Index: remoting/host/resizing_host_observer.cc |
diff --git a/remoting/host/resizing_host_observer.cc b/remoting/host/resizing_host_observer.cc |
new file mode 100644 |
index 0000000000000000000000000000000000000000..b78cb6ab373bb9c8f47b29b0ea57935ce1719833 |
--- /dev/null |
+++ b/remoting/host/resizing_host_observer.cc |
@@ -0,0 +1,158 @@ |
+// 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. |
+ |
+#include "remoting/host/resizing_host_observer.h" |
+#include "remoting/host/desktop_resizer.h" |
+ |
+#include <set> |
+ |
+#include "base/logging.h" |
+ |
+namespace remoting { |
+ |
+ResizingHostObserver::ResizingHostObserver( |
+ DesktopResizer* desktop_resizer, ChromotingHost* host) |
+ : desktop_resizer_(desktop_resizer), |
+ host_(host), |
+ original_size_(SkISize::Make(0, 0)), |
+ previous_size_(SkISize::Make(0, 0)) { |
+ if (host_) { |
+ host_->AddStatusObserver(this); |
+ } |
+} |
+ |
+ResizingHostObserver::~ResizingHostObserver() { |
+ if (host_) { |
+ host_->RemoveStatusObserver(this); |
+ } |
+} |
+ |
+void ResizingHostObserver::OnClientAuthenticated(const std::string& jid) { |
+ // Resize-to-client doesn't make sense if multiple clients are connected, |
+ // and this is not currently supported anyway. |
Wez
2012/09/25 20:48:29
nit: Suggest "This implementation assumes a single
Jamie
2012/09/25 23:20:20
Done.
|
+ DCHECK(client_jid_.empty()); |
+ original_size_ = desktop_resizer_->GetCurrentSize(); |
+ previous_size_ = original_size_; |
+} |
+ |
+void ResizingHostObserver::OnClientDisconnected(const std::string& jid) { |
+ if (!original_size_.isZero()) { |
+ desktop_resizer_->RestoreSize(original_size_); |
+ original_size_.set(0, 0); |
+ } |
+ client_jid_.clear(); |
+} |
+ |
+class CandidateSize { |
+ public: |
+ CandidateSize(const SkISize& candidate, const SkISize& preferred) |
+ : size_(candidate) { |
+ // The client scale factor is the smaller of the candidate:preferred ratios |
+ // for width and height. |
+ if ((candidate.width() > preferred.width()) || |
+ (candidate.height() > preferred.height())) { |
+ float ratio_width = |
+ static_cast<float>(preferred.width()) / candidate.width(); |
+ float ratio_height = |
+ static_cast<float>(preferred.height()) / candidate.height(); |
+ client_scale_factor_ = std::min(ratio_width, ratio_height); |
+ } else { |
+ // Since clients do not scale up, 1.0 is the maximum. |
+ client_scale_factor_ = 1.0; |
+ } |
+ |
+ // The aspect ratio "goodness" is defined as being the ratio of the smaller |
+ // of the two aspect ratios (candidate and preferred) to the larger. The |
+ // best aspect ratio is the one that most closely matches the preferred |
+ // aspect ratio (in other words, the ideal aspect ratio "goodness" is 1.0). |
+ // By keeping the values < 1.0, it allows ratios the differ in opposite |
+ // directions to be compared numerically. |
+ float candidate_aspect_ratio = |
+ static_cast<float>(candidate.width()) / candidate.height(); |
+ float preferred_aspect_ratio = |
+ static_cast<float>(preferred.width()) / preferred.height(); |
+ if (candidate_aspect_ratio > preferred_aspect_ratio) { |
+ aspect_ratio_goodness_ = preferred_aspect_ratio / candidate_aspect_ratio; |
+ } else { |
+ aspect_ratio_goodness_ = candidate_aspect_ratio / preferred_aspect_ratio; |
+ } |
+ } |
+ |
+ const SkISize& size() const { return size_; } |
+ float client_scale_factor() const { return client_scale_factor_; } |
+ float aspect_ratio_goodness() const { return aspect_ratio_goodness_; } |
+ int64 area() const { |
+ return static_cast<int64>(size_.width()) * size_.height(); |
+ } |
+ |
+ bool IsBetterThan(const CandidateSize& other) const { |
+ // If either size would require down-scaling, prefer the one that down- |
+ // scales the least (since the client scale factor is at most 1.0, this |
+ // does not differentiate between sizes that don't require down-scaling). |
+ if (client_scale_factor() < other.client_scale_factor()) { |
+ return false; |
+ } else if (client_scale_factor() > other.client_scale_factor()) { |
+ return true; |
+ } |
+ |
+ // If the scale factors are the same, pick the size with the largest area. |
+ if (area() < other.area()) { |
+ return false; |
+ } else if (area() > other.area()) { |
+ return true; |
+ } |
+ |
+ // If the areas are equal, pick the size with the "best" aspect ratio. |
+ if (aspect_ratio_goodness() < other.aspect_ratio_goodness()) { |
+ return false; |
+ } else if (aspect_ratio_goodness() > other.aspect_ratio_goodness()) { |
+ return true; |
+ } |
+ |
+ // If the aspect ratios are equally good (for example, comparing 640x480 |
+ // to 480x640 w.r.t. 640x640), just pick the widest, since desktop UIs |
+ // are typically design for landscape aspect ratios. |
+ return size().width() > other.size().width(); |
+ } |
+ |
+ private: |
+ float client_scale_factor_; |
+ float aspect_ratio_goodness_; |
+ SkISize size_; |
+}; |
+ |
+void ResizingHostObserver::OnClientDimensionsChanged( |
+ const std::string& jid, const SkISize& preferred_size) { |
+ // If the host desktop size changes other than via the resize-to-client |
+ // mechanism, then set |previous_size_| to zero and give up. This is an |
+ // indication that the user doesn't want resize-to-client. |
+ if (previous_size_.isZero()) { |
Wez
2012/09/25 20:48:29
nit: I'd prefer that this check be above this comm
Jamie
2012/09/25 23:20:20
I want to do this check first because it avoids an
|
+ return; |
+ } |
+ SkISize new_size = desktop_resizer_->GetCurrentSize(); |
+ if (new_size != previous_size_) { |
+ previous_size_ = SkISize::Make(0, 0); |
+ return; |
+ } |
+ |
+ // If the implementation returns any sizes, pick the best one according to |
+ // the algorithm described in CandidateSize::IsBetterThen. |
+ std::list<SkISize> sizes = |
+ desktop_resizer_->GetSupportedSizes(preferred_size); |
+ if (sizes.empty()) { |
+ return; |
+ } |
+ CandidateSize best_size(sizes.front(), preferred_size); |
+ std::list<SkISize>::iterator i = sizes.begin(); |
+ for (++i; i != sizes.end(); ++i) { |
+ CandidateSize candidate_size(*i, preferred_size); |
+ if (candidate_size.IsBetterThan(best_size)) { |
+ best_size = candidate_size; |
+ } |
+ } |
+ previous_size_ = best_size.size(); |
+ desktop_resizer_->SetSize(previous_size_); |
+} |
+ |
+} // namespace remoting |