1 files changed, 254 insertions, 0 deletions
diff --git a/plug-ins/selection-to-path/pxl-outline.c b/plug-ins/selection-to-path/pxl-outline.c
new file mode 100644
index 0000000..a339ff3
--- /dev/null
+++ b/plug-ins/selection-to-path/pxl-outline.c
@@ -0,0 +1,254 @@
+/* pxl-outline.c: find the edges of the bitmap image; we call each such
+ *   edge an ``outline''; each outline is made up of one or more pixels;
+ *   and each pixel participates via one or more edges.
+ *
+ * Copyright (C) 1992 Free Software Foundation, Inc.
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 3, or (at your option)
+ * any later version.
+ *
+ * This program 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 General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+#include "config.h"
+
+#include "global.h"
+#include "selection-to-path.h"
+#include "bitmap.h"
+#include "edge.h"
+#include "pxl-outline.h"
+
+#include "libgimp/stdplugins-intl.h"
+
+static pixel_outline_type find_one_outline (edge_type,
+			  		    unsigned, unsigned, bitmap_type *);
+static void append_pixel_outline (pixel_outline_list_type *,
+                                  pixel_outline_type);
+static pixel_outline_type new_pixel_outline (void);
+static void append_outline_pixel (pixel_outline_type *, coordinate_type);
+static void append_coordinate (pixel_outline_type *, int, int, edge_type);
+
+
+static bitmap_type
+local_new_bitmap (unsigned width,unsigned height)
+{
+  bitmap_type answer;
+  unsigned size = width * height;
+
+
+  BITMAP_HEIGHT(answer) = height;
+  BITMAP_WIDTH(answer) = width;
+
+  BITMAP_BITS (answer) = g_new0 (one_byte, size);  /* g_new returns NULL if size == 0 */
+
+/*   printf("local_new_bitmap size = %d @[%p]\n",size,BITMAP_BITS (answer)); */
+
+  return answer;
+}
+
+static void
+local_free_bitmap (bitmap_type *b)
+{
+  if (BITMAP_BITS (*b) != NULL)
+    safe_free ((address *) &BITMAP_BITS (*b));
+}
+
+/* A character is made up of a list of one or more outlines.  Here, we
+   go through a character's bitmap top to bottom, left to right, looking
+   for the next pixel with an unmarked edge also on the character's outline.
+   Each one of these we find is the starting place for one outline.  We
+   find these outlines and put them in a list to return.  */
+
+pixel_outline_list_type
+find_outline_pixels (void)
+{
+  pixel_outline_list_type outline_list;
+  unsigned row, col;
+  gint height;
+  gint width;
+  bitmap_type marked = local_new_bitmap (sel_get_width(),sel_get_height());
+
+/*   printf("width = %d, height = %d\n",BITMAP_WIDTH(marked),BITMAP_HEIGHT(marked)); */
+
+  gimp_progress_init (_("Selection to Path"));
+
+  O_LIST_LENGTH (outline_list) = 0;
+  outline_list.data = NULL;
+
+  height = sel_get_height ();
+  width  = sel_get_width ();
+
+  for (row = 0; row < height; row++)
+  {
+    for (col = 0; col < width; col++)
+      {
+	edge_type edge;
+
+        if (sel_pixel_is_white(row, col))
+          continue;
+
+        edge = next_unmarked_outline_edge (row, col, START_EDGE,marked);
+
+	if (edge != no_edge)
+	  {
+            pixel_outline_type outline;
+            boolean clockwise = edge == bottom;
+
+            outline = find_one_outline (edge, row, col, &marked);
+
+            /* Outside outlines will start at a top edge, and move
+               counterclockwise, and inside outlines will start at a
+               bottom edge, and move clockwise.  This happens because of
+               the order in which we look at the edges.  */
+            O_CLOCKWISE (outline) = clockwise;
+	    append_pixel_outline (&outline_list, outline);
