diff options
Diffstat (limited to 'widgets/misc')
| -rw-r--r-- | widgets/misc/e-hsv-utils.c | 166 | ||||
| -rw-r--r-- | widgets/misc/e-hsv-utils.h | 31 |
2 files changed, 197 insertions, 0 deletions
diff --git a/widgets/misc/e-hsv-utils.c b/widgets/misc/e-hsv-utils.c new file mode 100644 index 0000000000..31561436dd --- /dev/null +++ b/widgets/misc/e-hsv-utils.c @@ -0,0 +1,166 @@ +/* -*- Mode: C; tab-width: 8; indent-tabs-mode: t; c-basic-offset: 8 -*- */ +/* + * e-hsv-utils.c: utilites for manipulating colours in HSV space + * + * Author: + * Seth Nickell <seth@eazel.com> + * + * Copyright (C) 1995-2001 Seth Nickell, Peter Mattis, Spencer Kimball and Josh MacDonald + * + */ + +#include <config.h> + +#include "e-hsv-utils.h" + +/* tweak_hsv is a really tweaky function. it modifies its first argument, which + should be the colour you want tweaked. delta_h, delta_s and delta_v specify + how much you want their respective channels modified (and in what direction). + if it can't do the specified modification, it does it in the oppositon direction */ +void +e_hsv_tweak (GdkColor *colour, gdouble delta_h, gdouble delta_s, gdouble delta_v) +{ + gdouble h, s, v, r, g, b; + + r = colour->red / 65535.0f; + g = colour->green / 65535.0f; + b = colour->blue / 65535.0f; + + e_rgb_to_hsv (r, g, b, &h, &s, &v); + + if (h + delta_h < 0) { + h -= delta_h; + } else { + h += delta_h; + } + + if (s + delta_s < 0) { + s -= delta_s; + } else { + s += delta_s; + } + + if (v + delta_v < 0) { + v -= delta_v; + } else { + v += delta_v; + } + + e_hsv_to_rgb (h, s, v, &r, &g, &b); + + colour->red = r * 65535.0f; + colour->green = g * 65535.0f; + colour->blue = b * 65535.0f; +} + +/* Copy n' Paste code from the GTK+ colour selector (gtkcolorsel.c) */ +/* Originally lifted, I suspect, from "Foley, van Dam" */ +void +e_hsv_to_rgb (gdouble h, gdouble s, gdouble v, + gdouble *r, gdouble *g, gdouble *b) +{ + gint i; + gdouble f, w, q, t; + + if (s == 0.0) + s = 0.000001; + + if (h == -1.0) + { + *r = v; + *g = v; + *b = v; + } + else + { + if (h == 360.0) + h = 0.0; + h = h / 60.0; + i = (gint) h; + f = h - i; + w = v * (1.0 - s); + q = v * (1.0 - (s * f)); + t = v * (1.0 - (s * (1.0 - f))); + + switch (i) + { + case 0: + *r = v; + *g = t; + *b = w; + break; + case 1: + *r = q; + *g = v; + *b = w; + break; + case 2: + *r = w; + *g = v; + *b = t; + break; + case 3: + *r = w; + *g = q; + *b = v; + break; + case 4: + *r = t; + *g = w; + *b = v; + break; + case 5: + *r = v; + *g = w; + *b = q; + break; + } + } +} + +void +e_rgb_to_hsv (gdouble r, gdouble g, gdouble b, + gdouble *h, gdouble *s, gdouble *v) +{ + double max, min, delta; + + max = r; + if (g > max) + max = g; + if (b > max) + max = b; + + min = r; + if (g < min) + min = g; + if (b < min) + min = b; + + *v = max; + + if (max != 0.0) + *s = (max - min) / max; + else + *s = 0.0; + + if (*s == 0.0) + *h = -1.0; + else + { + delta = max - min; + + if (r == max) + *h = (g - b) / delta; + else if (g == max) + *h = 2.0 + (b - r) / delta; + else if (b == max) + *h = 4.0 + (r - g) / delta; + + *h = *h * 60.0; + + if (*h < 0.0) + *h = *h + 360; + } +} + + diff --git a/widgets/misc/e-hsv-utils.h b/widgets/misc/e-hsv-utils.h new file mode 100644 index 0000000000..774d18585c --- /dev/null +++ b/widgets/misc/e-hsv-utils.h @@ -0,0 +1,31 @@ +/* -*- Mode: C; tab-width: 8; indent-tabs-mode: t; c-basic-offset: 8 -*- */ +#ifndef _E_HSV_UTILS_H_ +#define _E_HSV_UTILS_H_ + +#include <libgnome/gnome-defs.h> +#include <gdk/gdk.h> + +BEGIN_GNOME_DECLS + +void e_hsv_to_rgb (gdouble h, + gdouble s, + gdouble v, + gdouble *r, + gdouble *g, + gdouble *b); + +void e_rgb_to_hsv (gdouble r, + gdouble g, + gdouble b, + gdouble *h, + gdouble *s, + gdouble *v); + +void e_hsv_tweak (GdkColor *colour, + gdouble delta_h, + gdouble delta_s, + gdouble delta_v); + +END_GNOME_DECLS + +#endif /* _E_HSV_UTILS_H_ */ |