Add DPI information to video packets.

The intention is that capturers can add this information and the client can
make use of it to up-scale the desktop if it DPI is larger than that of the
host by an integer multiple. For example, a standard-DPI host viewed on a
retina-display Macbook Pro would no longer look tiny.

BUG=135089
TEST=EncoderVp8Test.TestDpiPropagation


Review URL: https://chromiumcodereview.appspot.com/10736046

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@146715 0039d316-1c4b-4281-b951-d872f2087c98

6 files changed, 56 insertions, 2 deletions

diff --git a/remoting/base/capture_data.cc b/remoting/base/capture_data.cc
index 4daa8dd..fb0d582 100644
--- a/remoting/base/capture_data.cc
+++ b/remoting/base/capture_data.cc
@@ -1,4 +1,4 @@
-// Copyright (c) 2011 The Chromium Authors. All rights reserved.
+// Copyright (c) 2012 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.
 
@@ -20,7 +20,8 @@ CaptureData::CaptureData(const DataPlanes &data_planes,
       size_(size),
       pixel_format_(format),
       capture_time_ms_(0),
-      client_sequence_number_(0) {
+      client_sequence_number_(0),
+      dpi_(SkIPoint::Make(0, 0)) {
 }
 
 CaptureData::~CaptureData() {}
diff --git a/remoting/base/capture_data.h b/remoting/base/capture_data.h
index cea18ac..7e65b37 100644
--- a/remoting/base/capture_data.h
+++ b/remoting/base/capture_data.h
@@ -59,6 +59,10 @@ class CaptureData : public base::RefCountedThreadSafe<CaptureData> {
     client_sequence_number_ = client_sequence_number;
   }
 
+  SkIPoint dpi() const { return dpi_; }
+
+  void set_dpi(const SkIPoint& dpi) { dpi_ = dpi; }
+
  private:
   friend class base::RefCountedThreadSafe<CaptureData>;
   virtual ~CaptureData();
@@ -73,6 +77,9 @@ class CaptureData : public base::RefCountedThreadSafe<CaptureData> {
 
   // Sequence number supplied by client for performance tracking.
   int64 client_sequence_number_;
+
+  // DPI for this frame.
+  SkIPoint dpi_;
 };
 
 }  // namespace remoting
diff --git a/remoting/base/encoder_row_based.cc b/remoting/base/encoder_row_based.cc
index 41d9e9e..c28c06c 100644
--- a/remoting/base/encoder_row_based.cc
+++ b/remoting/base/encoder_row_based.cc
@@ -124,6 +124,11 @@ void EncoderRowBased::EncodeRect(const SkIRect& rect, bool last) {
       packet->set_capture_time_ms(capture_data_->capture_time_ms());
       packet->set_client_sequence_number(
           capture_data_->client_sequence_number());
+      SkIPoint dpi(capture_data_->dpi());
+      if (dpi.x())
+        packet->mutable_format()->set_x_dpi(dpi.x());
+      if (dpi.y())
+        packet->mutable_format()->set_y_dpi(dpi.y());
       if (last)
         packet->set_flags(packet->flags() | VideoPacket::LAST_PARTITION);
       DCHECK(row_pos == row_size);
diff --git a/remoting/base/encoder_vp8.cc b/remoting/base/encoder_vp8.cc
index 2d8ae77..83fbffe 100644
--- a/remoting/base/encoder_vp8.cc
+++ b/remoting/base/encoder_vp8.cc
@@ -293,6 +293,11 @@ void EncoderVp8::Encode(scoped_refptr<CaptureData> capture_data,
   packet->mutable_format()->set_screen_height(capture_data->size().height());
   packet->set_capture_time_ms(capture_data->capture_time_ms());
   packet->set_client_sequence_number(capture_data->client_sequence_number());
+  SkIPoint dpi(capture_data->dpi());
+  if (dpi.x())
+    packet->mutable_format()->set_x_dpi(dpi.x());
+  if (dpi.y())
+    packet->mutable_format()->set_y_dpi(dpi.y());
   for (SkRegion::Iterator r(updated_region); !r.done(); r.next()) {
     Rect* rect = packet->add_dirty_rects();
     rect->set_x(r.rect().x());
diff --git a/remoting/base/encoder_vp8_unittest.cc b/remoting/base/encoder_vp8_unittest.cc
index 0060869..3f7f11c 100644
--- a/remoting/base/encoder_vp8_unittest.cc
+++ b/remoting/base/encoder_vp8_unittest.cc
@@ -62,4 +62,35 @@ TEST(EncoderVp8Test, TestSizeChangeNoLeak) {
                             base::Unretained(&callback)));
 }
 
+class EncoderDpiCallback {
+ public:
+  void DataAvailable(scoped_ptr<VideoPacket> packet) {
+    EXPECT_EQ(packet->format().x_dpi(), 96);
+    EXPECT_EQ(packet->format().y_dpi(), 97);
+  }
+};
+
+// Test that the DPI information is correctly propagated from the CaptureData
+// to the VideoPacket.
+TEST(EncoderVp8Test, TestDpiPropagation) {
+  int height = 1;
+  int width = 1;
+  const int kBytesPerPixel = 4;
+
+  EncoderVp8 encoder;
+  EncoderDpiCallback callback;
+
+  std::vector<uint8> buffer(width * height * kBytesPerPixel);
+  DataPlanes planes;
+  planes.data[0] = &buffer.front();
+  planes.strides[0] = width;
+
+  scoped_refptr<CaptureData> capture_data(new CaptureData(
+      planes, SkISize::Make(width, height), media::VideoFrame::RGB32));
+  capture_data->set_dpi(SkIPoint::Make(96, 97));
+  encoder.Encode(capture_data, false,
+                 base::Bind(&EncoderDpiCallback::DataAvailable,
+                            base::Unretained(&callback)));
+}
+
 }  // namespace remoting
diff --git a/remoting/proto/video.proto b/remoting/proto/video.proto
index 14415af..01c57d4 100644
--- a/remoting/proto/video.proto
+++ b/remoting/proto/video.proto
@@ -33,6 +33,11 @@ message VideoPacketFormat {
   // Width and height of the whole screen.
   optional int32 screen_width = 6;
   optional int32 screen_height = 7;
+
+  // Horizontal and vertical DPI of the screen. If either of these is zero or
+  // unset, the corresponding DPI should be assumed to be 96 (Windows' default)
+  optional int32 x_dpi = 8;
+  optional int32 y_dpi = 9;
 }
 
 // TODO(hclam): Remove this message once we can obtain dirty rects from libvpx.