Q182070: HOWTO: Create a Resolution-Independent Form
Article: Q182070
Product(s): Microsoft Visual Basic for Windows
Version(s): WINDOWS:4.0,5.0,6.0
Operating System(s):
Keyword(s): kbdisplay kbVBp kbVBp400 kbVBp500 kbVBp600 kbForms kbGrpDSVB kbDSupport
Last Modified: 11-JAN-2001
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The information in this article applies to:
- Microsoft Visual Basic Learning Edition for Windows, versions 5.0, 6.0
- Microsoft Visual Basic Professional Edition for Windows, versions 5.0, 6.0
- Microsoft Visual Basic Enterprise Edition for Windows, versions 5.0, 6.0
- Microsoft Visual Basic Standard Edition, 32-bit, for Windows, version 4.0
- Microsoft Visual Basic Professional Edition, 16-bit, for Windows, version 4.0
- Microsoft Visual Basic Professional Edition, 32-bit, for Windows, version 4.0
- Microsoft Visual Basic Enterprise Edition, 16-bit, for Windows, version 4.0
- Microsoft Visual Basic Enterprise Edition, 32-bit, for Windows, version 4.0
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SUMMARY
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If a Form takes up most of the screen at 640 x 480 (VGA) resolution, it only
takes up a small portion of the screen at 1600 x 1200. Normally, this is exactly
what you want to happen, but some circumstances arise where you want a Form to
retain the same proportional size and position regardless of screen resolution.
This article discusses a simple way to accomplish this for an Single Document
Interface (SDI) application. It does not address special considerations for
Multiple Document Interface (MDI) applications.
MORE INFORMATION
================
When designing Forms to be resized at run time, keep the following in mind:
- When designing Forms, it is best to design them for the lowest screen
resolution you expect users to run. Even using the technique outlined here,
it is best to stay with this rule because Forms resize better going to higher
resolutions than they do going to lower ones.
- Use TrueType Fonts because they are scalable. Also, try to use Fonts that
will be available on the user's system. Otherwise, a substituted Font may not
scale properly.
- Because resizing may not always be exact, especially with Fonts, make the
controls a little larger than the minimum necessary. Also, try to leave a
little space between controls.
- Some controls, like CheckBoxes and Option buttons, do not resize, and some
controls may require special handling. For example, the Height property of
ComboBoxes is read-only at run-time, but changing the font size adjusts the
Height. Other controls may not have a FontSize property and need some other
property set to make FontSize appear correctly.
Step-by-Step Example
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1. Change the video resolution to 800 x 600.
2. Start a new project in Visual Basic. Form1 is created by default.
3. Add a Label, a CommandButton, and any other types of controls you would like
to test.
4. Copy the following code into the Form's module:
Option Explicit
Dim MyForm As FRMSIZE
Dim DesignX As Integer
Dim DesignY As Integer
Private Sub Form_Load()
Dim ScaleFactorX As Single, ScaleFactorY As Single ' Scaling factors
' Size of Form in Pixels at design resolution
DesignX = 800
DesignY = 600
RePosForm = True ' Flag for positioning Form
DoResize = False ' Flag for Resize Event
' Set up the screen values
Xtwips = Screen.TwipsPerPixelX
Ytwips = Screen.TwipsPerPixelY
Ypixels = Screen.Height / Ytwips ' Y Pixel Resolution
Xpixels = Screen.Width / Xtwips ' X Pixel Resolution
' Determine scaling factors
ScaleFactorX = (Xpixels / DesignX)
ScaleFactorY = (Ypixels / DesignY)
ScaleMode = 1 ' twips
'Exit Sub ' uncomment to see how Form1 looks without resizing
Resize_For_Resolution ScaleFactorX, ScaleFactorY, Me
Label1.Caption = "Current resolution is " & Str$(Xpixels) + _
" by " + Str$(Ypixels)
MyForm.Height = Me.Height ' Remember the current size
MyForm.Width = Me.Width
End Sub
Private Sub Form_Resize()
Dim ScaleFactorX As Single, ScaleFactorY As Single
If Not DoResize Then ' To avoid infinite loop
DoResize = True
Exit Sub
End If
RePosForm = False
ScaleFactorX = Me.Width / MyForm.Width ' How much change?
