Example of using PowerPoint VBA graphics drawing library
using GDI32 instructions

Drawing Trigonometric Curves Using PolyLine

The execution speed has been significantly improved compared to the library using the AddShape directive. Even if the number of data points is about 10,000, it will be drawn almost instantly

Procedure

  1. Copy the source program of graphics drawing library by GDI32 instructions and paste to Module 2.
  2. Insert a command button on the slide and write the procedure for displaying the form.
  3. Insert a user form. The size of the user form should be larger than Viewport.
Private Sub CommandButton1_Click()
  UserForm1.Show
End Sub
  1. Insert a command button into Form
  2. Write a CALL statement for displaying trigonometric curves in the CommandButton1_Click procedure.
Private Sub CommandButton1_Click()
    DrawTrigonometricFunction   
End Sub
  1. Fill in Module 1 with procedures to obtain device context and display trigonometric curves.
Sub DrawTrigonometricFunction()
' Get device context handle
    monhdc = GetForegroundWindow()
    myhdc = GetDC(monhdc)
    If myhdc = 0 Then Exit Sub

    Const PI As Single = 3.14159
    Const NP As Long = 1000
    Dim x(NP), y(NP)
    Dim i, nDiv
     
    nDiv = NP - 1    ' Number of divisions
     
    InitializeGraphics
'  Specify correspondence between screen coordinates and world coordinates
   SetGraphicsWindow -0.5, 1.5, 7, -1.5
   DrawAxis2 6.5, 1.1        ' Draw axes
   DrawText 0, 1.3, "Trigonometric Functions", vbBlue      ' Draw title

'  Draw Sine function with blue lines
    For i = 0 To nDiv
        x(i + 1) = 2 * PI * i / nDiv
        y(i + 1) = Sin(x(i + 1))
    Next
    
    SetLineColor (vbBlue)
    DrawPolyLine x, y, NP
    
 ' Draw Cosine function with greenlines
    For i = 0 To nDiv
        y(i + 1) = Cos(x(i + 1))
    Next
    
    SetLineColor (vbGreen)
    DrawPolyLine x, y, NP
    
End Sub

Sub DrawAxis2(x_max, y_max)
    DrawLine 0, 0, x_max, 0
    DrawLine 0, y_max, 0, -y_max
End Sub

Execution

  1. Run the slide show and click the button to display the form.
  2. Click the button to call the procedure to calculate and display the trigonometric curves.

Trigonometric Curve

  Download PowerPoint file   glib_pp-gdi32-03.pptm

  Download Source file   trig-gdi32-eng.bas