Add new volume conversion API.

All Qt Multimedia volume APIs expect a linear volume factor. However,
UI volume controls should typically use a logarithmic or cubic scale
to match how the human ear perceives loudness.

The new helper function (C++ and QML) provides a way to do the
conversion from one scale to another.

Change-Id: If7795426b728ab0e8fd6635988dbc9be795e3e5e
Reviewed-by: Christian Stromme <christian.stromme@qt.io>

1 files changed, 67 insertions, 0 deletions

diff --git a/tests/auto/unit/qdeclarativemultimediaglobal/tst_qdeclarativemultimediaglobal.qml b/tests/auto/unit/qdeclarativemultimediaglobal/tst_qdeclarativemultimediaglobal.qml
index bce0ca791..22f4bf604 100644
--- a/tests/auto/unit/qdeclarativemultimediaglobal/tst_qdeclarativemultimediaglobal.qml
+++ b/tests/auto/unit/qdeclarativemultimediaglobal/tst_qdeclarativemultimediaglobal.qml
@@ -63,4 +63,71 @@ TestCase {
         compare(camera.orientation, 0, "orientation");
     }
 
+    function test_convertVolume_data() {
+        return [
+            { tag: "-1.0 from linear to linear", input: -1, from: QtMultimedia.LinearVolumeScale, to: QtMultimedia.LinearVolumeScale, expectedOutput: 0 },
+            { tag: "0.0 from linear to linear", input: 0, from: QtMultimedia.LinearVolumeScale, to: QtMultimedia.LinearVolumeScale, expectedOutput: 0 },
+            { tag: "0.5 from linear to linear", input: 0.5, from: QtMultimedia.LinearVolumeScale, to: QtMultimedia.LinearVolumeScale, expectedOutput: 0.5 },
+            { tag: "1.0 from linear to linear", input: 1.0, from: QtMultimedia.LinearVolumeScale, to: QtMultimedia.LinearVolumeScale, expectedOutput: 1.0 },
+
+            { tag: "-1.0 from linear to cubic", input: -1, from: QtMultimedia.LinearVolumeScale, to: QtMultimedia.CubicVolumeScale, expectedOutput: 0 },
+            { tag: "0.0 from linear to cubic", input: 0, from: QtMultimedia.LinearVolumeScale, to: QtMultimedia.CubicVolumeScale, expectedOutput: 0 },
+            { tag: "0.33 from linear to cubic", input: 0.33, from: QtMultimedia.LinearVolumeScale, to: QtMultimedia.CubicVolumeScale, expectedOutput: 0.69 },
+            { tag: "0.5 from linear to cubic", input: 0.5, from: QtMultimedia.LinearVolumeScale, to: QtMultimedia.CubicVolumeScale, expectedOutput: 0.79 },
+            { tag: "0.72 from linear to cubic", input: 0.72, from: QtMultimedia.LinearVolumeScale, to: QtMultimedia.CubicVolumeScale, expectedOutput: 0.89 },
+            { tag: "1.0 from linear to cubic", input: 1.0, from: QtMultimedia.LinearVolumeScale, to: QtMultimedia.CubicVolumeScale, expectedOutput: 1.0 },
+
+            { tag: "-1.0 from linear to decibel", input: -1, from: QtMultimedia.LinearVolumeScale, to: QtMultimedia.DecibelVolumeScale, expectedOutput: -200 },
+            { tag: "0.0 from linear to decibel", input: 0, from: QtMultimedia.LinearVolumeScale, to: QtMultimedia.DecibelVolumeScale, expectedOutput: -200 },
+            { tag: "0.33 from linear to decibel", input: 0.33, from: QtMultimedia.LinearVolumeScale, to: QtMultimedia.DecibelVolumeScale, expectedOutput: -9.63 },
+            { tag: "0.5 from linear to decibel", input: 0.5, from: QtMultimedia.LinearVolumeScale, to: QtMultimedia.DecibelVolumeScale, expectedOutput: -6.02 },
+            { tag: "0.72 from linear to decibel", input: 0.72, from: QtMultimedia.LinearVolumeScale, to: QtMultimedia.DecibelVolumeScale, expectedOutput: -2.85 },
+            { tag: "1.0 from linear to decibel", input: 1.0, from: QtMultimedia.LinearVolumeScale, to: QtMultimedia.DecibelVolumeScale, expectedOutput: 0 },
+
+            { tag: "-1.0 from cubic to linear", input: -1, from: QtMultimedia.CubicVolumeScale, to: QtMultimedia.LinearVolumeScale, expectedOutput: 0 },
+            { tag: "0.0 from cubic to linear", input: 0, from: QtMultimedia.CubicVolumeScale, to: QtMultimedia.LinearVolumeScale, expectedOutput: 0 },
+            { tag: "0.33 from cubic to linear", input: 0.33, from: QtMultimedia.CubicVolumeScale, to: QtMultimedia.LinearVolumeScale, expectedOutput: 0.04 },
+            { tag: "0.5 from cubic to linear", input: 0.5, from: QtMultimedia.CubicVolumeScale, to: QtMultimedia.LinearVolumeScale, expectedOutput: 0.13 },
+            { tag: "0.72 from cubic to linear", input: 0.72, from: QtMultimedia.CubicVolumeScale, to: QtMultimedia.LinearVolumeScale, expectedOutput: 0.37 },
+            { tag: "1.0 from cubic to linear", input: 1.0, from: QtMultimedia.CubicVolumeScale, to: QtMultimedia.LinearVolumeScale, expectedOutput: 1 },
