Welcome to this tutorial on resizing a form based on screen size in Visual Basic 6. In this tutorial I will discuss a couple issues:
- Resize a form based on screen size
- Resize the controls on the form based on the form size
- Resize the font size of all controls based on the above 2 items
I have received this question for many years, and in my time in </dream.in.code> I have also been asked this question several times, so I thought it would be a good idea to write a tutorial based on this question. THought there are many commercial products out there that will accomplish this, how many students and everyday Joe's actually have the money to be buying these solutions? Not many I can assure you, so after getting this question numerous time, I decided it was time to write my own solution to this problem, and give it back to the programming community.
The code I'm about to show you I have in a Code Module, names
FormControl that I include in all VB6 projects I create. This comes in real handy because as developers we don't know what screen resolution a client, or anyone else using our software, will be using. The first thing I have in my module is some Global variables that will be used through out the module, so I, of course, make them Global and accessible to the entire module. Here are the Globals you need to add to your Code Module:
CODE
Private List() As Control
Private curr_obj As Object
Private iHeight As Integer
Private iWidth As Integer
Private x_size As Double
Private y_size As Double
As you will see, the Globals are Private, I don't want them to be accessed from outside this Code Module. The first Global is an Array or type
Control. This is a private
Type I have created to hold all the properties of the controls on the form. Creating your own user defined type saves a lot of headaches down the road, and allows for resizing all controls in a single loop, referencing your type:
CODE
Private Type Control
Index As Integer
Name As String
Left As Integer
Top As Integer
width As Integer
height As Integer
End Type
As you can see, this
Type holds all the information needed about a control: Index, Name, Left, Top, Width and Height, these items will come in use later, when we write the procedure to resize all the controls at once. Now lets talk about resizing a form based on the current screen resolution we will be referencing the
Screen Object available to us in Visual Basic 6.
The 2 properties we're concerned with are
Width and Height. These properties of the
Screen Object give us access to the screen size available to us. So, to set the Forms size in relationship to the Screen size, we will be accessing the properties of the
Form Object, mainly the width and height properties. In my Module I set the forms size to the screen's size divided by 2, you may want to test and find your own resolution. Here's the simple procedure for resizing your form in relationship to the available screen resolution:
CODE
Public Sub ResizeForm(frm As Form)
'Set the forms height
frm.height = Screen.height / 2
'Set the forms width
frm.width = Screen.width / 2
'Resize all of the controls
'based on the forms new size
ResizeControls frm
End Sub
Simple isn't it, we change the forms size based on the screen size, then we reference a procedure called
ResizeControls, we do this because resizing the form alone isn't what we're after. Well doing only this will cause some pretty ugly user interfaces, simply because you may be resizing your form, but the controls are staying the same size, which isn't a good thing.
So, you can either write a really long and ugly procedure to resize each control individually,not very maintainable, especially if you rename or add controls, or you can write a nice neat little procedure, based on a user defined type, which we have in our Code Module, and loop through them like this:
CODE
Public Sub ResizeControls(frm As Form)
Dim i As Integer
' Get ratio of initial form size to current form size
x_size = frm.height / iHeight
y_size = frm.width / iWidth
'Loop though all the objects on the form
'Based on the upper bound of the # of controls
For i = 0 To UBound(List)
'Grad each control individually
For Each curr_obj In frm
'Check to make sure its the right control
If curr_obj.TabIndex = List(i).Index Then
'Then resize the control
With curr_obj
.Left = List(i).Left * y_size
.width = List(i).width * y_size
.height = List(i).height * x_size
.Top = List(i).Top * x_size
End With
End If
'Get the next control
Next curr_obj
Next i
End Sub
Here we use the
UBound Function To get the highest index on the form, which gives us the last control's index. We then loop through all the controls, stopping at the highest index, and change the size of the control. Before this procedure can actually work, we need to know the current location of each control, well I have a solution for that as well.
In this Module is a method called
GetLocation. What this method does is it
logs the current position of each control, looping through all the controls located in our
List() Array, which is populated with the controls on the form. On each iteration of the loop, we use the
ReDim Statement and the
Preserve keyword to increment the size of the array by 1 and preserve the objects already in the array. The code for that method is as follows:
CODE
Public Sub GetLocation(frm As Form)
Dim i As Integer
' Load the current positions of each object into a user defined type array.
' This information will be used to rescale them in the Resize function.
'Loop through each control
For Each curr_obj In frm
'Resize the Array by 1, and preserve
'the original objects in the array
ReDim Preserve List(i)
With List(i)
.Name = curr_obj
.Index = curr_obj.TabIndex
.Left = curr_obj.Left
.Top = curr_obj.Top
.width = curr_obj.width
.height = curr_obj.height
End With
i = i + 1
Next curr_obj
' This is what the object sizes will be compared to on rescaling.
iHeight = frm.height
iWidth = frm.width
End Sub
Our Code Module is almost complete, there is but one thing we need to think about resizing, and that is the font size used in the application. Resizing, say a Label, and not resizing the font being used on the label will make for an ugly User Interface as well. So what we do is, we get the value of
x_size, which is one of our Globals, and set in the
ResizeControls method, we multiply that by 8 and that gives the font size I'm looking for, you needs may vary. Here is the code for resizing the font size:
CODE
Public Function SetFontSize() As Integer
'Make sure x_size is greater than 0
If Int(x_size) > 0 Then
'Set the font size
SetFontSize = Int(x_size * 8)
End If
End Function
That's all the code you need for your form and control resizing based on the users screen resolution. It's all a matter of getting the mathematics right, then resetting the size of everything on the form to fit nicely in the current screen.
Now for how to use it, in the Form_Load Event you add a call to:
And set the FontSize property of your controls, like this:
CODE
Private Sub Form_Load()
GetLocation Me
CenterForm Me
ResizeForm Me
lblInstructions.Font = SetFontSize()
End Sub
This Code Module also offers another feature. If someone were the resize your form while havin the application running, if you put a call to
ResizeControls in the Form_Resize Event, this will take care of resizing everthing:
CODE
Private Sub Form_Resize()
ResizeControls Me
lblInstructions.FontSize = SetFontSize()
End Sub
I am providing the Code Module this code is in, this Module and code is under the
GNU General Public License, so you can use, modify or distribute as you see fit, but the license header must stay intact. I hope you have found this tutorial informative and useful. For all your Visual Basic 6 Reference Needs go to the
Visual Basic 6.0 Resource Center. Thank you for reading.
Happy Coding
FormControl.zip ( 12.7k )
Number of downloads: 2445This post has been edited by PsychoCoder: 6 Oct, 2007 - 03:17 PM
Resize Form & Controls For Screen Size - VB6
6 Oct, 2007 - 03:14 PM
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