Android 图像处理(类型转换,比例缩放,倒影,圆角)的小例子

1.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;   
    }

2.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;   
    }

3.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;   
    }

4.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;
}