How do I set the R, G, B and Alpha components of a color?

问题

There are 3 integer values that makes up a RGB value, and also i have the Alpha component value of the color. how do i set these 4 values to get the desired colour

回答1:

You can create a Color object (the values should either be ints between 0-255 or floats between 0f-1f:

Color c = new Color(red, green, blue, alpha);

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If you want to paint an image with that color:

BufferedImage image = new BufferedImage(300, 200, BufferedImage.TYPE_INT_ARGB);
Graphics graphics = image.getGraphics(); 
graphics.setColor(c);
graphics.fillRect(50, 50, 100, 100);
graphics.dispose();

If you only want to set a pixel (color model must be ARGB):

image.setRGB(50, 50, c.getRGB());

回答2:

you can also use

int colorToSet = Color.argb(alpha, red, green, blue); to set Alpha

来源：https://stackoverflow.com/questions/6734171/how-do-i-set-the-r-g-b-and-alpha-components-of-a-color