
 134   }
 135
 136   std::string base64_result;
 137   base::StringPiece stream_as_string(
 138       reinterpret_cast<const char*>(vector_as_array(&data)), data.size());
 139
 140   base::Base64Encode(stream_as_string, &base64_result);
 141   base64_result.insert(
 142       0, base::StringPrintf("data:%s;base64,", mime_type.c_str()));
 143   SetResult(new base::StringValue(base64_result));
 144   SendResponse(true);
 145 }
 146
 147 }  // namespace extensions