Remote assistance on Chrome OS Part IX - Input injection on Ozone

remoting/host/chromeos/display_transform_util.h

+// Copyright 2014 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.
+
+#ifndef REMOTING_HOST_CHROMEOS_DISPLAY_TRANSFORM_UTIL_H_
+#define REMOTING_HOST_CHROMEOS_DISPLAY_TRANSFORM_UTIL_H_
+
+#include "ui/gfx/geometry/point_f.h"
+
+namespace remoting {
+
+// Converts |location| from the window tree host coordinate system to the native
+// screen coordinate system. |location| is in device pixels.

[Wez, 2014/12/04 01:28:25]

It's confusing to say that |location| is in "window tree host" coordinates, but
then that it is "in device pixels" - which is it? Do you mean to say that
"window tree host" coordinates are always expressed in "device pixels" rather
than DIPs?

Looking at the implementation, it seems that |location| and the return value are
both expressed in DIPs, not device pixels?

[Wez, 2014/12/04 01:28:25]

Is there some design doc we can refer to that explains what the difference
between the "window tree host" and "native screen" coordinate systems is?

[kelvinp, 2014/12/05 03:17:28]

Unfortunately, we don't have a design docs.  The comments is updated to make it
clearer for the reader.  Both coordinate system is in DIP

+gfx::PointF ConvertPointToNativeScreen(const gfx::PointF& location);
+
+// Converts |location| from the native screen coordinate system to the window
+// tree host coordinate system. |location| is in device pixels.
+gfx::PointF ConvertPointFromNativeScreen(const gfx::PointF& location);
+
+}  // namespace remoting
+
+#endif  // REMOTING_HOST_CHROMEOS_DISPLAY_TRANSFORM_UTIL_H_