xaml-csharp-development-skill-for-avalonia

WinForms High DPI, Scaling, and RTL Flow Direction to Avalonia

Table of Contents

  1. Scope and APIs
  2. DPI and Scaling Mapping
  3. RTL Mapping
  4. Conversion Example
  5. C# Equivalent
  6. Troubleshooting

Scope and APIs

Primary WinForms APIs:

Primary Avalonia APIs:

DPI and Scaling Mapping

WinForms Avalonia
AutoScaleMode.Dpi platform-managed scaling with logical units
Form.DpiChanged TopLevel.ScalingChanged
manual pixel math rely on device-independent units, convert only at interop boundaries

RTL Mapping

WinForms Avalonia
RightToLeft = Yes FlowDirection="RightToLeft"
mixed-direction forms set FlowDirection at subtree scope

Conversion Example

WinForms C#:

AutoScaleMode = AutoScaleMode.Dpi;
RightToLeft = RightToLeft.Yes;

DpiChanged += (_, e) =>
{
    statusLabel.Text = $"DPI changed: {e.DeviceDpiNew}";
};

Avalonia XAML:

<Window xmlns="https://github.com/avaloniaui"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:vm="using:MyApp.ViewModels"
        x:DataType="vm:MainViewModel"
        FlowDirection="RightToLeft"
        Width="800"
        Height="480">
  <StackPanel Margin="12" Spacing="8">
    <TextBlock Text="{CompiledBinding ScalingText}" />
    <TextBox Watermark="Name" />
  </StackPanel>
</Window>

C# Equivalent

using Avalonia.Controls;
using Avalonia.Media;

public static void AttachScalingListener(Window window, MainViewModel viewModel)
{
    window.FlowDirection = FlowDirection.RightToLeft;
    viewModel.ScalingText = $"Scale: {window.RenderScaling:0.00}";

    window.ScalingChanged += (_, _) =>
    {
        viewModel.ScalingText = $"Scale: {window.RenderScaling:0.00}";
    };
}

Troubleshooting

  1. Layout appears over- or under-scaled.
    • avoid pixel constants; prefer logical units and container layout rules.
  2. RTL text direction is correct but layout order is not.
    • set FlowDirection on the correct subtree root.
  3. Image assets look blurry on high DPI displays.
    • provide suitable source resolutions and avoid runtime upscaling where possible.
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