Improving the decoder pipeline.

remoting/webapp/client_session.js

Index: remoting/webapp/client_session.js
diff --git a/remoting/webapp/client_session.js b/remoting/webapp/client_session.js
index 9977d58b2e98f34cc2bd7901f3e38a2d71b6482f..594ecf9e147e648c5faaa9821282d4fff3fea2a4 100644
--- a/remoting/webapp/client_session.js
+++ b/remoting/webapp/client_session.js
@@ -435,17 +435,56 @@ remoting.ClientSession.prototype.updateDimensions = function() {
 
   var windowWidth = window.innerWidth;
   var windowHeight = window.innerHeight;
-  var scale = 1.0;
+
+  // Estimate browser scale factor in order to be able to translate logical
+  // pixels on the page into physical pixels on the screen. Scale factor can
+  // be roughly estimated as a ratio between outerWidht and innerWidth of

[Jamie, 2012/02/16 00:26:32]

s/outerWidht/outerWidth/

[alexeypa (please no reviews), 2012/02/16 01:17:56]

Done.

+  // the document view. The result is not precise because outerWidth can
+  // include pixels allocated for toolbars, window borders and such.
+  var viewInnerWidth = document.defaultView.innerWidth;

[Jamie, 2012/02/16 00:26:32]

Why document.defaultView instead of window?

[alexeypa (please no reviews), 2012/02/16 01:17:56]

Done.

+  var viewOuterWidth = document.defaultView.outerWidth;
+  var scale = Math.round(100.0 * viewOuterWidth / viewInnerWidth) / 100.0;

[Jamie, 2012/02/16 00:26:32]

Why convert to int so early? You can stick with floats throughout--this isn't
performance critical.

[alexeypa (please no reviews), 2012/02/16 01:17:56]

Done.

+
+  // TODO(alexeypa): remove this hack once proper zooming API is available.

[Jamie, 2012/02/16 00:26:32]

Can you raise a ticket for this and include the number here, or reference an
existing ticket (109933 perhaps?)

+  // Now pick the exact scale factor from the list of known zoom levels.
+  var zoom_levels = [ 0.25, 1.0/3, 0.5, 2.0/3, 0.75, 0.9, 1, 1.1, 1.25, 1.5,
+      1.75, 2, 2.5, 3, 4 ];
+  var left = 0;
+  var right = zoom_levels.length;
+  while (left < right) {

[Jamie, 2012/02/16 00:26:32]

Binary search seems overkill. In fact, you can simplify this a lot if you assume
that outerWidth is at least innerWidth*zoom (you can't have scrollbars with
negative width). In essence, you want the value of |zoom| that minimzes |chrome|
in the equation:

  chrome = outer - inner*zoom

+    var middle = Math.floor((left + right) / 2);
+    remoting.debug.log('middle=' + middle);

[Jamie, 2012/02/16 00:26:32]

Remove this debug?

[alexeypa (please no reviews), 2012/02/16 01:17:56]

Done.

+    if (zoom_levels[middle] < scale) {
+      left = middle + 1;
+    } else {
+      right = middle;
+    }
+  }
+
+  if (left == 0) {
+    scale = zoom_levels[0];
+  } else if (left < zoom_levels.length) {
+    if (Math.abs(zoom_levels[left - 1] - scale) <
+        Math.abs(zoom_levels[left] - scale)) {
+      scale = zoom_levels[left - 1];
+    } else {
+      scale = zoom_levels[left];
+    }
+  } else {
+    scale = zoom_levels[zoom_levels.length - 1];
+  }
+
+  scale = 1.0 / scale;
 
   if (this.getScaleToFit()) {
-    var scaleFitHeight = 1.0 * windowHeight / this.plugin.desktopHeight;
-    var scaleFitWidth = 1.0 * windowWidth / this.plugin.desktopWidth;
-    scale = Math.min(1.0, scaleFitHeight, scaleFitWidth);
+    var scaledHeight = 1.0 * windowHeight / (scale * this.plugin.desktopHeight);
+    var scaledWidth = 1.0 * windowWidth / (scale * this.plugin.desktopWidth);
+    scale = Math.min(1.0, scaledHeight, scaledWidth, scale);
   }
 
   // Resize the plugin if necessary.
-  this.plugin.width = this.plugin.desktopWidth * scale;
-  this.plugin.height = this.plugin.desktopHeight * scale;
+  this.plugin.width = Math.ceil(this.plugin.desktopWidth * scale);
+  this.plugin.height = Math.ceil(this.plugin.desktopHeight * scale);
 
   // Position the container.
   // TODO(wez): We should take into account scrollbars when positioning.