CoverFlow extends Gallery : Gallery « UI « Android






CoverFlow extends Gallery

   
/*******************************************************************************
 * Copyright (c) 2011 Benjamin Gmeiner.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the GNU Public License v2.0
 * which accompanies this distribution, and is available at
 * http://www.gnu.org/licenses/old-licenses/gpl-2.0.html
 * 
 * Contributors:
 *     Benjamin Gmeiner - Project Owner
 ******************************************************************************/
//package com.mediaportal.ampdroid.lists;

/*
 * Copyright (C) 2010 Neil Davies
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 * 
 * This code is base on the Android Gallery widget and was Created 
 * by Neil Davies neild001 'at' gmail dot com to be a Coverflow widget
 * 
 * @author Neil Davies
 */
import android.content.Context;
import android.graphics.Camera;
import android.graphics.Matrix;
import android.util.AttributeSet;
import android.view.View;
import android.view.animation.Transformation;
import android.widget.Gallery;
import android.widget.ImageView;

public class CoverFlow extends Gallery {

  /**
   * Graphics Camera used for transforming the matrix of ImageViews
   */
  private Camera mCamera = new Camera();

  /**
   * The maximum angle the Child ImageView will be rotated by
   */
  private int mMaxRotationAngle = 70;

  /**
   * The maximum zoom on the centre Child
   */
  private int mMaxZoom = -180;

  /**
   * The Centre of the Coverflow
   */
  private int mCoveflowCenter;

  public CoverFlow(Context context) {
    super(context);
    this.setStaticTransformationsEnabled(true);
  }

  public CoverFlow(Context context, AttributeSet attrs) {
    super(context, attrs);
    this.setStaticTransformationsEnabled(true);
  }

  public CoverFlow(Context context, AttributeSet attrs, int defStyle) {
    super(context, attrs, defStyle);
    this.setStaticTransformationsEnabled(true);
  }

  /**
   * Get the max rotational angle of the image
   * 
   * @return the mMaxRotationAngle
   */
  public int getMaxRotationAngle() {
    return mMaxRotationAngle;
  }

  /**
   * Set the max rotational angle of each image
   * 
   * @param maxRotationAngle
   *            the mMaxRotationAngle to set
   */
  public void setMaxRotationAngle(int maxRotationAngle) {
    mMaxRotationAngle = maxRotationAngle;
  }

  /**
   * Get the Max zoom of the centre image
   * 
   * @return the mMaxZoom
   */
  public int getMaxZoom() {
    return mMaxZoom;
  }

  /**
   * Set the max zoom of the centre image
   * 
   * @param maxZoom
   *            the mMaxZoom to set
   */
  public void setMaxZoom(int maxZoom) {
    mMaxZoom = maxZoom;
  }

  /**
   * Get the Centre of the Coverflow
   * 
   * @return The centre of this Coverflow.
   */
  private int getCenterOfCoverflow() {
    return (getWidth() - getPaddingLeft() - getPaddingRight()) / 2
        + getPaddingLeft();
  }

  /**
   * Get the Centre of the View
   * 
   * @return The centre of the given view.
   */
  private static int getCenterOfView(View view) {
    return view.getLeft() + view.getWidth() / 2;
  }

  /**
   * {@inheritDoc}
   * 
   * @see #setStaticTransformationsEnabled(boolean)
   */
  protected boolean getChildStaticTransformation(View child, Transformation t) {

    final int childCenter = getCenterOfView(child);
    final int childWidth = child.getWidth();
    int rotationAngle = 0;

    t.clear();
    t.setTransformationType(Transformation.TYPE_MATRIX);

    if (childCenter == mCoveflowCenter) {
      transformImageBitmap((ImageView) child, t, 0);
    } else {
      rotationAngle = (int) (((float) (mCoveflowCenter - childCenter) / childWidth) * mMaxRotationAngle);
      if (Math.abs(rotationAngle) > mMaxRotationAngle) {
        rotationAngle = (rotationAngle < 0) ? -mMaxRotationAngle
            : mMaxRotationAngle;
      }
      transformImageBitmap((ImageView) child, t, rotationAngle);
    }

    return true;
  }

  /**
   * This is called during layout when the size of this view has changed. If
   * you were just added to the view hierarchy, you're called with the old
   * values of 0.
   * 
   * @param w
   *            Current width of this view.
   * @param h
   *            Current height of this view.
   * @param oldw
   *            Old width of this view.
   * @param oldh
   *            Old height of this view.
   */
  protected void onSizeChanged(int w, int h, int oldw, int oldh) {
    mCoveflowCenter = getCenterOfCoverflow();
    super.onSizeChanged(w, h, oldw, oldh);
  }

  /**
   * Transform the Image Bitmap by the Angle passed
   * 
   * @param imageView
   *            ImageView the ImageView whose bitmap we want to rotate
   * @param t
   *            transformation
   * @param rotationAngle
   *            the Angle by which to rotate the Bitmap
   */
  private void transformImageBitmap(ImageView child, Transformation t,
      int rotationAngle) {
    mCamera.save();
    final Matrix imageMatrix = t.getMatrix();
    ;
    final int imageHeight = child.getLayoutParams().height;
    ;
    final int imageWidth = child.getLayoutParams().width;
    final int rotation = Math.abs(rotationAngle);

    mCamera.translate(0.0f, 0.0f, 100.0f);

    // As the angle of the view gets less, zoom in
    if (rotation < mMaxRotationAngle) {
      float zoomAmount = (float) (mMaxZoom + (rotation * 1.5));
      mCamera.translate(0.0f, 0.0f, zoomAmount);
    }

    mCamera.rotateY(rotationAngle);
    mCamera.getMatrix(imageMatrix);
    imageMatrix.preTranslate(-(imageWidth / 2), -(imageHeight / 2));
    imageMatrix.postTranslate((imageWidth / 2), (imageHeight / 2));
    mCamera.restore();
  }
}

   
    
    
  








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