| 1 | /* Libart_LGPL - library of basic graphic primitives |
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| 2 | * Copyright (C) 1998 Raph Levien |
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| 3 | * |
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| 4 | * This library is free software; you can redistribute it and/or |
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| 5 | * modify it under the terms of the GNU Library General Public |
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| 6 | * License as published by the Free Software Foundation; either |
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| 7 | * version 2 of the License, or (at your option) any later version. |
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| 8 | * |
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| 9 | * This library is distributed in the hope that it will be useful, |
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| 10 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
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| 11 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
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| 12 | * Library General Public License for more details. |
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| 13 | * |
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| 14 | * You should have received a copy of the GNU Library General Public |
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| 15 | * License along with this library; if not, write to the |
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| 16 | * Free Software Foundation, Inc., 59 Temple Place - Suite 330, |
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| 17 | * Boston, MA 02111-1307, USA. |
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| 18 | */ |
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| 19 | |
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| 20 | #include "config.h" |
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| 21 | #include "art_rect_uta.h" |
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| 22 | |
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| 23 | /* Functions to decompose a microtile array into a list of rectangles. */ |
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| 24 | |
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| 25 | /** |
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| 26 | * art_rect_list_from_uta: Decompose uta into list of rectangles. |
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| 27 | * @uta: The source uta. |
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| 28 | * @max_width: The maximum width of the resulting rectangles. |
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| 29 | * @max_height: The maximum height of the resulting rectangles. |
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| 30 | * @p_nrects: Where to store the number of returned rectangles. |
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| 31 | * |
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| 32 | * Allocates a new list of rectangles, sets *@p_nrects to the number |
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| 33 | * in the list. This list should be freed with art_free(). |
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| 34 | * |
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| 35 | * Each rectangle bounded in size by (@max_width, @max_height). |
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| 36 | * However, these bounds must be at least the size of one tile. |
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| 37 | * |
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| 38 | * This routine provides a precise implementation, i.e. the rectangles |
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| 39 | * cover exactly the same area as the uta. It is thus appropriate in |
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| 40 | * cases where the overhead per rectangle is small compared with the |
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| 41 | * cost of filling in extra pixels. |
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| 42 | * |
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| 43 | * Return value: An array containing the resulting rectangles. |
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| 44 | **/ |
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| 45 | ArtIRect * |
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| 46 | art_rect_list_from_uta (ArtUta *uta, int max_width, int max_height, |
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| 47 | int *p_nrects) |
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| 48 | { |
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| 49 | ArtIRect *rects; |
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| 50 | int n_rects, n_rects_max; |
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| 51 | int x, y; |
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| 52 | int width, height; |
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| 53 | int ix; |
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| 54 | int left_ix; |
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| 55 | ArtUtaBbox *utiles; |
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| 56 | ArtUtaBbox bb; |
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| 57 | int x0, y0, x1, y1; |
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| 58 | int *glom; |
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| 59 | int glom_rect; |
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| 60 | |
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| 61 | n_rects = 0; |
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| 62 | n_rects_max = 1; |
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| 63 | rects = art_new (ArtIRect, n_rects_max); |
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| 64 | |
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| 65 | width = uta->width; |
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| 66 | height = uta->height; |
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| 67 | utiles = uta->utiles; |
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| 68 | |
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| 69 | glom = art_new (int, width * height); |
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| 70 | for (ix = 0; ix < width * height; ix++) |
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| 71 | glom[ix] = -1; |
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| 72 | |
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| 73 | ix = 0; |
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| 74 | for (y = 0; y < height; y++) |
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| 75 | for (x = 0; x < width; x++) |
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| 76 | { |
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| 77 | bb = utiles[ix]; |
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| 78 | if (bb) |
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| 79 | { |
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| 80 | x0 = ((uta->x0 + x) << ART_UTILE_SHIFT) + ART_UTA_BBOX_X0(bb); |
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| 81 | y0 = ((uta->y0 + y) << ART_UTILE_SHIFT) + ART_UTA_BBOX_Y0(bb); |
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| 82 | y1 = ((uta->y0 + y) << ART_UTILE_SHIFT) + ART_UTA_BBOX_Y1(bb); |
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| 83 | |
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| 84 | left_ix = ix; |
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| 85 | /* now try to extend to the right */ |
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| 86 | while (x != width - 1 && |
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| 87 | ART_UTA_BBOX_X1(bb) == ART_UTILE_SIZE && |
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| 88 | (((bb & 0xffffff) ^ utiles[ix + 1]) & 0xffff00ff) == 0 && |
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| 89 | (((uta->x0 + x + 1) << ART_UTILE_SHIFT) + |
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| 90 | ART_UTA_BBOX_X1(utiles[ix + 1]) - |
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| 91 | x0) <= max_width) |
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| 92 | { |
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| 93 | bb = utiles[ix + 1]; |
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| 94 | ix++; |
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| 95 | x++; |
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| 96 | } |
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| 97 | x1 = ((uta->x0 + x) << ART_UTILE_SHIFT) + ART_UTA_BBOX_X1(bb); |
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| 98 | |
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| 99 | |
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| 100 | /* if rectangle nonempty */ |
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| 101 | if ((x1 ^ x0) | (y1 ^ y0)) |
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| 102 | { |
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| 103 | /* try to glom onto an existing rectangle */ |
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| 104 | glom_rect = glom[left_ix]; |
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| 105 | if (glom_rect != -1 && |
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| 106 | x0 == rects[glom_rect].x0 && |
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| 107 | x1 == rects[glom_rect].x1 && |
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| 108 | y0 == rects[glom_rect].y1 && |
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| 109 | y1 - rects[glom_rect].y0 <= max_height) |
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| 110 | { |
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| 111 | rects[glom_rect].y1 = y1; |
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| 112 | } |
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| 113 | else |
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| 114 | { |
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| 115 | if (n_rects == n_rects_max) |
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| 116 | art_expand (rects, ArtIRect, n_rects_max); |
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| 117 | rects[n_rects].x0 = x0; |
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| 118 | rects[n_rects].y0 = y0; |
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| 119 | rects[n_rects].x1 = x1; |
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| 120 | rects[n_rects].y1 = y1; |
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| 121 | glom_rect = n_rects; |
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| 122 | n_rects++; |
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| 123 | } |
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| 124 | if (y != height - 1) |
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| 125 | glom[left_ix + width] = glom_rect; |
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| 126 | } |
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| 127 | } |
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| 128 | ix++; |
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| 129 | } |
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| 130 | |
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| 131 | art_free (glom); |
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| 132 | *p_nrects = n_rects; |
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| 133 | return rects; |
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| 134 | } |
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