improve creation of click points, so that we can have a pixel be a perfect square, even if the canvas isn't

fcore/app-with.sml

@@ -160,9 +160,7 @@ struct
       }
     end
 
-  fun helpWindowResize
-    (app: app_type, windowWidth, windowHeight, wStart, wFinish, hStart, hFinish) :
-    app_type =
+  fun windowResize (app: app_type, windowWidth, windowHeight) : app_type =
     let
       val
         { mode
@@ -188,9 +186,9 @@ struct
         , modalNum
         } = app
 
-      val maxPoints = Int.max (canvasWidth, canvasHeight)
-      val xClickPoints = ClickPoints.generate (wStart, wFinish, maxPoints)
-      val yClickPoints = ClickPoints.generate (hStart, hFinish, maxPoints)
+      val (xClickPoints, yClickPoints) =
+        ClickPoints.generate
+          (windowWidth, windowHeight, canvasWidth, canvasHeight)
     in
       { mode = mode
       , squares = squares
@@ -216,29 +214,6 @@ struct
       }
     end
 
-  fun windowResize (app: app_type, windowWidth, windowHeight) =
-    if windowWidth = windowHeight then
-      helpWindowResize
-        (app, windowWidth, windowHeight, 0, windowWidth, 0, windowHeight)
-    else if windowWidth > windowHeight then
-      let
-        val difference = windowWidth - windowHeight
-        val wStart = difference div 2
-        val wFinish = wStart + windowHeight
-      in
-        helpWindowResize
-          (app, windowWidth, windowHeight, wStart, wFinish, 0, windowHeight)
-      end
-    else
-      let
-        val difference = windowHeight - windowWidth
-        val hStart = difference div 2
-        val hFinish = hStart + windowWidth
-      in
-        helpWindowResize
-          (app, windowWidth, windowHeight, 0, windowWidth, hStart, hFinish)
-      end
-
   fun mousePosition (app: app_type, mouseX, mouseY) =
     let
       val