libart 2.3.16

[swftools.git] / lib / art / art_rect_uta.c

diff --git a/lib/art/art_rect_uta.c b/lib/art/art_rect_uta.c
new file mode 100644 (file)
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+++ b/lib/art/art_rect_uta.c
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+/* Libart_LGPL - library of basic graphic primitives
+ * Copyright (C) 1998 Raph Levien
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Library General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This library 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
+ * Library General Public License for more details.
+ *
+ * You should have received a copy of the GNU Library General Public
+ * License along with this library; if not, write to the
+ * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+ * Boston, MA 02111-1307, USA.
+ */
+
+#include "config.h"
+#include "art_rect_uta.h"
+
+/* Functions to decompose a microtile array into a list of rectangles. */
+
+/**
+ * art_rect_list_from_uta: Decompose uta into list of rectangles.
+ * @uta: The source uta.
+ * @max_width: The maximum width of the resulting rectangles.
+ * @max_height: The maximum height of the resulting rectangles.
+ * @p_nrects: Where to store the number of returned rectangles.
+ *
+ * Allocates a new list of rectangles, sets *@p_nrects to the number
+ * in the list. This list should be freed with art_free().
+ *
+ * Each rectangle bounded in size by (@max_width, @max_height).
+ * However, these bounds must be at least the size of one tile.
+ *
+ * This routine provides a precise implementation, i.e. the rectangles
+ * cover exactly the same area as the uta. It is thus appropriate in
+ * cases where the overhead per rectangle is small compared with the
+ * cost of filling in extra pixels.
+ *
+ * Return value: An array containing the resulting rectangles.
+ **/
+ArtIRect *
+art_rect_list_from_uta (ArtUta *uta, int max_width, int max_height,
+                       int *p_nrects)
+{
+  ArtIRect *rects;
+  int n_rects, n_rects_max;
+  int x, y;
+  int width, height;
+  int ix;
+  int left_ix;
+  ArtUtaBbox *utiles;
+  ArtUtaBbox bb;
+  int x0, y0, x1, y1;
+  int *glom;
+  int glom_rect;
+
+  n_rects = 0;
+  n_rects_max = 1;
+  rects = art_new (ArtIRect, n_rects_max);
+
+  width = uta->width;
+  height = uta->height;
+  utiles = uta->utiles;
+
+  glom = art_new (int, width * height);
+  for (ix = 0; ix < width * height; ix++)
+    glom[ix] = -1;
+
+  ix = 0;
+  for (y = 0; y < height; y++)
+    for (x = 0; x < width; x++)
+      {
+       bb = utiles[ix];
+       if (bb)
+         {
+           x0 = ((uta->x0 + x) << ART_UTILE_SHIFT) + ART_UTA_BBOX_X0(bb);
+           y0 = ((uta->y0 + y) << ART_UTILE_SHIFT) + ART_UTA_BBOX_Y0(bb);
+           y1 = ((uta->y0 + y) << ART_UTILE_SHIFT) + ART_UTA_BBOX_Y1(bb);
+
+           left_ix = ix;
+           /* now try to extend to the right */
+           while (x != width - 1 &&
+                  ART_UTA_BBOX_X1(bb) == ART_UTILE_SIZE &&
+                  (((bb & 0xffffff) ^ utiles[ix + 1]) & 0xffff00ff) == 0 &&
+                  (((uta->x0 + x + 1) << ART_UTILE_SHIFT) +
+                   ART_UTA_BBOX_X1(utiles[ix + 1]) -
+                   x0) <= max_width)
+             {
+               bb = utiles[ix + 1];
+               ix++;
+               x++;
+             }
+           x1 = ((uta->x0 + x) << ART_UTILE_SHIFT) + ART_UTA_BBOX_X1(bb);
+
+
+           /* if rectangle nonempty */
+           if ((x1 ^ x0) | (y1 ^ y0))
+             {
+               /* try to glom onto an existing rectangle */
+               glom_rect = glom[left_ix];
+               if (glom_rect != -1 &&
+                   x0 == rects[glom_rect].x0 &&
+                   x1 == rects[glom_rect].x1 &&
+                   y0 == rects[glom_rect].y1 &&
+                   y1 - rects[glom_rect].y0 <= max_height)
+                 {
+                   rects[glom_rect].y1 = y1;
+                 }
+               else
+                 {
+                   if (n_rects == n_rects_max)
+                     art_expand (rects, ArtIRect, n_rects_max);
+                   rects[n_rects].x0 = x0;
+                   rects[n_rects].y0 = y0;
+                   rects[n_rects].x1 = x1;
+                   rects[n_rects].y1 = y1;
+                   glom_rect = n_rects;
+                   n_rects++;
+                 }
+               if (y != height - 1)
+                 glom[left_ix + width] = glom_rect;
+             }
+         }
+       ix++;
+      }
+
+  art_free (glom);
+  *p_nrects = n_rects;
+  return rects;
+}