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;
}

}