Ursa.Avalonia/src/Ursa.Themes.Semi/Controls/Resizer.axaml

<ResourceDictionary
    xmlns="https://github.com/avaloniaui"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:u="https://irihi.tech/ursa"
    xmlns:iri="https://irihi.tech/shared">
    <ControlTheme x:Key="{x:Type u:WindowResizerThumb}" TargetType="u:WindowResizerThumb">
        <Setter Property="Background" Value="Transparent" />
        <Setter Property="Template">
            <ControlTemplate TargetType="u:WindowResizerThumb">
                <iri:PureRectangle
                    HorizontalAlignment="Stretch"
                    VerticalAlignment="Stretch"
                    Background="{TemplateBinding Background}" />
            </ControlTemplate>
        </Setter>
    </ControlTheme>

    <ControlTheme x:Key="{x:Type u:DialogResizerThumb}" TargetType="u:DialogResizerThumb">
        <Setter Property="Background" Value="Transparent" />
        <Setter Property="Template">
            <ControlTemplate TargetType="u:DialogResizerThumb">
                <Panel>
                    <iri:PureRectangle
                        HorizontalAlignment="Stretch"
                        VerticalAlignment="Stretch"
                        Background="{TemplateBinding Background}" />
                </Panel>
            </ControlTemplate>
        </Setter>
    </ControlTheme>

    <ControlTheme x:Key="{x:Type u:DialogResizer}" TargetType="u:DialogResizer">
        <Setter Property="Template">
            <ControlTemplate TargetType="u:WindowResizer">
                <Grid ColumnDefinitions="Auto, *, Auto" RowDefinitions="Auto, *, Auto">
                    <u:DialogResizerThumb
                        Name="{x:Static u:DialogResizer.PART_TopLeft}"
                        Grid.Row="0"
                        Grid.Column="0"
                        Cursor="TopLeftCorner"
                        ResizeDirection="TopLeft" />
                    <u:DialogResizerThumb
                        Name="{x:Static u:DialogResizer.PART_Top}"
                        Grid.Row="0"
                        Grid.Column="1"
                        Height="{DynamicResource ResizerThumbHeight}"
                        Cursor="TopSide"
                        ResizeDirection="Top" />
                    <u:DialogResizerThumb
                        Name="{x:Static u:DialogResizer.PART_TopRight}"
                        Grid.Row="0"
                        Grid.Column="2"
                        Cursor="TopRightCorner"
                        ResizeDirection="TopRight" />
                    <u:DialogResizerThumb
                        Name="{x:Static u:DialogResizer.PART_Left}"
                        Grid.Row="1"
                        Grid.Column="0"
                        Width="{DynamicResource ResizerThumbWidth}"
                        Cursor="LeftSide"
                        ResizeDirection="Left" />
                    <u:DialogResizerThumb
                        Name="{x:Static u:DialogResizer.PART_Right}"
                        Grid.Row="1"
                        Grid.Column="2"
                        Width="{DynamicResource ResizerThumbWidth}"
                        Cursor="RightSide"
                        ResizeDirection="Right" />
                    <u:DialogResizerThumb
                        Name="{x:Static u:DialogResizer.PART_BottomLeft}"
                        Grid.Row="2"
                        Grid.Column="0"
                        Cursor="BottomLeftCorner"
                        ResizeDirection="BottomLeft" />
                    <u:DialogResizerThumb
                        Name="{x:Static u:DialogResizer.PART_Bottom}"
                        Grid.Row="2"
                        Grid.Column="1"
                        Height="{DynamicResource ResizerThumbHeight}"
                        Cursor="BottomSide"
                        ResizeDirection="Bottom" />
                    <u:DialogResizerThumb
                        Name="{x:Static u:DialogResizer.PART_BottomRight}"
                        Grid.Row="2"
                        Grid.Column="2"
                        Cursor="BottomRightCorner"
                        ResizeDirection="BottomRight" />
                </Grid>
            </ControlTemplate>
        </Setter>
    </ControlTheme>

    <ControlTheme x:Key="{x:Type u:WindowResizer}" TargetType="u:WindowResizer">
        <Setter Property="Template">
            <ControlTemplate TargetType="u:WindowResizer">
                <Grid ColumnDefinitions="Auto, *, Auto" RowDefinitions="Auto, *, Auto">
                    <u:WindowResizerThumb
                        Grid.Row="0"
                        Grid.Column="0"
                        Cursor="TopLeftCorner"
                        ResizeDirection="TopLeft" />
                    <u:WindowResizerThumb
                        Grid.Row="0"
                        Grid.Column="1"
                        Height="{DynamicResource ResizerThumbHeight}"
                        Cursor="TopSide"
                        ResizeDirection="Top" />
                    <u:WindowResizerThumb
                        Grid.Row="0"
                        Grid.Column="2"
                        Cursor="TopRightCorner"
                        ResizeDirection="TopRight" />
                    <u:WindowResizerThumb
                        Grid.Row="1"
                        Grid.Column="0"
                        Width="{DynamicResource ResizerThumbWidth}"
                        Cursor="LeftSide"
                        ResizeDirection="Left" />
                    <u:WindowResizerThumb
                        Grid.Row="1"
                        Grid.Column="2"
                        Width="{DynamicResource ResizerThumbWidth}"
                        Cursor="RightSide"
                        ResizeDirection="Right" />
                    <u:WindowResizerThumb
                        Grid.Row="2"
                        Grid.Column="0"
                        Cursor="BottomLeftCorner"
                        ResizeDirection="BottomLeft" />
                    <u:WindowResizerThumb
                        Grid.Row="2"
                        Grid.Column="1"
                        Height="{DynamicResource ResizerThumbHeight}"
                        Cursor="BottomSide"
                        ResizeDirection="Bottom" />
                    <u:WindowResizerThumb
                        Grid.Row="2"
                        Grid.Column="2"
                        Cursor="BottomRightCorner"
                        ResizeDirection="BottomRight" />
                </Grid>
            </ControlTemplate>
        </Setter>
    </ControlTheme>
</ResourceDictionary>