diff options
Diffstat (limited to 'gsk/gl/stb_rect_pack.c')
-rw-r--r-- | gsk/gl/stb_rect_pack.c | 431 |
1 files changed, 431 insertions, 0 deletions
diff --git a/gsk/gl/stb_rect_pack.c b/gsk/gl/stb_rect_pack.c new file mode 100644 index 0000000000..ff658466a1 --- /dev/null +++ b/gsk/gl/stb_rect_pack.c @@ -0,0 +1,431 @@ + +#include "stb_rect_pack.h" +#define STB_RECT_PACK_IMPLEMENTATION +////////////////////////////////////////////////////////////////////////////// +// +// IMPLEMENTATION SECTION +// + +#ifdef STB_RECT_PACK_IMPLEMENTATION +#ifndef STBRP_SORT +#include <stdlib.h> +#define STBRP_SORT qsort +#endif + +#ifndef STBRP_ASSERT +#include <assert.h> +#define STBRP_ASSERT assert +#endif + +#ifdef _MSC_VER +#define STBRP__NOTUSED(v) (void)(v) +#else +#define STBRP__NOTUSED(v) (void)sizeof(v) +#endif + +enum +{ + STBRP__INIT_skyline = 1 +}; + +STBRP_DEF void stbrp_setup_heuristic(stbrp_context *context, int heuristic) +{ + switch (context->init_mode) { + case STBRP__INIT_skyline: + STBRP_ASSERT(heuristic == STBRP_HEURISTIC_Skyline_BL_sortHeight || heuristic == STBRP_HEURISTIC_Skyline_BF_sortHeight); + context->heuristic = heuristic; + break; + default: + STBRP_ASSERT(0); + } +} + +STBRP_DEF void stbrp_setup_allow_out_of_mem(stbrp_context *context, int allow_out_of_mem) +{ + if (allow_out_of_mem) + // if it's ok to run out of memory, then don't bother aligning them; + // this gives better packing, but may fail due to OOM (even though + // the rectangles easily fit). @TODO a smarter approach would be to only + // quantize once we've hit OOM, then we could get rid of this parameter. + context->align = 1; + else { + // if it's not ok to run out of memory, then quantize the widths + // so that num_nodes is always enough nodes. + // + // I.e. num_nodes * align >= width + // align >= width / num_nodes + // align = ceil(width/num_nodes) + + context->align = (context->width + context->num_nodes-1) / context->num_nodes; + } +} + +STBRP_DEF void stbrp_init_target(stbrp_context *context, int width, int height, stbrp_node *nodes, int num_nodes) +{ + int i; +#ifndef STBRP_LARGE_RECTS + STBRP_ASSERT(width <= 0xffff && height <= 0xffff); +#endif + + for (i=0; i < num_nodes-1; ++i) + nodes[i].next = &nodes[i+1]; + nodes[i].next = NULL; + context->init_mode = STBRP__INIT_skyline; + context->heuristic = STBRP_HEURISTIC_Skyline_default; + context->free_head = &nodes[0]; + context->active_head = &context->extra[0]; + context->width = width; + context->height = height; + context->num_nodes = num_nodes; + stbrp_setup_allow_out_of_mem(context, 0); + + // node 0 is the full width, node 1 is the sentinel (lets us not store width explicitly) + context->extra[0].x = 0; + context->extra[0].y = 0; + context->extra[0].next = &context->extra[1]; + context->extra[1].x = (stbrp_coord) width; +#ifdef STBRP_LARGE_RECTS + context->extra[1].y = (1<<30); +#else + context->extra[1].y = 65535; +#endif + context->extra[1].next = NULL; +} + +// find minimum y position if it starts at x1 +static int stbrp__skyline_find_min_y(stbrp_context *c, stbrp_node *first, int x0, int width, int *pwaste) +{ + stbrp_node *node = first; + int x1 = x0 + width; + int min_y, visited_width, waste_area; + + STBRP__NOTUSED(c); + + STBRP_ASSERT(first->x <= x0); + + #if 0 + // skip in case we're past the node + while (node->next->x <= x0) + ++node; + #else + STBRP_ASSERT(node->next->x > x0); // we ended up handling this in the caller for efficiency + #endif + + STBRP_ASSERT(node->x <= x0); + + min_y = 0; + waste_area = 0; + visited_width = 0; + while (node->x < x1) { + if (node->y > min_y) { + // raise min_y higher. + // we've accounted for all waste up to min_y, + // but we'll now add more waste for everything we've visited + waste_area += visited_width * (node->y - min_y); + min_y = node->y; + // the first time through, visited_width might be reduced + if (node->x < x0) + visited_width += node->next->x - x0; + else + visited_width += node->next->x - node->x; + } else { + // add waste area + int under_width = node->next->x - node->x; + if (under_width + visited_width > width) + under_width = width - visited_width; + waste_area += under_width * (min_y - node->y); + visited_width += under_width; + } + node = node->next; + } + + *pwaste = waste_area; + return min_y; +} + +typedef struct +{ + int x,y; + stbrp_node **prev_link; +} stbrp__findresult; + +static stbrp__findresult stbrp__skyline_find_best_pos(stbrp_context *c, int width, int height) +{ + int best_waste = (1<<30), best_x, best_y = (1 << 30); + stbrp__findresult fr; + stbrp_node **prev, *node, *tail, **best = NULL; + + // align to multiple of c->align + width = (width + c->align - 1); + width -= width % c->align; + STBRP_ASSERT(width % c->align == 0); + + node = c->active_head; + prev = &c->active_head; + while (node->x + width <= c->width) { + int y,waste; + y = stbrp__skyline_find_min_y(c, node, node->x, width, &waste); + if (c->heuristic == STBRP_HEURISTIC_Skyline_BL_sortHeight) { // actually just want to test BL + // bottom left + if (y < best_y) { + best_y = y; + best = prev; + } + } else { + // best-fit + if (y + height <= c->height) { + // can only use it if it first vertically + if (y < best_y || (y == best_y && waste < best_waste)) { + best_y = y; + best_waste = waste; + best = prev; + } + } + } + prev = &node->next; + node = node->next; + } + + best_x = (best == NULL) ? 0 : (*best)->x; + + // if doing best-fit (BF), we also have to try aligning right edge to each node position + // + // e.g, if fitting + // + // ____________________ + // |____________________| + // + // into + // + // | | + // | ____________| + // |____________| + // + // then right-aligned reduces waste, but bottom-left BL is always chooses left-aligned + // + // This makes BF take about 2x the time + + if (c->heuristic == STBRP_HEURISTIC_Skyline_BF_sortHeight) { + tail = c->active_head; + node = c->active_head; + prev = &c->active_head; + // find first node that's admissible + while (tail->x < width) + tail = tail->next; + while (tail) { + int xpos = tail->x - width; + int y,waste; + STBRP_ASSERT(xpos >= 0); + // find the left position that matches this + while (node->next->x <= xpos) { + prev = &node->next; + node = node->next; + } + STBRP_ASSERT(node->next->x > xpos && node->x <= xpos); + y = stbrp__skyline_find_min_y(c, node, xpos, width, &waste); + if (y + height < c->height) { + if (y <= best_y) { + if (y < best_y || waste < best_waste || (waste==best_waste && xpos < best_x)) { + best_x = xpos; + STBRP_ASSERT(y <= best_y); + best_y = y; + best_waste = waste; + best = prev; + } + } + } + tail = tail->next; + } + } + + fr.prev_link = best; + fr.x = best_x; + fr.y = best_y; + return fr; +} + +static stbrp__findresult stbrp__skyline_pack_rectangle(stbrp_context *context, int width, int height) +{ + // find best position according to heuristic + stbrp__findresult res = stbrp__skyline_find_best_pos(context, width, height); + stbrp_node *node, *cur; + + // bail if: + // 1. it failed + // 2. the best node doesn't fit (we don't always check this) + // 3. we're out of memory + if (res.prev_link == NULL || res.y + height > context->height || context->free_head == NULL) { + res.prev_link = NULL; + return res; + } + + // on success, create new node + node = context->free_head; + node->x = (stbrp_coord) res.x; + node->y = (stbrp_coord) (res.y + height); + + context->free_head = node->next; + + // insert the new node into the right starting point, and + // let 'cur' point to the remaining nodes needing to be + // stiched back in + + cur = *res.prev_link; + if (cur->x < res.x) { + // preserve the existing one, so start testing with the next one + stbrp_node *next = cur->next; + cur->next = node; + cur = next; + } else { + *res.prev_link = node; + } + + // from here, traverse cur and free the nodes, until we get to one + // that shouldn't be freed + while (cur->next && cur->next->x <= res.x + width) { + stbrp_node *next = cur->next; + // move the current node to the free list + cur->next = context->free_head; + context->free_head = cur; + cur = next; + } + + // stitch the list back in + node->next = cur; + + if (cur->x < res.x + width) + cur->x = (stbrp_coord) (res.x + width); + +#ifdef _DEBUG + cur = context->active_head; + while (cur->x < context->width) { + STBRP_ASSERT(cur->x < cur->next->x); + cur = cur->next; + } + STBRP_ASSERT(cur->next == NULL); + + { + int count=0; + cur = context->active_head; + while (cur) { + cur = cur->next; + ++count; + } + cur = context->free_head; + while (cur) { + cur = cur->next; + ++count; + } + STBRP_ASSERT(count == context->num_nodes+2); + } +#endif + + return res; +} + +static int rect_height_compare(const void *a, const void *b) +{ + const stbrp_rect *p = (const stbrp_rect *) a; + const stbrp_rect *q = (const stbrp_rect *) b; + if (p->h > q->h) + return -1; + if (p->h < q->h) + return 1; + return (p->w > q->w) ? -1 : (p->w < q->w); +} + +static int rect_original_order(const void *a, const void *b) +{ + const stbrp_rect *p = (const stbrp_rect *) a; + const stbrp_rect *q = (const stbrp_rect *) b; + return (p->was_packed < q->was_packed) ? -1 : (p->was_packed > q->was_packed); +} + +#ifdef STBRP_LARGE_RECTS +#define STBRP__MAXVAL 0xffffffff +#else +#define STBRP__MAXVAL 0xffff +#endif + +STBRP_DEF int stbrp_pack_rects(stbrp_context *context, stbrp_rect *rects, int num_rects) +{ + int i, all_rects_packed = 1; + + // we use the 'was_packed' field internally to allow sorting/unsorting + for (i=0; i < num_rects; ++i) { + rects[i].was_packed = i; + } + + // sort according to heuristic + STBRP_SORT(rects, num_rects, sizeof(rects[0]), rect_height_compare); + + for (i=0; i < num_rects; ++i) { + if (rects[i].w == 0 || rects[i].h == 0) { + rects[i].x = rects[i].y = 0; // empty rect needs no space + } else { + stbrp__findresult fr = stbrp__skyline_pack_rectangle(context, rects[i].w, rects[i].h); + if (fr.prev_link) { + rects[i].x = (stbrp_coord) fr.x; + rects[i].y = (stbrp_coord) fr.y; + } else { + rects[i].x = rects[i].y = STBRP__MAXVAL; + } + } + } + + // unsort + STBRP_SORT(rects, num_rects, sizeof(rects[0]), rect_original_order); + + // set was_packed flags and all_rects_packed status + for (i=0; i < num_rects; ++i) { + rects[i].was_packed = !(rects[i].x == STBRP__MAXVAL && rects[i].y == STBRP__MAXVAL); + if (!rects[i].was_packed) + all_rects_packed = 0; + } + + // return the all_rects_packed status + return all_rects_packed; +} +#endif + +/* +------------------------------------------------------------------------------ +This software is available under 2 licenses -- choose whichever you prefer. +------------------------------------------------------------------------------ +ALTERNATIVE A - MIT License +Copyright (c) 2017 Sean Barrett +Permission is hereby granted, free of charge, to any person obtaining a copy of +this software and associated documentation files (the "Software"), to deal in +the Software without restriction, including without limitation the rights to +use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies +of the Software, and to permit persons to whom the Software is furnished to do +so, subject to the following conditions: +The above copyright notice and this permission notice shall be included in all +copies or substantial portions of the Software. +THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR +IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, +FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE +AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER +LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, +OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE +SOFTWARE. +------------------------------------------------------------------------------ +ALTERNATIVE B - Public Domain (www.unlicense.org) +This is free and unencumbered software released into the public domain. +Anyone is free to copy, modify, publish, use, compile, sell, or distribute this +software, either in source code form or as a compiled binary, for any purpose, +commercial or non-commercial, and by any means. +In jurisdictions that recognize copyright laws, the author or authors of this +software dedicate any and all copyright interest in the software to the public +domain. We make this dedication for the benefit of the public at large and to +the detriment of our heirs and successors. We intend this dedication to be an +overt act of relinquishment in perpetuity of all present and future rights to +this software under copyright law. +THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR +IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, +FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE +AUTHORS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN +ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION +WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. +------------------------------------------------------------------------------ +*/ |