# Circualr compass gauge: StartAngle and Value questions.

Gauge for WPF Forum

Posted 11 years ago
Version: 13.2.0590

Hi,

I'm trying to make a circular gauge that displays the angle of an object (0-360 degrees).

The Gage needs to have 0 at the top of the gauge. The scale rotates instead of the needle (like a compass).

I created a stationary needle by making a scale with only a needle, which has a Value = 270 to get the pointer to point straight up.

Then I made the core scale rotate by binding the scale's StartAngle to an angle value...

I'm close, but a couple of things I have not found how to do - a pointer to the right properties would be appreciated.

The questions:

Question 1) To get the center scale to rotate the correct amount AND on the correct direction,  I have to set the StartAngle to

(360 - Angle + StartAngle ) modulo  360

I'm wishing there were separate properties for a) Scale angular offset, and b) "scale rotation value", but that does not appear to be how things were constructed as the pointer only has Value and the scale only has StartAngle. Thus I have to do some value fiddling outside the control (which feels a bit messy).

Is there a better approach I've missed?

Question 2) The scale has 360 degrees... but I don't want to show the number 360 at the top, I want to show 0.... so I set SkipValues="360" ...

Yeah, the 360 goes away, but I'm stumped as to how to get a 0 to show up... what am I not seeing?

In case it helps, here is the Gauge XAML

``````<!-- Angle Display; 0 @ TDC; Rotating scale -->
FrameType="CircularThickRim" Background="#FF063818" RimBrush="#504E5F"
ToolTip="Part Angle" Margin="84.4,301,23,8.2" Grid.RowSpan="2">
<gauge:CircularGauge.Items>
<TextBlock gauge:GaugeBase.Y="30" Text="Angle" FontFamily="Arial" Foreground="Wheat"
FontSize="18" Margin="0,-3.996,0,3.996" />
</gauge:CircularGauge.Items>
<gauge:CircularTickSet Maximum="360" MajorInterval="30" MinorInterval="5">
<gauge:CircularTickSet.Ticks>
<gauge:CircularTickMarkMinor TickMarkExtent="3" TickMarkAscent="3"
TickMarkType="Rectangle" ScalePlacement="Outside" />
<gauge:CircularTickMarkMajor TickMarkExtent="10" TickMarkAscent="3"
TickMarkType="Rectangle" ScalePlacement="Outside" ScaleOffset="1" />
<gauge:CircularTickLabelMajor FontFamily="Tahoma" FontSize="11"
ScalePlacement="Outside" SkipValues="360"
ScaleOffset="11" Foreground="Wheat" />
</gauge:CircularTickSet.Ticks>
</gauge:CircularTickSet>
</gauge:CircularScale>
<gauge:CircularScale StartAngle="{Binding GaugeStartAngle}" AllowDrop="False">
<gauge:CircularTickSet >
<gauge:CircularTickSet.Pointers>
<gauge:CircularPointerNeedle x:Name="RightSensorForce12" BorderBrush="Wheat"
PointerAscent="5" PointerExtent="70" NeedleType="PivotSwordSharp"
<gauge:CircularPointerCap CapType="CircleConvex" PointerExtent="10"
Background="#58667A" />
</gauge:CircularTickSet.Pointers>
</gauge:CircularTickSet>
</gauge:CircularScale>
</gauge:CircularGauge>``````

Dave

[Modified 11 years ago]

Answer - Posted 11 years ago

Hi Dave,

1) Sorry but as you saw, there is only the StartAngle on scale.  So what you are doing is probably best.

2) 0 and 360 are the same value, so what you did to remove 360 is correct.  Then you can manually add in zero like this:

``<gauge:CircularTickLabelCustom Value="0" Text="0" FontFamily="Tahoma" FontSize="11" ScalePlacement="Outside" ScaleOffset="11" Foreground="Wheat" />``

Actipro Software Support

Posted 11 years ago

Thanks. That did what was needed.

Dave

The latest build of this product (v24.1.2) was released 2 months ago, which was after the last post in this thread.