Documentation: ChartOptionsModel.cs

1. Purpose

ChartOptionsModel is a state-bearing model class that encapsulates all configuration options for chart display within the DTS Viewer application. It manages chart unit types (EU, mV, V, PSD, FFT), time units, Y-axis scaling modes, filter selections, cursor behavior, and axis locking states. The class implements INotifyPropertyChanged (via BasePropertyChanged) to support data binding and coordinates with a parent IChartOptionsViewModel to publish changes and execute commands.

2. Public Interface

Class Signature

public class ChartOptionsModel : Common.Base.BasePropertyChanged, IChartOptionsModel

Properties

Property	Type	Default	Description
`DisplayingVolts`	`bool`	`false`	Toggles between Volts (true) and millivolts (false) display. Raises `OnPropertyChanged` for `"MVOrV"` and `"UnitTypeDescription"` when changed.
`MVOrV`	`string`	—	Read-only. Returns `"V"` if `DisplayingVolts` is true, otherwise `"mV"`.
`IsDigitalChannel`	`bool`	`false`	Indicates whether the channel is digital.
`SupportsADC`	`bool`	`true`	Indicates ADC support.
`SupportsMV`	`bool`	`true`	Indicates millivolt support.
`UnitType`	`ChartUnitTypeEnum`	`ChartUnitTypeEnum.EU`	The unit type for the chart. Changing this sets `ReadData = true` and auto-adjusts `Filter` based on unit type.
`UnitTypeDescription`	`string`	—	Read-only. Returns `"V"` or `"mV"` for `ChartUnitTypeEnum.mV`, otherwise returns `UnitType.ToString()`.
`TimeUnitType`	`TimeUnitTypeEnum`	`TimeUnitTypeEnum.MS`	Time unit for the X-axis. Sets `ReadData = true` on change.
`TimeUnitTypeDescription`	`string`	`"MS"`	String representation of `TimeUnitType`.
`SelectedFilter`	`IFilterClass`	`FilterClass(Unfiltered)`	The selected software filter. Sets `ReadData = true` on change.
`MinFixedY`	`double`	`0.00`	Minimum Y-axis value for fixed range.
`MaxFixedY`	`double`	`0.00`	Maximum Y-axis value for fixed range.
`MinFixedT`	`double`	`0.00`	Minimum X-axis (time) value for fixed range.
`MaxFixedT`	`double`	`0.00`	Maximum X-axis (time) value for fixed range.
`FullScaleValues`	`List<double>`	—	Returns `_euValues` for EU/PSD unit types, otherwise `_fullScaleValues`.
`SelectedFullScaleValue`	`double`	`100`	Currently selected full-scale value.
`LockedT`	`bool`	`false`	Indicates if the X-axis is locked.
`LockedY`	`bool`	`false`	Indicates if the Y-axis is locked.
`ShowCursor`	`bool`	`false`	Cursor visibility. Calls `Parent?.ShowCusor(value)` on change.
`CurrentCursorValues`	`string`	`""`	String representation of current cursor values.
`YRange`	`YRangeScaleEnum`	`YRangeScaleEnum.AutoRange`	Y-axis range mode. Setting to `Fixed` automatically sets `LockedY = true`.
`Filter`	`FilterOptionEnum`	`FilterOptionEnum.TestSetupDefault`	Filter option enum. Sets `ReadData = true` on change.
`Parent`	`IChartOptionsViewModel`	`null`	Reference to parent view model.
`CanPublishChanges`	`bool`	`true`	Controls whether property changes trigger `Parent?.PublishChanges()`.
`IsCursorsAvailable`	`bool`	`false`	Indicates if cursors are available for the current context.
`T0Cursor`	`bool`	`false`	T0 cursor flag.
`MinMaxCursors`	`bool`	`false`	Min/Max cursors flag.
`ReadData`	`bool`	`false`	Flag indicating data should be re-read.
`IsSaved`	`bool`	—	Read-only auto-property (no setter visible).
`DecimateData`	`bool`	`false`	Getter returns `false` if `UnitType` is `PSD` or `FFT`, otherwise returns backing field value.
`WidthPoints`	`long`	`0`	Width points for decimation.

