You've run out of graph paper, but you need a sheet of it right now. You'd like to brush up on your .NET printing skills at the same time.
Sample code folder: Chapter 11\GraphPaper
Build a simple application that prints some graph paper for you, using the printing features presented throughout this chapter and various GDI+ methods.
Create a new Windows Forms project, and add the following controls to the form:
Add informational labels if desired. The form should look something like the one in Figure 11-6.
Figure 11-6. User interface for the Graph Paper application
Add the following source code to the form's class template:
Imports System.Drawing.Printing Public Class Form1 Private WithEvents GraphPaper As Printing.PrintDocument Private Sub ShowPreview_Click( _ ByVal sender As System.Object, _ ByVal e As System.EventArgs) _ Handles ShowPreview.Click ' ----- Preview the graph paper. Dim previewMode As New PrintPreviewDialog GraphPaper = New Printing.PrintDocument previewMode.Document = GraphPaper previewMode.ShowDialog() GraphPaper = Nothing End Sub Private Sub SendToPrinter_Click( _ ByVal sender As System.Object, _ ByVal e As System.EventArgs) _ Handles SendToPrinter.Click ' ----- Preview the graph paper. Dim pageSetup As New PageSetupDialog GraphPaper = New Printing.PrintDocument pageSetup.Document = GraphPaper If (pageSetup.ShowDialog( ) = _ Windows.Forms.DialogResult.OK) Then _ GraphPaper.Print() GraphPaper = Nothing End Sub Private Sub GraphPaper_PrintPage(ByVal sender As Object, _ ByVal e As Printing.PrintPageEventArgs) _ Handles GraphPaper.PrintPage ' ----- Printing of the graph paper occurs here. Dim unitLines As Single = CSng(LinesPerUnit.Text) Dim totalWidth As Single = CSng(UnitsWide.Text) Dim totalHeight As Single = CSng(UnitsHigh.Text) Dim x1, y1, x2, y2 As Single Dim fineBlackPen As New Pen(Color.Black, 0.00001) Dim eachLine As Integer Dim factor As Single ' ----- Set the units. If (UseInches.Checked = True) Then e.Graphics.PageUnit = GraphicsUnit.Inch factor = 1.0! Else e.Graphics.PageUnit = GraphicsUnit.Millimeter factor = 10.0! End If ' ----- Draw the vertical lines. For eachLine = 0 To CInt(totalWidth * unitLines) x1 = factor + (eachLine * factor) / unitLines y1 = factor x2 = x1 y2 = y1 + (totalHeight * factor) If ((eachLine Mod unitLines) = 0) Then ' ----- Each unit marker is thicker. fineBlackPen.Width = 0.01 * factor Else fineBlackPen.Width = 0.000001 * factor End If e.Graphics.DrawLine(fineBlackPen, x1, y1, x2, y2) Next eachLine ' ----- Draw the horizontal lines. For eachLine = 0 To CInt(totalHeight * unitLines) x1 = factor y1 = factor + (eachLine * factor) / unitLines x2 = x1 + (totalWidth * factor) y2 = y1 If ((eachLine Mod unitLines) = 0) Then ' ----- Each unit marker is thicker. fineBlackPen.Width = 0.01 * factor Else fineBlackPen.Width = 0.000001 * factor End If e.Graphics.DrawLine(fineBlackPen, x1, y1, x2, y2) Next eachLine ' ----- Limit output to a single page. e.HasMorePages = False End Sub End Class
This program builds on the recipes presented throughout this chapter. It creates distinct PrintDocument (with WithEvents specified), PrintPreviewDialog, and PageSetupDialog classes, and it responds to the print document's PrintPage event to perform the actual printing.
The code simply loops through the specified number of vertical and horizontal lines destined for the output based on the user's input, and draws lines at each interval position. The e.Graphics.PageUnit property lets the code easily process both English and metric measurement systems, although the lack of a basic centimeter unit requires the code to combine the millimeter unit with a scaling factor.