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623 lines
20 KiB
623 lines
20 KiB
// stb_rect_pack.h - v1.01 - public domain - rectangle packing |
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// Sean Barrett 2014 |
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// |
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// Useful for e.g. packing rectangular textures into an atlas. |
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// Does not do rotation. |
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// |
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// Before #including, |
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// |
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// #define STB_RECT_PACK_IMPLEMENTATION |
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// |
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// in the file that you want to have the implementation. |
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// |
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// Not necessarily the awesomest packing method, but better than |
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// the totally naive one in stb_truetype (which is primarily what |
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// this is meant to replace). |
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// |
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// Has only had a few tests run, may have issues. |
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// |
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// More docs to come. |
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// |
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// No memory allocations; uses qsort() and assert() from stdlib. |
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// Can override those by defining STBRP_SORT and STBRP_ASSERT. |
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// |
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// This library currently uses the Skyline Bottom-Left algorithm. |
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// |
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// Please note: better rectangle packers are welcome! Please |
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// implement them to the same API, but with a different init |
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// function. |
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// |
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// Credits |
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// |
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// Library |
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// Sean Barrett |
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// Minor features |
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// Martins Mozeiko |
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// github:IntellectualKitty |
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// |
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// Bugfixes / warning fixes |
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// Jeremy Jaussaud |
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// Fabian Giesen |
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// |
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// Version history: |
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// |
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// 1.01 (2021-07-11) always use large rect mode, expose STBRP__MAXVAL in public section |
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// 1.00 (2019-02-25) avoid small space waste; gracefully fail too-wide rectangles |
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// 0.99 (2019-02-07) warning fixes |
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// 0.11 (2017-03-03) return packing success/fail result |
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// 0.10 (2016-10-25) remove cast-away-const to avoid warnings |
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// 0.09 (2016-08-27) fix compiler warnings |
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// 0.08 (2015-09-13) really fix bug with empty rects (w=0 or h=0) |
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// 0.07 (2015-09-13) fix bug with empty rects (w=0 or h=0) |
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// 0.06 (2015-04-15) added STBRP_SORT to allow replacing qsort |
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// 0.05: added STBRP_ASSERT to allow replacing assert |
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// 0.04: fixed minor bug in STBRP_LARGE_RECTS support |
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// 0.01: initial release |
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// |
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// LICENSE |
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// |
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// See end of file for license information. |
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////////////////////////////////////////////////////////////////////////////// |
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// |
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// INCLUDE SECTION |
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// |
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#ifndef STB_INCLUDE_STB_RECT_PACK_H |
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#define STB_INCLUDE_STB_RECT_PACK_H |
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#define STB_RECT_PACK_VERSION 1 |
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#ifdef STBRP_STATIC |
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#define STBRP_DEF static |
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#else |
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#define STBRP_DEF extern |
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#endif |
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#ifdef __cplusplus |
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extern "C" { |
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#endif |
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typedef struct stbrp_context stbrp_context; |
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typedef struct stbrp_node stbrp_node; |
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typedef struct stbrp_rect stbrp_rect; |
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typedef int stbrp_coord; |
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#define STBRP__MAXVAL 0x7fffffff |
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// Mostly for internal use, but this is the maximum supported coordinate value. |
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STBRP_DEF int stbrp_pack_rects (stbrp_context *context, stbrp_rect *rects, int num_rects); |
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// Assign packed locations to rectangles. The rectangles are of type |
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// 'stbrp_rect' defined below, stored in the array 'rects', and there |
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// are 'num_rects' many of them. |
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// |
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// Rectangles which are successfully packed have the 'was_packed' flag |
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// set to a non-zero value and 'x' and 'y' store the minimum location |
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// on each axis (i.e. bottom-left in cartesian coordinates, top-left |
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// if you imagine y increasing downwards). Rectangles which do not fit |
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// have the 'was_packed' flag set to 0. |
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// |
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// You should not try to access the 'rects' array from another thread |
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// while this function is running, as the function temporarily reorders |
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// the array while it executes. |
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// |
