1 files changed, 117 insertions, 0 deletions
diff --git a/src/old_imresize.c b/src/old_imresize.c
new file mode 100644
index 0000000..8191037
--- /dev/null
+++ b/src/old_imresize.c
@@ -0,0 +1,117 @@
+/** \file
+ * \brief Old resize/stretch functions
+ *
+ * See Copyright Notice in im_lib.h
+ * $Id: old_imresize.c,v 1.1 2008/10/17 06:10:16 scuri Exp $
+ */
+
+#include "old_im.h"
+
+#include <stdlib.h>
+#include <math.h>
+#include <memory.h>
+
+
+/*
+  BILINEAR INTERPOLATION:
+
+  x' = floor(x)                                        f(x'   , y')    = fll
+  y' = floor(y)                                        f(x'   , y'+ 1) = flh
+                                                       f(x'+ 1, y')    = fhl
+  t = x - x'                                           f(x'+ 1, y'+ 1) = fhh
+  u = y - y'
+
+  f(x,y) = (1-t) * (1-u) * f(x'   , y'),
+           (1-t) *    u  * f(x'   , y'+ 1),
+               t * (1-u) * f(x'+ 1, y'),
+               t *    u  * f(x'+ 1, y'+ 1)
+
+  f(x,y) =          fll +                              (re-arranging)
+               t * (fhl - fll),
+               u * (flh - fll),
+           u * t * (fhh - flh - fhl + fll)
+          
+*/
+
+void imResize(int src_width, int src_height, unsigned char *src_map, int dst_width, int dst_height, unsigned char *dst_map)
+{
+  /* Do bilinear interpolation */
+
+	unsigned char *line_mapl, *line_maph;
+  double t, u, src_x, src_y, factor;
+  int fhh, fll, fhl, flh, xl, yl, xh, yh, x, y;
+
+  int *XL = (int*)malloc(dst_width * sizeof(int));
+  double *T = (double*)malloc(dst_width * sizeof(double));
+
+	factor = (double)(src_width-1) / (double)(dst_width-1);
+  for (x = 0; x < dst_width; x++)
+  {
+	  src_x = x * factor;
+	  xl = (int)floor(src_x);
+	  T[x] = src_x - xl;
+	  XL[x] = xl;
+  }
+
+	factor = (double)(src_height-1) / (double)(dst_height-1);
+
+  for (y = 0; y < dst_height; y++)
+  {
+	  src_y = y * factor;
+	  yl = (int)floor(src_y);
+    yh = (yl == src_height-1)? yl: yl + 1;
+	  u = src_y - yl;
+
+	  line_mapl = src_map + yl * src_width;
+	  line_maph = src_map + yh * src_width;
+
+	  for (x = 0; x < dst_width; x++)
+	  {
+		  xl = XL[x];
+      xh = (xl == src_width-1)? xl: xl + 1;
+		  t = T[x];
+
+		  fll = line_mapl[xl];
+		  fhl = line_mapl[xh];
+		  flh = line_maph[xl];
+		  fhh = line_maph[xh];
+
+		  *(dst_map++) = (unsigned char)(u * t * (fhh - flh - fhl + fll) + t * (fhl - fll) + u * (flh - fll) + fll);
+	  }
+  }
+
+  free(XL);
+  free(T);
+}
+
+void imStretch(int src_width, int src_height, unsigned char *src_map, int dst_width, int dst_height, unsigned char *dst_map)
+{
+  int x, y, offset;
+  double factor;
+  unsigned char *line_map;
+	int* XTab = (int*)malloc(dst_width*sizeof(int));
+
+  /* initialize convertion tables to speed up the stretch process */
+	factor = (double)(src_width-1) / (double)(dst_width-1);
+	for(x = 0; x < dst_width; x++)
+		XTab[x] = (int)(factor * x + 0.5);
+
+	factor = (double)(src_height-1) / (double)(dst_height-1);
+
+  line_map = src_map;
+
+  for (y = 0; y < dst_height; y++)
+  {
+    for (x = 0; x < dst_width; x++)
+    {
+      offset = XTab[x];
+      *(dst_map++) = line_map[offset];
+    }
+
+    offset = ((int)(factor * y + 0.5)) * src_width;
+		line_map = src_map + offset;
+  }
+
+  free(XTab);
+}
+