xo-alloc/include/indentlog/color.hpp

177 lines
6.6 KiB
C++

/* color.hpp */
#pragma once
#include <ostream>
//#include <utility> // for std::move
#include <cstdint>
namespace xo {
enum class color_encoding : std::uint8_t {
none,
ansi,
xterm,
rgb
};
/* specify a color (consistent with ANSI escape sequences - the Select Graphics Rendition subset
* see [[https://stackoverflow.com/questions/4842424/list-of-ansi-color-escape-sequences]]
*
* this provides three ways to specify foreground color:
*
* | enum | escape | example | description | foreground codes |
* +-------+-----------+---------------------+---------------+------------------+
* | ansi | \033[31 | \033[31;42m | 4-bit colors | 30..37, 90..97 |
* | xterm | \033[38;5 | \033[38;5;143m | 8-bit colors | 0..255 |
* | rgb | \033[38;2 | \033[38;2;10;20;30m | 24-bit colors | 3x 0..255 |
*
*/
class color_spec_type {
public:
color_spec_type() = default;
color_spec_type(color_encoding encoding, std::uint32_t code)
: encoding_{encoding}, code_{code} {}
static color_spec_type none() { return color_spec_type(); }
static color_spec_type ansi(std::uint32_t code) { return color_spec_type(color_encoding::ansi, code); }
static color_spec_type xterm(std::uint32_t code) { return color_spec_type(color_encoding::xterm, code); }
static color_spec_type rgb(std::uint8_t red, std::uint8_t green, std::uint8_t blue) {
return color_spec_type(color_encoding::rgb, (red << 16 | green << 8 | blue));
}
/* 4-bit foreground colors */
static color_spec_type black () { return ansi(30); }
static color_spec_type red () { return ansi(31); }
static color_spec_type green () { return ansi(32); }
static color_spec_type yellow () { return ansi(33); }
static color_spec_type blue () { return ansi(34); }
static color_spec_type magenta () { return ansi(35); }
static color_spec_type cyan () { return ansi(36); }
static color_spec_type white () { return ansi(37); }
static color_spec_type bright_black () { return ansi(90); }
static color_spec_type bright_red () { return ansi(91); }
static color_spec_type bright_green () { return ansi(92); }
static color_spec_type bright_yellow () { return ansi(99); }
static color_spec_type bright_blue () { return ansi(94); }
static color_spec_type bright_magenta () { return ansi(95); }
static color_spec_type bright_cyan () { return ansi(96); }
static color_spec_type bright_white () { return ansi(97); }
color_encoding encoding() const { return encoding_; }
std::uint32_t code() const { return code_; }
void print_fg_color_on (std::ostream & os) const {
switch (encoding_) {
case color_encoding::none:
break;
case color_encoding::ansi:
os << "\033[31;" << code_ << "m";
break;
case color_encoding::xterm:
os << "\033[38;5;" << code_ << "m";
break;
case color_encoding::rgb:
os << "\033[38;2;"
<< (0xff & (code_ >> 16)) << ";"
<< (0xff & (code_ >> 8)) << ";"
<< (0xff & (code_ >> 0)) << "m";
}
} /*print_fg_color_on*/
/* escape to reverse effect of .print_on() */
void print_fg_color_off (std::ostream & os) const {
switch (encoding_) {
case color_encoding::none:
break;
case color_encoding::ansi:
case color_encoding::xterm:
case color_encoding::rgb:
os << "\033[0m";
break;
}
} /*print_fg_color_off*/
private:
/* none | ansi | xterm | rgb */
color_encoding encoding_ = color_encoding::none;
/* ansi : 30..37, 90..97
* xterm : 0..255
* see [[https://i.stack.imgur.com/KTSQa.png]]
* 0..7 standard colors (muted: grey, red, green, yellow, blue, pink, cyan, white)
* 8..15 high-intensity colors (grey, red, green, yellow, blue, pink, cyan, white)
* 16..51 chooses hue
* 16..51 + (0..5)x36 increases whiteness
* rgb : r={hi 8 bits}, g={mid 8 bits}, b={lo 8 bits}
*/
std::uint32_t code_ = 0;
}; /*color_spec_type*/
enum color_flags {
CF_None = 0x0,
CF_ColorOn = 0x01,
CF_Contents = 0x02,
CF_ColorOff = 0x04,
CF_All = 0x07
};
/* stream-insertable color control */
template <typename Contents>
class color_impl {
public:
color_impl(color_flags flags, color_spec_type spec, Contents && contents)
: flags_{flags}, spec_{spec}, contents_{std::forward<Contents>(contents)} {}
color_spec_type const & spec() const { return spec_; }
std::uint32_t color() const { return spec_.code(); }
Contents const & contents() const { return contents_; }
void print(std::ostream & os) const {
if (flags_ & CF_ColorOn)
spec_.print_fg_color_on(os);
if (flags_ & CF_Contents)
os << contents_;
if (flags_ & CF_ColorOff)
spec_.print_fg_color_off(os);
} /*print*/
private:
/* controls independently what to print
* \033[38;5;117m hello, world! \033[0m
* <------------> <-----------> <----->
* CF_ColorOn CF_Contents CF_ColorOff
*/
color_flags flags_ = CF_None;
color_spec_type spec_;
Contents contents_;
}; /*color_impl*/
template <typename Contents>
color_impl<Contents> with_color(color_spec_type spec, Contents && contents) {
return color_impl<Contents>(CF_All, spec, std::forward<Contents>(contents));
} /*with_color*/
inline color_impl<int>
color_on(color_spec_type spec) {
return color_impl<int>(CF_ColorOn, spec, 0);
} /*color_on*/
inline color_impl<int>
color_off() {
/* any spec other than color_spec_type::none() works here */
return color_impl<int>(CF_ColorOff, color_spec_type::white(), 0);
} /*color_off*/
template <typename Contents>
inline std::ostream &
operator<<(std::ostream & os, color_impl<Contents> const & x) {
x.print(os);
return os;
} /*operator<<*/
} /*namespace xo*/
/* end color.hpp */