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/base/dragdrop/drag_utils.h"
6
7#include "base/files/file_util.h"
8#include "base/logging.h"
9#include "base/strings/utf_string_conversions.h"
10#include "ui/base/dragdrop/os_exchange_data.h"
11#include "ui/gfx/canvas.h"
12#include "ui/gfx/font_list.h"
13#include "ui/gfx/geometry/point.h"
14#include "ui/gfx/geometry/rect.h"
15#include "ui/gfx/geometry/size.h"
16#include "ui/gfx/image/canvas_image_source.h"
17#include "url/gurl.h"
18
19namespace drag_utils {
20
21namespace {
22
23// Maximum width of the link drag image in pixels.
24static const int kLinkDragImageVPadding = 3;
25
26// File dragging pixel measurements
27static const int kFileDragImageMaxWidth = 200;
28static const SkColor kFileDragImageTextColor = SK_ColorBLACK;
29
30class FileDragImageSource : public gfx::CanvasImageSource {
31 public:
32  FileDragImageSource(const base::FilePath& file_name,
33                      const gfx::ImageSkia& icon)
34      : CanvasImageSource(CalculateSize(icon), false),
35        file_name_(file_name),
36        icon_(icon) {
37  }
38
39  virtual ~FileDragImageSource() {
40  }
41
42  // Overridden from gfx::CanvasImageSource.
43  virtual void Draw(gfx::Canvas* canvas) OVERRIDE {
44    if (!icon_.isNull()) {
45      // Paint the icon.
46      canvas->DrawImageInt(icon_, (size().width() - icon_.width()) / 2, 0);
47    }
48
49    base::string16 name = file_name_.BaseName().LossyDisplayName();
50    const int flags = gfx::Canvas::TEXT_ALIGN_CENTER;
51    const gfx::FontList font_list;
52#if defined(OS_WIN)
53    // Paint the file name. We inset it one pixel to allow room for the halo.
54    const gfx::Rect rect(1, icon_.height() + kLinkDragImageVPadding + 1,
55                         size().width() - 2, font_list.GetHeight());
56    canvas->DrawStringRectWithHalo(name, font_list, kFileDragImageTextColor,
57                                   SK_ColorWHITE, rect, flags);
58#else
59    // NO_SUBPIXEL_RENDERING is required when drawing to a non-opaque canvas.
60    const gfx::Rect rect(0, icon_.height() + kLinkDragImageVPadding,
61                         size().width(), font_list.GetHeight());
62    canvas->DrawStringRectWithFlags(name, font_list, kFileDragImageTextColor,
63                                    rect,
64                                    flags | gfx::Canvas::NO_SUBPIXEL_RENDERING);
65#endif
66  }
67
68 private:
69  gfx::Size CalculateSize(const gfx::ImageSkia& icon) const {
70    const int width = kFileDragImageMaxWidth;
71    // Add +2 here to allow room for the halo.
72    const int height = gfx::FontList().GetHeight() + icon.height() +
73                       kLinkDragImageVPadding + 2;
74    return gfx::Size(width, height);
75  }
76
77  const base::FilePath file_name_;
78  const gfx::ImageSkia icon_;
79
80  DISALLOW_COPY_AND_ASSIGN(FileDragImageSource);
81};
82
83}  // namespace
84
85void CreateDragImageForFile(const base::FilePath& file_name,
86                            const gfx::ImageSkia& icon,
87                            ui::OSExchangeData* data_object) {
88  DCHECK(data_object);
89  gfx::CanvasImageSource* source = new FileDragImageSource(file_name, icon);
90  gfx::Size size = source->size();
91  // ImageSkia takes ownership of |source|.
92  gfx::ImageSkia image = gfx::ImageSkia(source, size);
93
94  gfx::Vector2d cursor_offset(size.width() / 2, kLinkDragImageVPadding);
95  SetDragImageOnDataObject(image, cursor_offset, data_object);
96}
97
98void SetDragImageOnDataObject(const gfx::Canvas& canvas,
99                              const gfx::Vector2d& cursor_offset,
100                              ui::OSExchangeData* data_object) {
101  gfx::ImageSkia image = gfx::ImageSkia(canvas.ExtractImageRep());
102  SetDragImageOnDataObject(image, cursor_offset, data_object);
103}
104
105}  // namespace drag_utils
106