From: Jann Horn <jann@thejh.net>
Date: Tue, 5 Nov 2013 21:50:40 +0000 (+0100)
Subject: initial commit
X-Git-Url: http://git.thejh.net/?p=detafelator.git;a=commitdiff_plain;h=5021ac04daddff52b9a4629e261bb891e03536d1

initial commit
---

5021ac04daddff52b9a4629e261bb891e03536d1
diff --git a/detafelator.c b/detafelator.c
new file mode 100644
index 0000000..ebc68b5
--- /dev/null
+++ b/detafelator.c
@@ -0,0 +1,56 @@
+#include <jh.h>
+#include <assert.h>
+#include <stdbool.h>
+
+int avg(int a, int b) { return (a+b)/2; }
+
+int nuldif(int n) { return abs(128-n); }
+
+int blimround(int a) { return (a<0)?0:((a>255)?255:a); }
+
+unsigned char *pxptr(pnm_image *img, int x, int y) {
+  return img->data + 3*(x + y*img->width);
+}
+
+#define TRESH 4
+
+int main(int argc, char **argv) {
+  pnm_image *iimg = CHK_PTR(read_image("/dev/stdin"), "can't read image from stdin", 1);
+
+  int rowsize = 3*iimg->width;
+
+  for (int y=0; y<iimg->height-1; y++) {
+    unsigned char *irow = iimg->data + rowsize*y;
+    //unsigned char *orow = oimg->data + rowsize*y;
+    for (int x=0; x<iimg->width-1; x++) {
+      unsigned char *ipx = irow + 3*x;
+      for (int i=0; i<3; i++) {
+        unsigned char *ipxc = ipx+i;
+        int xdiff = ipxc[3]-ipxc[0];
+        int ydiff = ipxc[rowsize]-ipxc[0];
+        ipxc[0] = blimround(128+xdiff/*+ydiff*/);
+      }
+    }
+  }
+
+  pnm_image *oimg = CHK_PTR(dup_image(iimg), "can't dup image", 1);
+
+  for (int x=5; x<iimg->width; x++) {
+    for (int y=/*1*/0; y<iimg->height; y++) {
+      bool notresh = true;
+      if (nuldif(*pxptr(iimg,x,y))>TRESH) notresh=false;
+      for (int x_=x-5; x_<x; x_++) if (nuldif(*pxptr(iimg,x_,y))>TRESH) notresh=false;
+      //for (int y_=y-10; y_<y; y_++) if (nuldif(*pxptr(iimg,x,y_))>TRESH) notresh=false;
+      if (notresh) {
+        pxptr(oimg,x,y)[0]=255;
+      } else {
+        pxptr(oimg,x,y)[0]=blimround(
+          /*avg(*/pxptr(oimg,x-1,y)[0]/*,pxptr(oimg,x,y-1)[0])*/ - (pxptr(iimg, x, y)[0]-128)
+        );
+      }
+    }
+  }
+
+  if (write_image(oimg, "/dev/stdout")) xperror("unable to write image to stdout", 1);
+  return 0;
+}
\ No newline at end of file