Give error message in -d bilinear when formula does not work

src/Downscaler/Bilinear.cpp

@@ -54,16 +54,19 @@ float DownscalerBilinear::bilinear(float x, float y, float x0, float x1, float x
    else
       calcGeneral(x, y, x0, x1, x2, x3, y0, y1, y2, y3, t, s);
 
-   if(t >= 1 && t <= 1.05)
+   if(t >= 1 && t <= 1.15)
       t = 1;
-   if(t <= 0 && t >= -0.05)
+   if(t <= 0 && t >= -0.15)
       t = 0;
-   if(s >= 1 && s <= 1.05)
+   if(s >= 1 && s <= 1.15)
       s = 1;
-   if(s <= 0 && s >= -0.05)
+   if(s <= 0 && s >= -0.15)
       s = 0;
-   if(!(s >= 0 && s <= 1 && t >= 0 && t <= 1))
-      std::cout << "s = " << s << " t = " << t << std::endl;
+   if(!(s >= 0 && s <= 1 && t >= 0 && t <= 1)) {
+      std::stringstream ss;
+      ss << "Problem with bilinear interpolation. Grid is rotated/distorted in a way that is not supported. s=" << s << " and t=" << t << " are outside [-0.05,1.05].";
+      Util::error(ss.str());
+   }
    assert(s >= 0 && s <= 1 && t >= 0 && t <= 1);
    float value = P1 * (1 - s) * ( 1 - t) + P2 * s * (1 - t) + P3 * (1 - s) * t + P4 * s * t;