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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 "media/video/capture/screen/screen_capturer.h" | |
6 | |
7 #include <windows.h> | |
8 | |
9 #include "base/logging.h" | |
10 #include "base/memory/scoped_ptr.h" | |
11 #include "base/time.h" | |
12 #include "media/video/capture/screen/differ.h" | |
13 #include "media/video/capture/screen/mouse_cursor_shape.h" | |
14 #include "media/video/capture/screen/screen_capture_frame_queue.h" | |
15 #include "media/video/capture/screen/screen_capturer_helper.h" | |
16 #include "media/video/capture/screen/win/desktop.h" | |
17 #include "media/video/capture/screen/win/scoped_thread_desktop.h" | |
18 #include "third_party/webrtc/modules/desktop_capture/desktop_frame.h" | |
19 #include "third_party/webrtc/modules/desktop_capture/desktop_frame_win.h" | |
20 #include "third_party/webrtc/modules/desktop_capture/desktop_region.h" | |
21 | |
22 namespace media { | |
23 | |
24 namespace { | |
25 | |
26 // Constants from dwmapi.h. | |
27 const UINT DWM_EC_DISABLECOMPOSITION = 0; | |
28 const UINT DWM_EC_ENABLECOMPOSITION = 1; | |
29 | |
30 typedef HRESULT (WINAPI * DwmEnableCompositionFunc)(UINT); | |
31 | |
32 const wchar_t kDwmapiLibraryName[] = L"dwmapi.dll"; | |
33 | |
34 // Pixel colors used when generating cursor outlines. | |
35 const uint32 kPixelBgraBlack = 0xff000000; | |
36 const uint32 kPixelBgraWhite = 0xffffffff; | |
37 const uint32 kPixelBgraTransparent = 0x00000000; | |
38 | |
39 uint8_t AlphaMul(uint8_t v, uint8_t alpha) { | |
40 return (static_cast<uint16_t>(v) * alpha) >> 8; | |
41 } | |
42 | |
43 // ScreenCapturerWin captures 32bit RGB using GDI. | |
44 // | |
45 // ScreenCapturerWin is double-buffered as required by ScreenCapturer. | |
46 class ScreenCapturerWin : public ScreenCapturer { | |
47 public: | |
48 ScreenCapturerWin(bool disable_aero); | |
49 virtual ~ScreenCapturerWin(); | |
50 | |
51 // Overridden from ScreenCapturer: | |
52 virtual void Start(Callback* callback) OVERRIDE; | |
53 virtual void Capture(const webrtc::DesktopRegion& region) OVERRIDE; | |
54 virtual void SetMouseShapeObserver( | |
55 MouseShapeObserver* mouse_shape_observer) OVERRIDE; | |
56 | |
57 private: | |
58 // Make sure that the device contexts match the screen configuration. | |
59 void PrepareCaptureResources(); | |
60 | |
61 // Captures the current screen contents into the current buffer. | |
62 void CaptureImage(); | |
63 | |
64 // Expand the cursor shape to add a white outline for visibility against | |
65 // dark backgrounds. | |
66 void AddCursorOutline(int width, int height, uint32* dst); | |
67 | |
68 // Capture the current cursor shape. | |
69 void CaptureCursor(); | |
70 | |
71 Callback* callback_; | |
72 MouseShapeObserver* mouse_shape_observer_; | |
73 | |
74 // A thread-safe list of invalid rectangles, and the size of the most | |
75 // recently captured screen. | |
76 ScreenCapturerHelper helper_; | |
77 | |
78 // Snapshot of the last cursor bitmap we sent to the client. This is used | |
79 // to diff against the current cursor so we only send a cursor-change | |
80 // message when the shape has changed. | |
81 MouseCursorShape last_cursor_; | |
82 | |
83 ScopedThreadDesktop desktop_; | |
84 | |
85 // GDI resources used for screen capture. | |
86 HDC desktop_dc_; | |
