LinearScale: CustomItems spanning range

[Alexander]

LinearScale.CustomItems spanning range

Is it possible to have a custom item inside a linear scale span a certain range of values?
When you use the attached property ScaleObject.Value, it centers the item at the specified value. However, I would like to have the left end of the item (e.g. an rectangle or border) at one value and the right end at another.

Thank you.

[Andrey]

Hello Alexander,

In the case you like to have a resizable custom item you can use the relative measurement and relative location for the item. You can use the ScaleObject.RelativeX, RelativeY, RelativeWidth, RelativeHeight and HotSpot properties.
The following example places the Rectangle from 25 to 50 in HorizontalLinearScale:

<Window x:Class="LinearScaleCustomItems.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:telerik="http://schemas.telerik.com/2008/xaml/presentation"
        Title="MainWindow" Height="350" Width="525">
    <Grid>
        <telerik:RadHorizontalLinearGauge>
            <telerik:HorizontalLinearScale
                x:Name="scale"
                Min="0" Max="100"
                RelativeX="0.1" RelativeY="0.5"
                RelativeHeight="0.1" RelativeWidth="0.8">
                <telerik:HorizontalLinearScale.CustomItems>
                    <Rectangle
                        x:Name="item" Fill="Red"
                        telerik:ScaleObject.RelativeX="0.3"
                        telerik:ScaleObject.RelativeY="0.57"
                        telerik:ScaleObject.HotSpot="0, 1"
                        telerik:ScaleObject.RelativeWidth="0.2*"
                        telerik:ScaleObject.RelativeHeight="0.075*" />
                </telerik:HorizontalLinearScale.CustomItems>
            </telerik:HorizontalLinearScale>
        </telerik:RadHorizontalLinearGauge>
    </Grid>
</Window>

The ScaleObject.RelativeX and RelativeWidth properties for the item are calculated using the following formulas which you can use also in the case when you should add the item dynamically or you should change its position when the Min-Max of the scale is changed):

double leftValue = 25;
double rightValue = 50;
double scaleFactor = this.scale.RelativeWidth / (this.scale.Max - this.scale.Min);

ScaleObject.SetRelativeX(this.item, this.scale.RelativeX + ((leftValue - this.scale.Min) * scaleFactor));
ScaleObject.SetRelativeWidth(this.item, new GaugeMeasure((rightValue - leftValue) * scaleFactor, GridUnitType.Star));

Regards,
Andrey Murzov
Telerik