+ // If the border color is black, it doesn't matter if we're pre- or postmultiplied.
+ // Note that for non-solid black (i.e. alpha < 1.0), we're equally fine with
+ // pre- and postmultiplied, but later effects might change this status
+ // (consider e.g. blur), so setting DONT_CARE_ALPHA_TYPE is inappropriate,
+ // as it propagate blank alpha through this effect.
+ if (border_color.r == 0.0 && border_color.g == 0.0 && border_color.b == 0.0 && border_color.a == 1.0) {