fresco 加载本地路径图片，并修改图片尺寸

最新推荐文章于 2021-05-26 17:59:47 发布

kiwill

最新推荐文章于 2021-05-26 17:59:47 发布

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CC 4.0 BY-SA版权

本文链接：https://blog.youkuaiyun.com/kiwill/article/details/78652142

本文介绍了一种使用自定义Postprocessor实现图片缩放的方法。通过计算缩放比例并对原始图片进行像素级采样，最终生成指定宽度的新图片。该方法适用于需要调整图片尺寸而不改变其长宽比的应用场景。

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int width =100;//目标宽度
Postprocessor postprocessor = new Postprocessor() {
    @Override    public CloseableReference<Bitmap> process(Bitmap sourceBitmap, PlatformBitmapFactory bitmapFactory) {    
    int sw = sourceBitmap.getWidth();     
   int sh = sourceBitmap.getHeight();     
   float scale = (float) width / (float) sw;    
    int mscale = sw / width;       
 float heigh = scale * (float) sh;      
  int nscale = sh / (int) heigh;     
   CloseableReference<Bitmap> bitmapRef = bitmapFactory.createBitmap(                width,                (int) heigh);    
    try {        
    Bitmap destBitmap = bitmapRef.get();      
      for (int x = 0, m = 0; x < destBitmap.getWidth() && m < sw; x++, m += mscale) {     
           for (int y = 0, n = 0; y < destBitmap.getHeight() && n < sh; y++, n += nscale) {    
                destBitmap.setPixel(x, y, sourceBitmap.getPixel(m, n));           
     }         
   }        
    return CloseableReference.cloneOrNull(bitmapRef);    
    } finally {         
   CloseableReference.closeSafely(bitmapRef);    
    } 
   }  
  @Override   
 public String getName() {        return null;    }  
  @Override   
 public CacheKey getPostprocessorCacheKey() {        return null;    }};
ImageRequest request = 
 //此处是加载本地图片路径的图片
ImageRequestBuilder.newBuilderWithSource(Uri.parse("file://" + MyBimp.tempSelectBitmap.get(position).path))
         
        .setPostprocessor(postprocessor)
        .build();

PipelineDraweeController controller = (PipelineDraweeController)
        Fresco.newDraweeControllerBuilder()
                .setImageRequest(request)
                .setOldController(holder.mainView.getController())
                        // other setters as you need
                .build();
mainView.setController(controller);