Implement a chromoting client using X11

remoting/client/x11_view.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/client/x11_view.h"
+
+#include <X11/Xlib.h>
+#include <X11/Xutil.h>
+#include <X11/extensions/Xrender.h>
+#include <X11/extensions/Xcomposite.h>
+#include "remoting/client/decoder_verbatim.h"
+
+namespace remoting {
+
+X11View::X11View(Display* display, int window, int width, int height)
+    : display_(display),
+      window_(window),
+      picture_(0),
+      width_(width),
+      height_(height) {
+}
+
+X11View::~X11View() {
+}
+
+void X11View::Paint() {
+  // TODO(hclam): Paint only the updated regions.
+  all_update_rects_.clear();
+
+  // If we have not initialized the render target then do it now.
+  if (!frame_)
+    InitPaintTarget();
+
+  // Upload the image to a pixmap. And then creats a picture from the pixmap
+  // and composite the picture over the picture represending the window.
+
+  // Creates a XImage.
+  XImage image;
+  memset(&image, 0, sizeof(image));
+  image.width = width_;
+  image.height = height_;
+  image.depth = 32;
+  image.bits_per_pixel = 32;
+  image.format = ZPixmap;
+  image.byte_order = LSBFirst;
+  image.bitmap_unit = 8;
+  image.bitmap_bit_order = LSBFirst;
+  image.bytes_per_line = frame_->stride(media::VideoFrame::kRGBPlane);
+  image.red_mask = 0xff;
+  image.green_mask = 0xff00;
+  image.blue_mask = 0xff0000;
+  image.data = reinterpret_cast<char*>(
+      frame_->data(media::VideoFrame::kRGBPlane));
+
+  // Creates a pixmap and uploads from the XImage.
+  unsigned long pixmap = XCreatePixmap(display_, window_, width_, height_, 32);
+
+  GC gc = XCreateGC(display_, pixmap, 0, NULL);
+  XPutImage(display_, pixmap, gc, &image, 0, 0, 0, 0, width_, height_);
+  XFreeGC(display_, gc);
+
+  // Creates the picture representing the pixmap.
+  unsigned long picture = XRenderCreatePicture(
+      display_, pixmap,
+      XRenderFindStandardFormat(display_, PictStandardARGB32),
+      0, NULL);
+
+  // Composite the picture over the picture representing the window.
+  XRenderComposite(display_, PictOpSrc, picture, 0,
+                   picture_, 0, 0, 0, 0, 0, 0,
+                   width_, height_);
+
+  XRenderFreePicture(display_, picture);
+  XFreePixmap(display_, pixmap);
+}
+
+void X11View::InitPaintTarget() {
+  // Testing XRender support.
+  int dummy;
+  bool xrender_support = XRenderQueryExtension(display_, &dummy, &dummy);
+  CHECK(xrender_support) << "XRender is not supported!";
+
+  XWindowAttributes attr;
+  XGetWindowAttributes(display_, window_, &attr);
+
+  XRenderPictFormat* pictformat = XRenderFindVisualFormat(
+      display_,
+      attr.visual);
+  CHECK(pictformat) << "XRENDER does not support default visual";
+
+  picture_ = XRenderCreatePicture(display_, window_, pictformat, 0, NULL);
+  CHECK(picture_) << "Backing picture not created";
+
+  // Create the video frame to carry the decoded image.
+  media::VideoFrame::CreateFrame(media::VideoFrame::RGB32, width_, height_,
+                                 base::TimeDelta(), base::TimeDelta(), &frame_);
+  DCHECK(frame_);
+}
+
+void X11View::HandleBeginUpdateStream(HostMessage* msg) {
+  scoped_ptr<HostMessage> deleter(msg);
+
+  // TODO(hclam): Use the information from the message to create the decoder.
+  // We lazily construct the decoder.
+  if (!decoder_.get()) {
+    decoder_.reset(new DecoderVerbatim());
+  }
+
+  // Tell the decoder to do start decoding.
+  decoder_->BeginDecode(frame_, &update_rects_,
+      NewRunnableMethod(this, &X11View::OnPartialDecodeDone),
+      NewRunnableMethod(this, &X11View::OnDecodeDone));
+}
+
+void X11View::HandleUpdateStreamPacket(HostMessage* msg) {
+  decoder_->PartialDecode(msg);
+}
+
+void X11View::HandleEndUpdateStream(HostMessage* msg) {
+  scoped_ptr<HostMessage> deleter(msg);
+  decoder_->EndDecode();
+}
+
+void X11View::OnPartialDecodeDone() {
+  // Decoder has produced some output so schedule a paint. We'll get a Paint()
+  // call in the short future. Note that we can get UpdateStreamPacket during
+  // this short period of time and we will perform decode again and the
+  // information of updated rects will be lost.
+  // There are several ways to solve this problem.
+  // 1. Merge the updated rects and perform one paint.
+  // 2. Queue the updated rects and perform two paints.
+  // 3. Ignore the updated rects and always paint the full image. Since we
+  //    use one frame as output this will always be correct.
+  // We will take (1) and simply concat the list of rectangles.
+  all_update_rects_.insert(all_update_rects_.begin() +
+                           all_update_rects_.size(),
+                           update_rects_.begin(), update_rects_.end());
+
+  // TODO(hclam): Make sure we call this method on the right thread. Since
+  // decoder is single-threaded we don't have a problem but we better post
+  // a task to do the right thing.
+  XEvent event;
+  event.type = Expose;
+  XSendEvent(display_, static_cast<int>(window_), true, ExposureMask, &event);
+}
+
+void X11View::OnDecodeDone() {
+  // Since we do synchronous decoding here there's nothing in this method.
+}
+
+}  // namespace remoting