michael@0: /*
michael@0:  * Copyright (C) 2007 The Android Open Source Project
michael@0:  *
michael@0:  * Licensed under the Apache License, Version 2.0 (the "License");
michael@0:  * you may not use this file except in compliance with the License.
michael@0:  * You may obtain a copy of the License at
michael@0:  *
michael@0:  *      http://www.apache.org/licenses/LICENSE-2.0
michael@0:  *
michael@0:  * Unless required by applicable law or agreed to in writing, software
michael@0:  * distributed under the License is distributed on an "AS IS" BASIS,
michael@0:  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
michael@0:  * See the License for the specific language governing permissions and
michael@0:  * limitations under the License.
michael@0:  */
michael@0: 
michael@0: package org.mozilla.gecko.animation;
michael@0: 
michael@0: import android.view.animation.Animation;
michael@0: import android.view.animation.Transformation;
michael@0: 
michael@0: import android.graphics.Camera;
michael@0: import android.graphics.Matrix;
michael@0: 
michael@0: /**
michael@0:  * An animation that rotates the view on the Y axis between two specified angles.
michael@0:  * This animation also adds a translation on the Z axis (depth) to improve the effect.
michael@0:  */
michael@0: public class Rotate3DAnimation extends Animation {
michael@0:     private final float mFromDegrees;
michael@0:     private final float mToDegrees;
michael@0: 
michael@0:     private final float mCenterX;
michael@0:     private final float mCenterY;
michael@0: 
michael@0:     private final float mDepthZ;
michael@0:     private final boolean mReverse;
michael@0:     private Camera mCamera;
michael@0: 
michael@0:     private int mWidth = 1;
michael@0:     private int mHeight = 1;
michael@0: 
michael@0:     /**
michael@0:      * Creates a new 3D rotation on the Y axis. The rotation is defined by its
michael@0:      * start angle and its end angle. Both angles are in degrees. The rotation
michael@0:      * is performed around a center point on the 2D space, definied by a pair
michael@0:      * of X and Y coordinates, called centerX and centerY. When the animation
michael@0:      * starts, a translation on the Z axis (depth) is performed. The length
michael@0:      * of the translation can be specified, as well as whether the translation
michael@0:      * should be reversed in time.
michael@0:      *
michael@0:      * @param fromDegrees the start angle of the 3D rotation
michael@0:      * @param toDegrees the end angle of the 3D rotation
michael@0:      * @param centerX the X center of the 3D rotation
michael@0:      * @param centerY the Y center of the 3D rotation
michael@0:      * @param reverse true if the translation should be reversed, false otherwise
michael@0:      */
michael@0:     public Rotate3DAnimation(float fromDegrees, float toDegrees,
michael@0:             float centerX, float centerY, float depthZ, boolean reverse) {
michael@0:         mFromDegrees = fromDegrees;
michael@0:         mToDegrees = toDegrees;
michael@0:         mCenterX = centerX;
michael@0:         mCenterY = centerY;
michael@0:         mDepthZ = depthZ;
michael@0:         mReverse = reverse;
michael@0:     }
michael@0: 
michael@0:    @Override
michael@0:     public void initialize(int width, int height, int parentWidth, int parentHeight) {
michael@0:         super.initialize(width, height, parentWidth, parentHeight);
michael@0:         mCamera = new Camera();
michael@0:         mWidth = width;
michael@0:         mHeight = height;
michael@0:     }
michael@0: 
michael@0:     @Override
michael@0:     protected void applyTransformation(float interpolatedTime, Transformation t) {
michael@0:         final float fromDegrees = mFromDegrees;
michael@0:         float degrees = fromDegrees + ((mToDegrees - fromDegrees) * interpolatedTime);
michael@0: 
michael@0:         final Camera camera = mCamera;
michael@0:         final Matrix matrix = t.getMatrix();
michael@0: 
michael@0:         camera.save();
michael@0:         if (mReverse) {
michael@0:             camera.translate(0.0f, 0.0f, mDepthZ * interpolatedTime);
michael@0:         } else {
michael@0:             camera.translate(0.0f, 0.0f, mDepthZ * (1.0f - interpolatedTime));
michael@0:         }
michael@0:         camera.rotateX(degrees);
michael@0:         camera.getMatrix(matrix);
michael@0:         camera.restore();
michael@0: 
michael@0:         matrix.preTranslate(-mCenterX * mWidth, -mCenterY * mHeight);
michael@0:         matrix.postTranslate(mCenterX * mWidth, mCenterY * mHeight);
michael@0:     }
michael@0: }