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Diffstat (limited to 'libs/canvas/utils.cc')
-rw-r--r-- | libs/canvas/utils.cc | 156 |
1 files changed, 156 insertions, 0 deletions
diff --git a/libs/canvas/utils.cc b/libs/canvas/utils.cc new file mode 100644 index 0000000000..b431042c35 --- /dev/null +++ b/libs/canvas/utils.cc @@ -0,0 +1,156 @@ +/* + 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 <algorithm> +#include <cmath> +#include <stdint.h> +#include <cairomm/context.h> +#include "canvas/utils.h" + +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; +} + +void +ArdourCanvas::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 + ); +} + |