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livetrax/libs/gtkmm2ext/colors.cc

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/*
* Copyright (C) 2017 Robin Gareus <robin@gareus.org>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License along
* with this program; if not, write to the Free Software Foundation, Inc.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*/
#include <algorithm>
#include <sstream>
#include <cmath>
#include <stdint.h>
#include <cfloat>
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#include <cstdlib>
#include "pbd/failed_constructor.h"
#include "pbd/string_convert.h"
#include "gtkmm2ext/colors.h"
#include "gtkmm2ext/colorspace.h"
using namespace std;
using namespace Gtkmm2ext;
using std::max;
using std::min;
Gtkmm2ext::Color
Gtkmm2ext::change_alpha (Color c, double a)
{
return ((c & ~0xff) | (lrintf (a*255.0) & 0xff));
}
void
Gtkmm2ext::color_to_hsv (Color color, double& h, double& s, double& v)
{
double a;
color_to_hsva (color, h, s, v, a);
}
void
Gtkmm2ext::color_to_hsva (Color color, double& h, double& s, double& v, double& a)
{
double r, g, b;
double cmax;
double cmin;
double delta;
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color_to_rgba (color, r, g, b, a);
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if (r > g) {
cmax = max (r, b);
} else {
cmax = max (g, b);
}
if (r < g) {
cmin = min (r, b);
} else {
cmin = min (g, b);
}
v = cmax;
delta = cmax - cmin;
if (cmax == 0) {
// r = g = b == 0 ... v is undefined, s = 0
s = 0.0;
h = 0.0;
return;
}
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if (delta != 0.0) {
if (cmax == r) {
h = fmod ((g - b)/delta, 6.0);
} else if (cmax == g) {
h = ((b - r)/delta) + 2;
} else {
h = ((r - g)/delta) + 4;
}
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h *= 60.0;
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if (h < 0.0) {
/* negative values are legal but confusing, because
they alias positive values.
*/
h = 360 + h;
}
}
if (delta == 0 || cmax == 0) {
s = 0;
} else {
s = delta / cmax;
}
}
Gtkmm2ext::Color
Gtkmm2ext::hsva_to_color (double h, double s, double v, double a)
{
s = min (1.0, max (0.0, s));
v = min (1.0, max (0.0, v));
if (s == 0) {
return rgba_to_color (v, v, v, a);
}
h = fmod (h + 360.0, 360.0);
double c = v * s;
double x = c * (1.0 - fabs(fmod(h / 60.0, 2) - 1.0));
double m = v - c;
if (h >= 0.0 && h < 60.0) {
return rgba_to_color (c + m, x + m, m, a);
} else if (h >= 60.0 && h < 120.0) {
return rgba_to_color (x + m, c + m, m, a);
} else if (h >= 120.0 && h < 180.0) {
return rgba_to_color (m, c + m, x + m, a);
} else if (h >= 180.0 && h < 240.0) {
return rgba_to_color (m, x + m, c + m, a);
} else if (h >= 240.0 && h < 300.0) {
return rgba_to_color (x + m, m, c + m, a);
} else if (h >= 300.0 && h < 360.0) {
return rgba_to_color (c + m, m, x + m, a);
}
return rgba_to_color (m, m, m, a);
}
void
Gtkmm2ext::color_to_rgba (Color color, double& r, double& g, double& b, double& a)
{
r = ((color >> 24) & 0xff) / 255.0;
g = ((color >> 16) & 0xff) / 255.0;
b = ((color >> 8) & 0xff) / 255.0;
a = ((color >> 0) & 0xff) / 255.0;
}
Gtkmm2ext::Color
Gtkmm2ext::rgba_to_color (double r, double g, double b, double a)
{
/* clamp to [0 .. 1] range */
r = min (1.0, max (0.0, r));
g = min (1.0, max (0.0, g));
b = min (1.0, max (0.0, b));
a = min (1.0, max (0.0, a));
/* convert to [0..255] range */
unsigned int rc, gc, bc, ac;
rc = rint (r * 255.0);
gc = rint (g * 255.0);
bc = rint (b * 255.0);
ac = rint (a * 255.0);
/* build-an-integer */
return (rc << 24) | (gc << 16) | (bc << 8) | ac;
}
// Inverse of sRGB "gamma" function.
