How to use Alpha value in BITMAP?

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I am using SetDIBitsToDevice to write the pixel array (containing the RGB value) to picture box.
Its happening, How can I use Alpha value for draw the transparent pixel in the same?

Posted 23-May-13 20:10pm

Rajeshkumar Ramasamy

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Santhosh G_ · Answer 1 · 2013-05-24T05:13:00

Solution 1

Please use GDI+ to use Alpha channel of the bitmap.

If you need to get semi transparent display of an image, AlphaBlend() will help you.
Perpixel Alpha blending will be difficult.

Following links will help to achieve alpha blending of the entire image while drawing to screen.
Using the AlphaBlend function[^]

http://msdn.microsoft.com/en-us/library/windows/desktop/dd183353(v=vs.85).aspx[^]

Posted 24-May-13 5:13am

Santhosh G_

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Rajeshkumar Ramasamy 3-Jun-13 8:07am

Alpha Blend function apply the transparency to all pixels. What i want is, I have the pixel array containing the RGBA (RGB and Alpha)values consequently. I want to apply the alpha value for each pixel.
For that I am using BITMAPV4HEADER and SetDIBitsToDevice function to draw the pixel array into picture box. But the Alpha value is not working (RGB is working fine).
How can i use alpha value??