+
+            { tag: "-1.0 from cubic to cubic", input: -1, from: QtMultimedia.CubicVolumeScale, to: QtMultimedia.CubicVolumeScale, expectedOutput: 0 },
+            { tag: "0.0 from cubic to cubic", input: 0, from: QtMultimedia.CubicVolumeScale, to: QtMultimedia.CubicVolumeScale, expectedOutput: 0 },
+            { tag: "0.5 from cubic to cubic", input: 0.5, from: QtMultimedia.CubicVolumeScale, to: QtMultimedia.CubicVolumeScale, expectedOutput: 0.5 },
+            { tag: "1.0 from cubic to cubic", input: 1.0, from: QtMultimedia.CubicVolumeScale, to: QtMultimedia.CubicVolumeScale, expectedOutput: 1.0 },
+
+            { tag: "-1.0 from cubic to decibel", input: -1, from: QtMultimedia.CubicVolumeScale, to: QtMultimedia.DecibelVolumeScale, expectedOutput: -200 },
+            { tag: "0.0 from cubic to decibel", input: 0, from: QtMultimedia.CubicVolumeScale, to: QtMultimedia.DecibelVolumeScale, expectedOutput: -200 },
+            { tag: "0.33 from cubic to decibel", input: 0.33, from: QtMultimedia.CubicVolumeScale, to: QtMultimedia.DecibelVolumeScale, expectedOutput: -28.89 },
+            { tag: "0.5 from cubic to decibel", input: 0.5, from: QtMultimedia.CubicVolumeScale, to: QtMultimedia.DecibelVolumeScale, expectedOutput: -18.06 },
+            { tag: "0.72 from cubic to decibel", input: 0.72, from: QtMultimedia.CubicVolumeScale, to: QtMultimedia.DecibelVolumeScale, expectedOutput: -8.56 },
+            { tag: "1.0 from cubic to decibel", input: 1.0, from: QtMultimedia.CubicVolumeScale, to: QtMultimedia.DecibelVolumeScale, expectedOutput: 0 },
+
+            { tag: "-1000 from decibel to linear", input: -1000, from: QtMultimedia.DecibelVolumeScale, to: QtMultimedia.LinearVolumeScale, expectedOutput: 0 },
+            { tag: "-200 from decibel to linear", input: -200, from: QtMultimedia.DecibelVolumeScale, to: QtMultimedia.LinearVolumeScale, expectedOutput: 0 },
+            { tag: "-40 from decibel to linear", input: -40, from: QtMultimedia.DecibelVolumeScale, to: QtMultimedia.LinearVolumeScale, expectedOutput: 0.01 },
+            { tag: "-10 from decibel to linear", input: -10, from: QtMultimedia.DecibelVolumeScale, to: QtMultimedia.LinearVolumeScale, expectedOutput: 0.32 },
+            { tag: "-5 from decibel to linear", input: -5, from: QtMultimedia.DecibelVolumeScale, to: QtMultimedia.LinearVolumeScale, expectedOutput: 0.56 },
+            { tag: "0 from decibel to linear", input: 0, from: QtMultimedia.DecibelVolumeScale, to: QtMultimedia.LinearVolumeScale, expectedOutput: 1 },
+
+            { tag: "-1000 from decibel to cubic", input: -1000, from: QtMultimedia.DecibelVolumeScale, to: QtMultimedia.CubicVolumeScale, expectedOutput: 0 },
+            { tag: "-200 from decibel to cubic", input: -200, from: QtMultimedia.DecibelVolumeScale, to: QtMultimedia.CubicVolumeScale, expectedOutput: 0 },
+            { tag: "-40 from decibel to cubic", input: -40, from: QtMultimedia.DecibelVolumeScale, to: QtMultimedia.CubicVolumeScale, expectedOutput: 0.22 },
+            { tag: "-10 from decibel to cubic", input: -10, from: QtMultimedia.DecibelVolumeScale, to: QtMultimedia.CubicVolumeScale, expectedOutput: 0.68 },
+            { tag: "-5 from decibel to cubic", input: -5, from: QtMultimedia.DecibelVolumeScale, to: QtMultimedia.CubicVolumeScale, expectedOutput: 0.83 },
+            { tag: "0 from decibel to cubic", input: 0, from: QtMultimedia.DecibelVolumeScale, to: QtMultimedia.CubicVolumeScale, expectedOutput: 1 },
+
+            { tag: "-1000 from decibel to decibel", input: -1000, from: QtMultimedia.DecibelVolumeScale, to: QtMultimedia.DecibelVolumeScale, expectedOutput: -1000 },
+            { tag: "-200 from decibel to decibel", input: -200, from: QtMultimedia.DecibelVolumeScale, to: QtMultimedia.DecibelVolumeScale, expectedOutput: -200 },
+            { tag: "-30 from decibel to decibel", input: -30, from: QtMultimedia.DecibelVolumeScale, to: QtMultimedia.DecibelVolumeScale, expectedOutput: -30 },
+            { tag: "0 from decibel to decibel", input: 0, from: QtMultimedia.DecibelVolumeScale, to: QtMultimedia.DecibelVolumeScale, expectedOutput: 0 },
+        ]
+    }
+
+    function test_convertVolume(data) {
+        fuzzyCompare(QtMultimedia.convertVolume(data.input, data.from, data.to),
+                     data.expectedOutput,
+                     0.01);
+    }
+
 }