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Diffstat (limited to 'pixman/pixman/pixman-gradient-walker.c')
| -rw-r--r-- | pixman/pixman/pixman-gradient-walker.c | 254 |
1 files changed, 254 insertions, 0 deletions
diff --git a/pixman/pixman/pixman-gradient-walker.c b/pixman/pixman/pixman-gradient-walker.c new file mode 100644 index 000000000..dd666b412 --- /dev/null +++ b/pixman/pixman/pixman-gradient-walker.c @@ -0,0 +1,254 @@ +/* + * + * Copyright © 2000 Keith Packard, member of The XFree86 Project, Inc. + * 2005 Lars Knoll & Zack Rusin, Trolltech + * + * Permission to use, copy, modify, distribute, and sell this software and its + * documentation for any purpose is hereby granted without fee, provided that + * the above copyright notice appear in all copies and that both that + * copyright notice and this permission notice appear in supporting + * documentation, and that the name of Keith Packard not be used in + * advertising or publicity pertaining to distribution of the software without + * specific, written prior permission. Keith Packard makes no + * representations about the suitability of this software for any purpose. It + * is provided "as is" without express or implied warranty. + * + * THE COPYRIGHT HOLDERS DISCLAIM ALL WARRANTIES WITH REGARD TO THIS + * SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND + * FITNESS, IN NO EVENT SHALL THE COPYRIGHT HOLDERS BE LIABLE FOR ANY + * SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES + * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN + * AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING + * OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS + * SOFTWARE. + */ + +#ifdef HAVE_CONFIG_H +#include <config.h> +#endif +#include "pixman-private.h" + +void +_pixman_gradient_walker_init (pixman_gradient_walker_t *walker, + gradient_t * gradient, + unsigned int spread) +{ + walker->num_stops = gradient->n_stops; + walker->stops = gradient->stops; + walker->left_x = 0; + walker->right_x = 0x10000; + walker->stepper = 0; + walker->left_ag = 0; + walker->left_rb = 0; + walker->right_ag = 0; + walker->right_rb = 0; + walker->spread = spread; + + walker->need_reset = TRUE; +} + +void +_pixman_gradient_walker_reset (pixman_gradient_walker_t *walker, + pixman_fixed_32_32_t pos) +{ + int32_t x, left_x, right_x; + pixman_color_t *left_c, *right_c; + int n, count = walker->num_stops; + pixman_gradient_stop_t * stops = walker->stops; + + static const pixman_color_t transparent_black = { 0, 0, 0, 0 }; + + switch (walker->spread) + { + case PIXMAN_REPEAT_NORMAL: + x = (int32_t)pos & 0xFFFF; + for (n = 0; n < count; n++) + if (x < stops[n].x) + break; + if (n == 0) + { + left_x = stops[count - 1].x - 0x10000; + left_c = &stops[count - 1].color; + } + else + { + left_x = stops[n - 1].x; + left_c = &stops[n - 1].color; + } + + if (n == count) + { + right_x = stops[0].x + 0x10000; + right_c = &stops[0].color; + } + else + { + right_x = stops[n].x; + right_c = &stops[n].color; + } + left_x += (pos - x); + right_x += (pos - x); + break; + + case PIXMAN_REPEAT_PAD: + for (n = 0; n < count; n++) + if (pos < stops[n].x) + break; + + if (n == 0) + { + left_x = INT32_MIN; + left_c = &stops[0].color; + } + else + { + left_x = stops[n - 1].x; + left_c = &stops[n - 1].color; + } + + if (n == count) + { + right_x = INT32_MAX; + right_c = &stops[n - 1].color; + } + else + { + right_x = stops[n].x; + right_c = &stops[n].color; + } + break; + + case PIXMAN_REPEAT_REFLECT: + x = (int32_t)pos & 0xFFFF; + if ((int32_t)pos & 0x10000) + x = 0x10000 - x; + for (n = 0; n < count; n++) + if (x < stops[n].x) + break; + + if (n == 0) + { + left_x = -stops[0].x; + left_c = &stops[0].color; + } + else + { + left_x = stops[n - 1].x; + left_c = &stops[n - 1].color; + } + + if (n == count) + { + right_x = 0x20000 - stops[n - 1].x; + right_c = &stops[n - 1].color; + } + else + { + right_x = stops[n].x; + right_c = &stops[n].color; + } + + if ((int32_t)pos & 0x10000) + { + pixman_color_t *tmp_c; + int32_t tmp_x; + + tmp_x = 0x10000 - right_x; + right_x = 0x10000 - left_x; + left_x = tmp_x; + + tmp_c = right_c; + right_c = left_c; + left_c = tmp_c; + + x = 0x10000 - x; + } + left_x += (pos - x); + right_x += (pos - x); + break; + + default: /* REPEAT_NONE */ + for (n = 0; n < count; n++) + if (pos < stops[n].x) + break; + + if (n == 0) + { + left_x = INT32_MIN; + right_x = stops[0].x; + left_c = right_c = (pixman_color_t*) &transparent_black; + } + else if (n == count) + { + left_x = stops[n - 1].x; + right_x = INT32_MAX; + left_c = right_c = (pixman_color_t*) &transparent_black; + } + else + { + left_x = stops[n - 1].x; + right_x = stops[n].x; + left_c = &stops[n - 1].color; + right_c = &stops[n].color; + } + } + + walker->left_x = left_x; + walker->right_x = right_x; + walker->left_ag = ((left_c->alpha >> 8) << 16) | (left_c->green >> 8); + walker->left_rb = ((left_c->red & 0xff00) << 8) | (left_c->blue >> 8); + walker->right_ag = ((right_c->alpha >> 8) << 16) | (right_c->green >> 8); + walker->right_rb = ((right_c->red & 0xff00) << 8) | (right_c->blue >> 8); + + if (walker->left_x == walker->right_x || + ( walker->left_ag == walker->right_ag && + walker->left_rb == walker->right_rb ) ) + { + walker->stepper = 0; + } + else + { + int32_t width = right_x - left_x; + walker->stepper = ((1 << 24) + width / 2) / width; + } + + walker->need_reset = FALSE; +} + +#define PIXMAN_GRADIENT_WALKER_NEED_RESET(w, x) \ + ( (w)->need_reset || (x) < (w)->left_x || (x) >= (w)->right_x) + + +/* the following assumes that PIXMAN_GRADIENT_WALKER_NEED_RESET(w,x) is FALSE */ +uint32_t +_pixman_gradient_walker_pixel (pixman_gradient_walker_t *walker, + pixman_fixed_32_32_t x) +{ + int dist, idist; + uint32_t t1, t2, a, color; + + if (PIXMAN_GRADIENT_WALKER_NEED_RESET (walker, x)) + _pixman_gradient_walker_reset (walker, x); + + dist = ((int)(x - walker->left_x) * walker->stepper) >> 16; + idist = 256 - dist; + + /* combined INTERPOLATE and premultiply */ + t1 = walker->left_rb * idist + walker->right_rb * dist; + t1 = (t1 >> 8) & 0xff00ff; + + t2 = walker->left_ag * idist + walker->right_ag * dist; + t2 &= 0xff00ff00; + + color = t2 & 0xff000000; + a = t2 >> 24; + + t1 = t1 * a + 0x800080; + t1 = (t1 + ((t1 >> 8) & 0xff00ff)) >> 8; + + t2 = (t2 >> 8) * a + 0x800080; + t2 = (t2 + ((t2 >> 8) & 0xff00ff)); + + return (color | (t1 & 0xff00ff) | (t2 & 0xff00)); +} + |