Andengine之点击时实现图片的缩放和扩大

１.实现图片的缩放要使用的Cream对象是SmoothCamera类型的。也就是说Camera camera = newSmoothCamera(0, 0, CAMERA_WIDTH, CAMERA_HEIGHT, 0, 0, 0.1f)

２.图片放在文件夹下(raw),图片的类型可以是pvr,bin扩展名。在openGL中以上图片所占用的内存资源比较少。

在Andengine中有三个demo,下面直接来代码，

一：

package org.andengine.examples;
import java.io.IOException;import java.io.InputStream;
import org.andengine.engine.camera.Camera;import org.andengine.engine.camera.SmoothCamera;import org.andengine.engine.options.EngineOptions;import org.andengine.engine.options.ScreenOrientation;import org.andengine.engine.options.resolutionpolicy.RatioResolutionPolicy;import org.andengine.entity.scene.IOnSceneTouchListener;import org.andengine.entity.scene.Scene;import org.andengine.entity.scene.background.Background;import org.andengine.entity.sprite.Sprite;import org.andengine.entity.util.FPSLogger;import org.andengine.examples.adt.ZoomState;import org.andengine.input.touch.TouchEvent;import org.andengine.opengl.texture.ITexture;import org.andengine.opengl.texture.TextureOptions;import org.andengine.opengl.texture.compressed.pvr.PVRGZTexture;import org.andengine.opengl.texture.compressed.pvr.PVRTexture.PVRTextureFormat;import org.andengine.opengl.texture.region.ITextureRegion;import org.andengine.opengl.texture.region.TextureRegionFactory;import org.andengine.ui.activity.SimpleBaseGameActivity;import org.andengine.util.debug.Debug;
import android.widget.Toast;
/** * (c) 2010 Nicolas Gramlich * (c) 2011 Zynga * * @author Nicolas Gramlich * @since 13:54:51 - 13.07.2011 */public class PVRGZTextureExample extends SimpleBaseGameActivity { // =========================================================== // Constants // ===========================================================
 private static final int CAMERA_WIDTH = 720; private static final int CAMERA_HEIGHT = 480;
 // =========================================================== // Fields // ===========================================================
 private ITexture mTexture; private ITextureRegion mHouseTextureRegion;
 private ZoomState mZoomState = ZoomState.NONE;
 // =========================================================== // Constructors // ===========================================================
 // =========================================================== // Getter & Setter // ===========================================================
 // =========================================================== // Methods for/from SuperClass/Interfaces // ===========================================================
 @Override public EngineOptions onCreateEngineOptions() {  Toast.makeText(this, "Click the top half of the screen to zoom in or the bottom half to zoom out!", Toast.LENGTH_LONG);
  final Camera camera = new SmoothCamera(0, 0, CAMERA_WIDTH, CAMERA_HEIGHT, 0, 0, 0.1f) {   @Override
//根据mZoomState的状态值来决定是放大还是缩小，该mZoomState的值由下面的代码给以赋值   public void onUpdate(final float pSecondsElapsed) {    switch (PVRGZTextureExample.this.mZoomState) {     case IN:      this.setZoomFactor(this.getZoomFactor() + 0.1f * pSecondsElapsed);      break;     case OUT:      this.setZoomFactor(this.getZoomFactor() - 0.1f * pSecondsElapsed);      break;    }    super.onUpdate(pSecondsElapsed);   }  };
  return new EngineOptions(true, ScreenOrientation.LANDSCAPE_FIXED, new RatioResolutionPolicy(CAMERA_WIDTH, CAMERA_HEIGHT), camera); }
 @Override public void onCreateResources() {  try {   this.mTexture = new PVRGZTexture(this.getTextureManager(), PVRTextureFormat.RGBA_8888, TextureOptions.BILINEAR) {    @Override    protected InputStream onGetInputStream() throws IOException {
//读取图片文件的数据     return PVRGZTextureExample.this.getResources().openRawResource(R.raw.house_pvrgz_argb_8888);    }   };   this.mTexture.load();
//从已有的Texture中抽取图片
   this.mHouseTextureRegion = TextureRegionFactory.extractFromTexture(this.mTexture, 0, 0, 512, 512);  } catch (final Throwable e) {   Debug.e(e);  } }
 @Override public Scene onCreateScene() {  this.mEngine.registerUpdateHandler(new FPSLogger());
  final Scene scene = new Scene();  scene.setBackground(new Background(0.09804f, 0.6274f, 0.8784f));
  final float centerX = (CAMERA_WIDTH - this.mHouseTextureRegion.getWidth()) / 2;  final float centerY = (CAMERA_HEIGHT - this.mHouseTextureRegion.getHeight()) / 2;
  scene.attachChild(new Sprite(centerX, centerY, this.mHouseTextureRegion, this.getVertexBufferObjectManager()));
//触摸屏幕时，根据触摸的位置来决定是mZoomState的取值
  scene.setOnSceneTouchListener(new IOnSceneTouchListener() {   @Override   public boolean onSceneTouchEvent(final Scene pScene, final TouchEvent pSceneTouchEvent) {    if (pSceneTouchEvent.isActionDown() || pSceneTouchEvent.isActionMove()) {     if(pSceneTouchEvent.getY() < CAMERA_HEIGHT / 2) {      PVRGZTextureExample.this.mZoomState = ZoomState.IN;     } else {      PVRGZTextureExample.this.mZoomState = ZoomState.OUT;     }    } else {     PVRGZTextureExample.this.mZoomState = ZoomState.NONE;    }    return true;   }  });
  return scene; }
 // =========================================================== // Methods // ===========================================================
 // =========================================================== // Inner and Anonymous Classes // ===========================================================}