fixed an issue with image display where image pixel size was not draw…

…n correctly

gui/polyView.cpp

@@ -444,10 +444,11 @@ void polyView::imageToScreenRect(// inputs
                                  utils::PositionedImage const& positioned_img,
                                  QRect & screenRect) { // output
 
-  std::vector<int> x = {imageRect.left(), imageRect.right(),
-                        imageRect.right(), imageRect.left()};
+  // Increase the right and bottom by 1 seems to work properly for Qt image display
+  std::vector<int> x = {imageRect.left(), imageRect.right()+1,
+                        imageRect.right()+1, imageRect.left()};
   std::vector<int> y = {imageRect.top(), imageRect.top(),
-                        imageRect.bottom(), imageRect.bottom()};
+                        imageRect.bottom()+1, imageRect.bottom()+1};
 
   int big = std::numeric_limits<int>::max();
   int min_ix = big, min_iy = big, max_ix = -big, max_iy = -big;

gui/utils.cpp

@@ -506,8 +506,9 @@ bool utils::readImagePosition(std::string const& filename, std::vector<double> &
 // Convert from world coordinates to this image's pixel coordinates.
 void utils::worldToImage(double wx, double wy, utils::PositionedImage const& img, // inputs
                   double & ix, double & iy) { // outputs
-   ix = (wx - img.pos[0]) / img.pos[2];
-   iy = (wy - img.pos[1]) / img.pos[3];
+   // half grid shift for pixel center
+   ix = (wx - img.pos[0] + img.pos[2]/2) / img.pos[2];
+   iy = (wy - img.pos[1] + img.pos[3]/2) / img.pos[3];
 
    // Flip in y
    iy = img.qimg.height() - 1 - iy;
@@ -520,8 +521,9 @@ void utils::imageToWorld(double ix, double iy, utils::PositionedImage const& img
    // Flip in y
   iy = img.qimg.height() - 1 - iy;
 
-  wx = ix * img.pos[2] + img.pos[0];
-  wy = iy * img.pos[3] + img.pos[1];
+  // half grid shift for pixel center
+  wx = ix * img.pos[2] + img.pos[0] - img.pos[2]/2;
+  wy = iy * img.pos[3] + img.pos[1] - img.pos[3]/2;
 }
 
 // Find the box containing all polygons and images