Index: chrome/android/java/src/org/chromium/chrome/browser/widget/ProgressAnimationFastStart.java |
diff --git a/chrome/android/java/src/org/chromium/chrome/browser/widget/ProgressAnimationFastStart.java b/chrome/android/java/src/org/chromium/chrome/browser/widget/ProgressAnimationFastStart.java |
new file mode 100644 |
index 0000000000000000000000000000000000000000..7e04161a17c8bec260e1bd6f5d5429053ca60545 |
--- /dev/null |
+++ b/chrome/android/java/src/org/chromium/chrome/browser/widget/ProgressAnimationFastStart.java |
@@ -0,0 +1,40 @@ |
+// 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. |
+ |
+package org.chromium.chrome.browser.widget; |
+ |
+/** |
+ * Progress bar animation logic that starts fast at the beginning and slows down approaching to the |
+ * end. |
+ */ |
+class ProgressAnimationFastStart implements ToolbarProgressBar.AnimationLogic { |
+ // The speed unit is progress per second where 0 <= progress <= 1. |
+ private static final float NORMALIZED_INITIAL_SPEED = 1.5f; |
+ private static final float FINISHING_SPEED = 2.0f; |
+ |
+ private float mProgress; |
+ |
+ @Override |
+ public void reset() { |
+ mProgress = 0.0f; |
+ } |
+ |
+ @Override |
+ public float updateProgress(float targetProgress, float frameTimeSec, int resolution) { |
+ assert mProgress <= targetProgress; |
+ |
+ float progressChange; |
+ if (targetProgress == 1.0f) { |
+ progressChange = FINISHING_SPEED * frameTimeSec; |
+ } else { |
+ progressChange = (targetProgress - mProgress) |
+ * (1.0f - (float) Math.exp(-frameTimeSec * NORMALIZED_INITIAL_SPEED)); |
+ } |
+ |
+ mProgress = Math.min(mProgress + progressChange, targetProgress); |
+ if (targetProgress - mProgress < 0.5f / resolution) mProgress = targetProgress; |
+ |
+ return mProgress; |
+ } |
+} |