How to Create Flashing/Rotating Rubber-Band Box in VB

• Standard and Professional Editions of Microsoft Visual Basic for Windows, versions 2.0 and 3.0
• Microsoft Visual Basic programming system for Windows, version 1.0

SUMMARY

Several programs, such as Excel, create a flashing border (which appears to rotate) when selecting items of the windows when using the Edit Copy selection of the menu system. You can create a flashing, rotating border with the DrawMode and DrawStyle properties of a Visual Basic form.

MORE INFORMATION

By drawing a dashed line on the form and then within a timer event creating a solid line on the dashed line with DrawMode set to INVERSE, you can create a special effect of a flashing border that appears to rotate.

You can draw a rotating rubber-band box as follows:

1. Draw a line using:

         DrawStyle = 2 {Dot}
   

2. Save the [form].DrawMode and the [form].DrawStyle.

3. Set the [form].DrawMode = 6 {Inverse}.

4. Set [form].DrawStyle = 0 {Solid}.

5. Draw the same line as in step 1.

6. Reset the properties saved in step 2.

7. Delay some time interval.

8. Repeat starting at step 2.

In VB.EXE, create a form called Form1. On Form1, create a timer control with the name Timer1 and with an interval of 100.

Duplicate the following code within the general declaration section of your code window:

Const INVERSE = 6     'Characteristic of DrawStyle property(Inverse).
Const SOLID = 0       'Characteristic of DrawMode property.
Const DOT = 2         'Characteristic of DrawMode property.

Add the following code in the appropriate event procedures for Form1:

Sub Form_Load ()
   '* Must draw a dotted line to create effect.  Load a bitmap. Not
      required but shows full extent of line drawing.
   DrawStyle = DOT
End Sub

Sub Timer1_Timer ()
   SavedDrawStyle% = DrawStyle

  '* Solid is need to create the inverse of the dashed line.
   DrawStyle = SOLID

 '* Invert the dashed line.
   Call DrawLine(StartX, StartY, OldX, OldY)

  '* Restore the DrawStyle back to what it was previously.
   DrawStyle = SavedDrawStyle%
End Sub

Sub Form_MouseDown (Button As Integer, Shift As Integer, X As
                                       Single, Y As Single)
' The above Sub statement must be on just one line.
   '* Don't add effect as you draw box.
   Timer1.Enabled = FALSE
   '* Save the start locations.
   StartX = X
   StartY = Y
   '* Set the last coord. to start locations.
   OldX = StartX
   OldY = StartY
End Sub

Sub Form_MouseMove (Button As Integer, Shift As Integer, X As
                                       Single, Y As Single)
' (The above Sub statement must be on just one line.)
'* If button is depress then...

      '* Restore previous lines background.
      Call DrawLine(StartX, StartY, OldX, OldY)
      '* Draw new line.
      Call DrawLine(StartX, StartY, X, Y)
      '* Save coordinates for next call.
      OldX = X : OldY = Y
   End If
End Sub

Sub DrawLine (X1 As Single, Y1 As Single, X2 As Single, Y2 As Single)
   '* Save the current mode so that you can reset it on
   '* exit from this sub routine. Not needed in the sample
   '* but would need it if you are not sure what the
   '* DrawMode was on entry to this procedure.
   SavedMode% = DrawMode

   '* Set to XOR
   DrawMode = INVERSE

   '*Draw a box
   Line (X1, Y1)-(X2, Y2), , B

   '* Reset the DrawMode
   DrawMode = SavedMode%
End Sub

Sub Form_MouseUp (Button As Integer, Shift As Integer, X As Single,
                                         Y As Single)
' (The above Sub statement must be on just one line.)
   StartEvent = FALSE
   Timer1.Enabled = TRUE
End Sub