static inline double
inv_gam_sRGB (double c)
{
if (c <= 0.04045) {
return c/12.92;
} else {
return pow(((c+0.055)/(1.055)),2.4);
}
}
// sRGB "gamma" function
static inline int
gam_sRGB(double v)
{
if (v <= 0.0031308) {
v *= 12.92;
} else {
v = 1.055 * pow (v, 1.0 / 2.4) - 0.055;
}
return int (v*255+.5);
}
static double
luminance (uint32_t c)
{
// sRGB luminance(Y) values
const double rY = 0.212655;
const double gY = 0.715158;
const double bY = 0.072187;
double r, g, b, a;
Gtkmm2ext::color_to_rgba (c, r, g, b, a);
return (gam_sRGB (rY*inv_gam_sRGB(r) + gY*inv_gam_sRGB(g) + bY*inv_gam_sRGB(b))) / 255.0;
}
uint32_t
Gtkmm2ext::contrasting_text_color (uint32_t c)
{
/* use a slightly off-white... XXX should really look this up */
static const uint32_t white = Gtkmm2ext::rgba_to_color (0.98, 0.98, 0.98, 1.0);
static const uint32_t black = Gtkmm2ext::rgba_to_color (0.0, 0.0, 0.0, 1.0);
return (luminance (c) < 0.50) ? white : black;
}
HSV::HSV ()
: h (0.0)
, s (1.0)
, v (1.0)
, a (1.0)
{
}
HSV::HSV (double hh, double ss, double vv, double aa)
: h (hh)
, s (ss)
, v (vv)
, a (aa)
{
if (h < 0.0) {
/* normalize negative hue values into positive range */
h = 360.0 + h;
}
s = max (0.0, min (1.0, s));
v = max (0.0, min (1.0, v));
a = max (0.0, min (1.0, a));
}
HSV::HSV (Color c)
{
color_to_hsva (c, h, s, v, a);
}
string
HSV::to_string () const
{
stringstream ss;
ss << PBD::to_string(h) << ' ';
ss << PBD::to_string(s) << ' ';
ss << PBD::to_string(v) << ' ';
ss << PBD::to_string(a);
return ss.str();
}
bool
HSV::is_gray () const
{
return s == 0;
}
void
HSV::clamp ()
{
h = fmod (h, 360.0);
if (h < 0.0) {
/* normalize negative hue values into positive range */
h = 360.0 + h;
}
s = min (1.0, s);
v = min (1.0, v);
a = min (1.0, a);
}
HSV
HSV::operator+ (const HSV& operand) const
{
HSV hsv;
hsv.h = h + operand.h;
hsv.s = s + operand.s;
hsv.v = v + operand.v;
hsv.a = a + operand.a;
hsv.clamp ();
return hsv;
}
HSV
HSV::operator- (const HSV& operand) const
{
HSV hsv;
hsv.h = h - operand.h;
hsv.s = s - operand.s;
hsv.v = s - operand.v;
hsv.a = a - operand.a;
hsv.clamp ();
return hsv;
}
HSV&
HSV::operator=(Color c)
{
color_to_hsva (c, h, s, v, a);
clamp ();
return *this;
}
HSV&
HSV::operator=(const std::string& str)
{
uint32_t c;
c = strtol (str.c_str(), 0, 16);
color_to_hsva (c, h, s, v, a);
clamp ();
return *this;
}
bool
HSV::operator== (const HSV& other)
{
return h == other.h &&
s == other.s &&
v == other.v &&
a == other.a;
}
HSV
HSV::darker (double factor) const
{
HSV hsv (*this);
/* factor == 1.0: reduce all the way to zero */
hsv.v -= max (0.0, min (1.0, factor)) * hsv.v;
return hsv;
}
HSV
HSV::lighter (double factor) const
{
HSV hsv (*this);
/* factor == 1.0: increase all the way to 1.0 */
hsv.v += max (0.0, min (1.0, factor)) * (1.0 - hsv.v);
return hsv;
}
HSV
HSV::shade (double factor) const
{
HSV hsv (*this);
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/* algorithm derived from a google palette website
and analysis of their color palettes.
basic rule: to make a color darker, increase its saturation
until it reaches 88%, but then additionally reduce value/lightness
by a larger amount.
invert rule to make a color lighter.