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// To pack into another rectangle, you need to call stbrp_init_target |
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// again. To continue packing into the same rectangle, you can call |
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// this function again. Calling this multiple times with multiple rect |
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// arrays will probably produce worse packing results than calling it |
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// a single time with the full rectangle array, but the option is |
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// available. |
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// |
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// The function returns 1 if all of the rectangles were successfully |
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// packed and 0 otherwise. |
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struct stbrp_rect |
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{ |
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// reserved for your use: |
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int id; |
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// input: |
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stbrp_coord w, h; |
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// output: |
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stbrp_coord x, y; |
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int was_packed; // non-zero if valid packing |
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}; // 16 bytes, nominally |
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STBRP_DEF void stbrp_init_target (stbrp_context *context, int width, int height, stbrp_node *nodes, int num_nodes); |
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// Initialize a rectangle packer to: |
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// pack a rectangle that is 'width' by 'height' in dimensions |
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// using temporary storage provided by the array 'nodes', which is 'num_nodes' long |
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// |
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// You must call this function every time you start packing into a new target. |
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// |
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// There is no "shutdown" function. The 'nodes' memory must stay valid for |
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// the following stbrp_pack_rects() call (or calls), but can be freed after |
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// the call (or calls) finish. |
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// |
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// Note: to guarantee best results, either: |
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// 1. make sure 'num_nodes' >= 'width' |
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// or 2. call stbrp_allow_out_of_mem() defined below with 'allow_out_of_mem = 1' |
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// |
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// If you don't do either of the above things, widths will be quantized to multiples |
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// of small integers to guarantee the algorithm doesn't run out of temporary storage. |
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// |
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// If you do #2, then the non-quantized algorithm will be used, but the algorithm |
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// may run out of temporary storage and be unable to pack some rectangles. |
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STBRP_DEF void stbrp_setup_allow_out_of_mem (stbrp_context *context, int allow_out_of_mem); |
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// Optionally call this function after init but before doing any packing to |
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// change the handling of the out-of-temp-memory scenario, described above. |
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// If you call init again, this will be reset to the default (false). |
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STBRP_DEF void stbrp_setup_heuristic (stbrp_context *context, int heuristic); |
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// Optionally select which packing heuristic the library should use. Different |
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// heuristics will produce better/worse results for different data sets. |
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// If you call init again, this will be reset to the default. |
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enum |
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{ |
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STBRP_HEURISTIC_Skyline_default=0, |
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STBRP_HEURISTIC_Skyline_BL_sortHeight = STBRP_HEURISTIC_Skyline_default, |
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STBRP_HEURISTIC_Skyline_BF_sortHeight |
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}; |
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////////////////////////////////////////////////////////////////////////////// |
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// |
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// the details of the following structures don't matter to you, but they must |
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// be visible so you can handle the memory allocations for them |
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struct stbrp_node |
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{ |
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stbrp_coord x,y; |
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stbrp_node *next; |
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}; |
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struct stbrp_context |
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{ |
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int width; |
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int height; |
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int align; |
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int init_mode; |
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int heuristic; |
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int num_nodes; |
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stbrp_node *active_head; |
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stbrp_node *free_head; |
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stbrp_node extra[2]; // we allocate two extra nodes so optimal user-node-count is 'width' not 'width+2' |
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}; |
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#ifdef __cplusplus |
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} |
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#endif |
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#endif |
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////////////////////////////////////////////////////////////////////////////// |
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// |
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// IMPLEMENTATION SECTION |
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// |
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#ifdef STB_RECT_PACK_IMPLEMENTATION |
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#ifndef STBRP_SORT |
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#include <stdlib.h> |
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#define STBRP_SORT qsort |
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#endif |
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#ifndef STBRP_ASSERT |
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#include <assert.h> |
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#define STBRP_ASSERT assert |
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#endif |
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#ifdef _MSC_VER |
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#define STBRP__NOTUSED(v) (void)(v) |
