tiffdec: fix EXTRASAMPLES check

the TIFFGetField() return for TIFFTAG_EXTRASAMPLES is defined as (count,
types array) [1]. previously the count was being checked rather than the
first element of the array to determine whether the alpha was associated
(pre-multiplied) and the result needed to be unmultiplied.

since:
9273e441 fix TIFF encoder regarding rgbA/RGBA

[1] http://www.libtiff.org/man/TIFFSetField.3t.html

Change-Id: I6e41be9d038fe8afb6d0aa3c8048925dc901113b
This commit is contained in:
James Zern 2017-04-26 22:49:11 -07:00
parent 97cce5ba83
commit 1923ff0222

View File

@ -215,7 +215,8 @@ int ReadTIFF(const uint8_t* const data, size_t data_size,
TIFFSwabArrayOfLong(raster, width * height); TIFFSwabArrayOfLong(raster, width * height);
#endif #endif
// if we have an alpha channel, we must un-multiply from rgbA to RGBA // if we have an alpha channel, we must un-multiply from rgbA to RGBA
if (samples_per_px > 3 && extra_samples == 1) { if (extra_samples == 1 && extra_samples_ptr != NULL &&
extra_samples_ptr[0] == EXTRASAMPLE_ASSOCALPHA) {
uint32_t y; uint32_t y;
uint8_t* tmp = (uint8_t*)raster; uint8_t* tmp = (uint8_t*)raster;
for (y = 0; y < height; ++y) { for (y = 0; y < height; ++y) {