将一个覆盖图（图像过滤器）应用到位图

Question

我试图从相机意图捕获图像，然后在其上应用图像过滤器。详细说明图像将是由相机捕获的图像，并且图像过滤器将作为png文件在资源中可用。我可以将滤镜叠加在原始图像的顶部。但是，一旦叠加，原始图像几乎是不可见的（这意味着过滤器实际上堆叠在原始图像上，而不仅仅是替换它）。我有几张图片来说明我的问题。第一张图片是在Photoshop中 - 当我在图片上放置滤镜时，它看起来很好。第二个图像是由下面引用的代码生成的 - 您可以清楚地看到滤镜效果丢失。有人会知道为什么会发生这样的事情。我在这里错过了一些逻辑吗？

下面是我的代码。如果您在此找不到任何最佳做法，我很抱歉。我最初想测试代码：

mPictureView = (ImageView) findViewById(R.id.pictureView); 
filterButton = (Button) findViewById(R.id.filter_button1); 

// define the threshold fro scaling the image 
private final double SCALE_THRESHOLD = 6.0; 

// acquire the bitmap (photo captured) from the Camera Intent - the uri is 
// passed from a previous activity that accesses the camera and the current 
// activity is used to display the bitmap 
Uri imageUri = getIntent().getData(); 
Bitmap imageBitmap = MediaStore.Images.Media.getBitmap(this.getContentResolver(), imageUri); 

// set the imageView in the current activity to display the picture retrieved 
// from the camera 
mPictureView.setImageBitmap(imageBitmap); 

// get the dimensions of the original bitmap 
int photoWidth = imageBitmap.getWidth(); 
int photoHeight = imageBitmap.getHeight(); 

filterButton.setOnClickListener(new View.OnClickListener() { 
    @Override 
    public void onClick(View v) { 
    // set the options 
    Options options = new BitmapFactory.Options(); 
    options.inScaled = false; 
    options.inPreferredConfig = Bitmap.Config.ARGB_8888; 

    // get the image (png file) filter from resources using the options 
    Bitmap filter = BitmapFactory.decodeResource(getResources(), R.drawable.colorful_filter,options); 

    // create a scaled copy of the filter 
    Bitmap filtercopy = Bitmap.createScaledBitmap(filter, (int)(photoWidth/SCALE_THRESHOLD,(int)(photoHeight/SCALE_THRESHOLD), true); 

    // recycle the used bitmap 
    filter.recycle(); 
    filter = null; 

    // get a scaled, mutable copy of the orginial image 
    Bitmap imagecopy = Bitmap.createScaledBitmap(imageBitmap,(int)(photoWidth/SCALE_THRESHOLD), (int)(photoHeight/SCALE_THRESHOLD),true); 

    // recycle the used bitmap  
    imageBitmap.recycle(); 
    imageBitmap = null; 


    Paint paint = new Paint(); 
    paint.setAntiAlias(true); 

    //paint.setAlpha(230); - if a discrete value is set, then the image beneath 
    // the filter is visible. But, I don't understand why I need to do this. 
    // Besides, that reduces the efficacy of the filter 

    // create a canvas with the original image as the underlying image  
    Canvas canvas = new Canvas(imagecopy); 
    // now, draw the filter on top of the bitmap 
    canvas.drawBitmap(filtercopy, 0, 0, paint); 

    // recycle the used bitmap    
    filtercopy.recycle(); 
    filtercopy = null; 

    //set the filtered bitmap as the image 
    mPictureView.setImageBitmap(imagecopy); 

} 

编辑1：我能够做出与乔鲁提供了文章的帮助下取得了一些进展。问题似乎是混合了2个位图。 drawBitmap方法只会在我有的情况下绘制一个位图。下面的代码行实际上会尝试混合2个位图。我还附上了一张描述我进步的图片。底层的位图现在是明显更加明显：

paint.setXfermode(new PorterDuffXfermode(Mode.MULTIPLY));  

我仍然玩弄了一段时间，实现期望的输出之前。

Answer 1

你可以尝试一些事情：

Bitmap new = old.copy(Config.ARGB_8888, true); 

为了确保您从MediaStore打开位图是该格式。如果不是，那很可能会导致你的问题。