float clamp(float value, float lower, float upper) { if (value < lower) return lower; if (value > upper) return upper; return value; } void changealpha(const Arg *arg) { if ((alpha > 0 && arg->f < 0) || (alpha < 1 && arg->f > 0)) alpha += arg->f; alpha = clamp(alpha, 0.0, 1.0); xloadcols(); redraw(); }