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#define STBRP__CDECL __cdecl |
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#else |
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#define STBRP__NOTUSED(v) (void)sizeof(v) |
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#define STBRP__CDECL |
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#endif |
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enum |
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{ |
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STBRP__INIT_skyline = 1 |
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}; |
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STBRP_DEF void stbrp_setup_heuristic(stbrp_context *context, int heuristic) |
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{ |
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switch (context->init_mode) { |
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case STBRP__INIT_skyline: |
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STBRP_ASSERT(heuristic == STBRP_HEURISTIC_Skyline_BL_sortHeight || heuristic == STBRP_HEURISTIC_Skyline_BF_sortHeight); |
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context->heuristic = heuristic; |
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break; |
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default: |
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STBRP_ASSERT(0); |
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} |
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} |
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STBRP_DEF void stbrp_setup_allow_out_of_mem(stbrp_context *context, int allow_out_of_mem) |
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{ |
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if (allow_out_of_mem) |
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// if it's ok to run out of memory, then don't bother aligning them; |
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// this gives better packing, but may fail due to OOM (even though |
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// the rectangles easily fit). @TODO a smarter approach would be to only |
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// quantize once we've hit OOM, then we could get rid of this parameter. |
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context->align = 1; |
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else { |
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// if it's not ok to run out of memory, then quantize the widths |
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// so that num_nodes is always enough nodes. |
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// |
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// I.e. num_nodes * align >= width |
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// align >= width / num_nodes |
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// align = ceil(width/num_nodes) |
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context->align = (context->width + context->num_nodes-1) / context->num_nodes; |
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} |
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} |
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STBRP_DEF void stbrp_init_target(stbrp_context *context, int width, int height, stbrp_node *nodes, int num_nodes) |
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{ |
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int i; |
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for (i=0; i < num_nodes-1; ++i) |
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nodes[i].next = &nodes[i+1]; |
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nodes[i].next = NULL; |
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context->init_mode = STBRP__INIT_skyline; |
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context->heuristic = STBRP_HEURISTIC_Skyline_default; |
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context->free_head = &nodes[0]; |
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context->active_head = &context->extra[0]; |
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context->width = width; |
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context->height = height; |
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context->num_nodes = num_nodes; |
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stbrp_setup_allow_out_of_mem(context, 0); |
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// node 0 is the full width, node 1 is the sentinel (lets us not store width explicitly) |
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context->extra[0].x = 0; |
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context->extra[0].y = 0; |
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context->extra[0].next = &context->extra[1]; |
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context->extra[1].x = (stbrp_coord) width; |
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context->extra[1].y = (1<<30); |
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context->extra[1].next = NULL; |
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} |
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// find minimum y position if it starts at x1 |
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static int stbrp__skyline_find_min_y(stbrp_context *c, stbrp_node *first, int x0, int width, int *pwaste) |
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{ |
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stbrp_node *node = first; |
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int x1 = x0 + width; |
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int min_y, visited_width, waste_area; |
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STBRP__NOTUSED(c); |
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STBRP_ASSERT(first->x <= x0); |
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#if 0 |
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// skip in case we're past the node |
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while (node->next->x <= x0) |
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++node; |
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#else |
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STBRP_ASSERT(node->next->x > x0); // we ended up handling this in the caller for efficiency |
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#endif |
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STBRP_ASSERT(node->x <= x0); |
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min_y = 0; |
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waste_area = 0; |
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visited_width = 0; |
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while (node->x < x1) { |
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if (node->y > min_y) { |
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// raise min_y higher. |
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// we've accounted for all waste up to min_y, |
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// but we'll now add more waste for everything we've visted |
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waste_area += visited_width * (node->y - min_y); |
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min_y = node->y; |
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// the first time through, visited_width might be reduced |
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if (node->x < x0) |
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visited_width += node->next->x - x0; |
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else |
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visited_width += node->next->x - node->x; |
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} else { |
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// add waste area |
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int under_width = node->next->x - node->x; |
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if (under_width + visited_width > width) |
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under_width = width - visited_width; |
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waste_area += under_width * (min_y - node->y); |
