diff options
author | Paul Davis <paul@linuxaudiosystems.com> | 2014-11-07 14:24:13 -0500 |
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committer | Paul Davis <paul@linuxaudiosystems.com> | 2014-11-07 14:24:13 -0500 |
commit | 69fd25f6f406940411183f65ecd7fb956306321b (patch) | |
tree | 597314e935c4c13900f439f377763369de31d1af /libs | |
parent | 1e8645bb8e16b6dbb0aeb578aae46d4c9c1246f3 (diff) |
move canvas colors code into its own file(s)
Diffstat (limited to 'libs')
-rw-r--r-- | libs/canvas/canvas/colors.h | 35 | ||||
-rw-r--r-- | libs/canvas/colors.cc | 193 |
2 files changed, 228 insertions, 0 deletions
diff --git a/libs/canvas/canvas/colors.h b/libs/canvas/canvas/colors.h new file mode 100644 index 0000000000..80d57c698f --- /dev/null +++ b/libs/canvas/canvas/colors.h @@ -0,0 +1,35 @@ +/* + Copyright (C) 2011-2013 Paul Davis + Author: Carl Hetherington <cth@carlh.net> + + 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., 675 Mass Ave, Cambridge, MA 02139, USA. +*/ + +#include <cairomm/context.h> + +#include "canvas/visibility.h" +#include "canvas/types.h" + +namespace ArdourCanvas { + + extern LIBCANVAS_API void color_to_hsv (Color color, double& h, double& s, double& v); + extern LIBCANVAS_API Color hsv_to_color (double h, double s, double v, double a); + + extern LIBCANVAS_API void color_to_rgba (Color, double& r, double& g, double& b, double& a); + extern LIBCANVAS_API Color rgba_to_color (double r, double g, double b, double a); + + uint32_t LIBCANVAS_API contrasting_text_color (uint32_t c); +} + diff --git a/libs/canvas/colors.cc b/libs/canvas/colors.cc new file mode 100644 index 0000000000..3c638935ec --- /dev/null +++ b/libs/canvas/colors.cc @@ -0,0 +1,193 @@ +/* + Copyright (C) 2014 Paul Davis + + 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., 675 Mass Ave, Cambridge, MA 02139, USA. +*/ + +#include <algorithm> +#include <cmath> +#include <stdint.h> + +#include "canvas/colors.h" + +using namespace std; +using namespace ArdourCanvas; + +using std::max; +using std::min; + +void +ArdourCanvas::color_to_hsv (Color color, double& h, double& s, double& v) +{ + double r, g, b, a; + double cmax; + double cmin; + double delta; + + color_to_rgba (color, r, g, b, a); + + 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 = -1.0; + } + + 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; + } + + h *= 60.0; + } + + if (delta == 0 || cmax == 0) { + s = 0; + } else { + s = delta / cmax; + } + +} + +ArdourCanvas::Color +ArdourCanvas::hsv_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) { + // achromatic (grey) + return rgba_to_color (v, v, v, a); + } + + h = min (360.0, max (0.0, h)); + + 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 +ArdourCanvas::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; +} + +ArdourCanvas::Color +ArdourCanvas::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; + + ArdourCanvas::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 +ArdourCanvas::contrasting_text_color (uint32_t c) +{ + static const uint32_t white = ArdourCanvas::rgba_to_color (1.0, 1.0, 1.0, 1.0); + static const uint32_t black = ArdourCanvas::rgba_to_color (0.0, 0.0, 0.0, 1.0); + + return (luminance (c) < 0.50) ? white : black; +} |