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 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