87 HDC memory_dc_; | |
88 | |
89 // Queue of the frames buffers. | |
90 ScreenCaptureFrameQueue queue_; | |
91 | |
92 // Rectangle describing the bounds of the desktop device context. | |
93 webrtc::DesktopRect desktop_dc_rect_; | |
94 | |
95 // Class to calculate the difference between two screen bitmaps. | |
96 scoped_ptr<Differ> differ_; | |
97 | |
98 HMODULE dwmapi_library_; | |
99 DwmEnableCompositionFunc composition_func_; | |
100 | |
101 // Used to suppress duplicate logging of SetThreadExecutionState errors. | |
102 bool set_thread_execution_state_failed_; | |
103 | |
104 DISALLOW_COPY_AND_ASSIGN(ScreenCapturerWin); | |
105 }; | |
106 | |
107 ScreenCapturerWin::ScreenCapturerWin(bool disable_aero) | |
108 : callback_(NULL), | |
109 mouse_shape_observer_(NULL), | |
110 desktop_dc_(NULL), | |
111 memory_dc_(NULL), | |
112 dwmapi_library_(NULL), | |
113 composition_func_(NULL), | |
114 set_thread_execution_state_failed_(false) { | |
115 if (disable_aero) { | |
116 // Load dwmapi.dll dynamically since it is not available on XP. | |
117 if (!dwmapi_library_) | |
118 dwmapi_library_ = LoadLibrary(kDwmapiLibraryName); | |
119 | |
120 if (dwmapi_library_) { | |
121 composition_func_ = reinterpret_cast<DwmEnableCompositionFunc>( | |
122 GetProcAddress(dwmapi_library_, "DwmEnableComposition")); | |
123 } | |
124 } | |
125 } | |
126 | |
127 ScreenCapturerWin::~ScreenCapturerWin() { | |
128 if (desktop_dc_) | |
129 ReleaseDC(NULL, desktop_dc_); | |
130 if (memory_dc_) | |
131 DeleteDC(memory_dc_); | |
132 | |
133 // Restore Aero. | |
134 if (composition_func_) | |
135 (*composition_func_)(DWM_EC_ENABLECOMPOSITION); | |
136 | |
137 if (dwmapi_library_) | |
138 FreeLibrary(dwmapi_library_); | |
139 } | |
140 | |
141 void ScreenCapturerWin::Capture(const webrtc::DesktopRegion& region) { | |
142 base::Time capture_start_time = base::Time::Now(); | |
143 | |
144 queue_.MoveToNextFrame(); | |
145 | |
146 // Request that the system not power-down the system, or the display hardware. | |
147 if (!SetThreadExecutionState(ES_DISPLAY_REQUIRED | ES_SYSTEM_REQUIRED)) { | |
148 if (!set_thread_execution_state_failed_) { | |
149 set_thread_execution_state_failed_ = true; | |
150 LOG_GETLASTERROR(WARNING) | |
151 << "Failed to make system & display power assertion"; | |
152 } | |
153 } | |
154 | |
155 // Make sure the GDI capture resources are up-to-date. | |
156 PrepareCaptureResources(); | |
157 | |
158 // Copy screen bits to the current buffer. | |
159 CaptureImage(); | |
160 | |
161 const webrtc::DesktopFrame* current_frame = queue_.current_frame(); | |
162 const webrtc::DesktopFrame* last_frame = queue_.previous_frame(); | |
163 if (last_frame) { | |
164 // Make sure the differencer is set up correctly for these previous and | |
165 // current screens. | |
166 if (!differ_.get() || | |
167 (differ_->width() != current_frame->size().width()) || | |
168 (differ_->height() != current_frame->size().height()) || | |
169 (differ_->bytes_per_row() != current_frame->stride())) { | |
170 differ_.reset(new Differ(current_frame->size().width(), | |
171 current_frame->size().height(), | |
172 webrtc::DesktopFrame::kBytesPerPixel, | |
173 current_frame->stride())); | |
174 } | |
175 | |
176 // Calculate difference between the two last captured frames. | |
177 webrtc::DesktopRegion region; | |
