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LibPDF: Ignore input whitepoint in convert_to_d65()

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CalRGBColorSpace::color() converts into a flat xyz space,
which already takes input whitepoint into account.

It shouldn't be taken into account again when converting from
the flat color space to D65.
This commit is contained in:
Nico Weber 2023-10-31 21:03:19 -04:00 • committed by Tim Flynn
parent e35a5da2fb
commit bdd2404453
1 changed files with 3 additions and 7 deletions
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10
Userland/Libraries/LibPDF/ColorSpace.cpp
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@ -293,17 +293,13 @@ constexpr Array<float, 3> scale_black_point(Array<float, 3> blackpoint, Array<fl
}
// https://en.wikipedia.org/wiki/Illuminant_D65
constexpr Array<float, 3> convert_to_d65(Array<float, 3> whitepoint, Array<float, 3> xyz)
constexpr Array<float, 3> convert_to_d65(Array<float, 3> xyz)
{
constexpr float d65x = 0.95047f;
constexpr float d65y = 1.0f;
constexpr float d65z = 1.08883f;
return {
(xyz[0] * d65x) / whitepoint[0],
(xyz[1] * d65y) / whitepoint[1],
(xyz[2] * d65z) / whitepoint[2],
};
return { xyz[0] * d65x, xyz[1] * d65y, xyz[2] * d65z };
}
// https://en.wikipedia.org/wiki/SRGB
@ -343,7 +339,7 @@ PDFErrorOr<Color> CalRGBColorSpace::color(ReadonlySpan<Value> arguments) const
auto flattened_xyz = flatten_and_normalize_whitepoint(m_whitepoint, { x, y, z });
auto scaled_black_point_xyz = scale_black_point(m_blackpoint, flattened_xyz);
auto d65_normalized = convert_to_d65(m_whitepoint, scaled_black_point_xyz);
auto d65_normalized = convert_to_d65(scaled_black_point_xyz);
auto srgb = convert_to_srgb(d65_normalized);
auto red = static_cast<u8>(srgb[0] * 255.0f);