Converting from signed char to unsigned char and back again?

Question

I\'m working with JNI and have an array of type jbyte, where jbyte is represented as an signed char i.e. ranging from -128 to 127. The jbytes represent image pixels. For ima

Answer 1

Do you realize, that CLAMP255 returns 0 for v < 0 and 255 for v >= 0?
IMHO, CLAMP255 should be defined as:

#define CLAMP255(v) (v > 255 ? 255 : (v < 0 ? 0 : v))

Difference: If v is not greater than 255 and not less than 0: return v instead of 255