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gpu_backing_store_win.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 "chrome/gpu/gpu_backing_store_win.h"

#include "app/win_util.h"
#include "base/logging.h"
#include "chrome/common/gpu_messages.h"
#include "chrome/gpu/gpu_view_win.h"
#include "chrome/gpu/gpu_thread.h"
#include "gfx/gdi_util.h"

namespace {

// Creates a dib conforming to the height/width/section parameters passed in.
HANDLE CreateDIB(HDC dc, int width, int height, int color_depth) {
  BITMAPV5HEADER hdr = {0};
  ZeroMemory(&hdr, sizeof(BITMAPV5HEADER));

  // These values are shared with gfx::PlatformDevice
  hdr.bV5Size = sizeof(BITMAPINFOHEADER);
  hdr.bV5Width = width;
  hdr.bV5Height = -height;  // minus means top-down bitmap
  hdr.bV5Planes = 1;
  hdr.bV5BitCount = color_depth;
  hdr.bV5Compression = BI_RGB;  // no compression
  hdr.bV5SizeImage = 0;
  hdr.bV5XPelsPerMeter = 1;
  hdr.bV5YPelsPerMeter = 1;
  hdr.bV5ClrUsed = 0;
  hdr.bV5ClrImportant = 0;


  void* data = NULL;
  HANDLE dib = CreateDIBSection(dc, reinterpret_cast<BITMAPINFO*>(&hdr),
                                0, &data, NULL, 0);
  DCHECK(data);
  return dib;
}

void CallStretchDIBits(HDC hdc, int dest_x, int dest_y, int dest_w, int dest_h,
                       int src_x, int src_y, int src_w, int src_h, void* pixels,
                       const BITMAPINFO* bitmap_info) {
  // When blitting a rectangle that touches the bottom, left corner of the
  // bitmap, StretchDIBits looks at it top-down!  For more details, see
  // http://wiki.allegro.cc/index.php?title=StretchDIBits.
  int rv;
  int bitmap_h = -bitmap_info->bmiHeader.biHeight;
  int bottom_up_src_y = bitmap_h - src_y - src_h;
  if (bottom_up_src_y == 0 && src_x == 0 && src_h != bitmap_h) {
    rv = StretchDIBits(hdc,
                       dest_x, dest_h + dest_y - 1, dest_w, -dest_h,
                       src_x, bitmap_h - src_y + 1, src_w, -src_h,
                       pixels, bitmap_info, DIB_RGB_COLORS, SRCCOPY);
  } else {
    rv = StretchDIBits(hdc,
                       dest_x, dest_y, dest_w, dest_h,
                       src_x, bottom_up_src_y, src_w, src_h,
                       pixels, bitmap_info, DIB_RGB_COLORS, SRCCOPY);
  }
  DCHECK(rv != GDI_ERROR);
}

}  // namespace


GpuBackingStoreWin::GpuBackingStoreWin(GpuViewWin* view,
                                       GpuThread* gpu_thread,
                                       int32 routing_id,
                                       const gfx::Size& size)
    : view_(view),
      gpu_thread_(gpu_thread),
      routing_id_(routing_id),
      size_(size) {
  gpu_thread_->AddRoute(routing_id_, this);

  HDC screen_dc = ::GetDC(NULL);
  color_depth_ = ::GetDeviceCaps(screen_dc, BITSPIXEL);
  // Color depths less than 16 bpp require a palette to be specified. Instead,
  // we specify the desired color depth as 16 which lets the OS to come up
  // with an approximation.
  if (color_depth_ < 16)
    color_depth_ = 16;
  hdc_ = CreateCompatibleDC(screen_dc);
  ReleaseDC(NULL, screen_dc);
}

GpuBackingStoreWin::~GpuBackingStoreWin() {
  gpu_thread_->RemoveRoute(routing_id_);

