X-Git-Url: http://git.asbjorn.biz/?a=blobdiff_plain;f=lib%2Fart%2Fart_rgb_rgba_affine.c;fp=lib%2Fart%2Fart_rgb_rgba_affine.c;h=41c7397270ea9836bdce74ea03538bd3ac8e867d;hb=418ef05b5d0b74e6f19200ffa40bcc3afccb5029;hp=0000000000000000000000000000000000000000;hpb=c1f4a906117e98e2f4ba59abc1ce153e8129bc19;p=swftools.git

diff --git a/lib/art/art_rgb_rgba_affine.c b/lib/art/art_rgb_rgba_affine.c
new file mode 100644
index 0000000..41c7397
--- /dev/null
+++ b/lib/art/art_rgb_rgba_affine.c
@@ -0,0 +1,142 @@
+/* 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_rgb_rgba_affine.h"
+
+#include <math.h>
+#include "art_misc.h"
+#include "art_point.h"
+#include "art_affine.h"
+#include "art_rgb_affine_private.h"
+
+/* This module handles compositing of affine-transformed rgba images
+   over rgb pixel buffers. */
+
+/* Composite the source image over the destination image, applying the
+   affine transform. */
+
+/**
+ * art_rgb_rgba_affine: Affine transform source RGBA image and composite.
+ * @dst: Destination image RGB buffer.
+ * @x0: Left coordinate of destination rectangle.
+ * @y0: Top coordinate of destination rectangle.
+ * @x1: Right coordinate of destination rectangle.
+ * @y1: Bottom coordinate of destination rectangle.
+ * @dst_rowstride: Rowstride of @dst buffer.
+ * @src: Source image RGBA buffer.
+ * @src_width: Width of source image.
+ * @src_height: Height of source image.
+ * @src_rowstride: Rowstride of @src buffer.
+ * @affine: Affine transform.
+ * @level: Filter level.
+ * @alphagamma: #ArtAlphaGamma for gamma-correcting the compositing.
+ *
+ * Affine transform the source image stored in @src, compositing over
+ * the area of destination image @dst specified by the rectangle
+ * (@x0, @y0) - (@x1, @y1). As usual in libart, the left and top edges
+ * of this rectangle are included, and the right and bottom edges are
+ * excluded.
+ *
+ * The @alphagamma parameter specifies that the alpha compositing be
+ * done in a gamma-corrected color space. In the current
+ * implementation, it is ignored.
+ *
+ * The @level parameter specifies the speed/quality tradeoff of the
+ * image interpolation. Currently, only ART_FILTER_NEAREST is
+ * implemented.
+ **/
+void
+art_rgb_rgba_affine (art_u8 *dst,
+		     int x0, int y0, int x1, int y1, int dst_rowstride,
+		     const art_u8 *src,
+		     int src_width, int src_height, int src_rowstride,
+		     const double affine[6],
+		     ArtFilterLevel level,
+		     ArtAlphaGamma *alphagamma)
+{
+  /* Note: this is a slow implementation, and is missing all filter
+     levels other than NEAREST. It is here for clarity of presentation
+     and to establish the interface. */
+  int x, y;
+  double inv[6];
+  art_u8 *dst_p, *dst_linestart;
+  const art_u8 *src_p;
+  ArtPoint pt, src_pt;
+  int src_x, src_y;
+  int alpha;
+  art_u8 bg_r, bg_g, bg_b;
+  art_u8 fg_r, fg_g, fg_b;
+  int tmp;
+  int run_x0, run_x1;
+
+  dst_linestart = dst;
+  art_affine_invert (inv, affine);
+  for (y = y0; y < y1; y++)
+    {
+      pt.y = y + 0.5;
+      run_x0 = x0;
+      run_x1 = x1;
+      art_rgb_affine_run (&run_x0, &run_x1, y, src_width, src_height,
+			  inv);
+      dst_p = dst_linestart + (run_x0 - x0) * 3;
+      for (x = run_x0; x < run_x1; x++)
+	{
+	  pt.x = x + 0.5;
+	  art_affine_point (&src_pt, &pt, inv);
+	  src_x = floor (src_pt.x);
+	  src_y = floor (src_pt.y);
+	  src_p = src + (src_y * src_rowstride) + src_x * 4;
+	  if (src_x >= 0 && src_x < src_width &&
+	      src_y >= 0 && src_y < src_height)
+	    {
+
+	  alpha = src_p[3];
+	  if (alpha)
+	    {
+	      if (alpha == 255)
+		{
+		  dst_p[0] = src_p[0];
+		  dst_p[1] = src_p[1];
+		  dst_p[2] = src_p[2];
+		}
+	      else
+		{
+		  bg_r = dst_p[0];
+		  bg_g = dst_p[1];
+		  bg_b = dst_p[2];
+		  
+		  tmp = (src_p[0] - bg_r) * alpha;
+		  fg_r = bg_r + ((tmp + (tmp >> 8) + 0x80) >> 8);
+		  tmp = (src_p[1] - bg_g) * alpha;
+		  fg_g = bg_g + ((tmp + (tmp >> 8) + 0x80) >> 8);
+		  tmp = (src_p[2] - bg_b) * alpha;
+		  fg_b = bg_b + ((tmp + (tmp >> 8) + 0x80) >> 8);
+		  
+		  dst_p[0] = fg_r;
+		  dst_p[1] = fg_g;
+		  dst_p[2] = fg_b;
+		}
+	    }
+	    } else { dst_p[0] = 255; dst_p[1] = 0; dst_p[2] = 0; }
+	  dst_p += 3;
+	}
+      dst_linestart += dst_rowstride;
+    }
+}