add functions to create vertical and horizontal pen points.

Include a 1000x1000 image (for testing) and cratch pad scripts for the horizontal and vertical points code, in library.

DeathSocket/DeathSocket.fsproj

@@ -5,10 +5,12 @@
   </PropertyGroup>
 
   <ItemGroup>
+    <Content Include="1000x1000.png" />
     <Content Include="test-img.jpg" />
     <Compile Include="Domain.fs" />
     <Compile Include="IO.fs" />
     <Compile Include="Validation.fs" />
+    <Compile Include="ImageServices.fs" />
     <Compile Include="GridPainter.fs" />
     <None Include="ScratchPad.fsx" />
   </ItemGroup>

DeathSocket/GridPainter.fs

@@ -3,7 +3,9 @@ namespace DeathSocket
     module GridPainter =
 
         open Validation
+        open ImageServices
 
         let applyGridToImage spec =
             validateFilePath |> ignore
+            drawGrid spec
             0

DeathSocket/ImageServices.fs

@@ -0,0 +1,27 @@
+module internal ImageServices
+
+open System.Drawing
+open DeathSocket.Domain
+
+    let createHorizontalLines width height columns =
+        let interval = width / columns
+        [| for point in 1 .. columns ->
+            [|Point (0, (interval * point))
+              Point (height, (interval * point) )|]|]
+
+    let createVerticalLines width height columns =
+        let interval = height / columns
+        [| for point in 1 .. columns ->
+            [| Point ((interval * point), 0)
+               Point ((interval * point), height)|]|]
+
+    let drawGrid spec =
+        let img = Bitmap.FromFile spec.filePath
+        let graphics = Graphics.FromImage img
+        let pen = new Pen (spec.colour, width = spec.penWidth)
+        let horizontalLines =
+            createHorizontalLines (img.Size.Width) (img.Size.Height) (spec.columns)
+        let verticalLines =
+            createVerticalLines (img.Size.Width) (img.Size.Height) (spec.columns)
+        0
+

DeathSocket/ScratchPad.fsx

@@ -1,11 +1,16 @@
-#load "Validation.fs"
+#load "Domain.fs"
+#load "Validation.fs"
+#load "ImageServices.fs"
 #load "GridPainter.fs"
 
 open System.Drawing
 open System
 open System.Drawing.Imaging
-open Validation
 open DeathSocket
+open Domain
+open Validation
+open ImageServices
+
 
 // INITIAL IDEA ===============================================================
 
@@ -16,11 +21,11 @@ let imgWidth = img.Size.Width
 let imgHeight = img.Size.Height
 (* Keeping it simple here. Going to just create a 2x2 grid.
 In other words, I'm just halving the width and the height. *)
-let verticalLine = 
+let horizontalLine = 
     let midpoint = imgHeight / 2
     [|Point (0, midpoint);
       Point (imgWidth, midpoint)|]
-let horizontalLine =
+let verticalLine =
     let midpoint = imgWidth / 2
     [| Point (midpoint, 0);
        Point (midpoint, imgWidth)|]
@@ -38,7 +43,13 @@ pen.Dispose
 // DEATH SOCKET TESTING =======================================================
 
 let desktop = Environment.GetFolderPath (Environment.SpecialFolder.Desktop)
-let savePath = desktop + "/test-grid.png" // Change this to suit you.
+let savePath = desktop + "/1000x1000.png" // Change this to suit you.
+
+let testImg = Bitmap.FromFile (__SOURCE_DIRECTORY__ + "/1000x1000.png")
 
 // Throws an exception if no file is found.
-let validationTest = validateFilePath savePath
+let validationTest = validateFilePath savePath
+let horizontalLines =
+    createHorizontalLines (testImg.Size.Width) (testImg.Size.Height) 10
+let verticalLines =
+    createVerticalLines (testImg.Size.Width) (testImg.Size.Height) 10