How Do I Change 4 Separate Int Values For Alpha, Red, Green, Blue into TYPE_INT_RGB?

Question

thank you for your time :). I have already taken a look at Format of TYPE_INT_RGB and TYPE_INT_ARGB and now know how to convert this TYPE_INT_RGB into 4 separate values, but if I were to do a modification to each (say add 20 to each, so Alpha+=20, red+=20, and so on) how would I recombine these values into this TYPE_INT_RGB formatting? Thank you!

score 5 · Answer 1 · answered May 12 '12 at 22:48

// to extract the components into individual ints.
int argb = something();
int red = 0xFF & ( argb >> 16);
int alpha = 0xFF & (argb >> 24);
int blue = 0xFF & (argb >> 0 );
int green = 0xFF & (argb >> 8 );

// to recreate the argb
int argb = (alpha << 24) | (red << 16 ) | (green<<8) | blue;

nullpotent · Answer 2 · 2012-05-12T23:02:17.540

3

I believe this should work

int RGB = alpha;
RGB = (RGB << 8) + red;
RGB = (RGB << 8) + green;
Rgb = (RGB << 8) + blue;

There's another way without bit shifting, but I'm sure you'll figure it out.

This one is okay, too:

int rgba = new java.awt.Color(r,g,b,a).getRGB();

edited May 12 '12 at 23:02

answered May 12 '12 at 22:20

nullpotent

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You are absolutely amazing! Thanks! Oh, found one small issue with this, the order was a bit off, here is the syntax that worked for me: int newRGB = alpha; newRGB = (newRGB << 8) + red; newRGB = (newRGB << 8) + green; newRGB = (newRGB << 8) + blue; – Maxwell Sanchez May 12 '12 at 22:30
Your bit shifting is wrong and `Color` does not have `toRGB`. I strongly believe that bitwise manipulation should be avoided wherever possible and `Color` allows one to do so. – David Heffernan May 12 '12 at 23:01
`Color` has `getRGB()` as of JDK1.0? It returns `int`. See http://docs.oracle.com/javase/7/docs/api/java/awt/Color.html#getRGB%28%29. – Chris Dennett May 13 '12 at 05:49

score 3 · Answer 3 · answered May 12 '12 at 22:47

I would use java.awt.Color for this.

int ARGB = new Color(red, green, blue, alpha).getRGB();

I guess you are using bitwise operations to pull out the individual color channels, but again the Color class can hide those gory details.

Color color = new Color(ARGB);
int red = color.getRed();
int green = color.getGreen();
// etc.

How Do I Change 4 Separate Int Values For Alpha, Red, Green, Blue into TYPE_INT_RGB?

3 Answers3