Cleanup: move bitmap drawing into its own module

Bitmap drawing is out-of-scope for a general math API,
move to BLI_bitmap_draw_2d.

1 files changed, 181 insertions, 0 deletions

diff --git a/source/blender/blenlib/intern/bitmap_draw_2d.c b/source/blender/blenlib/intern/bitmap_draw_2d.c
new file mode 100644
index 00000000000..06d21855197
--- /dev/null
+++ b/source/blender/blenlib/intern/bitmap_draw_2d.c
@@ -0,0 +1,181 @@
+/*
+ * ***** BEGIN GPL LICENSE BLOCK *****
+ *
+ * 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 2
+ * of the License, 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, write to the Free Software Foundation,
+ * Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+ *
+ * The Original Code is Copyright (C) 2001-2002 by NaN Holding BV.
+ * All rights reserved.
+ *
+ * The Original Code is: some of this file.
+ *
+ * ***** END GPL LICENSE BLOCK *****
+ * */
+
+/** \file blender/blenlib/intern/bitmap_draw_2d.c
+ *  \ingroup bli
+ *
+ * Utility functions for primitive drawing operations.
+ */
+
+#include "MEM_guardedalloc.h"
+
+#include "BLI_bitmap_draw_2d.h"
+
+#include "BLI_utildefines.h"
+
+#include "BLI_strict_flags.h"
+
+/**
+ * Plot a line from \a p1 to \a p2 (inclusive).
+ */
+void plot_line_v2v2i(
+        const int p1[2], const int p2[2],
+        bool (*callback)(int, int, void *), void *userData)
+{
+	/* Bresenham's line algorithm. */
+	int x1 = p1[0];
+	int y1 = p1[1];
+	int x2 = p2[0];
+	int y2 = p2[1];
+
+	int ix;
+	int iy;
+
+	/* if x1 == x2 or y1 == y2, then it does not matter what we set here */
+	int delta_x = (x2 > x1 ? ((void)(ix = 1), x2 - x1) : ((void)(ix = -1), x1 - x2)) << 1;
+	int delta_y = (y2 > y1 ? ((void)(iy = 1), y2 - y1) : ((void)(iy = -1), y1 - y2)) << 1;
+
+	if (callback(x1, y1, userData) == 0) {
+		return;
+	}
+
+	if (delta_x >= delta_y) {
+		/* error may go below zero */
+		int error = delta_y - (delta_x >> 1);
+
+		while (x1 != x2) {
+			if (error >= 0) {
+				if (error || (ix > 0)) {
+					y1 += iy;
+					error -= delta_x;
+				}
+				/* else do nothing */
+			}
+			/* else do nothing */
+
+			x1 += ix;
+			error += delta_y;
+
+			if (callback(x1, y1, userData) == 0) {
+				return;
+			}
+		}
+	}
+	else {
+		/* error may go below zero */
+		int error = delta_x - (delta_y >> 1);
+
+		while (y1 != y2) {
+			if (error >= 0) {
+				if (error || (iy > 0)) {
+					x1 += ix;
+					error -= delta_y;
+				}
+				/* else do nothing */
+			}
+			/* else do nothing */
+
+			y1 += iy;
+			error += delta_x;
+
+			if (callback(x1, y1, userData) == 0) {
+				return;
+			}
+		}
+	}
+}
+
+/**
+ * \param callback: Takes the x, y coords and x-span (\a x_end is not inclusive),
+ * note that \a x_end will always be greater than \a x, so we can use:
+ *
+ * \code{.c}
+ * do {
+ *     func(x, y);
+ * } while (++x != x_end);
+ * \endcode
+ */
+void fill_poly_v2i_n(
+        const int xmin, const int ymin, const int xmax, const int ymax,
+        const int verts[][2], const int nr,
+        void (*callback)(int x, int x_end, int y, void *), void *userData)
+{
+	/* Originally by Darel Rex Finley, 2007.
+	 */
+
+	int  nodes, pixel_y, i, j, swap;
+	int *node_x = MEM_mallocN(sizeof(*node_x) * (size_t)(nr + 1), __func__);
+
+	/* Loop through the rows of the image. */
+	for (pixel_y = ymin; pixel_y < ymax; pixel_y++) {
+
+		/* Build a list of nodes. */
+		nodes = 0; j = nr - 1;
+		for (i = 0; i < nr; i++) {
+			if ((verts[i][1] < pixel_y && verts[j][1] >= pixel_y) ||
+			    (verts[j][1] < pixel_y && verts[i][1] >= pixel_y))
+			{
+				node_x[nodes++] = (int)(verts[i][0] +
+				                        ((double)(pixel_y - verts[i][1]) / (verts[j][1] - verts[i][1])) *
+				                        (verts[j][0] - verts[i][0]));
+			}
+			j = i;
+		}
+
+		/* Sort the nodes, via a simple "Bubble" sort. */
+		i = 0;
+		while (i < nodes - 1) {
+			if (node_x[i] > node_x[i + 1]) {
+				SWAP_TVAL(swap, node_x[i], node_x[i + 1]);
+				if (i) i--;
+			}
+			else {
+				i++;
+			}
+		}
+
+		/* Fill the pixels between node pairs. */
+		for (i = 0; i < nodes; i += 2) {
+			if (node_x[i] >= xmax) break;
+			if (node_x[i + 1] >  xmin) {
+				if (node_x[i    ] < xmin) node_x[i    ] = xmin;
+				if (node_x[i + 1] > xmax) node_x[i + 1] = xmax;
+
+#if 0
+				/* for many x/y calls */
+				for (j = node_x[i]; j < node_x[i + 1]; j++) {
+					callback(j - xmin, pixel_y - ymin, userData);
+				}
+#else
+				/* for single call per x-span */
+				if (node_x[i] < node_x[i + 1]) {
+					callback(node_x[i] - xmin, node_x[i + 1] - xmin, pixel_y - ymin, userData);
+				}
+#endif
+			}
+		}
+	}
+	MEM_freeN(node_x);
+}