diff --git a/src/tiff/tiffread.c b/src/tiff/tiffread.c index 20ed256..d588342 100644 --- a/src/tiff/tiffread.c +++ b/src/tiff/tiffread.c @@ -221,6 +221,8 @@ internal bool read_field(const TiffField *field, TiffImage *img); internal bool validate_image_type(const TiffImage *img); internal void fread_with_offset(FILE *fp, void *dst, u64 count, u64 offset); internal bool valid_tiff_file(const char *file); +internal f32 u8_normalise(u8 value); +internal u8 u8_denormalise(f32 value); Image *read_baseline_tiff(const char *file, Arena *arena) { Image *img_out = NULL; @@ -608,9 +610,11 @@ internal void read_strips(TiffReader *reader) { fread_with_offset(reader->fp, &(p->a), 1, alpha_offset); if (alpha.type == ALPHA_TYPE_UNASSOCIATED) { - p->r *= p->a; - p->g *= p->a; - p->b *= p->a; + f32 a_norm = u8_normalise(p->a); + + p->r = u8_denormalise(u8_normalise(p->r) * a_norm); + p->g = u8_denormalise(u8_normalise(p->g) * a_norm); + p->b = u8_denormalise(u8_normalise(p->b) * a_norm); } } @@ -857,3 +861,7 @@ internal bool valid_tiff_file(const char *file) { return true; } + +internal f32 u8_normalise(u8 value) { return (f32)value / (f32)UINT8_MAX; } + +internal u8 u8_denormalise(f32 value) { return (u8)(value * UINT8_MAX); }