*/
if (factor > 1.0) {
/* darker */
/* increase saturation (factor is > 1.0, so s grows) */
hsv.s *= factor;
if (hsv.s >= 0.88) {
/* above saturation threshold, so decrease v a bit */
hsv.v -= (hsv.v * 0.05);
}
} else {
/* lighter */
/* reduce saturation, (factor is < 1.0, so s shrinks) */
hsv.s *= factor;
if (hsv.s > 0.88) {
/* still above 88% saturation, so increase v a bit */
hsv.v += (hsv.v * 0.05);
}
}
hsv.clamp();
return hsv;
}
HSV
HSV::outline () const
{
if (luminance (color()) < 0.50) {
/* light color, darker outline: black with 15% opacity */
return HSV (0.0, 0.0, 0.0, 0.15);
} else {
/* dark color, lighter outline: white with 15% opacity */
return HSV (0.0, 0.0, 1.0, 0.15);
}
}
HSV
HSV::mix (const HSV& other, double amount) const
{
HSV hsv;
hsv.h = h + (amount * (other.h - h));
hsv.v = v + (amount * (other.s - s));
hsv.s = s + (amount * (other.v - v));
hsv.clamp();
return hsv;
}
HSV
HSV::delta (const HSV& other) const
{
HSV d;
if (is_gray() && other.is_gray()) {
d.h = 0.0;
d.s = 0.0;
d.v = v - other.v;
} else {
d.h = h - other.h;
d.s = s - other.s;
d.v = v - other.v;
}
d.a = a - other.a;
/* do not clamp - we are returning a delta */
return d;
}
double
HSV::distance (const HSV& other) const
{
if (is_gray() && other.is_gray()) {
/* human color perception of achromatics generates about 450
distinct colors. By contrast, CIE94 could give a maximal
perceptual distance of sqrt ((360^2) + 1 + 1) = 360. The 450
are not evenly spread (Webers Law), so lets use 360 as an
approximation of the number of distinct achromatics.
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So, scale up the achromatic difference to give about
a maximal distance between v = 1.0 and v = 0.0 of 360.
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A difference of about 0.0055 will generate a return value of
2, which is roughly the limit of human perceptual
discrimination for chromatics.
*/
return fabs (360.0 * (v - other.v));
}
if (is_gray() != other.is_gray()) {
/* no comparison possible */
return DBL_MAX;
}
/* Use CIE94 definition for now */
double sL, sA, sB;
double oL, oA, oB;
double r, g, b, alpha; // Careful, "a" is a field of this
Color c;
c = hsva_to_color (h, s, v, a);
color_to_rgba (c, r, g, b, alpha);
Rgb2Lab (&sL, &sA, &sB, r, g, b);
c = hsva_to_color (other.h, other.s, other.v, other.a);
color_to_rgba (c, r, g, b, alpha);
Rgb2Lab (&oL, &oA, &oB, r, g, b);
// Weighting factors depending on the application (1 = default)
const double whtL = 1.0;
const double whtC = 1.0;
const double whtH = 1.0;
const double xC1 = sqrt ((sA * sA) + (sB * oB));
const double xC2 = sqrt ((oA * oA) + (oB * oB));
double xDL = oL - sL;
double xDC = xC2 - xC1;
const double xDE = sqrt (((sL - oL) * (sL - oL))
+ ((sA - oA) * (sA - oA))
+ ((sB - oB) * (sB - oB)));
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double xDH;
if (sqrt (xDE) > (sqrt (abs (xDL)) + sqrt (abs (xDC)))) {
xDH = sqrt ((xDE * xDE) - (xDL * xDL) - (xDC * xDC));
} else {
xDH = 0;
}
const double xSC = 1 + (0.045 * xC1);
const double xSH = 1 + (0.015 * xC1);
xDL /= whtL;
xDC /= whtC * xSC;
xDH /= whtH * xSH;
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return sqrt ((xDL * xDL) + (xDC * xDC) + (xDH * xDH));
}
HSV
HSV::opposite () const
{
HSV hsv (*this);
hsv.h = fmod (h + 180.0, 360.0);
return hsv;
}
HSV
HSV::bw_text () const
{
return HSV (contrasting_text_color (color()));
}
HSV
HSV::text () const
{
return opposite ();
}
HSV
HSV::selected () const
{
/* XXX hack */
return HSV (Color (0xff0000));
}
void
HSV::print (std::ostream& o) const
{
if (!is_gray()) {
o << '(' << h << ',' << s << ',' << v << ',' << a << ')';
} else {
o << "gray(" << v << ')';
}
}
