diff options
| -rw-r--r-- | libass/ass_parse.c | 5 |
1 files changed, 3 insertions, 2 deletions
diff --git a/libass/ass_parse.c b/libass/ass_parse.c index 3e4264d..3456410 100644 --- a/libass/ass_parse.c +++ b/libass/ass_parse.c @@ -176,11 +176,12 @@ inline void change_alpha(uint32_t *var, int32_t new, double pwr) * \param a first value * \param b second value * \return result of multiplication - * Parameters and result are limited by 0xFF. + * At least one of the parameters must be less than or equal to 0xFF. + * The result is less than or equal to max(a, b, 0xFF). */ inline uint32_t mult_alpha(uint32_t a, uint32_t b) { - return 0xFF - (0xFF - a) * (0xFF - b) / 0xFF; + return a - (uint64_t) a * b / 0xFF + b; } /** |