這一節給大家分享的是Android中幾種影象特效處理的小技巧,比如圓角,倒影,還有就是圖片縮放,Drawable轉化為Bitmap,Bitmap轉化為Drawable等等.

廢話少說了,直接講解今天的例項,本例主要是先獲取桌布(getWallpaper()),然後對當前桌布的一些特效處理.大家按步驟一步一步來:

第一步:新建一個Android工程命名為ImageDemo,工程結構如下:

第二步:新建一個.java檔案,命名為ImageUtil.java,在裡面定義一些圖片處理方法,程式碼如下:

package com.android.tutor;
import android.graphics.Bitmap;
import android.graphics.Canvas;
import android.graphics.LinearGradient;
import android.graphics.Matrix;
import android.graphics.Paint;
import android.graphics.PixelFormat;
import android.graphics.PorterDuffXfermode;
import android.graphics.Rect;
import android.graphics.RectF;
import android.graphics.Bitmap.Config;
import android.graphics.PorterDuff.Mode;
import android.graphics.Shader.TileMode;
import android.graphics.drawable.Drawable;
public class ImageUtil {
	
	//放大縮小圖片
	public static Bitmap zoomBitmap(Bitmap bitmap,int w,int h){
		int width = bitmap.getWidth();
		int height = bitmap.getHeight();
		Matrix matrix = new Matrix();
		float scaleWidht = ((float)w / width);
    	float scaleHeight = ((float)h / height);
    	matrix.postScale(scaleWidht, scaleHeight);
    	Bitmap newbmp = Bitmap.createBitmap(bitmap, 0, 0, width, height, matrix, true);
		return newbmp;
	}
	//將Drawable轉化為Bitmap
	 public static Bitmap drawableToBitmap(Drawable drawable){
	    	int width = drawable.getIntrinsicWidth();
	    	int height = drawable.getIntrinsicHeight();
	    	Bitmap bitmap = Bitmap.createBitmap(width, height,
	    			drawable.getOpacity() != PixelFormat.OPAQUE ? Bitmap.Config.ARGB_8888
	                        : Bitmap.Config.RGB_565);
	    	Canvas canvas = new Canvas(bitmap);
	    	drawable.setBounds(0,0,width,height);
	    	drawable.draw(canvas);
	    	return bitmap;
	    	
	    }
	 
	 //獲得圓角圖片的方法
	public static Bitmap getRoundedCornerBitmap(Bitmap bitmap,float roundPx){
		
		Bitmap output = Bitmap.createBitmap(bitmap.getWidth(), bitmap
				.getHeight(), Config.ARGB_8888);
		Canvas canvas = new Canvas(output);
 
		final int color = 0xff424242;
		final Paint paint = new Paint();
		final Rect rect = new Rect(0, 0, bitmap.getWidth(), bitmap.getHeight());
		final RectF rectF = new RectF(rect);
 
		paint.setAntiAlias(true);
		canvas.drawARGB(0, 0, 0, 0);
		paint.setColor(color);
		canvas.drawRoundRect(rectF, roundPx, roundPx, paint);
 
		paint.setXfermode(new PorterDuffXfermode(Mode.SRC_IN));
		canvas.drawBitmap(bitmap, rect, rect, paint);
 
		return output;
	}
	//獲得帶倒影的圖片方法
	public static Bitmap createReflectionImageWithOrigin(Bitmap bitmap){
		final int reflectionGap = 4;
		int width = bitmap.getWidth();
		int height = bitmap.getHeight();
		
		Matrix matrix = new Matrix();
		matrix.preScale(1, -1);
		
		Bitmap reflectionImage = Bitmap.createBitmap(bitmap, 
				0, height/2, width, height/2, matrix, false);
		
		Bitmap bitmapWithReflection = Bitmap.createBitmap(width, (height + height/2), Config.ARGB_8888);
		
		Canvas canvas = new Canvas(bitmapWithReflection);
		canvas.drawBitmap(bitmap, 0, 0, null);
		Paint deafalutPaint = new Paint();
		canvas.drawRect(0, height,width,height + reflectionGap,
				deafalutPaint);
		
		canvas.drawBitmap(reflectionImage, 0, height + reflectionGap, null);
		
		Paint paint = new Paint();
		LinearGradient shader = new LinearGradient(0,
				bitmap.getHeight(), 0, bitmapWithReflection.getHeight()
				+ reflectionGap, 0x70ffffff, 0x00ffffff, TileMode.CLAMP);
		paint.setShader(shader);
		// Set the Transfer mode to be porter duff and destination in
		paint.setXfermode(new PorterDuffXfermode(Mode.DST_IN));
		// Draw a rectangle using the paint with our linear gradient
		canvas.drawRect(0, height, width, bitmapWithReflection.getHeight()
				+ reflectionGap, paint);
 
		return bitmapWithReflection;
	}
	
}
 

第三步:修改main.xml佈局檔案,主要放了兩個ImageView控制元件,程式碼如下:

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    >
	<ImageView 
		android:id="@+id/image01" 
	    android:layout_width="wrap_content" 
	    android:layout_height="wrap_content" 
	    android:padding="10px"
	    />
	<ImageView
		android:id="@+id/image02"
		android:layout_width="wrap_content" 
	    android:layout_height="wrap_content" 
	    android:padding="10px"
	/>
</LinearLayout>
 

第四步:修改主核心程式,ImageDemo.java,程式碼如下:

package com.android.tutor;
import android.app.Activity;
import android.graphics.Bitmap;
import android.graphics.drawable.Drawable;
import android.os.Bundle;
import android.widget.ImageView;
public class Imagedemo extends Activity {
	private ImageView mImageView01,mImageView02;
	
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        setupViews();
    }
   
    private void setupViews(){
    	mImageView01 = (ImageView)findViewById(R.id.image01);
    	mImageView02 = (ImageView)findViewById(R.id.image02);
    	
    	//獲取桌布返回值是Drawable
    	Drawable drawable = getWallpaper();
    	//將Drawable轉化為Bitmap
    	Bitmap bitmap = ImageUtil.drawableToBitmap(drawable);
    	//縮放圖片
    	Bitmap zoomBitmap = ImageUtil.zoomBitmap(bitmap, 100, 100);
    	//獲取圓角圖片
    	Bitmap roundBitmap = ImageUtil.getRoundedCornerBitmap(zoomBitmap, 10.0f);
    	//獲取倒影圖片
    	Bitmap reflectBitmap = ImageUtil.createReflectionImageWithOrigin(zoomBitmap);
    	//這裡可以讓Bitmap再轉化為Drawable
//    	Drawable roundDrawable = new BitmapDrawable(roundBitmap);    	
//    	Drawable reflectDrawable = new BitmapDrawable(reflectBitmap);   	
//    	mImageView01.setBackgroundDrawable(roundDrawable);
//    	mImageView02.setBackgroundDrawable(reflectDrawable);
    	    	
    	mImageView01.setImageBitmap(roundBitmap);
    	mImageView02.setImageBitmap(reflectBitmap);
    }
      
       
}
 

第五步:執行上述工程,檢視效果如下:

OK大功告成了!!

本文參考文獻:http://wiki.impjq.net/doku.php?id=code:android-code:image-convert&rev=1275640889&mddo=print