From d25e0a72f48fe9efe4ec799e4c24671cf04c1b5f Mon Sep 17 00:00:00 2001 From: isaac Date: Mon, 9 Nov 2020 01:08:27 +0700 Subject: [PATCH] added hsv gradient --- src/colours.cc | 166 +++++++++++++++++++++++++++++++++++++++++++++++++ src/colours.h | 1 + 2 files changed, 167 insertions(+) diff --git a/src/colours.cc b/src/colours.cc index efd14086..d6a8b220 100644 --- a/src/colours.cc +++ b/src/colours.cc @@ -36,6 +36,18 @@ #define CONST_8_TO_5_BITS 0.12156862745098 #define CONST_8_TO_6_BITS 0.247058823529412 +#define CONST_SCALE 512L +#define CONST_SCALE_HALF (CONST_SCALE / 2) +#define CONST_SCALE2 (CONST_SCALE * 2L) +#define CONST_SCALE4 (CONST_SCALE * 4L) +#define CONST_SCALE6 (CONST_SCALE * 6L) +#define CONST_SCALE60 (CONST_SCALE * 60L) +#define CONST_SCALE120 (CONST_SCALE * 120L) +#define CONST_SCALE180 (CONST_SCALE * 180L) +#define CONST_SCALE240 (CONST_SCALE * 240L) +#define CONST_SCALE300 (CONST_SCALE * 300L) +#define CONST_SCALE360 (CONST_SCALE * 360L) + static short colour_depth = 0; static long redmask, greenmask, bluemask; @@ -144,6 +156,160 @@ unsigned long *do_gradient(int width, unsigned long first_colour, return colours; } +long to_decimal_scale(long value, long max_value) { + if (value == 0) { + return 0; + } else if (value > 0) { + return (value * CONST_SCALE + max_value - 1) / max_value; + } + return -((abs(value) * CONST_SCALE + max_value - 1) / max_value); +} + +long from_decimal_scale(long value, long max_value) { + if (value == 0) { + return 0; + } else if (value > 0) { + return (value * max_value + CONST_SCALE_HALF) / CONST_SCALE; + } + return -((abs(value) * max_value + CONST_SCALE_HALF) / CONST_SCALE); +} + +void scaled_rgb_to_scaled_hsv(long * const rgb, long *hsv) { + long val = rgb[0] > rgb[1] ? MAX(rgb[0], rgb[2]) : MAX(rgb[1], rgb[2]); + long cmin = rgb[0] < rgb[1] ? MIN(rgb[0], rgb[2]) : MIN(rgb[1], rgb[2]); + long delta = val - cmin; + + long hue; + + if (delta == 0) { + hue = 0; + } else { + long d; + long offset; + + if (rgb[0] == val) { + d = rgb[1] - rgb[2]; + offset = 0; + } else if (rgb[1] == val) { + d = rgb[2] - rgb[0]; + offset = CONST_SCALE2; + } else { + d = rgb[0] - rgb[1]; + offset = CONST_SCALE4; + } + long h = (CONST_SCALE * d + delta / 2) / delta + offset; + hue = 60L * ((CONST_SCALE6 + h) % CONST_SCALE6); + } + + long sat; + if (val == 0) { + sat = 0; + } else { + sat = (CONST_SCALE * delta + val / 2) / val; + } + + hsv[0] = hue; + hsv[1] = sat; + hsv[2] = val; +} + +void scaled_hsv_to_scaled_rgb(long *const hsv, long *rgb) { + long c = (hsv[2] * hsv[1] + CONST_SCALE_HALF) / CONST_SCALE; + + long hue = hsv[0] % CONST_SCALE360; + long x = (c * + (CONST_SCALE - abs(((hue + 30L) / 60L) % CONST_SCALE2 - CONST_SCALE)) + + CONST_SCALE_HALF) / CONST_SCALE; + long m = hsv[2] - c; + + rgb[0] = m; + rgb[1] = m; + rgb[2] = m; + + if (hue < CONST_SCALE60) { + rgb[0] += c; + rgb[1] += x; + } else if (hue < CONST_SCALE120) { + rgb[0] += x; + rgb[1] += c; + } else if (hue < CONST_SCALE180) { + rgb[1] += c; + rgb[2] += x; + } else if (hue < CONST_SCALE240) { + rgb[1] += x; + rgb[2] += c; + } else if (hue < CONST_SCALE300) { + rgb[2] += c; + rgb[0] += x; + } else { + rgb[2] += x; + rgb[0] += c; + } +} + +/* this function returns the next colour between two colours in hsv space for a gradient */ +unsigned long *do_hsv_gradient( + int width, + unsigned long first_colour, + unsigned long last_colour) { + + long rgb1[3], rgb2[3], rgb3[3]; + long hsv1[3], hsv2[3]; + long hueDiff, satDiff, valDiff; + + int redshift = (2 * colour_depth / 3 + colour_depth % 3); + int greenshift = (colour_depth / 3); + auto *colours = + static_cast(malloc(width * sizeof(unsigned long))); + int i; + + if (colour_depth == 0) { set_up_gradient(); } + + rgb1[0] = to_decimal_scale((first_colour & redmask) >> redshift, redmask >> redshift); + rgb1[1] = to_decimal_scale((first_colour & greenmask) >> greenshift, greenmask >> greenshift); + rgb1[2] = to_decimal_scale(first_colour & bluemask, bluemask); + rgb2[0] = to_decimal_scale((last_colour & redmask) >> redshift, redmask >> redshift); + rgb2[1] = to_decimal_scale((last_colour & greenmask) >> greenshift, greenmask >> greenshift); + rgb2[2] = to_decimal_scale(last_colour & bluemask, bluemask); + + scaled_rgb_to_scaled_hsv(rgb1, hsv1); + scaled_rgb_to_scaled_hsv(rgb2, hsv2); + + hueDiff = hsv2[0] - hsv1[0]; + satDiff = hsv2[1] - hsv1[1]; + valDiff = hsv2[2] - hsv1[2]; + + colours[0] = first_colour; + colours[width - 1] = last_colour; + + for (i = 1; i < (width - 1); i++) { + long k; + + long divisor = width - i; + k = (hueDiff + divisor / 2) / divisor; + hueDiff -= k; + hsv1[0] += k; + + k = (satDiff + divisor / 2) / divisor; + satDiff -= k; + hsv1[1] += k; + + k = (valDiff + divisor / 2) / divisor; + valDiff -= k; + hsv1[2] += k; + + scaled_hsv_to_scaled_rgb(hsv1, rgb3); + + long red3 = from_decimal_scale(rgb3[0], bluemask); + long green3 = from_decimal_scale(rgb3[1], bluemask); + long blue3 = from_decimal_scale(rgb3[2], bluemask); + + colours[i] = (red3 << redshift) | (green3 << greenshift) | blue3; + + } + return colours; +} + #ifdef BUILD_X11 long get_x11_color(const char *name) { XColor color; diff --git a/src/colours.h b/src/colours.h index 0a468771..b8f8d4d4 100644 --- a/src/colours.h +++ b/src/colours.h @@ -33,6 +33,7 @@ unsigned int adjust_colours(unsigned int); unsigned long *do_gradient(int, unsigned long, unsigned long); +unsigned long *do_hsv_gradient(int, unsigned long, unsigned long); long get_x11_color(const std::string &colour); // XXX: when everyone uses C++ strings, remove this C version