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jpeskovandClaude Opus 5.5
ba09e1aefc
ISO 32000-2 §11.3.4: the elements of a transparency group blend in the group's colour space. For a subtractive space, each component is complemented before the blend function and again after it. §11.3.5.3: the nonseparable modes blend C, M and Y as their complements R, G and B, and K comes from the backdrop (Hue, Saturation, Color) or from the source (Luminosity). PdfCraft converted each colour to RGB and blended in RGB. A print test file's blend-mode patch then showed an X in almost every cell: magenta under black with Difference stayed magenta, not green. hayro-interpret patch (45): CmykGroup and Device::draw_isolated_cmyk_group (default false) for isolated, non-knockout groups with /CS /DeviceCMYK. interpret_form_contents is now a function of its own. Color::ink_tints and color::cmyk_to_srgb8 are new. hayro patch (21): the renderer draws such a group as a CMY pass and a K pass of complemented tints. It converts the tints to RGB with the CMYK profile and composites the result through the group's layer. The group is drawn as before with reading colours, for contents without process tints (RGB, spot colours, patterns, images) and above 2^24 pixels. Test: raster::tests::isolated_groups_blend_in_device_cmyk. Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>