android图片处理

通过内置的图片程序来选择图片

Intent intent = new Intent(Intent.ACTION_PICK,

android.provider.MediaStore.Images.Media.EXTERNAL_CONTENT_URI);

       startActivityForResult(intent, 0);

 

 

 

创建一个空的Bitmap，然后把一个已经存在的Bitmap放进去

/*

* 将原来的bitmap画到新的易变的alteredBitmap对象中

*/

Bitmap alteredBitmap = Bitmap.createBitmap(bmp.getWidth(), bmp.getHeight(), bmp.getConfig());

Canvas canvas = new Canvas(alteredBitmap);

Paint paint = new Paint();

canvas.drawBitmap(bmp, 0, 0, paint);

 

图片缩放和翻转

Matrix matrix = new Matrix();

//matrix.setRotate(15);

matrix.setRotate(15, bmp.getWidth()/2, bmp.getHeight()/2); //从图片中心点开始旋转

canvas.drawBitmap(bmp, matrix, paint);

 

            

matrix.setScale(1.5f, 1);

第一个参数是x轴上的缩放，第二个参数是y轴上的缩放

 

 
 

Translate：图片在x轴或y轴移动

setTranslate方法接收两个参数，分别是x、y轴上的移动

matrix.setTranslate(15, 10);

 

              

 

以上的方法都有pre和post版本，可以使我们在一次时间序列中执行多于一次的变换

matrix.setScale(1.5f, 1.5f);

matrix.postRotate(15, bmp.getWidth()/2, bmp.getHeight()/2);

 

实现镜面翻转效果

 matrix.setScale(-1, 1);

 matrix.postTranslate(bmp.getWidth(), 0);

matrix.setScale(1, -1);

matrix.postTranslate(0, bmp.getHeight());

 

 

//It is initialized with the same density as the original bitmap.

//变换后的图片与原图片同样大小

Matrix matrix = new Matrix();

matrix.setRotate(15,bmp.getWidth()/2,bmp.getHeight()/2);

Bitmap alteredBitmap = Bitmap.createBitmap(bmp, 0, 0, bmp.getWidth(), bmp.getHeight(), matrix, false);

alteredImageView.setImageBitmap(alteredBitmap);

 

package com.liang.imageTest;

import java.io.FileNotFoundException;

import android.app.Activity;
import android.content.Intent;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.Canvas;
import android.graphics.Matrix;
import android.graphics.Paint;
import android.net.Uri;
import android.os.Bundle;
import android.util.Log;
import android.view.Display;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.ImageView;

public class ChoosePictureActivity1 extends Activity implements OnClickListener{

	ImageView choseImageView;
	ImageView alteredImageView;
	Button choosePicture;
	
	@Override
	public void onCreate(Bundle savedInstanceState){
		super.onCreate(savedInstanceState);
		
		setContentView(R.layout.choosepicture1);
		
		choseImageView = (ImageView)findViewById(R.id.chosenImageView);
		alteredImageView = (ImageView)findViewById(R.id.alteredImageView);
		
		choosePicture = (Button)findViewById(R.id.choosePictureButton);
		choosePicture.setOnClickListener(this);
	}

	@Override
	public void onClick(View v) {
		Intent intent = new Intent(Intent.ACTION_PICK,
				android.provider.MediaStore.Images.Media.EXTERNAL_CONTENT_URI);
		startActivityForResult(intent, 0);
	}

	@Override
	protected void onActivityResult(int requestCode, int resultCode, Intent data) {
		super.onActivityResult(requestCode, resultCode, data);
		
		if(resultCode==RESULT_OK){
			Uri imageFileUri = data.getData();
			
			Display currentDisplay = getWindowManager().getDefaultDisplay();
			int dw = currentDisplay.getWidth();
			int dh = currentDisplay.getHeight();
			
			try{
				BitmapFactory.Options options = new BitmapFactory.Options();
				options.inJustDecodeBounds = true;
				
				Bitmap bmp = BitmapFactory.decodeStream(getContentResolver().openInputStream(imageFileUri),
						null,options);
				
				/*
				 * 图片得尺寸比屏幕大小大，按照图片尺寸与屏幕高、宽最大的比例来缩小图片
				 */
				int heightRatio = (int)Math.ceil(options.outHeight/(float)dh);
				int widthRatio = (int)Math.ceil(options.outWidth/(float)dw);
				
				if(heightRatio > 1 && widthRatio > 1){
					if(heightRatio > widthRatio)
						options.inSampleSize = heightRatio;
					else
						options.inSampleSize = widthRatio;
				}
				
				options.inJustDecodeBounds = false;
				bmp = BitmapFactory.decodeStream(getContentResolver().openInputStream(imageFileUri), null, options);
				
				choseImageView.setImageBitmap(bmp);
				/*
				 * 将原来的bitmap画到新的易变的alteredBitmap对象中
				 */
				Bitmap alteredBitmap = Bitmap.createBitmap(bmp.getWidth()*2, bmp.getHeight()*2, bmp.getConfig());
				Canvas canvas = new Canvas(alteredBitmap);
				Paint paint = new Paint();
				/*
				 * 1.
				 */
//				canvas.drawBitmap(bmp, 0, 0, paint);
				/*
				 * 2.旋转 
				 */
				Matrix matrix = new Matrix();
//				matrix.setRotate(15);
//				matrix.setRotate(15, bmp.getWidth()/2, bmp.getHeight()/2);//从图片中心点开始旋转
				/*
				 * 3.缩放
				 */
//				matrix.setScale(1.5f, 1);//x轴1.5倍，y轴1倍
				/*
				 * 3-1.翻转
				 */
//				matrix.setScale(-1, 1);
//				matrix.postTranslate(bmp.getWidth(), 0);
				/*
				 * 3-2.翻转
				 */
//				matrix.setScale(1, -1);
//				matrix.postTranslate(0, bmp.getHeight());
				/*
				 * 4.移动
				 */
//				matrix.setTranslate(15, 10);
				/*
				 * 5.序列
				 */
//				matrix.setScale(1.5f, 1.5f);
//				matrix.postRotate(15, bmp.getWidth()/2, bmp.getHeight()/2);
				
				canvas.drawBitmap(bmp, matrix, paint);
				alteredImageView.setImageBitmap(alteredBitmap);
				/*
				 * 图片与原图片大小一样
				 */
				/*
				Matrix matrix = new Matrix();
				matrix.setRotate(15,bmp.getWidth()/2,bmp.getHeight()/2);
				Bitmap alteredBitmap = Bitmap.createBitmap(bmp, 0, 0, bmp.getWidth(), bmp.getHeight(), matrix, false);
				alteredImageView.setImageBitmap(alteredBitmap);
				*/
			}catch(FileNotFoundException e){
				Log.v("ERROR",e.toString());
			}
		}
	}
	
}