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Diffstat (limited to 'video/out/bitmap_packer.c')
| -rw-r--r-- | video/out/bitmap_packer.c | 197 |
1 files changed, 197 insertions, 0 deletions
diff --git a/video/out/bitmap_packer.c b/video/out/bitmap_packer.c new file mode 100644 index 0000000..5ef090b --- /dev/null +++ b/video/out/bitmap_packer.c @@ -0,0 +1,197 @@ +/* + * Calculate how to pack bitmap rectangles into a larger surface + * + * Copyright 2009, 2012 Uoti Urpala + * + * This file is part of mpv. + * + * mpv is free software; you can redistribute it and/or + * modify it under the terms of the GNU Lesser General Public + * License as published by the Free Software Foundation; either + * version 2.1 of the License, or (at your option) any later version. + * + * mpv is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU Lesser General Public License for more details. + * + * You should have received a copy of the GNU Lesser General Public + * License along with mpv. If not, see <http://www.gnu.org/licenses/>. + */ + +#include <stdlib.h> +#include <assert.h> +#include <stdio.h> +#include <limits.h> + +#include "mpv_talloc.h" +#include "bitmap_packer.h" +#include "common/common.h" + +#define IS_POWER_OF_2(x) (((x) > 0) && !(((x) - 1) & (x))) + +void packer_reset(struct bitmap_packer *packer) +{ + struct bitmap_packer old = *packer; + *packer = (struct bitmap_packer) { + .w_max = old.w_max, + .h_max = old.h_max, + }; + talloc_free_children(packer); +} + +void packer_get_bb(struct bitmap_packer *packer, struct pos out_bb[2]) +{ + out_bb[0] = (struct pos) {0}; + out_bb[1] = (struct pos) {packer->used_width, packer->used_height}; +} + +#define HEIGHT_SORT_BITS 4 +static int size_index(int s) +{ + int n = mp_log2(s); + return (n << HEIGHT_SORT_BITS) + + ((- 1 - (s << HEIGHT_SORT_BITS >> n)) & ((1 << HEIGHT_SORT_BITS) - 1)); +} + +/* Pack the given rectangles into an area of size w * h. + * The size of each rectangle is read from in[i].x / in[i].y. + * The height of each rectangle must be less than 65536. + * 'scratch' must point to work memory for num_rects+16 ints. + * The packed position for rectangle number i is set in out[i]. + * Return 0 on success, -1 if the rectangles did not fit in w*h. + * + * The rectangles are placed in rows in order approximately sorted by + * height (the approximate sorting is simpler than a full one would be, + * and allows the algorithm to work in linear time). Additionally, to + * reduce wasted space when there are a few tall rectangles, empty + * lower-right parts of rows are filled recursively when the size of + * rectangles in the row drops past a power-of-two threshold. So if a + * row starts with rectangles of size 3x50, 10x40 and 5x20 then the + * free rectangle with corners (13, 20)-(w, 50) is filled recursively. + */ +static int pack_rectangles(struct pos *in, struct pos *out, int num_rects, + int w, int h, int *scratch, int *used_width) +{ + int bins[16 << HEIGHT_SORT_BITS]; + int sizes[16 << HEIGHT_SORT_BITS] = { 0 }; + for (int i = 0; i < num_rects; i++) + sizes[size_index(in[i].y)]++; + int idx = 0; + for (int i = 0; i < 16 << HEIGHT_SORT_BITS; i += 1 << HEIGHT_SORT_BITS) { + for (int j = 0; j < 1 << HEIGHT_SORT_BITS; j++) { + bins[i + j] = idx; + idx += sizes[i + j]; + } + scratch[idx++] = -1; + } + for (int i = 0; i < num_rects; i++) + scratch[bins[size_index(in[i].y)]++] = i; + for (int i = 0; i < 16; i++) + bins[i] = bins[i << HEIGHT_SORT_BITS] - sizes[i << HEIGHT_SORT_BITS]; + struct { + int size, x, bottom; + } stack[16] = {{15, 0, h}}, s = {0}; + int stackpos = 1; + int y; + while (stackpos) { + y = s.bottom; + s = stack[--stackpos]; + s.size++; + while (s.size--) { + int maxy = -1; + int obj; + while ((obj = scratch[bins[s.size]]) >= 0) { + int bottom = y + in[obj].y; + if (bottom > s.bottom) + break; + int right = s.x + in[obj].x; + if (right > w) + break; + bins[s.size]++; + out[obj] = (struct pos){s.x, y}; + num_rects--; + if (maxy < 0) + stack[stackpos++] = s; + s.x = right; + maxy = MPMAX(maxy, bottom); + } + *used_width = MPMAX(*used_width, s.x); + if (maxy > 0) + s.bottom = maxy; + } + } + return num_rects ? -1 : y; +} + +int packer_pack(struct bitmap_packer *packer) +{ + if (packer->count == 0) + return 0; + int w_orig = packer->w, h_orig = packer->h; + struct pos *in = packer->in; + int xmax = 0, ymax = 0; + for (int i = 0; i < packer->count; i++) { + if (in[i].x <= 0 || in[i].y <= 0) { + in[i] = (struct pos){0, 0}; + } else { + in[i].x += packer->padding * 2; + in[i].y += packer->padding * 2; + } + if (in[i].x < 0 || in [i].x > 65535 || in[i].y < 0 || in[i].y > 65535) { + fprintf(stderr, "Invalid OSD / subtitle bitmap size\n"); + abort(); + } + xmax = MPMAX(xmax, in[i].x); + ymax = MPMAX(ymax, in[i].y); + } + if (xmax > packer->w) + packer->w = 1 << (mp_log2(xmax - 1) + 1); + if (ymax > packer->h) + packer->h = 1 << (mp_log2(ymax - 1) + 1); + while (1) { + int used_width = 0; + int y = pack_rectangles(in, packer->result, packer->count, + packer->w, packer->h, + packer->scratch, &used_width); + if (y >= 0) { + packer->used_width = MPMIN(used_width, packer->w); + packer->used_height = MPMIN(y, packer->h); + assert(packer->w == 0 || IS_POWER_OF_2(packer->w)); + assert(packer->h == 0 || IS_POWER_OF_2(packer->h)); + if (packer->padding) { + for (int i = 0; i < packer->count; i++) { + packer->result[i].x += packer->padding; + packer->result[i].y += packer->padding; + } + } + return packer->w != w_orig || packer->h != h_orig; + } + int w_max = packer->w_max > 0 ? packer->w_max : INT_MAX; + int h_max = packer->h_max > 0 ? packer->h_max : INT_MAX; + if (packer->w <= packer->h && packer->w != w_max) + packer->w = MPMIN(packer->w * 2, w_max); + else if (packer->h != h_max) + packer->h = MPMIN(packer->h * 2, h_max); + else { + packer->w = w_orig; + packer->h = h_orig; + return -1; + } + } +} + +void packer_set_size(struct bitmap_packer *packer, int size) +{ + packer->count = size; + if (size <= packer->asize) + return; + packer->asize = MPMAX(packer->asize * 2, size); + talloc_free(packer->result); + talloc_free(packer->scratch); + packer->in = talloc_realloc(packer, packer->in, struct pos, packer->asize); + packer->result = talloc_array_ptrtype(packer, packer->result, + packer->asize); + packer->scratch = talloc_array_ptrtype(packer, packer->scratch, + packer->asize + 16); +} |