Improve DPI matching & scaling logic.

remoting/webapp/unittests/client_session_unittest.js

Index: remoting/webapp/unittests/client_session_unittest.js
diff --git a/remoting/webapp/unittests/client_session_unittest.js b/remoting/webapp/unittests/client_session_unittest.js
new file mode 100644
index 0000000000000000000000000000000000000000..f8e842850dcc0ab570e316065d9b00d197ec2cd9
--- /dev/null
+++ b/remoting/webapp/unittests/client_session_unittest.js
@@ -0,0 +1,102 @@
+// Copyright 2015 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.
+
+(function() {
+
+'use strict';
+
+module('client_session');
+
+function size(width, height) {
+  return {width: width, height: height};
+}
+
+function dpi(x, y) {
+  return {x: x, y: y};
+}
+
+test('choosePluginSize() chooses sensible sizes',
+  function() {
+    // Client and host w/ same DPI.

[Jamie, 2015/02/04 23:18:30]

I think these test cases need descriptions to make it clear why we expect the
output that we do (eg. "avoid non-integer scale-factors"). That can either be a
comment in this file, or you can split it into multiple tests with appropriate
descriptions.

[Wez, 2015/02/06 01:29:43]

Yeah, I think splitting into a set of distinct tests is preferable; it also
makes it easier to understand which case broke, in the case of a failure!

+    var pluginSize = remoting.ClientSession.choosePluginSize(
+        size(640, 480), 1.0, size(640, 480), dpi(96, 96), 1.0, false, true);
+    QUnit.deepEqual(pluginSize, size(640, 480));
+
+    pluginSize = remoting.ClientSession.choosePluginSize(
+        size(1280, 900), 1.0, size(640, 480), dpi(96, 96), 1.0, false, true);
+    QUnit.deepEqual(pluginSize, size(640, 480));
+
+    pluginSize = remoting.ClientSession.choosePluginSize(
+        size(1280, 1024), 1.0, size(640, 480), dpi(96, 96), 1.0, false, true);
+    QUnit.deepEqual(pluginSize, size(1280, 960));
+
+    // High DPI client, low DPI host.
+    pluginSize = remoting.ClientSession.choosePluginSize(
+        size(640, 450), 2.0, size(640, 480), dpi(96, 96), 1.0, false, true);
+    QUnit.deepEqual(pluginSize, size(600, 450));

[Jamie, 2015/02/04 23:18:30]

It took me a while to work out where the 600 came from. Expressing it as 640 *
450 / 480 might be clearer.

[Wez, 2015/02/06 01:29:43]

Acknowledged.

+
+    pluginSize = remoting.ClientSession.choosePluginSize(
+        size(640, 480), 2.0, size(640, 480), dpi(96, 96), 1.0, false, true);
+    QUnit.deepEqual(pluginSize, size(640, 480));
+
+    // High DPI host, low DPI client.
+    pluginSize = remoting.ClientSession.choosePluginSize(
+        size(640, 480), 1.0, size(640, 480), dpi(192, 192), 1.0, false, true);
+    QUnit.deepEqual(pluginSize, size(640, 480));
+
+    pluginSize = remoting.ClientSession.choosePluginSize(
+        size(640, 480), 1.0, size(1024, 768), dpi(192, 192), 1.0, false, true);
+    QUnit.deepEqual(pluginSize, size(640, 480));
+
+    pluginSize = remoting.ClientSession.choosePluginSize(
+        size(1024, 768), 1.0, size(640, 480), dpi(192, 192), 1.0, false, true);
+    QUnit.deepEqual(pluginSize, size(640, 480));
+
+    // High DPI host, high DPI client.
+    pluginSize = remoting.ClientSession.choosePluginSize(
+        size(640, 480), 2.0, size(640, 480), dpi(192, 192), 1.0, false, true);
+    QUnit.deepEqual(pluginSize, size(640, 480));
+
+    pluginSize = remoting.ClientSession.choosePluginSize(
+        size(640, 480), 2.0, size(1024, 768), dpi(192, 192), 1.0, false, true);
+    QUnit.deepEqual(pluginSize, size(512, 384));
+
+    pluginSize = remoting.ClientSession.choosePluginSize(
+        size(1024, 768), 2.0, size(640, 480), dpi(192, 192), 1.0, false, true);
+    QUnit.deepEqual(pluginSize, size(960, 720));
+
+    // 150% DPI host, high DPI client.
+    pluginSize = remoting.ClientSession.choosePluginSize(
+        size(640, 480), 2.0, size(640, 480), dpi(144, 144), 1.0, false, true);
+    QUnit.deepEqual(pluginSize, size(640, 480));
+
+    pluginSize = remoting.ClientSession.choosePluginSize(
+        size(640, 480), 2.0, size(1024, 768), dpi(144, 144), 1.0, false, true);
+    QUnit.deepEqual(pluginSize, size(512, 384));
+
+    pluginSize = remoting.ClientSession.choosePluginSize(
+        size(1024, 768), 2.0, size(640, 480), dpi(144, 144), 1.0, false, true);
+    QUnit.deepEqual(pluginSize, size(960, 720));
+
+    // Shrink-to-fit disabled.
+    pluginSize = remoting.ClientSession.choosePluginSize(
+        size(640, 480), 1.0, size(640, 480), dpi(96, 96), 1.0, false, false);
+    QUnit.deepEqual(pluginSize, size(640, 480));
+
+    pluginSize = remoting.ClientSession.choosePluginSize(
+        size(1280, 1024), 1.0, size(640, 480), dpi(96, 96), 1.0, false, false);
+    QUnit.deepEqual(pluginSize, size(1280, 960));
+
+    pluginSize = remoting.ClientSession.choosePluginSize(
+        size(640, 480), 1.0, size(1280, 1024), dpi(96, 96), 1.0, false, false);
+    QUnit.deepEqual(pluginSize, size(1280, 1024));
+
+    pluginSize = remoting.ClientSession.choosePluginSize(
+        size(640, 480), 2.0, size(1280, 1024), dpi(96, 96), 1.0, false, false);
+    QUnit.deepEqual(pluginSize, size(1280, 1024));
+
+     // Full-screen multi-monitor handling.
+});
+
+})();