Android高手进阶教程(十九)---Android中几种图像特效处理的集锦!!

大家好,这一节给大家分享的是Android中几种图像特效处理的小技巧,比如圆角,倒影,还有就是图片缩放,Drawable转化为Bitmap,Bitmap转化为Drawable等等.

废话少说了,直接讲解今天的实例,本例主要是先获取壁纸(getWallpaper()),然后对当前壁纸的一些特效处理.大家按步骤一步一步来:

第一步:新建一个Android工程命名为ImageDemo,工程结构如下:

第二步:新建一个.java文件,命名为ImageUtil.java,在里面定义一些图片处理方法,代码如下:

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 {

    //放大缩小图片
    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;
    }
    //将Drawable转化为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;

        }

     //获得圆角图片的方法
    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;
    }
    //获得带倒影的图片方法
    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布局文件,主要放了两个ImageView控件,代码如下:

<?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:修改主核心程序,ImageDemo.java,代码如下:

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);

        //获取壁纸返回值是Drawable
        Drawable drawable = getWallpaper();
        //将Drawable转化为Bitmap
        Bitmap bitmap = ImageUtil.drawableToBitmap(drawable);
        //缩放图片
        Bitmap zoomBitmap = ImageUtil.zoomBitmap(bitmap, 100, 100);
        //获取圆角图片
        Bitmap roundBitmap = ImageUtil.getRoundedCornerBitmap(zoomBitmap, 10.0f);
        //获取倒影图片
        Bitmap reflectBitmap = ImageUtil.createReflectionImageWithOrigin(zoomBitmap);
        //这里可以让Bitmap再转化为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:运行上述工程,查看效果如下:

 

OK大功告成了!!

 

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