178 differ_->CalcDirtyRegion(last_frame->data(), current_frame->data(), | |
179 ®ion); | |
180 helper_.InvalidateRegion(region); | |
181 } else { | |
182 // No previous frame is available. Invalidate the whole screen. | |
183 helper_.InvalidateScreen(current_frame->size()); | |
184 } | |
185 | |
186 helper_.set_size_most_recent(current_frame->size()); | |
187 | |
188 // Emit the current frame. | |
189 webrtc::DesktopFrame* frame = queue_.current_frame()->Share(); | |
190 frame->set_dpi(webrtc::DesktopVector( | |
191 GetDeviceCaps(desktop_dc_, LOGPIXELSX), | |
192 GetDeviceCaps(desktop_dc_, LOGPIXELSY))); | |
193 frame->mutable_updated_region()->Clear(); | |
194 helper_.TakeInvalidRegion(frame->mutable_updated_region()); | |
195 frame->set_capture_time_ms( | |
196 (base::Time::Now() - capture_start_time).InMillisecondsRoundedUp()); | |
197 callback_->OnCaptureCompleted(frame); | |
198 | |
199 // Check for cursor shape update. | |
200 CaptureCursor(); | |
201 } | |
202 | |
203 void ScreenCapturerWin::SetMouseShapeObserver( | |
204 MouseShapeObserver* mouse_shape_observer) { | |
205 DCHECK(!mouse_shape_observer_); | |
206 DCHECK(mouse_shape_observer); | |
207 | |
208 mouse_shape_observer_ = mouse_shape_observer; | |
209 } | |
210 | |
211 void ScreenCapturerWin::Start(Callback* callback) { | |
212 DCHECK(!callback_); | |
213 DCHECK(callback); | |
214 | |
215 callback_ = callback; | |
216 | |
217 // Vote to disable Aero composited desktop effects while capturing. Windows | |
218 // will restore Aero automatically if the process exits. This has no effect | |
219 // under Windows 8 or higher. See crbug.com/124018. | |
220 if (composition_func_) | |
221 (*composition_func_)(DWM_EC_DISABLECOMPOSITION); | |
222 } | |
223 | |
224 void ScreenCapturerWin::PrepareCaptureResources() { | |
225 // Switch to the desktop receiving user input if different from the current | |
226 // one. | |
227 scoped_ptr<Desktop> input_desktop = Desktop::GetInputDesktop(); | |
228 if (input_desktop.get() != NULL && !desktop_.IsSame(*input_desktop)) { | |
229 // Release GDI resources otherwise SetThreadDesktop will fail. | |
230 if (desktop_dc_) { | |
231 ReleaseDC(NULL, desktop_dc_); | |
232 desktop_dc_ = NULL; | |
233 } | |
234 | |
235 if (memory_dc_) { | |
236 DeleteDC(memory_dc_); | |
237 memory_dc_ = NULL; | |
238 } | |
239 | |
240 // If SetThreadDesktop() fails, the thread is still assigned a desktop. | |
241 // So we can continue capture screen bits, just from the wrong desktop. | |
242 desktop_.SetThreadDesktop(input_desktop.Pass()); | |
243 | |
244 // Re-assert our vote to disable Aero. | |
245 // See crbug.com/124018 and crbug.com/129906. | |
246 if (composition_func_ != NULL) { | |
247 (*composition_func_)(DWM_EC_DISABLECOMPOSITION); | |
248 } | |
249 } | |
250 | |
251 // If the display bounds have changed then recreate GDI resources. | |
252 // TODO(wez): Also check for pixel format changes. | |
253 webrtc::DesktopRect screen_rect(webrtc::DesktopRect::MakeXYWH( | |
254 GetSystemMetrics(SM_XVIRTUALSCREEN), | |
255 GetSystemMetrics(SM_YVIRTUALSCREEN), | |
256 GetSystemMetrics(SM_CXVIRTUALSCREEN), | |
257 GetSystemMetrics(SM_CYVIRTUALSCREEN))); | |
258 if (!screen_rect.equals(desktop_dc_rect_)) { | |
259 if (desktop_dc_) { | |
260 ReleaseDC(NULL, desktop_dc_); | |
