ui/views/drag_utils.cc

   1 // Copyright (c) 2012 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 "ui/views/drag_utils.h"
   6
   7 #include "ui/gfx/canvas.h"
   8 #include "ui/gfx/display.h"
   9 #include "ui/gfx/geometry/size.h"
  10 #include "ui/gfx/screen.h"
  11 #include "ui/views/widget/widget.h"
  12
  13 namespace {
  14
  15 float GetDeviceScaleForNativeView(views::Widget* widget) {
  16   float device_scale = 1.0f;
  17   // The following code should work on other platforms as well. But we do not
  18   // yet care about device scale factor on other platforms. So to keep drag and
  19   // drop behavior on other platforms un-touched, we wrap this in the #if guard.
  20   if (widget && widget->GetNativeView()) {
  21     gfx::NativeView view = widget->GetNativeView();
  22     gfx::Display display = gfx::Screen::GetScreenFor(view)->
  23         GetDisplayNearestWindow(view);
  24     device_scale = display.device_scale_factor();
  25   }
  26   return device_scale;
  27 }
  28
  29 }  // namespace
  30
  31 namespace views {
  32
  33 gfx::Canvas* GetCanvasForDragImage(views::Widget* widget,
  34                                    const gfx::Size& canvas_size) {
  35   float device_scale = GetDeviceScaleForNativeView(widget);
  36   return new gfx::Canvas(canvas_size, device_scale, false);
  37 }
  38
  39 }  // namespace views