// stb_rect_pack.h - v1.00 - public domain - rectangle packing // Sean Barrett 2014 // // Useful for e.g. packing rectangular textures into an atlas. // Does not do rotation. // // Not necessarily the awesomest packing method, but better than // the totally naive one in stb_truetype (which is primarily what // this is meant to replace). // // Has only had a few tests run, may have issues. // // More docs to come. // // No memory allocations; uses qsort() and assert() from stdlib. // Can override those by defining STBRP_SORT and STBRP_ASSERT. // // This library currently uses the Skyline Bottom-Left algorithm. // // Please note: better rectangle packers are welcome! Please // implement them to the same API, but with a different init // function. // // Credits // // Library // Sean Barrett // Minor features // Martins Mozeiko // github:IntellectualKitty // // Bugfixes / warning fixes // Jeremy Jaussaud // Fabian Giesen // // Version history: // // 1.00 (2019-02-25) avoid small space waste; gracefully fail too-wide rectangles // 0.99 (2019-02-07) warning fixes // 0.11 (2017-03-03) return packing success/fail result // 0.10 (2016-10-25) remove cast-away-const to avoid warnings // 0.09 (2016-08-27) fix compiler warnings // 0.08 (2015-09-13) really fix bug with empty rects (w=0 or h=0) // 0.07 (2015-09-13) fix bug with empty rects (w=0 or h=0) // 0.06 (2015-04-15) added STBRP_SORT to allow replacing qsort // 0.05: added STBRP_ASSERT to allow replacing assert // 0.04: fixed minor bug in STBRP_LARGE_RECTS support // 0.01: initial release // // LICENSE // // See end of file for license information. ////////////////////////////////////////////////////////////////////////////// // // INCLUDE SECTION // #ifndef STB_INCLUDE_STB_RECT_PACK_H #define STB_INCLUDE_STB_RECT_PACK_H #define STB_RECT_PACK_VERSION 1 #ifdef STBRP_STATIC #define STBRP_DEF static #else #define STBRP_DEF extern #endif #ifdef __cplusplus extern "C" { #endif typedef struct stbrp_context stbrp_context; typedef struct stbrp_node stbrp_node; typedef struct stbrp_rect stbrp_rect; #ifdef STBRP_LARGE_RECTS typedef int stbrp_coord; #else typedef unsigned short stbrp_coord; #endif STBRP_DEF int stbrp_pack_rects (stbrp_context *context, stbrp_rect *rects, int num_rects); // Assign packed locations to rectangles. The rectangles are of type // 'stbrp_rect' defined below, stored in the array 'rects', and there // are 'num_rects' many of them. // // Rectangles which are successfully packed have the 'was_packed' flag // set to a non-zero value and 'x' and 'y' store the minimum location // on each axis (i.e. bottom-left in cartesian coordinates, top-left // if you imagine y increasing downwards). Rectangles which do not fit // have the 'was_packed' flag set to 0. // // You should not try to access the 'rects' array from another thread // while this function is running, as the function temporarily reorders // the array while it executes. // // To pack into another rectangle, you need to call stbrp_init_target // again. To continue packing into the same rectangle, you can call // this function again. Calling this multiple times with multiple rect // arrays will probably produce worse packing results than calling it // a single time with the full rectangle array, but the option is // available. // // The function returns 1 if all of the rectangles were successfully // packed and 0 otherwise. struct stbrp_rect { // reserved for your use: int id; // input: stbrp_coord w, h; // output: stbrp_coord x, y; int was_packed; // non-zero if valid packing }; // 16 bytes, nominally STBRP_DEF void stbrp_init_target (stbrp_context *context, int width, int height, stbrp_node *nodes, int num_nodes); // Initialize a rectangle packer to: // pack a rectangle that is 'width' by 'height' in dimensions // using temporary storage provided by the array 'nodes', which is 'num_nodes' long // // You must call this function every time you start packing into a new target. // // There is no "shutdown" function. The 'nodes' memory must stay valid for // the following stbrp_pack_rects() call (or calls), but can be freed after // the call (or calls) finish. // // Note: to guarantee best results, either: // 1. make sure 'num_nodes' >= 'width' // or 2. call stbrp_allow_out_of_mem() defined below with 'allow_out_of_mem = 1' // // If you don't do either of the above things, widths will be quantized to multiples // of small integers to guarantee the algorithm doesn't run out of temporary storage. // // If you do #2, then the non-quantized algorithm will be used, but the algorithm // may run out of temporary storage and be unable to pack some rectangles. STBRP_DEF void stbrp_setup_allow_out_of_mem (stbrp_context *context, int allow_out_of_mem); // Optionally call this function after init but before doing any packing to // change the handling of the out-of-temp-memory scenario, described above. // If you call init again, this will be reset to the default (false). STBRP_DEF void stbrp_setup_heuristic (stbrp_context *context, int heuristic); // Optionally select which packing heuristic the library should use. Different // heuristics will produce better/worse results for different data sets. // If you call init again, this will be reset to the default. enum { STBRP_HEURISTIC_Skyline_default=0, STBRP_HEURISTIC_Skyline_BL_sortHeight = STBRP_HEURISTIC_Skyline_default, STBRP_HEURISTIC_Skyline_BF_sortHeight }; ////////////////////////////////////////////////////////////////////////////// // // the details of the following structures don't matter to you, but they must // be visible so you can handle the memory allocations for them struct stbrp_node { stbrp_coord x,y; stbrp_node *next; }; struct stbrp_context { int width; int height; int align; int init_mode; int heuristic; int num_nodes; stbrp_node *active_head; stbrp_node *free_head; stbrp_node extra[2]; // we allocate two extra nodes so optimal user-node-count is 'width' not 'width+2' }; #ifdef __cplusplus } #endif #endif ////////////////////////////////////////////////////////////////////////////// // // 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 visted 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); // if it can't possibly fit, bail immediately if (width > c->width || height > c->height) { fr.prev_link = NULL; fr.x = fr.y = 0; return fr; } 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. 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