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.
5 #include "ui/base/dragdrop/drag_utils.h"
11 #include "base/win/scoped_comptr.h"
12 #include "base/win/scoped_hdc.h"
13 #include "third_party/skia/include/core/SkBitmap.h"
14 #include "ui/base/dragdrop/os_exchange_data.h"
15 #include "ui/base/dragdrop/os_exchange_data_provider_win.h"
16 #include "ui/gfx/canvas.h"
17 #include "ui/gfx/gdi_util.h"
18 #include "ui/gfx/image/image_skia.h"
19 #include "ui/gfx/skbitmap_operations.h"
21 namespace drag_utils {
23 static void SetDragImageOnDataObject(HBITMAP hbitmap,
24 const gfx::Size& size,
25 const gfx::Vector2d& cursor_offset,
26 IDataObject* data_object) {
27 base::win::ScopedComPtr<IDragSourceHelper> helper;
28 HRESULT rv = CoCreateInstance(CLSID_DragDropHelper, 0, CLSCTX_INPROC_SERVER,
29 IID_IDragSourceHelper, helper.ReceiveVoid());
32 sdi.sizeDragImage = size.ToSIZE();
33 sdi.crColorKey = 0xFFFFFFFF;
34 sdi.hbmpDragImage = hbitmap;
35 sdi.ptOffset = gfx::PointAtOffsetFromOrigin(cursor_offset).ToPOINT();
36 helper->InitializeFromBitmap(&sdi, data_object);
40 // Blit the contents of the canvas to a new HBITMAP. It is the caller's
41 // responsibility to release the |bits| buffer.
42 static HBITMAP CreateHBITMAPFromSkBitmap(const SkBitmap& sk_bitmap) {
43 base::win::ScopedGetDC screen_dc(NULL);
44 BITMAPINFOHEADER header;
45 gfx::CreateBitmapHeader(sk_bitmap.width(), sk_bitmap.height(), &header);
48 CreateDIBSection(screen_dc, reinterpret_cast<BITMAPINFO*>(&header),
49 DIB_RGB_COLORS, &bits, NULL, 0);
52 DCHECK_EQ(sk_bitmap.rowBytes(), static_cast<size_t>(sk_bitmap.width() * 4));
53 SkAutoLockPixels lock(sk_bitmap);
55 bits, sk_bitmap.getPixels(), sk_bitmap.height() * sk_bitmap.rowBytes());
59 void SetDragImageOnDataObject(const gfx::ImageSkia& image_skia,
60 const gfx::Size& size,
61 const gfx::Vector2d& cursor_offset,
62 ui::OSExchangeData* data_object) {
63 DCHECK(data_object && !size.IsEmpty());
64 // InitializeFromBitmap() doesn't expect an alpha channel and is confused
65 // by premultiplied colors, so unpremultiply the bitmap.
66 // SetDragImageOnDataObject(HBITMAP) takes ownership of the bitmap.
67 HBITMAP bitmap = CreateHBITMAPFromSkBitmap(
68 SkBitmapOperations::UnPreMultiply(*image_skia.bitmap()));
70 // Attach 'bitmap' to the data_object.
71 SetDragImageOnDataObject(bitmap, size, cursor_offset,
72 ui::OSExchangeDataProviderWin::GetIDataObject(*data_object));
76 // TODO: the above code is used in non-Ash, while below is used in Ash. If we
77 // could figure this context out then we wouldn't do unnecessary work. However
78 // as it stands getting this information in ui/base would be a layering
80 data_object->provider().SetDragImage(image_skia, cursor_offset);
84 } // namespace drag_utils