Zoom for a windows form in C#

Question

Is there an easy way to set the zoom level for a windows form in C#? In VBA there was a zoom property of the form.

Decahedron

Can you specify what kind of form? Are we talking about web forms and text encoding sizes? – Hereditament

Answer 1

There is no way (that I know of) to do what you ask with typical WinForms.

If you're doing custom painting/drawing, you can zoom that by using a zoom transform, but so far as I know there is no "Zoom" property for the form in the entire world of .NET and native Windows/C++ APIs combined.

You could probably rig something yourself such that you scale controls by a constant factor. And you can probably find 3rd-party controls/surfaces which support this. And who knows what is possible with WPF. But in a typical WinForms world, no.

Bandaid

Here is the method: msdn.microsoft.com/en-us/library/…. Of course you shall keep track of original controls size since after having scaled controls their scaled value is approximated to an integer value (so, successive zoom in-out operation may lead to incorrect original sizes). – Septicemia

to bad this answer was marked as correct since the one from Fabrizio worked – Broadcasting

@ChopChop In fairness, I did say "You could probably rig something yourself such that you scale controls by a constant factor". The original question asked whether there was an EASY way (akin to the Zoom level on VB form) to scale a form in C#/WinForms versus going the DIY route. – Bandaid

Don't take it personnaly.Your answer is partialy right but I down voted to re-route people on a working answer. When you browsing pages you can miss the good answer just because of a check mark. It's not a downvote who will impact your e-reputation :) – Broadcasting

In a million years I'd never take anything about any Microsoft API surface personally :) Actually I agree with you-- Fabrizio's answer should be marked as correct for being more specific. Even if there's not a form-level "Zoom switch" his method is easy enough to implement. – Bandaid

Answer 2

I had the same problem and I solved it this way in c#. Code goes on Form load

float scaleX = ((float)Screen.PrimaryScreen.WorkingArea.Width / 1024);
float scaleY = ((float)Screen.PrimaryScreen.WorkingArea.Height / 768);
SizeF aSf = new SizeF(scaleX, scaleY);
this.Scale(aSf);

This "more or less" scales form and all children. Loops forever in 800x600 (?) You have to set the following Form properties:

AutoscaleMode = Font
AutoSize = False

Capel

Answer 3

You can get some kind of zoom by assigning different Font to the Form, all the controls will be zoomed accordingly if AutoScaleMode set to Font. Also settings AutoSize to False will keep form size intact, the controls will grow to the center of the form. You need to set up all Anchors correctly and test the look, since its just "kind of zoom".

So basically here is sample constructor:

public Form1()
{
    InitializeComponent();

    AutoSize = false;
    AutoScaleMode = AutoScaleMode.Font;
    Font = new Font("Trebuchet MS", 
        10.0f, 
        FontStyle.Regular, 
        GraphicsUnit.Point, 
        ((byte)(204))
    );
}

After form has been shown assigning new Font will mess up all the controls and this trick will not work.

Pickle

I work in a company where this approach has been used. At some point this caused too many handles to be used, so this was somehow badly optimised. Now we have a really shitty situation where this font changing is all over the software (some points relay on others to have their font set), and it is effectivly impossible to get rid off. - - -> So in a small example, could do the (possibly easier) trick. In real production code, I would strongly advise to not use this approach. – Message

Answer 4

This works

    
private void button1_Click(object sender, EventArgs e)
{
     ScaleForm(1.1f); // Scale up by 10%
    
     //ScaleForm(0.9f); // Scale down by 10%

}

private void ScaleForm(float scaleFactor)
{
    this.Scale(new SizeF(scaleFactor, scaleFactor));
    foreach (Control control in this.Controls)
    {
        control.Scale(new SizeF(scaleFactor, scaleFactor));
    }
}

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