color interpolate(const color& a, sample weight, const color& b)
noexcept
{
auto pre_red =
interpolate(a.alpha() * a.red(), weight, b.alpha() * b.red());
auto pre_green =
interpolate(a.alpha() * a.green(), weight, b.alpha() * b.green());
auto pre_blue =
interpolate(a.alpha() * a.blue(), weight, b.alpha() * b.blue());
auto new_alpha = interpolate(a.alpha(), weight, b.alpha());
return {pre_red / new_alpha, pre_green / new_alpha, pre_blue / new_alpha,
new_alpha};
}
inline bool operator==(color const& rhs) const
{
return (red_== rhs.red()) &&
(green_ == rhs.green()) &&
(blue_ == rhs.blue()) &&
(alpha_ == rhs.alpha());
}
color overlay(const color& fg, const color& bg) noexcept
{
if (opaque(fg) || transparent(bg)) return fg;
if (transparent(fg)) return bg;
return interpolate(bg, fg.alpha(), color{fg.red(), fg.green(), fg.blue()});
}
void set ( color& c )
{
free_color();
set_color ( c.red(), c.green(), c.blue() );
}
void cairo_context::set_color(color const& color, double opacity)
{
set_color(color.red()/255.0, color.green()/255.0, color.blue()/255.0, color.alpha() * opacity / 255.0);
}
static boost::python::tuple
getinitargs(const color& c)
{
using namespace boost::python;
return boost::python::make_tuple(c.red(),c.green(),c.blue(),c.alpha());
}
void api::clear_color( const color &c )
{
glClearColor( c.red(), c.green(), c.blue(), c.alpha() );
}
void texture::binding::set_border_color( const color &c )
{
float color[] = { c.red(), c.green(), c.blue(), c.alpha() };
glTexParameterfv( _target, GL_TEXTURE_BORDER_COLOR, color );
}