Make Chromoting client plugin always render at device DPI.

This addresses image quality issues when to a high-resolution device from a high-DPI but lower resolution client.  In this case Chromoting would down-scale to the plugin's DIP dimensions, only for Chrome to up-scale to device dimensions.

Follow-up CLs will add DPI information to the FrameConsumer interface, and try to optimize the plugin's up-scaling mode.

BUG=133349,135089


Review URL: https://chromiumcodereview.appspot.com/10785041

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@148012 0039d316-1c4b-4281-b951-d872f2087c98

4 files changed, 51 insertions, 25 deletions

diff --git a/remoting/client/plugin/chromoting_instance.cc b/remoting/client/plugin/chromoting_instance.cc
index 71ccd2a..fc7b46f 100644
--- a/remoting/client/plugin/chromoting_instance.cc
+++ b/remoting/client/plugin/chromoting_instance.cc
@@ -341,18 +341,13 @@ void ChromotingInstance::HandleMessage(const pp::Var& message) {
   }
 }
 
-void ChromotingInstance::DidChangeView(const pp::Rect& position,
-                                       const pp::Rect& clip) {
+void ChromotingInstance::DidChangeView(const pp::View& view) {
   DCHECK(plugin_message_loop_->BelongsToCurrentThread());
 
-  SkISize new_size = SkISize::Make(position.width(), position.height());
-  SkIRect new_clip =
-    SkIRect::MakeXYWH(clip.x(), clip.y(), clip.width(), clip.height());
-
-  view_->SetView(new_size, new_clip);
+  view_->SetView(view);
 
   if (mouse_input_filter_.get()) {
-    mouse_input_filter_->set_input_size(view_->get_view_size());
+    mouse_input_filter_->set_input_size(view_->get_view_size_dips());
   }
 }
 
@@ -484,7 +479,7 @@ void ChromotingInstance::Connect(const ClientConfig& config) {
   // Construct the input pipeline
   mouse_input_filter_.reset(
       new protocol::MouseInputFilter(host_connection_->input_stub()));
-  mouse_input_filter_->set_input_size(view_->get_view_size());
+  mouse_input_filter_->set_input_size(view_->get_view_size_dips());
   input_tracker_.reset(
       new protocol::InputEventTracker(mouse_input_filter_.get()));
 
diff --git a/remoting/client/plugin/chromoting_instance.h b/remoting/client/plugin/chromoting_instance.h
index 7d0e5a2..04a5449 100644
--- a/remoting/client/plugin/chromoting_instance.h
+++ b/remoting/client/plugin/chromoting_instance.h
@@ -98,8 +98,7 @@ class ChromotingInstance :
   virtual ~ChromotingInstance();
 
   // pp::Instance interface.
-  virtual void DidChangeView(const pp::Rect& position,
-                             const pp::Rect& clip) OVERRIDE;
+  virtual void DidChangeView(const pp::View& view) OVERRIDE;
   virtual bool Init(uint32_t argc, const char* argn[],
                     const char* argv[]) OVERRIDE;
   virtual void HandleMessage(const pp::Var& message) OVERRIDE;
diff --git a/remoting/client/plugin/pepper_view.cc b/remoting/client/plugin/pepper_view.cc
index b86af03..aabcba0 100644
--- a/remoting/client/plugin/pepper_view.cc
+++ b/remoting/client/plugin/pepper_view.cc
@@ -11,7 +11,8 @@
 #include "base/time.h"
 #include "base/synchronization/waitable_event.h"
 #include "ppapi/cpp/completion_callback.h"
-#include "ppapi/cpp/graphics_2d.h"
+#include "ppapi/cpp/dev/graphics_2d_dev.h"
+#include "ppapi/cpp/dev/view_dev.h"
 #include "ppapi/cpp/image_data.h"
 #include "ppapi/cpp/point.h"
 #include "ppapi/cpp/rect.h"
@@ -46,6 +47,8 @@ PepperView::PepperView(ChromotingInstance* instance,
     clip_area_(SkIRect::MakeEmpty()),
     source_size_(SkISize::Make(0, 0)),
     source_dpi_(SkIPoint::Make(0, 0)),
+    view_size_dips_(SkISize::Make(0, 0)),
+    view_scale_(1.0f),
     flush_pending_(false),
     frame_received_(false) {
   InitiateDrawing();
@@ -66,27 +69,46 @@ PepperView::~PepperView() {
   }
 }
 
-void PepperView::SetView(const SkISize& view_size, const SkIRect& clip_area) {
+void PepperView::SetView(const pp::View& view) {
   bool view_changed = false;
 
