Cross-platform plumbing for resize-to-client

remoting/host/desktop_resizer.h

+// 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.
+
+#ifndef REMOTING_HOST_DESKTOP_RESIZER_H_
+#define REMOTING_HOST_DESKTOP_RESIZER_H_
+
+#include <list>
+
+#include "base/memory/scoped_ptr.h"
+#include "third_party/skia/include/core/SkRect.h"
+
+namespace remoting {
+
+class DesktopResizer {
+ public:
+  virtual ~DesktopResizer() {}
+
+  // Create a platform-specific DesktopResizer instance.
+  static scoped_ptr<DesktopResizer> Create();
+
+  // Return the current size of the desktop. This size will be restored upon
+  // disconnection.

[Wez, 2012/09/20 21:35:15]

This interface has no concept of disconnection; do you mean destruction?  If so
then rename the call GetOriginalSize(), since it will return the original size
that will be restored, not the current size in the case that SetSize() has
already been used to change it.

[Jamie, 2012/09/20 22:59:59]

No, I meant disconnection. I was trying to give an explanation of how it might
be used, but I can remove it if you think it makes things less clear. I'd prefer
not to to call it GetOriginalSize, because it's less clear what the
implementation should do.

[Wez, 2012/09/21 00:59:32]

As I commented elsewhere, I think you need an explicit RestoreOriginalSize()
rather than fetching the original size in the resizer.

[Jamie, 2012/09/24 22:49:15]

I think the method should stay, so that we can turn off auto-resize in a
cross-platform way if the user changes the size mid-session. I'll remove the
part about disconnection, since it's no longer used solely for that purpose.

+  virtual SkISize GetCurrentSize() = 0;
+
+  // Get the list of supported sizes, which should ideally include |preferred|.
+  // Implementations will generally do one of two things:
+  //   1. Return the list of sizes supported by the underlying video driver,
+  //      regardless of |preferred|.
+  //   2. Return a list containing just |preferred|, perhaps after imposing
+  //      some minimum size constraint. This will typically be the case if
+  //      there are no constraints imposed by the underlying video driver.

[Wez, 2012/09/20 21:35:15]

3. Return no sizes if resize is not supported.

[Jamie, 2012/09/20 22:59:59]

Done.

+  virtual std::list<SkISize> GetSupportedSizes(const SkISize& preferred) = 0;
+
+  // Set the size of the desktop. |size| is guaranteed to be one of the sizes

[Wez, 2012/09/20 21:35:15]

|size| must be one of the sizes previously returned; implementations should
check that.

[Jamie, 2012/09/20 22:59:59]

I'm not sure what you're suggesting here. Are you asking that the comment
specify that implementations should check the supplied size? That would require
that they cache the sizes they previously returned, which is not something they
would necessarily do otherwise. Since monitor configurations can change on the
fly anyway, the implementations will need to fail gracefully if they're asked to
set a size that isn't supported anyway, so I'm not sure what such a check buys
us.

[Wez, 2012/09/21 00:59:32]

No, I'm asking that the comment state that the caller must supply one of the
previously-returned sizes.  And yes, implementations should check that the size
is valid in the current context.

[Jamie, 2012/09/24 22:49:15]

Done.

+  // previously returned by |GetSupportedSizes| or |GetCurrentSize|.
+  virtual void SetSize(const SkISize& size) = 0;
+};
+
+}  // namespace remoting
+
+#endif  // REMOTING_HOST_DESKTOP_RESIZER_H_