261 desktop_dc_ = NULL; | |
262 } | |
263 if (memory_dc_) { | |
264 DeleteDC(memory_dc_); | |
265 memory_dc_ = NULL; | |
266 } | |
267 desktop_dc_rect_ = webrtc::DesktopRect(); | |
268 } | |
269 | |
270 if (desktop_dc_ == NULL) { | |
271 DCHECK(memory_dc_ == NULL); | |
272 | |
273 // Create GDI device contexts to capture from the desktop into memory. | |
274 desktop_dc_ = GetDC(NULL); | |
275 CHECK(desktop_dc_); | |
276 memory_dc_ = CreateCompatibleDC(desktop_dc_); | |
277 CHECK(memory_dc_); | |
278 desktop_dc_rect_ = screen_rect; | |
279 | |
280 // Make sure the frame buffers will be reallocated. | |
281 queue_.Reset(); | |
282 | |
283 helper_.ClearInvalidRegion(); | |
284 } | |
285 } | |
286 | |
287 void ScreenCapturerWin::CaptureImage() { | |
288 // If the current buffer is from an older generation then allocate a new one. | |
289 // Note that we can't reallocate other buffers at this point, since the caller | |
290 // may still be reading from them. | |
291 if (!queue_.current_frame()) { | |
292 DCHECK(desktop_dc_ != NULL); | |
293 DCHECK(memory_dc_ != NULL); | |
294 | |
295 webrtc::DesktopSize size = webrtc::DesktopSize( | |
296 desktop_dc_rect_.width(), desktop_dc_rect_.height()); | |
297 | |
298 size_t buffer_size = size.width() * size.height() * | |
299 webrtc::DesktopFrame::kBytesPerPixel; | |
300 webrtc::SharedMemory* shared_memory = | |
301 callback_->CreateSharedMemory(buffer_size); | |
302 scoped_ptr<webrtc::DesktopFrameWin> buffer( | |
303 webrtc::DesktopFrameWin::Create(size, shared_memory, desktop_dc_)); | |
304 queue_.ReplaceCurrentFrame(buffer.PassAs<webrtc::DesktopFrame>()); | |
305 } | |
306 | |
307 // Select the target bitmap into the memory dc and copy the rect from desktop | |
308 // to memory. | |
309 webrtc::DesktopFrameWin* current = static_cast<webrtc::DesktopFrameWin*>( | |
310 queue_.current_frame()->GetUnderlyingFrame()); | |
311 HGDIOBJ previous_object = SelectObject(memory_dc_, current->bitmap()); | |
312 if (previous_object != NULL) { | |
313 BitBlt(memory_dc_, | |
314 0, 0, desktop_dc_rect_.width(), desktop_dc_rect_.height(), | |
315 desktop_dc_, | |
316 desktop_dc_rect_.left(), desktop_dc_rect_.top(), | |
317 SRCCOPY | CAPTUREBLT); | |
318 | |
319 // Select back the previously selected object to that the device contect | |
320 // could be destroyed independently of the bitmap if needed. | |
321 SelectObject(memory_dc_, previous_object); | |
322 } | |
323 } | |
324 | |
325 void ScreenCapturerWin::AddCursorOutline(int width, | |
326 int height, | |
327 uint32* dst) { | |
328 for (int y = 0; y < height; y++) { | |
329 for (int x = 0; x < width; x++) { | |
330 // If this is a transparent pixel (bgr == 0 and alpha = 0), check the | |
331 // neighbor pixels to see if this should be changed to an outline pixel. | |
332 if (*dst == kPixelBgraTransparent) { | |
333 // Change to white pixel if any neighbors (top, bottom, left, right) | |
334 // are black. | |
335 if ((y > 0 && dst[-width] == kPixelBgraBlack) || | |
336 (y < height - 1 && dst[width] == kPixelBgraBlack) || | |
337 (x > 0 && dst[-1] == kPixelBgraBlack) || | |
338 (x < width - 1 && dst[1] == kPixelBgraBlack)) { | |
339 *dst = kPixelBgraWhite; | |
340 } | |
341 } | |
342 dst++; | |
343 } | |
344 } | |
345 } | |
346 | |
347 void ScreenCapturerWin::CaptureCursor() { | |
