转换成位图后，Drawable会丢失滤色器

Question

I am trying to add a color filer in a drawable and then convert it in Bitmap. The problem is when convert the drawable into bitmap it loses it's color filter.I used drawable in imageview and its have the color filter but using bitmap in imageview doesn't have any color effect. Why this happen ? Thanks in advance.

Answer 1

Use a canvas to blit the Drawable back onto a bitmap:

    Canvas canvas;
    Drawable drawable = <yourDrawable created from wherever>;
    Bitmap bmp = <your Bitmap which is the same width/height as the drawable>

    // blit the drawable onto the bitmap using a Canvas
    canvas = new Canvas(bmp);
    drawable.draw(canvas);

http://developer.android.com/guide/topics/graphics/2d-graphics.html

Answer 2

I had the same problem and I figured it out finally!

We need to do following thing to get the bitmap with color filter applied on it.

image_view.setDrawingCacheEnabled(true);
Bitmap bitmap = Bitmap.createBitmap(image_view.getDrawingCache());

Answer 3

I've faced the same issue and finally found a solution. Drawable can have multiple states thus you might be drawing wrong state.

You should switch it to proper mode before drawing:

Drawable drawable = icon.loadDrawable(getContext());

        if (drawable == null) {
            return;
        }
        drawable.setState(new int[] {android.R.attr.state_enabled});

        Bitmap bitmap = Bitmap.createBitmap(drawable.getIntrinsicWidth(),
                drawable.getIntrinsicHeight(), Bitmap.Config.ARGB_8888);
        Canvas canvas = new Canvas(bitmap);
        drawable.setBounds(0, 0, canvas.getWidth(), canvas.getHeight());
        drawable.draw(canvas);
        bitmap.compress(Bitmap.CompressFormat.PNG, 100, out);