std::ostream& operator<<(std::ostream& o, const Gtkmm2ext::HSV& hsv) { hsv.print (o); return o; }
HSV
HSV::mod (SVAModifier const & svam)
{
return svam (*this);
}
SVAModifier::SVAModifier (string const &str)
: type (Add)
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, _s (0)
, _v (0)
, _a (0)
{
from_string (str);
}
void
SVAModifier::from_string (string const & str)
{
char op;
stringstream ss (str);
string mod;
ss >> op;
switch (op) {
case '*':
type = Multiply;
/* no-op values for multiply */
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_s = 1.0;
_v = 1.0;
_a = 1.0;
break;
case '+':
type = Add;
/* no-op values for add */
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_s = 0.0;
_v = 0.0;
_a = 0.0;
break;
case '=':
type = Assign;
/* this will avoid assignment in operator() (see below) */
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_s = -1.0;
_v = -1.0;
_a = -1.0;
break;
default:
throw failed_constructor ();
}
string::size_type pos;
while (ss) {
ss >> mod;
if ((pos = mod.find ("alpha:")) != string::npos) {
_a = PBD::string_to<double>(mod.substr (pos+6));
} else if ((pos = mod.find ("saturate:")) != string::npos) {
_s = PBD::string_to<double>(mod.substr (pos+9));
} else if ((pos = mod.find ("darkness:")) != string::npos) {
_v = PBD::string_to<double>(mod.substr (pos+9));
} else {
throw failed_constructor ();
}
}
}
string
SVAModifier::to_string () const
{
stringstream ss;
switch (type) {
case Add:
ss << '+';
break;
case Multiply:
ss << '*';
break;
case Assign:
ss << '=';
break;
}
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if (_s >= 0.0) {
ss << " saturate:" << PBD::to_string(_s);
}
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if (_v >= 0.0) {
ss << " darker:" << PBD::to_string(_v);
}
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if (_a >= 0.0) {
ss << " alpha:" << PBD::to_string(_a);
}
return ss.str();
}
HSV
SVAModifier::operator () (HSV& hsv) const
{
HSV r (hsv);
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switch (type) {
case Add:
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r.s += _s;
r.v += _v;
r.a += _a;
break;
case Multiply:
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r.s *= _s;
r.v *= _v;
r.a *= _a;
break;
case Assign:
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if (_s >= 0.0) {
r.s = _s;
}
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if (_v >= 0.) {
r.v = _v;
}
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if (_a >= 0.0) {
r.a = _a;
}
break;
}
return r;
}
Color
Gtkmm2ext::color_at_alpha (Gtkmm2ext::Color c, double a)
{
double r, g, b, unused;
color_to_rgba (c, r, g, b, unused);
return rgba_to_color( r,g,b, a );
}
void
Gtkmm2ext::set_source_rgba (Cairo::RefPtr<Cairo::Context> context, Color color)
{
context->set_source_rgba (
((color >> 24) & 0xff) / 255.0,
((color >> 16) & 0xff) / 255.0,
((color >> 8) & 0xff) / 255.0,
((color >> 0) & 0xff) / 255.0
);
}
void
Gtkmm2ext::set_source_rgb_a (Cairo::RefPtr<Cairo::Context> context, Color color, float alpha)
{
context->set_source_rgba (
((color >> 24) & 0xff) / 255.0,
((color >> 16) & 0xff) / 255.0,
((color >> 8) & 0xff) / 255.0,
alpha
);
}
void
Gtkmm2ext::set_source_rgba (cairo_t *cr, Color color)
{
cairo_set_source_rgba ( cr,
((color >> 24) & 0xff) / 255.0,
((color >> 16) & 0xff) / 255.0,
((color >> 8) & 0xff) / 255.0,
((color >> 0) & 0xff) / 255.0
);
}
void
Gtkmm2ext::set_source_rgb_a (cairo_t *cr, Color color, float alpha)
{
cairo_set_source_rgba ( cr,
((color >> 24) & 0xff) / 255.0,
((color >> 16) & 0xff) / 255.0,
((color >> 8) & 0xff) / 255.0,
alpha
);
}
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Color
Gtkmm2ext::random_color ()
{
return ((random() % 16777215) << 8 | 0xff);
}