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LibGfx/ICC: Add evaluate() member functions to both curve types

This commit is contained in:
Nico Weber 2023-04-11 08:54:15 -04:00 committed by Linus Groh
parent 5df35d030f
commit df6b47609a

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@ -13,6 +13,7 @@
#include <AK/String.h>
#include <AK/Vector.h>
#include <LibGfx/ICC/DistinctFourCC.h>
#include <math.h>
namespace Gfx::ICC {
@ -159,6 +160,26 @@ public:
// 65 535). Function values between the entries shall be obtained through linear interpolation."
Vector<u16> const& values() const { return m_values; }
// x must be in [0..1].
float evaluate(float x) const
{
VERIFY(0.f <= x && x <= 1.f);
if (values().is_empty())
return x;
if (values().size() == 1)
return powf(x, values()[0] / (float)0x100);
size_t i = static_cast<size_t>(x * (values().size() - 1));
if (i == values().size() - 1)
--i;
float f = x * (values().size() - 1) - i;
return (1 - f) * (values()[i] / 65535.f) + f * (values()[i + 1] / 65535.f);
}
private:
Vector<u16> m_values;
};
@ -691,6 +712,34 @@ public:
return m_parameters[6];
}
// x must be in [0..1].
float evaluate(float x) const
{
VERIFY(0.f <= x && x <= 1.f);
switch (function_type()) {
case FunctionType::Type0:
return powf(x, (float)g());
case FunctionType::Type1:
if (x >= -(float)b() / (float)a())
return powf((float)a() * x + (float)b(), (float)g());
return 0;
case FunctionType::Type2:
if (x >= -(float)b() / (float)a())
return powf((float)a() * x + (float)b(), (float)g()) + (float)c();
return (float)c();
case FunctionType::Type3:
if (x >= (float)d())
return powf((float)a() * x + (float)b(), (float)g());
return (float)c() * x;
case FunctionType::Type4:
if (x >= (float)d())
return powf((float)a() * x + (float)b(), (float)g()) + (float)e();
return (float)c() * x + (float)f();
}
VERIFY_NOT_REACHED();
}
private:
FunctionType m_function_type;