diff --git a/dotscape b/dotscape
index 2e99193..79adc5a 100755
Binary files a/dotscape and b/dotscape differ
diff --git a/fcore/graph-lines.sml b/fcore/graph-lines.sml
index 366a3b7..a71b62f 100644
--- a/fcore/graph-lines.sml
+++ b/fcore/graph-lines.sml
@@ -15,13 +15,13 @@ struct
         val halfHeight = Real32.fromInt windowHeight / 2.0
 
         val curX = Vector.sub (xClickPoints, pos)
-        val minusX = (curX - halfWidth - 1.0) / halfWidth
-        val plusX = (curX - halfWidth + 1.0) / halfWidth
+        val minusX = Ndc.fromPixelX (curX - 1.0, windowWidth, windowHeight)
+        val plusX = Ndc.fromPixelX (curX + 1.0, windowWidth, windowHeight)
 
         val minY = Vector.sub (yClickPoints, 0)
-        val minY = (~(minY - halfHeight)) / halfHeight
         val maxY = Vector.sub (yClickPoints, Vector.length yClickPoints - 1)
-        val maxY = (~(maxY - halfHeight)) / halfHeight
+        val minY = Ndc.fromPixelY (minY, windowWidth, windowHeight)
+        val maxY = Ndc.fromPixelY (maxY, windowWidth, windowHeight)
 
         val acc = Ndc.ltrbToVertex (minusX, maxY, plusX, minY) :: acc
       in
@@ -39,13 +39,13 @@ struct
         val halfHeight = Real32.fromInt windowHeight / 2.0
 
         val curY = Vector.sub (yClickPoints, pos)
-        val minusY = (~(curY - halfHeight - 1.0)) / halfHeight
-        val plusY = (~(curY - halfHeight + 1.0)) / halfHeight
+        val minusY = Ndc.fromPixelY (curY - 1.0, windowWidth, windowHeight)
+        val plusY = Ndc.fromPixelY (curY + 1.0, windowWidth, windowHeight)
 
         val minX = Vector.sub (xClickPoints, 0)
-        val minX = (minX - halfWidth) / halfWidth
         val maxX = Vector.sub (xClickPoints, Vector.length xClickPoints - 1)
-        val maxX = (maxX - halfWidth) / halfWidth
+        val minX = Ndc.fromPixelX (minX, windowWidth, windowHeight)
+        val maxX = Ndc.fromPixelX (maxX, windowWidth, windowHeight)
 
         val acc = Ndc.ltrbToVertex (minX, plusY, maxX, minusY) :: acc
       in