Android中几种图像特效处理的集锦

好，这一节给大家分享的是 Android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，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