  DCHECK(hdc_);
  if (original_bitmap_) {
    SelectObject(hdc_, original_bitmap_);
  }
  if (backing_store_dib_) {
    DeleteObject(backing_store_dib_);
    backing_store_dib_ = NULL;
  }
  DeleteDC(hdc_);
}

void GpuBackingStoreWin::OnMessageReceived(const IPC::Message& msg) {
  IPC_BEGIN_MESSAGE_MAP(GpuBackingStoreWin, msg)
    IPC_MESSAGE_HANDLER(GpuMsg_PaintToBackingStore, OnPaintToBackingStore)
    IPC_MESSAGE_HANDLER(GpuMsg_ScrollBackingStore, OnScrollBackingStore)
  IPC_END_MESSAGE_MAP_EX()
}

void GpuBackingStoreWin::OnChannelConnected(int32 peer_pid) {
}

void GpuBackingStoreWin::OnChannelError() {
  // FIXME(brettw) does this mean we aren't getting any more messages and we
  // should delete outselves?
}

void GpuBackingStoreWin::OnPaintToBackingStore(
    base::ProcessId source_process_id,
    TransportDIB::Id id,
    const gfx::Rect& bitmap_rect,
    const std::vector<gfx::Rect>& copy_rects) {
  HANDLE source_process_handle = OpenProcess(PROCESS_ALL_ACCESS,
                                             FALSE, source_process_id);
  CHECK(source_process_handle);

  // On Windows we need to duplicate the handle from the remote process.
  // See BrowserRenderProcessHost::MapTransportDIB for how to do this on other
  // platforms.
  HANDLE section = win_util::GetSectionFromProcess(
      id.handle, source_process_handle, false /* read write */);
  CHECK(section);
  TransportDIB* dib = TransportDIB::Map(section);
  CHECK(dib);

  if (!backing_store_dib_) {
    backing_store_dib_ = CreateDIB(hdc_, size_.width(),
                                   size_.height(), color_depth_);
    if (!backing_store_dib_) {
      NOTREACHED();

      // TODO(brettw): do this in such a way that we can't forget to
      // send the ACK.
      gpu_thread_->Send(new GpuHostMsg_PaintToBackingStore_ACK(routing_id_));
      return;
    }
    original_bitmap_ = SelectObject(hdc_, backing_store_dib_);
  }

  BITMAPINFOHEADER hdr;
  gfx::CreateBitmapHeader(bitmap_rect.width(), bitmap_rect.height(), &hdr);
  // Account for a bitmap_rect that exceeds the bounds of our view
  gfx::Rect view_rect(0, 0, size_.width(), size_.height());

  for (size_t i = 0; i < copy_rects.size(); i++) {
    gfx::Rect paint_rect = view_rect.Intersect(copy_rects[i]);
    CallStretchDIBits(hdc_,
                      paint_rect.x(),
                      paint_rect.y(),
                      paint_rect.width(),
                      paint_rect.height(),
                      paint_rect.x() - bitmap_rect.x(),
                      paint_rect.y() - bitmap_rect.y(),
                      paint_rect.width(),
                      paint_rect.height(),
                      dib->memory(),
                      reinterpret_cast<BITMAPINFO*>(&hdr));
    view_->InvalidateRect(&paint_rect.ToRECT());
  }

  CloseHandle(source_process_handle);
  gpu_thread_->Send(new GpuHostMsg_PaintToBackingStore_ACK(routing_id_));
}

void GpuBackingStoreWin::OnScrollBackingStore(int dx, int dy,
                                              const gfx::Rect& clip_rect,
                                              const gfx::Size& view_size) {
  RECT damaged_rect, r = clip_rect.ToRECT();
  ScrollDC(hdc_, dx, dy, NULL, &r, NULL, &damaged_rect);

  // TODO(darin): this doesn't work if dx and dy are both non-zero!
  DCHECK(dx == 0 || dy == 0);

  view_->DidScrollBackingStoreRect(dx, dy, clip_rect);
}

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