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/screen.h"
10#include "ui/gfx/size.h"
11#include "ui/views/widget/widget.h"
12
13namespace {
14
15float 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
31namespace views {
32
33gfx::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
40