In GDI+, every color is a combination of ARGB components; each of the alpha, red, green, and blue components is represented by 8 bits. The alpha component in a color structure represents the transparency of the color, which varies from 0 to 255. The value 0 represents full transparency, and 255 represents full opacity.
The final color of an ARGB color structure is calculated by the following formula:
Final Color = (Source Color × alpha / 255) +
[Background Color × (255 – alpha) / 255]
This formula is applied on each component of the source color and background color.
In alpha blending, an application creates a color with an alpha component and uses this color to create a pen or a brush. This pen or brush is used to draw and ...