android 笔记 --- Android中几种图像特效处理的集锦

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 inpaint.setXfermode(new PorterDuffXfermode(Mode.DST_IN));// Draw a rectangle using the paint with our linear gradientcanvas.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"    /><ImageViewandroid: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!!

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