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visited_width += under_width; |
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} |
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node = node->next; |
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} |
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*pwaste = waste_area; |
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return min_y; |
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} |
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typedef struct |
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{ |
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int x,y; |
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stbrp_node **prev_link; |
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} stbrp__findresult; |
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static stbrp__findresult stbrp__skyline_find_best_pos(stbrp_context *c, int width, int height) |
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{ |
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int best_waste = (1<<30), best_x, best_y = (1 << 30); |
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stbrp__findresult fr; |
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stbrp_node **prev, *node, *tail, **best = NULL; |
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// align to multiple of c->align |
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width = (width + c->align - 1); |
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width -= width % c->align; |
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STBRP_ASSERT(width % c->align == 0); |
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// if it can't possibly fit, bail immediately |
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if (width > c->width || height > c->height) { |
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fr.prev_link = NULL; |
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fr.x = fr.y = 0; |
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return fr; |
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} |
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node = c->active_head; |
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prev = &c->active_head; |
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while (node->x + width <= c->width) { |
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int y,waste; |
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y = stbrp__skyline_find_min_y(c, node, node->x, width, &waste); |
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if (c->heuristic == STBRP_HEURISTIC_Skyline_BL_sortHeight) { // actually just want to test BL |
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// bottom left |
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if (y < best_y) { |
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best_y = y; |
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best = prev; |
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} |
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} else { |
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// best-fit |
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if (y + height <= c->height) { |
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// can only use it if it first vertically |
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if (y < best_y || (y == best_y && waste < best_waste)) { |
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best_y = y; |
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best_waste = waste; |
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best = prev; |
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} |
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} |
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} |
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prev = &node->next; |
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node = node->next; |
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} |
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best_x = (best == NULL) ? 0 : (*best)->x; |
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// if doing best-fit (BF), we also have to try aligning right edge to each node position |
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// |
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// e.g, if fitting |
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// |
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// ____________________ |
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// |____________________| |
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// |
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// into |
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// |
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// | | |
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// | ____________| |
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// |____________| |
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// |
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// then right-aligned reduces waste, but bottom-left BL is always chooses left-aligned |
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// |
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// This makes BF take about 2x the time |
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if (c->heuristic == STBRP_HEURISTIC_Skyline_BF_sortHeight) { |
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tail = c->active_head; |
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node = c->active_head; |
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prev = &c->active_head; |
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// find first node that's admissible |
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while (tail->x < width) |
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tail = tail->next; |
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while (tail) { |
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int xpos = tail->x - width; |
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int y,waste; |
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STBRP_ASSERT(xpos >= 0); |
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// find the left position that matches this |
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while (node->next->x <= xpos) { |
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prev = &node->next; |
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node = node->next; |
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} |
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STBRP_ASSERT(node->next->x > xpos && node->x <= xpos); |
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y = stbrp__skyline_find_min_y(c, node, xpos, width, &waste); |
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if (y + height <= c->height) { |
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if (y <= best_y) { |
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if (y < best_y || waste < best_waste || (waste==best_waste && xpos < best_x)) { |
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best_x = xpos; |
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STBRP_ASSERT(y <= best_y); |
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best_y = y; |
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best_waste = waste; |
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best = prev; |
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} |
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} |
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} |
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tail = tail->next; |
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} |
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} |
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fr.prev_link = best; |
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fr.x = best_x; |
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fr.y = best_y; |
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return fr; |
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} |
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static stbrp__findresult stbrp__skyline_pack_rectangle(stbrp_context *context, int width, int height) |
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{ |
