android.graphics.Camera实现图像的旋转、缩放，配合Matrix实现图像的倾斜

 package lab.sodino.camera;
     
    import android.app.Activity;
    import android.graphics.Bitmap;
    import android.graphics.Camera;
    import android.graphics.Matrix;
    import android.graphics.drawable.BitmapDrawable;
    import android.os.Bundle;
    import android.util.Log;
    import android.widget.ImageView;
    import android.widget.SeekBar;
    import android.widget.SeekBar.OnSeekBarChangeListener;
    import android.widget.TextView;
     
    /**
     * Camera与Matrix的比较：<br/>
     * Camera的rotate()相关方法是指定某一维度上旋转指定的角度。<br/>
     * Matrix的rotate()相关方法实现的效果是顺时针旋转指定的角度；与Camera指定Z轴旋转效果相同，但方向相反。<br/>
     * 
     * Camera的translate()方法根据某一维度上视点的位移实现图像的缩放，与Matrix的scale()相关方法作用效果相似，
     * 只是Matrix的scale()相关方法是直接指定缩放比例。<br/>
     * 
     * Camera不支持倾斜操作，Matrix可以直接实现倾斜操作。<br/>
     * 
     * @author Sodino E-mail:sodinoopen@hotmail.com
     * @version Time：2011-9-26 下午04:17:49
     */
    public class ActCamera extends Activity implements OnSeekBarChangeListener {
        private Camera camera;
        // views
        private SeekBar seekbarXRotate;
        private SeekBar seekbarYRotate;
        private SeekBar seekbarZRotate;
        private TextView txtXRotate;
        private TextView txtYRotate;
        private TextView txtZRotate;
        private SeekBar seekbarXSkew;
        private SeekBar seekbarYSkew;
        private SeekBar seekbarZTranslate;
        private TextView txtXTranslate;
        private TextView txtYTranslate;
        private TextView txtZTranslate;
        private ImageView imgResult;
        // integer params
        private int rotateX, rotateY, rotateZ;
        private float skewX, skewY;
        private int translateZ;
     
        /** Called when the activity is first created. */
        @Override
        public void onCreate(Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);
            setContentView(R.layout.main);
            // camera
            camera = new Camera();
            // initViews
            // rotate
            seekbarXRotate = (SeekBar) findViewById(R.id.seekbarXRotate);
            seekbarXRotate.setOnSeekBarChangeListener(this);
            seekbarYRotate = (SeekBar) findViewById(R.id.seekbarYRotate);
            seekbarYRotate.setOnSeekBarChangeListener(this);
            seekbarZRotate = (SeekBar) findViewById(R.id.seekbarZRotate);
            seekbarZRotate.setOnSeekBarChangeListener(this);
            txtXRotate = (TextView) findViewById(R.id.txtXRotate);
            txtYRotate = (TextView) findViewById(R.id.txtYRotate);
            txtZRotate = (TextView) findViewById(R.id.txtZRotate);
            // translate
            seekbarXSkew = (SeekBar) findViewById(R.id.seekbarXSkew);
            seekbarXSkew.setOnSeekBarChangeListener(this);
            seekbarYSkew = (SeekBar) findViewById(R.id.seekbarYSkew);
            seekbarYSkew.setOnSeekBarChangeListener(this);
            seekbarZTranslate = (SeekBar) findViewById(R.id.seekbarZTranslate);
            seekbarZTranslate.setOnSeekBarChangeListener(this);
            txtXTranslate = (TextView) findViewById(R.id.txtXSkew);
            txtYTranslate = (TextView) findViewById(R.id.txtYSkew);
            txtZTranslate = (TextView) findViewById(R.id.txtZTranslate);
            imgResult = (ImageView) findViewById(R.id.imgResult);
            // refresh
            refreshImage();
        }
     
        private void refreshImage() {
            // 获取待处理的图像
            BitmapDrawable tmpBitDra = (BitmapDrawable) getResources().getDrawable(R.drawable.honeycomb);
            Bitmap tmpBit = tmpBitDra.getBitmap();
            // 开始处理图像
            // 1.获取处理矩阵
            // 记录一下初始状态。save()和restore()可以将图像过渡得柔和一些。
            // Each save should be balanced with a call to restore().
            camera.save();
            Matrix matrix = new Matrix();
            // rotate
            camera.rotateX(rotateX);
            camera.rotateY(rotateY);
            camera.rotateZ(rotateZ);
            // translate
            camera.translate(0, 0, translateZ);
            camera.getMatrix(matrix);
            // 恢复到之前的初始状态。
            camera.restore();
            // 设置图像处理的中心点
            matrix.preTranslate(tmpBit.getWidth() >> 1, tmpBit.getHeight() >> 1);
            matrix.preSkew(skewX, skewY);
            // matrix.postSkew(skewX, skewY);
            // 直接setSkew()，则前面处理的rotate()、translate()等等都将无效。
            // matrix.setSkew(skewX, skewY);
            // 2.通过矩阵生成新图像(或直接作用于Canvas)
            Log.d(“ANDROID_LAB”, “width=” + tmpBit.getWidth() + “ height=” + tmpBit.getHeight());
            Bitmap newBit = null;
            try {
                // 经过矩阵转换后的图像宽高有可能不大于0，此时会抛出IllegalArgumentException
                newBit = Bitmap.createBitmap(tmpBit, 0, 0, tmpBit.getWidth(), tmpBit.getHeight(), matrix, true);
            } catch (IllegalArgumentException iae) {
                iae.printStackTrace();
            }
            if (newBit != null) {
                imgResult.setImageBitmap(newBit);
            }
        }
     
        @Override
        public void onProgressChanged(SeekBar seekBar, int progress, boolean fromUser) {
            if (seekBar == seekbarXRotate) {
                txtXRotate.setText(progress + “゜”);
                rotateX = progress;
            } else if (seekBar == seekbarYRotate) {
                txtYRotate.setText(progress + “゜”);
                rotateY = progress;
            } else if (seekBar == seekbarZRotate) {
                txtZRotate.setText(progress + “゜”);
                rotateZ = progress;
            } else if (seekBar == seekbarXSkew) {
                skewX = (progress - 100) * 1.0f / 100;
                txtXTranslate.setText(String.valueOf(skewX));
            } else if (seekBar == seekbarYSkew) {
                skewY = (progress - 100) * 1.0f / 100;
                txtYTranslate.setText(String.valueOf(skewY));
            } else if (seekBar == seekbarZTranslate) {
                translateZ = progress - 100;
                txtZTranslate.setText(String.valueOf(translateZ));
            }
            refreshImage();
        }
     
        @Override
        public void onStartTrackingTouch(SeekBar seekBar) {
     
        }
     
        @Override
        public void onStopTrackingTouch(SeekBar seekBar) {
     
        }
    }