[Android]android.graphics.Camera实现图像的旋转缩放，配合Matrix实现图像的倾斜

Posted 2023-01-13 Sodino

android.graphics.Camera可以对图像执行一些比较复杂的操作，诸如旋转与绽放，与Matrix可实现图像的倾斜。

个人总结Camera与Matrix的一些区别如下：

1. Camera的rotate()相关方法是指定某一维度上旋转指定的角度。
2. 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。
3. 
   
4. 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。
5. 
   
6. Camera不支持倾斜操作，Matrix可以直接实现倾斜操作。

本文为练习Camera的使用。实现效果图如下：

Camera的处理结果只是生成一个Matrix，该Matrix用于Bitmap或Canvas绘制Bitmap时才能产生旋转或缩放的效果。

代码如下：

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:[e-mail]
 * @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) 

	

本文内容归CSDN博客博主Sodino 所有

转载请注明出处:http://blog.csdn.net/sodino/article/details/6823315