PowerShell - DPI Aware Form

Question

Hi everyone I am curious on how it's possible to make a winform DPI aware when creating it in PowerShell? Or at the very least, prevent it from autoscaling. I've googled it and searched and searched but I just can't seem to find an answer or an example of how to do it. The most common answer is to include it in a manifest, but this is not a viable option for PowerShell.

If anything I just want to prevent Windows from automatically rescaling my forms in DPI higher than 96 (100%). I tried AutoScaleMode = "DPI" and that unfortunately doesn't work and doesn't seem to do anything, as setting it to "None" or not including it at all is the same result.

A quick example...

Add-Type -AssemblyName 'System.Windows.Forms'
Add-Type -AssemblyName 'System.Drawing'

$Dialog = New-Object Windows.Forms.Form
$Dialog.Text = 'Main'
$Dialog.Size = New-Object Drawing.Size(200, 100)
$Dialog.AutoScaleMode = "DPI"

$Label = New-Object Windows.Forms.Label
$Label.Size = New-Object Drawing.Size(200, 16)
$Label.Location = New-Object Drawing.Size(10, 20)
$Label.Text = 'This text is to test autoscaling.'
$Dialog.Controls.Add($Label)

$Dialog.ShowDialog()

The image on the left is autoscaled and blurry. I don't want this, I want it to look like the right. If I can get that far, I'll try to figure out how I'm going to handle the scaling.

You want it to not scale according to OS DPI scaling at all, or you want it to just not be blurry when auto scaled? — Mathias R. Jessen, Sep 15 '20 at 17:47
Honestly I would like to know how to do both so I can experiment a bit with it. If I can get DPI scaling working correctly, then I would try that out. If not, then I can manually try to adjust all the scaling based on DPI. — Bighead, Sep 15 '20 at 17:52
Check this GitHub (test) project: [PSPreferExternalManifest](https://github.com/dotps1/PSPreferExternalManifest). It handles the `PreferExternalManifest` registry key to load a manifest that activates/deactivates the `DpiAware` option. — Jimi, Sep 15 '20 at 18:36
It doesn't make sense to close an older question as duplicate of a newer question. — Reza Aghaei, Feb 18 '23 at 20:16

score 1 · Answer 1 · answered Sep 16 '20 at 03:03

So I did manage to find a workaround by accident. I was looking into WPF forms (which I know little about) and came across an example. Adding the bare minimum of a dummy window in WPF that never actually gets shown, somehow prevents winforms from automatically scaling.

# Load assemblies.
Add-Type -AssemblyName 'System.Windows.Forms'
Add-Type -AssemblyName 'System.Drawing'
Add-Type -AssemblyName 'PresentationFramework'

# Dummy WPF window (prevents auto scaling).
[xml]$Xaml = @"
<Window
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    x:Name="Window">
</Window>
"@
$Reader = (New-Object System.Xml.XmlNodeReader $Xaml)
$Window = [Windows.Markup.XamlReader]::Load($Reader)

# Business as usual.
$Dialog = New-Object Windows.Forms.Form
$Dialog.Text = 'Main Window'
$Dialog.Size = New-Object Drawing.Size(200, 100)

$Label = New-Object Windows.Forms.Label
$Label.Size = New-Object Drawing.Size(200, 16)
$Label.Location = New-Object Drawing.Size(10, 20)
$Label.Text = 'This text is to test autoscaling.'
$Dialog.Controls.Add($Label)

$Dialog.ShowDialog()

score 0 · Answer 2 · answered Jan 24 '23 at 23:06

Old question, but interesting. And it's possible to make the form DPI aware without a dummy WPF window. The following example uses SetProcessDPIAware to make the form DPI aware:

using assembly System.Windows.Forms
using namespace System.Windows.Forms
using namespace System.Drawing

#Enable visual styles
[Application]::EnableVisualStyles()

#Enable DPI awareness
$code = @"
    [System.Runtime.InteropServices.DllImport("user32.dll")]
    public static extern bool SetProcessDPIAware();
"@
$Win32Helpers = Add-Type -MemberDefinition $code -Name "Win32Helpers" -PassThru
$null = $Win32Helpers::SetProcessDPIAware()

$form = [Form] @{
    ClientSize = [Point]::new(300, 80);
    StartPosition = "CenterScreen";
    Text = "Test";
    AutoScaleDimensions = [SizeF]::new(6, 13);
    AutoScaleMode = [AutoScaleMode]::Font;
}
$label = [Label] @{
    Text = "Hello, world!";
    AutoSize = $true;
    Location = [Point]::new(8,8)
}
$form.Controls.Add($label)

$null = $form.ShowDialog()
$form.Dispose()

You can see the difference, with SetProcessDPIAware:

Without SetProcessDPIAware:

PowerShell - DPI Aware Form

2 Answers2