Refactors drag_utils.

BUG=none
TEST=none

Review URL: http://codereview.chromium.org/113954

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@17080 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 78 insertions, 0 deletions

diff --git a/views/drag_utils_win.cc b/views/drag_utils_win.cc
new file mode 100644
index 0000000..ed01386
--- /dev/null
+++ b/views/drag_utils_win.cc
@@ -0,0 +1,78 @@
+// Copyright (c) 2006-2008 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "views/drag_utils.h"
+
+#include <objidl.h>
+#include <shlobj.h>
+#include <shobjidl.h>
+
+#include "app/gfx/canvas.h"
+#include "app/os_exchange_data.h"
+#include "base/gfx/gdi_util.h"
+
+namespace drag_utils {
+
+static void SetDragImageOnDataObject(HBITMAP hbitmap,
+                                     int width,
+                                     int height,
+                                     int cursor_offset_x,
+                                     int cursor_offset_y,
+                                     IDataObject* data_object) {
+  IDragSourceHelper* helper = NULL;
+  HRESULT rv = CoCreateInstance(CLSID_DragDropHelper, 0, CLSCTX_INPROC_SERVER,
+      IID_IDragSourceHelper, reinterpret_cast<LPVOID*>(&helper));
+  if (SUCCEEDED(rv)) {
+    SHDRAGIMAGE sdi;
+    sdi.sizeDragImage.cx = width;
+    sdi.sizeDragImage.cy = height;
+    sdi.crColorKey = 0xFFFFFFFF;
+    sdi.hbmpDragImage = hbitmap;
+    sdi.ptOffset.x = cursor_offset_x;
+    sdi.ptOffset.y = cursor_offset_y;
+    helper->InitializeFromBitmap(&sdi, data_object);
+  }
+};
+
+// Blit the contents of the canvas to a new HBITMAP. It is the caller's
+// responsibility to release the |bits| buffer.
+static HBITMAP CreateBitmapFromCanvas(const gfx::Canvas& canvas,
+                                      int width,
+                                      int height) {
+  HDC screen_dc = GetDC(NULL);
+  BITMAPINFOHEADER header;
+  gfx::CreateBitmapHeader(width, height, &header);
+  void* bits;
+  HBITMAP bitmap =
+      CreateDIBSection(screen_dc, reinterpret_cast<BITMAPINFO*>(&header),
+                       DIB_RGB_COLORS, &bits, NULL, 0);
+  HDC compatible_dc = CreateCompatibleDC(screen_dc);
+  HGDIOBJ old_object = SelectObject(compatible_dc, bitmap);
+  BitBlt(compatible_dc, 0, 0, width, height,
+         canvas.getTopPlatformDevice().getBitmapDC(),
+         0, 0, SRCCOPY);
+  SelectObject(compatible_dc, old_object);
+  ReleaseDC(NULL, compatible_dc);
+  ReleaseDC(NULL, screen_dc);
+  return bitmap;
+}
+
+void SetDragImageOnDataObject(const gfx::Canvas& canvas,
+                              int width,
+                              int height,
+                              int cursor_x_offset,
+                              int cursor_y_offset,
+                              OSExchangeData* data_object) {
+  DCHECK(data_object && width > 0 && height > 0);
+  // SetDragImageOnDataObject(HBITMAP) takes ownership of the bitmap.
+  HBITMAP bitmap = CreateBitmapFromCanvas(canvas, width, height);
+
+  // Attach 'bitmap' to the data_object.
+  SetDragImageOnDataObject(bitmap, width, height,
+                           cursor_x_offset,
+                           cursor_y_offset,
+                           data_object);
+}
+
+} // namespace drag_utils