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;
 }
 
}