home/src/face.hh
2020-07-31 15:45:52 +10:00

85 lines
2.4 KiB
C++

#ifndef face_hh_INCLUDED
#define face_hh_INCLUDED
#include "color.hh"
#include "flags.hh"
namespace Kakoune
{
enum class Attribute : int
{
Normal = 0,
Underline = 1 << 1,
Reverse = 1 << 2,
Blink = 1 << 3,
Bold = 1 << 4,
Dim = 1 << 5,
Italic = 1 << 6,
FinalFg = 1 << 7,
FinalBg = 1 << 8,
FinalAttr = 1 << 9,
Final = FinalFg | FinalBg | FinalAttr
};
constexpr bool with_bit_ops(Meta::Type<Attribute>) { return true; }
struct Face
{
Color fg = Color::Default;
Color bg = Color::Default;
Attribute attributes = Attribute::Normal;
friend constexpr bool operator==(const Face& lhs, const Face& rhs)
{
return lhs.fg == rhs.fg and
lhs.bg == rhs.bg and
lhs.attributes == rhs.attributes;
}
friend constexpr bool operator!=(const Face& lhs, const Face& rhs)
{
return not (lhs == rhs);
}
friend constexpr size_t hash_value(const Face& val)
{
return hash_values(val.fg, val.bg, val.attributes);
}
};
inline Face merge_faces(const Face& base, const Face& face)
{
auto alpha_blend = [](Color base, Color color) {
auto blend = [&](unsigned char Color::*field) {
int blended = (base.*field * (255 - color.a) + color.*field * color.a) / 255;
return static_cast<unsigned char>(blended <= 255 ? blended : 255);
};
int alpha = color.a + base.a * (255 - color.a) / 255;
return Color{blend(&Color::r), blend(&Color::g), blend(&Color::b),
static_cast<unsigned char>(alpha <= 255 ? alpha : 255)};
};
auto choose = [&](Color Face::*color, Attribute final_attr) {
if (face.attributes & final_attr)
return face.*color;
if (base.attributes & final_attr)
return base.*color;
if (face.*color == Color::Default)
return base.*color;
if ((base.*color).isRGB() and (face.*color).isRGB() and (face.*color).a != 255)
return alpha_blend(base.*color, face.*color);
return face.*color;
};
return Face{ choose(&Face::fg, Attribute::FinalFg),
choose(&Face::bg, Attribute::FinalBg),
face.attributes & Attribute::FinalAttr ? face.attributes :
base.attributes & Attribute::FinalAttr ? base.attributes :
face.attributes | base.attributes };
}
}
#endif // face_hh_INCLUDED