added "abs" func to fimgfx

lib/fimg-math.c

@@ -1,5 +1,5 @@
 /*
- *		fimg-core.c
+ *		fimg-math.c
  *
  *
  */
@@ -295,6 +295,22 @@ fimg_mul_cste(fi, coef);
 return 0;
 }
 /* ---------------------------------------------------------------- */
+int fimg_absolute(FloatImg *fi)
+{
+int		surface, idx;
+
+surface = fi->width * fi->height;
+
+for (idx=0; idx<surface; idx++) {
+	fi->R[idx] = fabsf(fi->R[idx]);
+	fi->G[idx] = fabsf(fi->G[idx]);
+	fi->B[idx] = fabsf(fi->B[idx]);
+	}
+
+return 0;
+}
+/* ---------------------------------------------------------------- */
+
 /*            Warning: this function is _very_ slow                 */
 void fimg_drand48(FloatImg *fi, float kmul)
 {