ICC: Implement Profile::to_pcs() for grayscale colors

There's probably a nicer way of doing this where we don't need to expand the gray value into a full Vector3, but for now this is good enough. Makes PDFs written by macOS 13.5.2's "Save as PDF..." feature show up.
Author: https://github.com/nico Commit: https://github.com/SerenityOS/serenity/commit/563bb9d20c Pull-request: https://github.com/SerenityOS/serenity/pull/21257 Reviewed-by: https://github.com/AtkinsSJ ✅
2023-09-28 10:06:47 -04:00 · 2023-09-28 10:06:47 -04:00 · 563bb9d20c · 2024-07-16 23:13:25 +09:00
commit 563bb9d20c
parent 6b4da8680d
1 changed files with 5 additions and 2 deletions
--- a/Userland/Libraries/LibGfx/ICC/Profile.cpp
+++ b/Userland/Libraries/LibGfx/ICC/Profile.cpp
@ -1437,9 +1437,12 @@ ErrorOr<FloatVector3> Profile::to_pcs(ReadonlyBytes color) const
        };

        if (data_color_space() == ColorSpace::Gray) {
+            VERIFY(color.size() == 1); // True because of color.size() check further up.
+
            // ICC v4, F.2 grayTRCTag
-            // FIXME
-            return Error::from_string_literal("ICC::Profile::to_pcs: Gray handling not yet implemented");
+            // "connection = grayTRC[device]"
+            float gray = evaluate_curve(grayTRCTag, color[0] / 255.f);
+            return FloatVector3 { gray, gray, gray };
        }

        // FIXME: Per ICC v4, A.1 General, this should also handle HLS, HSV, YCbCr.