348 CURSORINFO cursor_info; | |
349 cursor_info.cbSize = sizeof(CURSORINFO); | |
350 if (!GetCursorInfo(&cursor_info)) { | |
351 VLOG(3) << "Unable to get cursor info. Error = " << GetLastError(); | |
352 return; | |
353 } | |
354 | |
355 // Note that this does not need to be freed. | |
356 HCURSOR hcursor = cursor_info.hCursor; | |
357 ICONINFO iinfo; | |
358 if (!GetIconInfo(hcursor, &iinfo)) { | |
359 VLOG(3) << "Unable to get cursor icon info. Error = " << GetLastError(); | |
360 return; | |
361 } | |
362 int hotspot_x = iinfo.xHotspot; | |
363 int hotspot_y = iinfo.yHotspot; | |
364 | |
365 // Get the cursor bitmap. | |
366 HBITMAP hbitmap; | |
367 BITMAP bitmap; | |
368 bool color_bitmap; | |
369 if (iinfo.hbmColor) { | |
370 // Color cursor bitmap. | |
371 color_bitmap = true; | |
372 hbitmap = reinterpret_cast<HBITMAP>( | |
373 CopyImage(iinfo.hbmColor, IMAGE_BITMAP, 0, 0, LR_CREATEDIBSECTION)); | |
374 if (!hbitmap) { | |
375 VLOG(3) << "Unable to copy color cursor image. Error = " | |
376 << GetLastError(); | |
377 return; | |
378 } | |
379 | |
380 // Free the color and mask bitmaps since we only need our copy. | |
381 DeleteObject(iinfo.hbmColor); | |
382 DeleteObject(iinfo.hbmMask); | |
383 } else { | |
384 // Black and white (xor) cursor. | |
385 color_bitmap = false; | |
386 hbitmap = iinfo.hbmMask; | |
387 } | |
388 | |
389 if (!GetObject(hbitmap, sizeof(BITMAP), &bitmap)) { | |
390 VLOG(3) << "Unable to get cursor bitmap. Error = " << GetLastError(); | |
391 DeleteObject(hbitmap); | |
392 return; | |
393 } | |
394 | |
395 int width = bitmap.bmWidth; | |
396 int height = bitmap.bmHeight; | |
397 // For non-color cursors, the mask contains both an AND and an XOR mask and | |
398 // the height includes both. Thus, the width is correct, but we need to | |
399 // divide by 2 to get the correct mask height. | |
400 if (!color_bitmap) { | |
401 height /= 2; | |
402 } | |
403 int data_size = height * width * webrtc::DesktopFrame::kBytesPerPixel; | |
404 | |
405 scoped_ptr<MouseCursorShape> cursor(new MouseCursorShape()); | |
406 cursor->data.resize(data_size); | |
407 uint8* cursor_dst_data = | |
408 reinterpret_cast<uint8*>(&*(cursor->data.begin())); | |
409 | |
410 // Copy/convert cursor bitmap into format needed by chromotocol. | |
411 int row_bytes = bitmap.bmWidthBytes; | |
412 if (color_bitmap) { | |
413 if (bitmap.bmPlanes != 1 || bitmap.bmBitsPixel != 32) { | |
414 VLOG(3) << "Unsupported color cursor format. Error = " << GetLastError(); | |
415 DeleteObject(hbitmap); | |
416 return; | |
417 } | |
418 | |
419 // Copy across colour cursor imagery. | |
420 // MouseCursorShape stores imagery top-down, and premultiplied | |
421 // by the alpha channel, whereas windows stores them bottom-up | |
422 // and not premultiplied. | |
423 uint8* cursor_src_data = reinterpret_cast<uint8*>(bitmap.bmBits); | |
424 uint8* src = cursor_src_data + ((height - 1) * row_bytes); | |
425 uint8* dst = cursor_dst_data; | |
426 for (int row = 0; row < height; ++row) { | |
427 for (int column = 0; column < width; ++column) { | |
428 dst[0] = AlphaMul(src[0], src[3]); | |
429 dst[1] = AlphaMul(src[1], src[3]); | |
430 dst[2] = AlphaMul(src[2], src[3]); | |
431 dst[3] = src[3]; | |
432 dst += webrtc::DesktopFrame::kBytesPerPixel; | |
433 src += webrtc::DesktopFrame::kBytesPerPixel; | |
