Add support for high-DPI hosts under Mac OS X.

remoting/capturer/mac/desktop_configuration.h

+// Copyright (c) 2013 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_CAPTURER_MAC_DESKTOP_CONFIGURATION_H_
+#define REMOTING_CAPTURER_MAC_DESKTOP_CONFIGURATION_H_
+
+#include <ApplicationServices/ApplicationServices.h>
+#include <Carbon/Carbon.h>
+#include <vector>
+
+#include "base/basictypes.h"
+#include "third_party/skia/include/core/SkPoint.h"
+#include "third_party/skia/include/core/SkRect.h"
+
+namespace remoting {
+
+// Describes the configuration of a specific display.
+struct MacDisplayConfiguration {
+  MacDisplayConfiguration();
+
+  // Returns the current configuration of the specified display.
+  static MacDisplayConfiguration ForDisplay(CGDirectDisplayID display_id);
+
+  // Cocoa identifier for this display.
+  CGDirectDisplayID id;
+
+  // Bounds of this display in logical (72dpi) coordinates.

[Nico, 2013/01/24 00:26:58]

We call "logical coordinates" "dips" or "device-independent pixels" in chromium
code (following android's lead), and most things are in dips by default and only
stuff in pixels is called out as "pixel_foo".

[Wez, 2013/01/24 00:57:30]

Yes, I was going to describe these as DIPs but wanted to avoid confusion w/ web
content coordinate schemes.  It doesn't really matter; happy to change it to
DIPs here.

[Wez, 2013/01/25 00:32:49]

Done.

+  SkIRect logical_bounds;
+
+  // Bounds of the desktop in device resolution (i.e. physical) pixels.
+  SkIRect pixel_bounds;
+
+  // Resolution of the desktop in Dots-Per-Inch.
+  SkIPoint dpi;
+
+  // Scale factor from logical to pixel units.
+  float logical_to_pixel_scale;

[Nico, 2013/01/24 00:26:58]

For what it's worth, we call this "device_scale" in most other places in
chromium and webkit code.

[Wez, 2013/01/24 00:57:30]

Yes; I'm not keen on that name because we then end up with things like
Graphics2D::SetScale(1.0f / device_scale), which is hard to read - I think it's
best to be explicit as to the units between which the scale is expressed.

+};
+
+typedef std::vector<MacDisplayConfiguration> MacDisplayConfigurations;
+
+// Describes the configuration of the whole desktop.
+struct MacDesktopConfiguration {
+  MacDesktopConfiguration();
+  ~MacDesktopConfiguration();
+
+  // Returns the current configuration of the desktop.
+  static MacDesktopConfiguration GetCurrent();
+
+  // Bounds of the desktop in logical (72dpi) coordinates.
+  SkIRect logical_bounds;
+
+  // Bounds of the desktop in device resolution (i.e. physical) pixels.
+  SkIRect pixel_bounds;
+
+  // Resolution of the desktop in Dots-Per-Inch.
+  SkIPoint dpi;

[Nico, 2013/01/24 00:26:58]

I'm not sure if dpi is a useful metric on OS X, isn't it always 72?

[Wez, 2013/01/24 00:57:30]

We use DPI on-the-wire in Chromoting, but you're right, there's no need to deal
with DPI at this level.

[Wez, 2013/01/25 00:32:49]

Done.  Thanks for the suggestion!

+
+  // Scale factor from logical to pixel units.
+  float logical_to_pixel_scale;
+
+  // Configurations of the displays making up the desktop area.
+  MacDisplayConfigurations displays;
+};
+
+}  // namespace remoting
+
+#endif  // REMOTING_CAPTURER_MAC_DESKTOP_CONFIGURATION_H_