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authorPřemysl Eric Janouch <p@janouch.name>2021-12-29 02:46:19 +0100
committerPřemysl Eric Janouch <p@janouch.name>2021-12-29 02:46:40 +0100
commit4832474c5ff8fca946762de00c61ce2b5df67df8 (patch)
tree84af4a8749c2ab235f5d13c8085c389d2bf8e197
parent0110e0a5d2efaf837f5c8627036d613d42b38160 (diff)
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Partially colour-manage TIFFs
-rw-r--r--fiv-io.c33
1 files changed, 20 insertions, 13 deletions
diff --git a/fiv-io.c b/fiv-io.c
index ee597bb..e82265d 100644
--- a/fiv-io.c
+++ b/fiv-io.c
@@ -2082,8 +2082,10 @@ load_libtiff_directory(TIFF *tiff, GError **error)
goto fail;
}
- surface = cairo_image_surface_create(
- CAIRO_FORMAT_ARGB32, image.width, image.height);
+ surface = cairo_image_surface_create(image.alpha != EXTRASAMPLE_UNSPECIFIED
+ ? CAIRO_FORMAT_ARGB32
+ : CAIRO_FORMAT_RGB24,
+ image.width, image.height);
image.req_orientation = ORIENTATION_LEFTTOP;
uint32_t *raster = (uint32_t *) cairo_image_surface_get_data(surface);
@@ -2092,15 +2094,15 @@ load_libtiff_directory(TIFF *tiff, GError **error)
goto fail;
}
- // Needs to be converted from ABGR to alpha-premultiplied ARGB for Cairo.
- for (uint32_t i = image.width * image.height; i--;) {
- uint32_t pixel = raster[i],
- a = TIFFGetA(pixel),
- b = TIFFGetB(pixel) * a / 255,
- g = TIFFGetG(pixel) * a / 255,
- r = TIFFGetR(pixel) * a / 255;
- raster[i] = a << 24 | r << 16 | g << 8 | b;
+ // Needs to be byte-swapped from ABGR to alpha-premultiplied ARGB for Cairo.
+ for (uint64_t i = image.width * image.height; i--; ) {
+ uint32_t pixel = raster[i];
+ raster[i] = TIFFGetA(pixel) << 24 | TIFFGetR(pixel) << 16 |
+ TIFFGetG(pixel) << 8 | TIFFGetB(pixel);
}
+ // It seems that neither GIMP nor Photoshop use unassociated alpha.
+ if (image.alpha == EXTRASAMPLE_UNASSALPHA)
+ fiv_io_premultiply_argb32(surface);
cairo_surface_mark_dirty(surface);
// XXX: The whole file is essentially an Exif, any ideas?
@@ -2134,7 +2136,8 @@ fail:
}
static cairo_surface_t *
-open_libtiff(const gchar *data, gsize len, const gchar *path, GError **error)
+open_libtiff(const gchar *data, gsize len, const gchar *path,
+ FivIoProfile target, GError **error)
{
// Both kinds of handlers are called, redirect everything.
TIFFErrorHandler eh = TIFFSetErrorHandler(NULL);
@@ -2202,7 +2205,11 @@ fail:
TIFFSetWarningHandlerExt(whe);
TIFFSetErrorHandler(eh);
TIFFSetWarningHandler(wh);
- return result;
+
+ // TODO(p): Colour management even for un/associated alpha channels.
+ // Note that TIFF has a number of fields that an ICC profile can be
+ // constructed from--it's not a good idea to blindly assume sRGB.
+ return fiv_io_profile_finalize(result, target);
}
#endif // HAVE_LIBTIFF --------------------------------------------------------
@@ -2415,7 +2422,7 @@ fiv_io_open_from_data(const char *data, size_t len, const gchar *path,
#endif // HAVE_LIBHEIF --------------------------------------------------------
#ifdef HAVE_LIBTIFF //---------------------------------------------------------
// This needs to be positioned after LibRaw.
- if ((surface = open_libtiff(data, len, path, error)))
+ if ((surface = open_libtiff(data, len, path, profile, error)))
break;
if (error) {
g_debug("%s", (*error)->message);