1 // Copyright (c) 2011 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 "chrome/browser/ui/window_snapshot/window_snapshot.h"
6
7 #include "base/win/scoped_gdi_object.h"
8 #include "base/win/scoped_hdc.h"
9 #include "ui/gfx/codec/png_codec.h"
10 #include "ui/gfx/gdi_util.h"
11 #include "ui/gfx/rect.h"
12 #include "ui/gfx/size.h"
13
14 namespace browser {
15
GrabWindowSnapshot(gfx::NativeWindow window_handle,std::vector<unsigned char> * png_representation)16 gfx::Rect GrabWindowSnapshot(gfx::NativeWindow window_handle,
17 std::vector<unsigned char>* png_representation) {
18 // Create a memory DC that's compatible with the window.
19 HDC window_hdc = GetWindowDC(window_handle);
20 base::win::ScopedHDC mem_hdc(CreateCompatibleDC(window_hdc));
21
22 // Create a DIB that's the same size as the window.
23 RECT content_rect = {0, 0, 0, 0};
24 ::GetWindowRect(window_handle, &content_rect);
25 content_rect.right++; // Match what PrintWindow wants.
26 int width = content_rect.right - content_rect.left;
27 int height = content_rect.bottom - content_rect.top;
28 BITMAPINFOHEADER hdr;
29 gfx::CreateBitmapHeader(width, height, &hdr);
30 unsigned char *bit_ptr = NULL;
31 base::win::ScopedBitmap bitmap(
32 CreateDIBSection(mem_hdc,
33 reinterpret_cast<BITMAPINFO*>(&hdr),
34 DIB_RGB_COLORS,
35 reinterpret_cast<void **>(&bit_ptr),
36 NULL, 0));
37
38 SelectObject(mem_hdc, bitmap);
39 // Clear the bitmap to white (so that rounded corners on windows
40 // show up on a white background, and strangely-shaped windows
41 // look reasonable). Not capturing an alpha mask saves a
42 // bit of space.
43 PatBlt(mem_hdc, 0, 0, width, height, WHITENESS);
44 // Grab a copy of the window
45 // First, see if PrintWindow is defined (it's not in Windows 2000).
46 typedef BOOL (WINAPI *PrintWindowPointer)(HWND, HDC, UINT);
47 PrintWindowPointer print_window =
48 reinterpret_cast<PrintWindowPointer>(
49 GetProcAddress(GetModuleHandle(L"User32.dll"), "PrintWindow"));
50
51 // If PrintWindow is defined, use it. It will work on partially
52 // obscured windows, and works better for out of process sub-windows.
53 // Otherwise grab the bits we can get with BitBlt; it's better
54 // than nothing and will work fine in the average case (window is
55 // completely on screen).
56 if (print_window)
57 (*print_window)(window_handle, mem_hdc, 0);
58 else
59 BitBlt(mem_hdc, 0, 0, width, height, window_hdc, 0, 0, SRCCOPY);
60
61 // We now have a copy of the window contents in a DIB, so
62 // encode it into a useful format for posting to the bug report
63 // server.
64 gfx::PNGCodec::Encode(bit_ptr, gfx::PNGCodec::FORMAT_BGRA,
65 gfx::Size(width, height), width * 4, true,
66 std::vector<gfx::PNGCodec::Comment>(),
67 png_representation);
68
69 ReleaseDC(window_handle, window_hdc);
70
71 return gfx::Rect(width, height);
72 }
73
74 } // namespace browser
75