ScaleFactorY = Me.Height / MyForm.Height
Resize_For_Resolution ScaleFactorX, ScaleFactorY, Me
MyForm.Height = Me.Height ' Remember the current size
MyForm.Width = Me.Width
End Sub
Private Sub Command1_Click()
Dim ScaleFactorX As Single, ScaleFactorY As Single
DesignX = Xpixels
DesignY = Ypixels
RePosForm = True
DoResize = False
' Set up the screen values
Xtwips = Screen.TwipsPerPixelX
Ytwips = Screen.TwipsPerPixelY
Ypixels = Screen.Height / Ytwips ' Y Pixel Resolution
Xpixels = Screen.Width / Xtwips ' X Pixel Resolution
' Determine scaling factors
ScaleFactorX = (Xpixels / DesignX)
ScaleFactorY = (Ypixels / DesignY)
Resize_For_Resolution ScaleFactorX, ScaleFactorY, Me
Label1.Caption = "Current resolution is " & Str$(Xpixels) + _
" by " + Str$(Ypixels)
MyForm.Height = Me.Height ' Remember the current size
MyForm.Width = Me.Width
End Sub
5. Add a Module from the Project menu and paste in the following code:
Public Xtwips As Integer, Ytwips As Integer
Public Xpixels As Integer, Ypixels As Integer
Type FRMSIZE
Height As Long
Width As Long
End Type
Public RePosForm As Boolean
Public DoResize As Boolean
Sub Resize_For_Resolution(ByVal SFX As Single, _
ByVal SFY As Single, MyForm As Form)
Dim I As Integer
Dim SFFont As Single
SFFont = (SFX + SFY) / 2 ' average scale
' Size the Controls for the new resolution
On Error Resume Next ' for read-only or nonexistent properties
With MyForm
For I = 0 To .Count - 1
If TypeOf .Controls(I) Is ComboBox Then ' cannot change Height
.Controls(I).Left = .Controls(I).Left * SFX
.Controls(I).Top = .Controls(I).Top * SFY
.Controls(I).Width = .Controls(I).Width * SFX
Else
.Controls(I).Move .Controls(I).Left * SFX, _
.Controls(I).Top * SFY, _
.Controls(I).Width * SFX, _
.Controls(I).Height * SFY
End If
' Be sure to resize and reposition before changing the FontSize
.Controls(I).FontSize = .Controls(I).FontSize * SFFont
Next I
If RePosForm Then
' Now size the Form
.Move .Left * SFX, .Top * SFY, .Width * SFX, .Height * SFY
End If
End With
End Sub
Try running this under different screen resolutions and the Form should take up
the same desktop area and retain its look and screen position. You may notice
that your design resizes better when changing to a higher resolution than it
does when changing to a lower one. You can also use the Mouse to Resize the Form
and it will re-scale automatically. Finally, if you change video resolution
while the Form is open, you can click on Command1 and it adjusts for the new
resolution.
REFERENCES
==========
For additional information, please see the following articles in the Microsoft
Knowledge Base:
Q187562 HOWTO: Resize the Controls in SSTab When Form is Resized
Q253940 PRB: Incorrect Screen Object Width/Height After Desktop Resized
Q206907 BUG: Reposition or Resize a Control After Changing Font Causes
Incorrect Positioning and Sizing
Additional query words: scale
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Keywords : kbdisplay kbVBp kbVBp400 kbVBp500 kbVBp600 kbForms kbGrpDSVB kbDSupport
Technology : kbVBSearch kbAudDeveloper kbZNotKeyword6 kbZNotKeyword2 kbVB500Search kbVB600Search kbVBA500 kbVBA600 kbVB500 kbVB600 kbVB400Search kbVB400 kbVB16bitSearch
Version : WINDOWS:4.0,5.0,6.0
Issue type : kbhowto
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