382 lines
7.1 KiB
C++
382 lines
7.1 KiB
C++
/*
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Copyright (C) 2014 Paul Davis
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program; if not, write to the Free Software
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Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
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*/
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#include <algorithm>
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#include <cmath>
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#include <stdint.h>
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#include "canvas/colors.h"
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using namespace std;
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using namespace ArdourCanvas;
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using std::max;
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using std::min;
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void
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ArdourCanvas::color_to_hsv (Color color, double& h, double& s, double& v)
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{
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double r, g, b, a;
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double cmax;
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double cmin;
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double delta;
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color_to_rgba (color, r, g, b, a);
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if (r > g) {
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cmax = max (r, b);
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} else {
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cmax = max (g, b);
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}
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if (r < g) {
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cmin = min (r, b);
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} else {
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cmin = min (g, b);
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}
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v = cmax;
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delta = cmax - cmin;
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if (cmax == 0) {
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// r = g = b == 0 ... v is undefined, s = 0
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s = 0.0;
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h = -1.0;
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}
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if (delta != 0.0) {
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if (cmax == r) {
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h = fmod ((g - b)/delta, 6.0);
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} else if (cmax == g) {
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h = ((b - r)/delta) + 2;
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} else {
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h = ((r - g)/delta) + 4;
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}
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h *= 60.0;
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}
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if (delta == 0 || cmax == 0) {
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s = 0;
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} else {
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s = delta / cmax;
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}
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}
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ArdourCanvas::Color
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ArdourCanvas::hsv_to_color (const HSV& hsv, double a)
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{
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return hsv_to_color (hsv.h, hsv.s, hsv.v, a);
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}
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ArdourCanvas::Color
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ArdourCanvas::hsv_to_color (double h, double s, double v, double a)
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{
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s = min (1.0, max (0.0, s));
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v = min (1.0, max (0.0, v));
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if (s == 0) {
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// achromatic (grey)
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return rgba_to_color (v, v, v, a);
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}
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h = min (360.0, max (0.0, h));
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double c = v * s;
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double x = c * (1.0 - fabs(fmod(h / 60.0, 2) - 1.0));
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double m = v - c;
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if (h >= 0.0 && h < 60.0) {
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return rgba_to_color (c + m, x + m, m, a);
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} else if (h >= 60.0 && h < 120.0) {
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return rgba_to_color (x + m, c + m, m, a);
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} else if (h >= 120.0 && h < 180.0) {
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return rgba_to_color (m, c + m, x + m, a);
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} else if (h >= 180.0 && h < 240.0) {
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return rgba_to_color (m, x + m, c + m, a);
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} else if (h >= 240.0 && h < 300.0) {
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return rgba_to_color (x + m, m, c + m, a);
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} else if (h >= 300.0 && h < 360.0) {
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return rgba_to_color (c + m, m, x + m, a);
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}
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return rgba_to_color (m, m, m, a);
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}
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void
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ArdourCanvas::color_to_rgba (Color color, double& r, double& g, double& b, double& a)
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{
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r = ((color >> 24) & 0xff) / 255.0;
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g = ((color >> 16) & 0xff) / 255.0;
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b = ((color >> 8) & 0xff) / 255.0;
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a = ((color >> 0) & 0xff) / 255.0;
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}
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ArdourCanvas::Color
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ArdourCanvas::rgba_to_color (double r, double g, double b, double a)
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{
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/* clamp to [0 .. 1] range */
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r = min (1.0, max (0.0, r));
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g = min (1.0, max (0.0, g));
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b = min (1.0, max (0.0, b));
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a = min (1.0, max (0.0, a));
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/* convert to [0..255] range */
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unsigned int rc, gc, bc, ac;
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rc = rint (r * 255.0);
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gc = rint (g * 255.0);
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bc = rint (b * 255.0);
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ac = rint (a * 255.0);
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/* build-an-integer */
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return (rc << 24) | (gc << 16) | (bc << 8) | ac;
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}
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// Inverse of sRGB "gamma" function.
