Copy the (early prototype of) remoting in Chrome into the public tree....

remoting/host/capturer_gdi.cc

+// Copyright (c) 2010 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 "remoting/host/capturer_gdi.h"
+
+#include "gfx/rect.h"
+
+namespace remoting {
+
+// 3780 pixels per meter is equivalent to 96 DPI, typical on desktop monitors.
+static const int kPixelsPerMeter = 3780;
+// 24 bit RGB is 3 bytes per pixel.
+static const int kBytesPerPixel = 3;
+
+CapturerGdi::CapturerGdi()
+    : initialized_(false) {
+}
+
+CapturerGdi::~CapturerGdi() {
+  if (initialized_) {
+    for (int i = kNumBuffers - 1; i >= 0; i--) {
+      DeleteObject(target_bitmap_[i]);
+    }
+  }
+}
+
+void CapturerGdi::CaptureFullScreen(Task* done_task) {
+  dirty_rects_.clear();
+
+  CaptureImage();
+  dirty_rects_.push_back(gfx::Rect(width_, height_));
+
+  FinishCapture(done_task);
+}
+
+void CapturerGdi::CaptureDirtyRects(Task* done_task) {
+  dirty_rects_.clear();
+
+  CaptureImage();
+  // TODO(garykac): Diff old/new images and generate |dirty_rects_|.
+  // Currently, this just marks the entire screen as dirty.
+  dirty_rects_.push_back(gfx::Rect(width_, height_));
+
+  FinishCapture(done_task);
+}
+
+void CapturerGdi::CaptureRect(const gfx::Rect& rect, Task* done_task) {
+  dirty_rects_.clear();
+
+  CaptureImage();
+  dirty_rects_.push_back(rect);
+
+  FinishCapture(done_task);
+}
+
+void CapturerGdi::GetData(const uint8* planes[]) const {
+  planes[0] = static_cast<const uint8*>(buffers_[current_buffer_]);
+  planes[1] = planes[2] = NULL;
+}
+
+void CapturerGdi::GetDataStride(int strides[]) const {
+  // Only the first plane has data.
+  strides[0] = bytes_per_row_;
+  strides[1] = strides[2] = 0;
+}
+
+int CapturerGdi::GetWidth() const {
+  if (!width_)
+    width_ = GetSystemMetrics(SM_CXSCREEN);
+  return width_;
+}
+
+int CapturerGdi::GetHeight() const {
+  if (!height_)
+    height_ = GetSystemMetrics(SM_CYSCREEN);
+  return height_;
+}
+
+// TODO(fbarchard): handle error cases.
+void CapturerGdi::InitializeBuffers() {
+  desktop_dc_ = GetDC(GetDesktopWindow());
+  memory_dc_ = CreateCompatibleDC(desktop_dc_);
+
+  // Create a bitmap to keep the desktop image.
+  width_ = GetSystemMetrics(SM_CXSCREEN);
+  height_ = GetSystemMetrics(SM_CYSCREEN);
+  int rounded_width = (width_ + 3) & (~3);
+
+  // Dimensions of screen.
+  pixel_format_ = chromotocol_pb::PixelFormatRgb24;
+  bytes_per_pixel_ = kBytesPerPixel;
+  bytes_per_row_ = rounded_width * bytes_per_pixel_;
+
+  // Create a device independant bitmap (DIB) that is the same size.
+  BITMAPINFO bmi;
+  memset(&bmi, 0, sizeof(bmi));
+  bmi.bmiHeader.biHeight = height_;
+  bmi.bmiHeader.biWidth = width_;
+  bmi.bmiHeader.biPlanes = 1;
+  bmi.bmiHeader.biBitCount = bytes_per_pixel_ * 8;
+  bmi.bmiHeader.biSize = sizeof(bmi.bmiHeader);
+  bmi.bmiHeader.biSizeImage = bytes_per_row_ * height_;
+  bmi.bmiHeader.biXPelsPerMeter = kPixelsPerMeter;
+  bmi.bmiHeader.biYPelsPerMeter = kPixelsPerMeter;
+
+  // Create memory for the buffers.
+  for (int i = 0; i < kNumBuffers; i++) {
+    target_bitmap_[i] = CreateDIBSection(desktop_dc_, &bmi, DIB_RGB_COLORS,
+                                         static_cast<void**>(&buffers_[i]),
+                                         NULL, 0);
+  }
+  initialized_ = true;
+}
+
+void CapturerGdi::CaptureImage() {
+  if (initialized_ == false) {
+    InitializeBuffers();
+  }
+  // Selection the target bitmap into the memory dc.
+  SelectObject(memory_dc_, target_bitmap_[current_buffer_]);
+
+  // And then copy the rect from desktop to memory.
+  BitBlt(memory_dc_, 0, 0, width_, height_, desktop_dc_, 0, 0,
+      SRCCOPY | CAPTUREBLT);
+}
+
+}  // namespace remoting