434 } | |
435 src -= row_bytes + (width * webrtc::DesktopFrame::kBytesPerPixel); | |
436 } | |
437 } else { | |
438 if (bitmap.bmPlanes != 1 || bitmap.bmBitsPixel != 1) { | |
439 VLOG(3) << "Unsupported cursor mask format. Error = " << GetLastError(); | |
440 DeleteObject(hbitmap); | |
441 return; | |
442 } | |
443 | |
444 // x2 because there are 2 masks in the bitmap: AND and XOR. | |
445 int mask_bytes = height * row_bytes * 2; | |
446 scoped_ptr<uint8[]> mask(new uint8[mask_bytes]); | |
447 if (!GetBitmapBits(hbitmap, mask_bytes, mask.get())) { | |
448 VLOG(3) << "Unable to get cursor mask bits. Error = " << GetLastError(); | |
449 DeleteObject(hbitmap); | |
450 return; | |
451 } | |
452 uint8* and_mask = mask.get(); | |
453 uint8* xor_mask = mask.get() + height * row_bytes; | |
454 uint8* dst = cursor_dst_data; | |
455 bool add_outline = false; | |
456 for (int y = 0; y < height; y++) { | |
457 for (int x = 0; x < width; x++) { | |
458 int byte = y * row_bytes + x / 8; | |
459 int bit = 7 - x % 8; | |
460 int and_bit = and_mask[byte] & (1 << bit); | |
461 int xor_bit = xor_mask[byte] & (1 << bit); | |
462 | |
463 // The two cursor masks combine as follows: | |
464 // AND XOR Windows Result Our result RGB Alpha | |
465 // 0 0 Black Black 00 ff | |
466 // 0 1 White White ff ff | |
467 // 1 0 Screen Transparent 00 00 | |
468 // 1 1 Reverse-screen Black 00 ff | |
469 // Since we don't support XOR cursors, we replace the "Reverse Screen" | |
470 // with black. In this case, we also add an outline around the cursor | |
471 // so that it is visible against a dark background. | |
472 int rgb = (!and_bit && xor_bit) ? 0xff : 0x00; | |
473 int alpha = (and_bit && !xor_bit) ? 0x00 : 0xff; | |
474 *dst++ = rgb; | |
475 *dst++ = rgb; | |
476 *dst++ = rgb; | |
477 *dst++ = alpha; | |
478 if (and_bit && xor_bit) { | |
479 add_outline = true; | |
480 } | |
481 } | |
482 } | |
483 if (add_outline) { | |
484 AddCursorOutline(width, height, | |
485 reinterpret_cast<uint32*>(cursor_dst_data)); | |
486 } | |
487 } | |
488 | |
489 DeleteObject(hbitmap); | |
490 | |
491 cursor->size.set(width, height); | |
492 cursor->hotspot.set(hotspot_x, hotspot_y); | |
493 | |
494 // Compare the current cursor with the last one we sent to the client. If | |
495 // they're the same, then don't bother sending the cursor again. | |
496 if (last_cursor_.size.equals(cursor->size) && | |
497 last_cursor_.hotspot.equals(cursor->hotspot) && | |
498 last_cursor_.data == cursor->data) { | |
499 return; | |
500 } | |
501 | |
502 VLOG(3) << "Sending updated cursor: " << width << "x" << height; | |
503 | |
504 // Record the last cursor image that we sent to the client. | |
505 last_cursor_ = *cursor; | |
506 | |
507 if (mouse_shape_observer_) | |
508 mouse_shape_observer_->OnCursorShapeChanged(cursor.Pass()); | |
509 } | |
510 | |
511 } // namespace | |
512 | |
513 // static | |
514 scoped_ptr<ScreenCapturer> ScreenCapturer::Create() { | |
515 return CreateWithDisableAero(true); | |
516 } | |
517 | |
518 // static | |
519 scoped_ptr<ScreenCapturer> ScreenCapturer::CreateWithDisableAero( | |
520 bool disable_aero) { | |
521 return scoped_ptr<ScreenCapturer>(new ScreenCapturerWin(disable_aero)); | |
522 } | |
523 | |
524 } // namespace media | |
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