-  if (view_size_ != view_size) {
+  pp::Rect pp_size = view.GetRect();
+  SkISize new_size_dips = SkISize::Make(pp_size.width(), pp_size.height());
+  pp::ViewDev view_dev(view);
+  float new_scale = view_dev.GetDeviceScale();
+
+  if (view_size_dips_ != new_size_dips || view_scale_ != new_scale) {
     view_changed = true;
-    view_size_ = view_size;
+    view_scale_ = new_scale;
+    view_size_dips_ = new_size_dips;
+    view_size_ = SkISize::Make(ceilf(view_size_dips_.width() * view_scale_),
+                               ceilf(view_size_dips_.height() * view_scale_));
 
     pp::Size pp_size = pp::Size(view_size_.width(), view_size_.height());
     graphics2d_ = pp::Graphics2D(instance_, pp_size, true);
+
+    // Ideally we would always let Graphics2D scale us, but the output quality
+    // is lousy, so we don't.
+    pp::Graphics2DDev graphics2d_dev(graphics2d_);
+    graphics2d_dev.SetScale(1.0f / view_scale_);
+
     bool result = instance_->BindGraphics(graphics2d_);
 
     // There is no good way to handle this error currently.
     DCHECK(result) << "Couldn't bind the device context.";
   }
 
-  if (clip_area_ != clip_area) {
+  pp::Rect pp_clip = view.GetClipRect();
+  SkIRect new_clip = SkIRect::MakeLTRB(floorf(pp_clip.x() * view_scale_),
+                                       floorf(pp_clip.y() * view_scale_),
+                                       ceilf(pp_clip.right() * view_scale_),
+                                       ceilf(pp_clip.bottom() * view_scale_));
+  if (clip_area_ != new_clip) {
     view_changed = true;
 
     // YUV to RGB conversion may require even X and Y coordinates for
     // the top left corner of the clipping area.
-    clip_area_ = AlignRect(clip_area);
+    clip_area_ = AlignRect(new_clip);
     clip_area_.intersect(SkIRect::MakeSize(view_size_));
   }
 
diff --git a/remoting/client/plugin/pepper_view.h b/remoting/client/plugin/pepper_view.h
index 68446e4..cd015f0 100644
--- a/remoting/client/plugin/pepper_view.h
+++ b/remoting/client/plugin/pepper_view.h
@@ -12,6 +12,7 @@
 
 #include "base/memory/weak_ptr.h"
 #include "ppapi/cpp/graphics_2d.h"
+#include "ppapi/cpp/view.h"
 #include "ppapi/cpp/point.h"
 #include "remoting/client/frame_consumer.h"
 
@@ -44,10 +45,10 @@ class PepperView : public FrameConsumer,
   virtual void SetSourceSize(const SkISize& source_size,
                              const SkIPoint& dpi) OVERRIDE;
 
-  // Sets the display size and clipping area of this view.
-  void SetView(const SkISize& view_size, const SkIRect& clip_area);
+  // Updates the PepperView's size, clipping area and scale factor.
+  void SetView(const pp::View& view);
 
-  // Return the client view and original host dimensions.
+  // Return the dimensions of the view and source in device pixels.
   const SkISize& get_view_size() const {
     return view_size_;
   }
@@ -55,6 +56,12 @@ class PepperView : public FrameConsumer,
     return source_size_;
   }
 
+  // Return the dimensions of the view in Density Independent Pixels (DIPs).
+  // On high-DPI devices this will be smaller than the size in device pixels.
+  const SkISize& get_view_size_dips() const {
+    return view_size_dips_;
+  }
+
  private:
   // This routine allocates an image buffer.
   pp::ImageData* AllocateBuffer();
@@ -91,22 +98,25 @@ class PepperView : public FrameConsumer,
   // List of allocated image buffers.
   std::list<pp::ImageData*> buffers_;
 
+  // Queued buffer to paint, with clip area and dirty region in device pixels.
   pp::ImageData* merge_buffer_;
   SkIRect merge_clip_area_;
   SkRegion merge_region_;
 
-  // The size of the plugin element.
+  // View size, clip area and host dimensions, in device pixels.
   SkISize view_size_;
-
-  // The current clip area rectangle.
   SkIRect clip_area_;
-
-  // The size of the host screen.
   SkISize source_size_;
 
   // The DPI of the host screen.
   SkIPoint source_dpi_;
 
+  // View size in Density-Independent pixels.
+  SkISize view_size_dips_;
+
+  // DIP-to-device pixel scale factor.
+  float view_scale_;
+
   // True if there is already a Flush() pending on the Graphics2D context.
   bool flush_pending_;