CODEWITHSUNDEEP
androidgraphicsbitmapimageview
Dolev Pearl
Dolev Pearl

Reputation: 284

Set all black in image to another color (ImageView/Bitmap)

I'm trying to convert all the black pixels in one Bitmap (Created from an ImageView that was a PNG file).. I've tried it in many ways but I still couldn't succeed in that. Please help me I'm trying it for like 3 days straight... A little example of my code:

headSkin.buildDrawingCache();
            final Bitmap bmp = headSkin.getDrawingCache();


            int w = bmp.getWidth();
            int h = bmp.getHeight();

            for (int x = 0; x < w; x++) {
                for (int y = 0; y < h; y++) {
                    int color = bmp.getPixel(x, y);

                    // Shift your alpha component value to the red component's.


                    bmp.setPixel(x, y, Color.RED);

                }
            }

As you can see... I didn't even state an IF statement.. I just tried to make all the pixels red in this bitmap and even this didn't work.. pls help?

Upvotes: 0

Views: 363

Answers (3)

Anil
Anil

Reputation: 553

headSkin.buildDrawingCache();
        final Bitmap bmp = headSkin.getDrawingCache();

I think you have problem on these lines. The rest of the code looks fine. Maybe the bitmap is not initialized, so you only have a Bitmap reference, instead of Bitmap object with data inside.

Can you delete the bitmap part from your code and initialize Bitmap like this:

 Bitmap myBitmap = Bitmap.createBitmap(500, 500, Bitmap.Config.RGB8888);

and then perform pixel operations like you did above, just set all the pixels to same color.

Upvotes: 0

Dolev Pearl
Dolev Pearl

Reputation: 284

@Anil

Hi dude, just tried it and I can't use it 'cuz of IndexOutOfBound exception...

 headSkin.buildDrawingCache();
            bmp = headSkin.getDrawingCache();




            int [] allpixels = new int [bmp.getHeight()*bmp.getWidth()];

            bmp.getPixels(allpixels, 0, bmp.getWidth(), 0, 0, bmp.getWidth(), bmp.getHeight());

            for(int i = 0; i < allpixels.length; i++)
            {
                if(allpixels[i] == Color.BLACK)
                {
                    allpixels[i] = Color.RED;
                }
            }
            bmp.setPixels(allpixels, 0, bmp.getWidth(), 0, 0, bmp.getWidth(), bmp.getHeight());


            headSkin.setImageBitmap(bmp);

what is the problem here?

EDIT: Just tried it now while running, not debugging and it doesn't even show me an error or something.. It just makes about 1-2 single pixels red in this whole bitmap

Upvotes: 0

Anil
Anil

Reputation: 553

I see 2 problems here,

First, you have this Bitmap object in your memory, and you change the black pixels to red, but how do you know if it is changed or not? You should set an ImageView to this Bitmap to see the result (or save it to file etc.)

Second, use getPixels and setPixels instead, getPixels will give you 1 dimensional array, it goes like 1.row, 2.row, 3.row etc. And setPixels also accepts a 1 dimensional array. This function is incredibly faster than altering pixels 1 by 1.

Upvotes: 1

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