Converting Bitmap in memory to Bitmap with Bitmap.Config.RGB_565

Question

I have a loaded Bitmap which I would like to convert to set the config to Bitmap.Config.RGB_565. Is there a simple way of converting a Bitmap to this configuration after the Bitmap is already loaded into memory? For example, below I have a bitmap being decoded from the application resources, however, how would I convert an already loaded Bitmap to RGB_565? I'm sure it's something simple, however, I'm fairly new to working with Bitmaps and after a few hours of looking online, unfortunately I couldn't find what I needed specifically.

BitmapFactory.Options options = new BitmapFactory.Options();
options.inPreferredConfig=Bitmap.Config.RGB_565
bitmap=BitmapFactory.decodeResource(getResources(), R.drawable.myphoto ,options);

score 34 · Answer 1 · answered Aug 15 '14 at 18:29

You can also try this:

Bitmap converted = original.copy(Config.RGB_565, false);

From the documentation of Bitmap.copy():

Tries to make a new bitmap based on the dimensions of this bitmap, setting the new bitmap's config to the one specified, and then copying this bitmap's pixels into the new bitmap. If the conversion is not supported, or the allocator fails, then this returns NULL.

Looking through the native source code, you should be fine converting between any values of Bitmap.Config.

If you want to retain transparency be sure to use Config.ARGB_8888 instead — Yannick, Sep 08 '19 at 13:13

score 29 · Accepted Answer · answered Feb 25 '13 at 03:29

29

I haven't tested this but it should work:

private Bitmap convert(Bitmap bitmap, Bitmap.Config config) {
    Bitmap convertedBitmap = Bitmap.createBitmap(bitmap.getWidth(), bitmap.getHeight(), config);
    Canvas canvas = new Canvas(convertedBitmap);
    Paint paint = new Paint();
    paint.setColor(Color.BLACK);
    canvas.drawBitmap(bitmap, 0, 0, paint);
    return convertedBitmap;
}

call the methods like this:

Bitmap convertedBitmap = convert(bitmap, Bitmap.Config.RGB_565);

You can do all kinds of additional transformations like rotating, stretching etc. if you use the drawBitmap with a Matrix.

answered Feb 25 '13 at 03:29

Emanuel Moecklin

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@JasonStack not sure I understand your question. Do you want to know what can be done with matrices applied to bitmap or how it can be done? – Emanuel Moecklin Aug 24 '18 at 16:34
Google it, there are tons of examples like: https://www.programcreek.com/java-api-examples/android.graphics.Matrix – Emanuel Moecklin Aug 24 '18 at 17:06
do all bitmap operations use matrices under the hood? – Mehdi Haghgoo Aug 25 '18 at 11:29

score 0 · Answer 3 · edited May 23 '17 at 12:10

0

Found the answer here https://stackoverflow.com/a/12148450/1364673, thanks to siliconeagle.

The solution is to create a new bitmap with the required encoding as per link above example.

edited May 23 '17 at 12:10

Community

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answered Feb 25 '13 at 03:24

Euthyphro

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Converting Bitmap in memory to Bitmap with Bitmap.Config.RGB_565

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