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// find best position according to heuristic |
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stbrp__findresult res = stbrp__skyline_find_best_pos(context, width, height); |
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stbrp_node *node, *cur; |
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// bail if: |
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// 1. it failed |
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// 2. the best node doesn't fit (we don't always check this) |
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// 3. we're out of memory |
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if (res.prev_link == NULL || res.y + height > context->height || context->free_head == NULL) { |
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res.prev_link = NULL; |
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return res; |
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} |
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// on success, create new node |
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node = context->free_head; |
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node->x = (stbrp_coord) res.x; |
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node->y = (stbrp_coord) (res.y + height); |
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context->free_head = node->next; |
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// insert the new node into the right starting point, and |
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// let 'cur' point to the remaining nodes needing to be |
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// stiched back in |
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cur = *res.prev_link; |
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if (cur->x < res.x) { |
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// preserve the existing one, so start testing with the next one |
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stbrp_node *next = cur->next; |
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cur->next = node; |
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cur = next; |
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} else { |
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*res.prev_link = node; |
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} |
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// from here, traverse cur and free the nodes, until we get to one |
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// that shouldn't be freed |
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while (cur->next && cur->next->x <= res.x + width) { |
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stbrp_node *next = cur->next; |
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// move the current node to the free list |
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cur->next = context->free_head; |
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context->free_head = cur; |
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cur = next; |
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} |
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// stitch the list back in |
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node->next = cur; |
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if (cur->x < res.x + width) |
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cur->x = (stbrp_coord) (res.x + width); |
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#ifdef _DEBUG |
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cur = context->active_head; |
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while (cur->x < context->width) { |
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STBRP_ASSERT(cur->x < cur->next->x); |
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cur = cur->next; |
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} |
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STBRP_ASSERT(cur->next == NULL); |
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{ |
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int count=0; |
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cur = context->active_head; |
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while (cur) { |
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cur = cur->next; |
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++count; |
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} |
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cur = context->free_head; |
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while (cur) { |
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cur = cur->next; |
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++count; |
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} |
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STBRP_ASSERT(count == context->num_nodes+2); |
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} |
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#endif |
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return res; |
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} |
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static int STBRP__CDECL rect_height_compare(const void *a, const void *b) |
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{ |
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const stbrp_rect *p = (const stbrp_rect *) a; |
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const stbrp_rect *q = (const stbrp_rect *) b; |
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if (p->h > q->h) |
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return -1; |
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if (p->h < q->h) |
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return 1; |
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return (p->w > q->w) ? -1 : (p->w < q->w); |
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} |
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static int STBRP__CDECL rect_original_order(const void *a, const void *b) |
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{ |
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const stbrp_rect *p = (const stbrp_rect *) a; |
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const stbrp_rect *q = (const stbrp_rect *) b; |
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return (p->was_packed < q->was_packed) ? -1 : (p->was_packed > q->was_packed); |
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} |
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STBRP_DEF int stbrp_pack_rects(stbrp_context *context, stbrp_rect *rects, int num_rects) |
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{ |
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int i, all_rects_packed = 1; |
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// we use the 'was_packed' field internally to allow sorting/unsorting |
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for (i=0; i < num_rects; ++i) { |
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rects[i].was_packed = i; |
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} |
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// sort according to heuristic |
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STBRP_SORT(rects, num_rects, sizeof(rects[0]), rect_height_compare); |
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for (i=0; i < num_rects; ++i) { |
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if (rects[i].w == 0 || rects[i].h == 0) { |
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rects[i].x = rects[i].y = 0; // empty rect needs no space |
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} else { |
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stbrp__findresult fr = stbrp__skyline_pack_rectangle(context, rects[i].w, rects[i].h); |
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if (fr.prev_link) { |
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rects[i].x = (stbrp_coord) fr.x; |
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rects[i].y = (stbrp_coord) fr.y; |
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} 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. |
|
------------------------------------------------------------------------------ |
|
*/
|
|
|