From 2f993502fc6584a5877b300a1353cabf58c4e0e9 Mon Sep 17 00:00:00 2001 From: Přemysl Eric Janouch Date: Sun, 26 Dec 2021 03:10:50 +0100 Subject: Make use of gAMA and sRGB PNG chunks Neither EoG nor gThumb handle this correctly. --- fiv-io.c | 49 +++++++++++++++++++++++++++++++++++++++++++++---- 1 file changed, 45 insertions(+), 4 deletions(-) diff --git a/fiv-io.c b/fiv-io.c index 2ab97f1..468f223 100644 --- a/fiv-io.c +++ b/fiv-io.c @@ -198,6 +198,30 @@ fiv_io_profile_new_sRGB(void) #endif } +FivIoProfile +fiv_io_profile_new_sRGB_gamma(double gamma) +{ +#ifdef HAVE_LCMS2 + // TODO(p): Make sure to use the library in a thread-safe manner. + cmsContext context = NULL; + + static const cmsCIExyY D65 = {0.3127, 0.3290, 1.0}; + static const cmsCIExyYTRIPLE primaries = { + {0.6400, 0.3300, 1.0}, {0.3000, 0.6000, 1.0}, {0.1500, 0.0600, 1.0}}; + cmsToneCurve *curve = cmsBuildGamma(context, gamma); + if (!curve) + return NULL; + + cmsHPROFILE profile = cmsCreateRGBProfileTHR( + context, &D65, &primaries, (cmsToneCurve *[3]){curve, curve, curve}); + cmsFreeToneCurve(curve); + return profile; +#else + (void) gamma; + return NULL; +#endif +} + static FivIoProfile fiv_io_profile_new_from_bytes(GBytes *bytes) { @@ -740,13 +764,17 @@ open_wuffs(wuffs_base__image_decoder *dec, wuffs_base__io_buffer src, struct load_wuffs_frame_context ctx = { .dec = dec, .src = &src, .target = profile}; - // TODO(p): PNG also has sRGB and gAMA, as well as text chunks (Wuffs #58). - // The former two use WUFFS_BASE__MORE_INFORMATION__FLAVOR__METADATA_PARSED. + // TODO(p): PNG text chunks (Wuffs #58). wuffs_base__image_decoder__set_report_metadata( ctx.dec, WUFFS_BASE__FOURCC__EXIF, true); wuffs_base__image_decoder__set_report_metadata( ctx.dec, WUFFS_BASE__FOURCC__ICCP, true); + wuffs_base__image_decoder__set_report_metadata( + ctx.dec, WUFFS_BASE__FOURCC__SRGB, true); + wuffs_base__image_decoder__set_report_metadata( + ctx.dec, WUFFS_BASE__FOURCC__GAMA, true); + double gamma = 0; while (true) { wuffs_base__status status = wuffs_base__image_decoder__decode_image_config( @@ -786,6 +814,14 @@ open_wuffs(wuffs_base__image_decoder *dec, wuffs_base__io_buffer src, } ctx.meta_xmp = bytes; continue; + + case WUFFS_BASE__FOURCC__SRGB: + gamma = 2.2; + break; + case WUFFS_BASE__FOURCC__GAMA: + gamma = 1e5 / + wuffs_base__more_information__metadata_parsed__gama(&minfo); + break; } g_bytes_unref(bytes); @@ -805,8 +841,13 @@ open_wuffs(wuffs_base__image_decoder *dec, wuffs_base__io_buffer src, goto fail; } - if (ctx.target && ctx.meta_iccp) - ctx.source = fiv_io_profile_new_from_bytes(ctx.meta_iccp); + // TODO(p): Improve our simplistic PNG handling of: gAMA, cHRM, sRGB. + if (ctx.target) { + if (ctx.meta_iccp) + ctx.source = fiv_io_profile_new_from_bytes(ctx.meta_iccp); + else if (isfinite(gamma) && gamma > 0) + ctx.source = fiv_io_profile_new_sRGB_gamma(gamma); + } // Wuffs maps tRNS to BGRA in `decoder.decode_trns?`, we should be fine. // wuffs_base__pixel_format__transparency() doesn't reflect the image file. -- cgit v1.2.3-70-g09d2