1 /* Libart_LGPL - library of basic graphic primitives
2 * Copyright (C) 1998 Raph Levien
3 *
4 * This library is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU Library General Public
6 * License as published by the Free Software Foundation; either
7 * version 2 of the License, or (at your option) any later version.
8 *
9 * This library is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
12 * Library General Public License for more details.
13 *
14 * You should have received a copy of the GNU Library General Public
15 * License along with this library; if not, write to the
16 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
17 * Boston, MA 02111-1307, USA.
18 */
19
20 #include "config.h"
21 #include "art_rect_uta.h"
22
23 /* Functions to decompose a microtile array into a list of rectangles. */
24
25 /**
26 * art_rect_list_from_uta: Decompose uta into list of rectangles.
27 * @uta: The source uta.
28 * @max_width: The maximum width of the resulting rectangles.
29 * @max_height: The maximum height of the resulting rectangles.
30 * @p_nrects: Where to store the number of returned rectangles.
31 *
32 * Allocates a new list of rectangles, sets *@p_nrects to the number
33 * in the list. This list should be freed with art_free().
34 *
35 * Each rectangle bounded in size by (@max_width, @max_height).
36 * However, these bounds must be at least the size of one tile.
37 *
38 * This routine provides a precise implementation, i.e. the rectangles
39 * cover exactly the same area as the uta. It is thus appropriate in
40 * cases where the overhead per rectangle is small compared with the
41 * cost of filling in extra pixels.
42 *
43 * Return value: An array containing the resulting rectangles.
44 **/
45 ArtIRect *
art_rect_list_from_uta(ArtUta * uta,int max_width,int max_height,int * p_nrects)46 art_rect_list_from_uta (ArtUta *uta, int max_width, int max_height,
47 int *p_nrects)
48 {
49 ArtIRect *rects;
50 int n_rects, n_rects_max;
51 int x, y;
52 int width, height;
53 int ix;
54 int left_ix;
55 ArtUtaBbox *utiles;
56 ArtUtaBbox bb;
57 int x0, y0, x1, y1;
58 int *glom;
59 int glom_rect;
60
61 n_rects = 0;
62 n_rects_max = 1;
63 rects = art_new (ArtIRect, n_rects_max);
64
65 width = uta->width;
66 height = uta->height;
67 utiles = uta->utiles;
68
69 glom = art_new (int, width * height);
70 for (ix = 0; ix < width * height; ix++)
71 glom[ix] = -1;
72
73 ix = 0;
74 for (y = 0; y < height; y++)
75 for (x = 0; x < width; x++)
76 {
77 bb = utiles[ix];
78 if (bb)
79 {
80 x0 = ((uta->x0 + x) << ART_UTILE_SHIFT) + ART_UTA_BBOX_X0(bb);
81 y0 = ((uta->y0 + y) << ART_UTILE_SHIFT) + ART_UTA_BBOX_Y0(bb);
82 y1 = ((uta->y0 + y) << ART_UTILE_SHIFT) + ART_UTA_BBOX_Y1(bb);
83
84 left_ix = ix;
85 /* now try to extend to the right */
86 while (x != width - 1 &&
87 ART_UTA_BBOX_X1(bb) == ART_UTILE_SIZE &&
88 (((bb & 0xffffff) ^ utiles[ix + 1]) & 0xffff00ff) == 0 &&
89 (((uta->x0 + x + 1) << ART_UTILE_SHIFT) +
90 ART_UTA_BBOX_X1(utiles[ix + 1]) -
91 x0) <= max_width)
92 {
93 bb = utiles[ix + 1];
94 ix++;
95 x++;
96 }
97 x1 = ((uta->x0 + x) << ART_UTILE_SHIFT) + ART_UTA_BBOX_X1(bb);
98
99
100 /* if rectangle nonempty */
101 if ((x1 ^ x0) | (y1 ^ y0))
102 {
103 /* try to glom onto an existing rectangle */
104 glom_rect = glom[left_ix];
105 if (glom_rect != -1 &&
106 x0 == rects[glom_rect].x0 &&
107 x1 == rects[glom_rect].x1 &&
108 y0 == rects[glom_rect].y1 &&
109 y1 - rects[glom_rect].y0 <= max_height)
110 {
111 rects[glom_rect].y1 = y1;
112 }
113 else
114 {
115 if (n_rects == n_rects_max)
116 art_expand (rects, ArtIRect, n_rects_max);
117 rects[n_rects].x0 = x0;
118 rects[n_rects].y0 = y0;
119 rects[n_rects].x1 = x1;
120 rects[n_rects].y1 = y1;
121 glom_rect = n_rects;
122 n_rects++;
123 }
124 if (y != height - 1)
125 glom[left_ix + width] = glom_rect;
126 }
127 }
128 ix++;
129 }
130
131 art_free (glom);
132 *p_nrects = n_rects;
133 return rects;
134 }
135