+
+	  }
+      }
+
+    if ((row & 0xf) == 0)
+	gimp_progress_update (((gdouble)row) / height);
+  }
+
+  gimp_progress_update (1.0);
+
+  local_free_bitmap (&marked);
+
+  return outline_list;
+}
+
+
+/* Here we find one of a character C's outlines.  We're passed the
+   position (ORIGINAL_ROW and ORIGINAL_COL) of a starting pixel and one
+   of its unmarked edges, ORIGINAL_EDGE.  We traverse the adjacent edges
+   of the outline pixels, appending to the coordinate list.  We keep
+   track of the marked edges in MARKED, so it should be initialized to
+   zeros when we first get it.  */
+
+static pixel_outline_type
+find_one_outline (edge_type original_edge,
+		  unsigned original_row, unsigned original_col,
+		  bitmap_type *marked)
+{
+  pixel_outline_type outline = new_pixel_outline ();
+  unsigned row = original_row, col = original_col;
+  edge_type edge = original_edge;
+
+  do
+    {
+      /* Put this edge on to the output list, changing to Cartesian, and
+         taking account of the side bearings.  */
+      append_coordinate (&outline, col,
+                         sel_get_height() - row, edge);
+
+      mark_edge (edge, row, col, marked);
+      next_outline_edge (&edge, &row, &col);
+    }
+  while (row != original_row || col != original_col || edge != original_edge);
+
+  return outline;
+}
+
+
+/* Append an outline to an outline list.  This is called when we have
+   completed an entire pixel outline.  */
+
+static void
+append_pixel_outline (pixel_outline_list_type *outline_list,
+		      pixel_outline_type outline)
+{
+  O_LIST_LENGTH (*outline_list)++;
+  outline_list->data = (pixel_outline_type *)g_realloc(outline_list->data,outline_list->length *sizeof(pixel_outline_type));
+  O_LIST_OUTLINE (*outline_list, O_LIST_LENGTH (*outline_list) - 1) = outline;
+}
+
+
+/* Here is a routine that frees a list of such lists.  */
+
+void
+free_pixel_outline_list (pixel_outline_list_type *outline_list)
+{
+  unsigned this_outline;
+
+  for (this_outline = 0; this_outline < outline_list->length; this_outline++)
+    {
+      pixel_outline_type o = outline_list->data[this_outline];
+      safe_free ((address *) &(o.data));
+    }
+
+  if (outline_list->data != NULL)
+    safe_free ((address *) &(outline_list->data));
+}
+
+
+/* Return an empty list of pixels.  */
+
+
+static pixel_outline_type
+new_pixel_outline (void)
+{
+  pixel_outline_type pixel_outline;
+
+  O_LENGTH (pixel_outline) = 0;
+  pixel_outline.data = NULL;
+
+  return pixel_outline;
+}
+
+
+/* Add the coordinate C to the pixel list O.  */
+
+static void
+append_outline_pixel (pixel_outline_type *o, coordinate_type c)
+{
+  O_LENGTH (*o)++;
+  o->data = (coordinate_type *)g_realloc(o->data, O_LENGTH (*o)*sizeof(coordinate_type));
+  O_COORDINATE (*o, O_LENGTH (*o) - 1) = c;
+}
+
+
+/* We are given an (X,Y) in Cartesian coordinates, and the edge of the pixel
+   we're on.  We append a corner of that pixel as our coordinate.
+   If we're on a top edge, we use the upper-left hand corner; right edge
+   => upper right; bottom edge => lower right; left edge => lower left.  */
+
+static void
+append_coordinate (pixel_outline_type *o, int x, int y, edge_type edge)
+{
+  coordinate_type c;
+
+  c.x = x;
+  c.y = y;
+
+  switch (edge)
+    {
+    case top:
+      c.y++;
+      break;
+
+    case right:
+      c.x++;
+      c.y++;
+      break;
+
+    case bottom:
+      c.x++;
+      break;
+
+    case left:
+      break;
+
+    default:
+      g_printerr ("append_coordinate: Bad edge (%d)", edge);
+    }
+
+  append_outline_pixel (o, c);
+}