1 files changed, 68 insertions, 0 deletions
diff --git a/plug-ins/selection-to-path/pxl-outline.h b/plug-ins/selection-to-path/pxl-outline.h
new file mode 100644
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--- /dev/null
+++ b/plug-ins/selection-to-path/pxl-outline.h
@@ -0,0 +1,68 @@
+/* pxl-outline.h: find a list of outlines which make up one character.
+ *
+ * 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/>.
+ */
+
+#ifndef PXL_OUTLINE_H
+#define PXL_OUTLINE_H
+
+#include "types.h"
+
+
+/* This is a list of contiguous points on the bitmap.  */
+typedef struct
+{
+  coordinate_type *data;
+  unsigned length;
+  boolean clockwise;
+} pixel_outline_type;
+
+/* The Nth coordinate in the list.  */
+#define O_COORDINATE(p_o, n) ((p_o).data[n])
+
+/* The length of the list.  */
+#define O_LENGTH(p_o) ((p_o).length)
+
+/* Whether the outline moves clockwise or counterclockwise.  */
+#define O_CLOCKWISE(p_o) ((p_o).clockwise)
+
+/* Since a pixel outline is cyclic, the index of the next coordinate
+   after the last is the first, and the previous coordinate before the
+   first is the last.  */
+#define O_NEXT(p_o, n) (((n) + 1) % O_LENGTH (p_o))
+#define O_PREV(p_o, n) ((n) == 0 ? O_LENGTH (p_o) - 1 : (n) - 1)
+
+/* And the character turns into a list of such lists.  */
+typedef struct
+{
+  pixel_outline_type *data;
+  unsigned length;
+} pixel_outline_list_type;
+
+/* The Nth list in the list of lists.  */
+#define O_LIST_OUTLINE(p_o_l, n) ((p_o_l).data[n])
+
+/* The length of the list of lists.  */
+#define O_LIST_LENGTH(p_o_l) ((p_o_l).length)
+
+
+/* Find all pixels on the outline in the character C.  */
+extern pixel_outline_list_type find_outline_pixels (void);
+
+/* Free the memory in the list.  */
+extern void free_pixel_outline_list (pixel_outline_list_type *);
+
+#endif /* not PXL_OUTLINE_H */