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static inline double
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inv_gam_sRGB (double c)
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{
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if (c <= 0.04045) {
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return c/12.92;
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} else {
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return pow(((c+0.055)/(1.055)),2.4);
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}
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}
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// sRGB "gamma" function
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static inline int
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gam_sRGB(double v)
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{
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if (v <= 0.0031308) {
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v *= 12.92;
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} else {
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v = 1.055 * pow (v, 1.0 / 2.4) - 0.055;
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}
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return int (v*255+.5);
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}
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static double
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luminance (uint32_t c)
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{
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// sRGB luminance(Y) values
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const double rY = 0.212655;
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const double gY = 0.715158;
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const double bY = 0.072187;
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double r, g, b, a;
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ArdourCanvas::color_to_rgba (c, r, g, b, a);
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return (gam_sRGB (rY*inv_gam_sRGB(r) + gY*inv_gam_sRGB(g) + bY*inv_gam_sRGB(b))) / 255.0;
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}
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uint32_t
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ArdourCanvas::contrasting_text_color (uint32_t c)
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{
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static const uint32_t white = ArdourCanvas::rgba_to_color (1.0, 1.0, 1.0, 1.0);
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static const uint32_t black = ArdourCanvas::rgba_to_color (0.0, 0.0, 0.0, 1.0);
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return (luminance (c) < 0.50) ? white : black;
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}
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HSV::HSV ()
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: h (1.0)
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, s (1.0)
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, v (1.0)
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{
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}
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HSV::HSV (double hh, double ss, double vv)
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: h (hh)
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, s (ss)
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, v (vv)
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{
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}
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HSV::HSV (Color c)
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{
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color_to_hsv (c, h, s, v);
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}
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void
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HSV::clamp ()
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{
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s = min (s, 1.0);
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v = min (v, 1.0);
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h = min (255.0, h);
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}
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HSV
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HSV::operator+ (const HSV& operand) const
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{
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HSV hsv;
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hsv.h = h + operand.h;
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hsv.s = s + operand.s;
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hsv.v = v + operand.v;
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hsv.clamp();
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return hsv;
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}
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HSV
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HSV::operator- (const HSV& operand) const
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{
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HSV hsv;
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hsv.h = h - operand.h;
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hsv.s = s - operand.s;
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hsv.v = v - operand.v;
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hsv.clamp();
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return hsv;
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}
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HSV
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HSV::operator* (double d) const
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{
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HSV hsv;
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hsv.h = h * d;
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hsv.s = s * d;
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hsv.v = v * d;
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hsv.clamp();
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return hsv;
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}
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HSV
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HSV::shade (double factor) const
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{
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HSV hsv (*this);
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/* algorithm derived from a google palette website
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and analysis of their color palettes.
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basic rule: to make a color darker, increase its saturation
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until it reaches 88%, but then additionally reduce value/lightness
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by a larger amount.
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invert rule to make a color lighter.
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*/
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if (factor > 1.0) {
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if (s < 88) {
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hsv.v *= 1.0/(factor/10.0);
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} else {
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hsv.s *= factor;
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}
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} else {
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if (s < 88) {
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hsv.v *= 1.0/factor;
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} else {
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hsv.s *= factor;
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}
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}
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hsv.clamp();
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return hsv;
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}
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HSV
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HSV::mix (const HSV& other, double amount) const
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{
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HSV hsv;
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hsv.h = h + (amount * (other.h - h));
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hsv.v = v + (amount * (other.s - s));
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hsv.s = s + (amount * (other.v - v));
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hsv.clamp();
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return hsv;
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}
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void
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HSV::print (std::ostream& o) const
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{
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if (!is_gray()) {
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o << "hsv " << h << '|' << s << '|' << v;
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} else {
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o << "hsv gray";
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}
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}
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HSVA::HSVA ()
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: a (1.0)
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{
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}
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HSVA::HSVA (double hh, double ss, double vv, double aa)
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: HSV (hh, ss, vv)
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, a (aa)
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{
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}
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HSVA::HSVA (Color c)
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{
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color_to_hsv (c, h, s, v);
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a = c & 0xff;
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}
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void
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HSVA::clamp ()
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{
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HSV::clamp ();
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a = min (1.0, a);
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}
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HSVA
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HSVA::operator+ (const HSVA& operand) const
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{
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HSVA hsv;
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hsv.h = h + operand.h;
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hsv.s = s + operand.s;
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hsv.v = v + operand.v;
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hsv.a = a + operand.a;
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return hsv;
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}
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HSVA
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HSVA::operator- (const HSVA& operand) const
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{
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HSVA hsv;
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hsv.h = h - operand.h;
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hsv.s = s - operand.s;
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hsv.a = a - operand.a;
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return hsv;
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}
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void
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HSVA::print (std::ostream& o) const
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{
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if (!is_gray()) {
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o << "hsva " << h << '|' << s << '|' << v << '|' << a;
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} else {
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o << "hsva gray";
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}
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}
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ArdourCanvas::Color
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ArdourCanvas::hsva_to_color (const HSVA& hsva)
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{
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return hsv_to_color (hsva.h, hsva.s, hsva.v, hsva.a);
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}
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std::ostream& operator<<(std::ostream& o, const ArdourCanvas::HSV& hsv) { hsv.print (o); return o; }
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std::ostream& operator<<(std::ostream& o, const ArdourCanvas::HSVA& hsva) { hsva.print (o); return o; }
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