Commands

Command	Type	Description
`ResetZoomCommand`	`DelegateCommand`	Executes `ResetZoomMethod()`, which delegates to `Parent.ResetZoomMethod()`.
`ResetTCommand`	`DelegateCommand`	Executes `ResetTMethod()`, which delegates to `Parent.ResetTMethod()`.
`SaveToPDFCommand`	`DelegateCommand`	Executes `SaveToPDFMethod()`, which delegates to `Parent.SaveToPDFMethod()`.

Methods

Method	Signature	Description
`ChartOptionsModel`	`ctor()`	Empty parameterless constructor.
`SetSelectedFilterToUnfilteredNoRead`	`void SetSelectedFilterToUnfilteredNoRead()`	Sets `_selectedFilter` to `FilterClass(Unfiltered)` with `ReadData = false`. Raises `OnPropertyChanged("SelectedFilter")`.
`OnPropertyChanged`	`void OnPropertyChanged(string propertyName)`	Raises `PropertyChanged` event. Conditionally calls `Parent?.PublishChanges()` unless the property is in an exclusion list.

Events

Event	Type	Description
`PropertyChanged`	`PropertyChangedEventHandler`	Standard INotifyPropertyChanged event.

3. Invariants

UnitType → Filter coupling: When UnitType is set to anything other than EU or PSD, Filter is automatically set to FilterOptionEnum.Unfiltered. When UnitType is EU or PSD, Filter is set to FilterOptionEnum.TestSetupDefault.
YRange → LockedY coupling: Setting YRange to YRangeScaleEnum.Fixed automatically sets LockedY = true.
DecimateData conditional return: The DecimateData getter always returns false when UnitType is ChartUnitTypeEnum.PSD or ChartUnitTypeEnum.FFT, regardless of the backing field _decimateData.
FullScaleValues selection: The property returns _euValues list when UnitType is EU or PSD; otherwise returns _fullScaleValues.
Change publishing exclusion: The following properties do not trigger Parent?.PublishChanges() when changed:
- CanPublishChanges, Parent, ReadData, UnitTypeDescription, ShowCursor, LockedT, LockedY, MVOrV, DisplayingVolts, DecimateData, WidthPoints

4. Dependencies

This Module Depends On

System, System.Collections.Generic, System.ComponentModel (BCL)
DTS.Common — Base namespace
DTS.Common.Base.BasePropertyChanged — Base class providing SetProperty method
DTS.Common.Classes.Sensors — FilterClass implementation
DTS.Common.Enums.Viewer — ChartUnitTypeEnum, TimeUnitTypeEnum, FilterOptionEnum, YRangeScaleEnum
DTS.Common.Interface — IChartOptionsModel (implied), IChartOptionsViewModel
DTS.Common.Interface.Sensors.SoftwareFilters — IFilterClass
Prism.Commands — DelegateCommand

What Depends On This Module

Unknown from source alone — The IChartOptionsViewModel interface references this model via the Parent property, but concrete consumers are not visible in this file.

5. Gotchas

Typo in method call: In the ShowCursor setter, the code calls Parent?.ShowCusor(_showCursor) — note the spelling "Cusor" instead of "Cursor". This is either a typo in the method name on IChartOptionsViewModel or a historical naming quirk.
SetSelectedFilterToUnfilteredNoRead exists as a workaround: The method SetSelectedFilterToUnfilteredNoRead() specifically bypasses the automatic ReadData = true behavior that occurs when setting SelectedFilter via the property. This suggests the automatic data refresh is sometimes undesirable and requires explicit circumvention.
Inconsistent property setter patterns: Some properties use SetProperty(ref _field, value, "PropertyName") (e.g., IsDigitalChannel, DisplayingVolts), while others manually implement equality checks and OnPropertyChanged calls (e.g., UnitType, MinFixedY). This inconsistency may reflect different authors or refactoring over time.
IsSaved is unassigned: The IsSaved property has no setter and no initialization. The ReSharper annotation // ReSharper disable UnassignedGetOnlyAutoProperty at the top of the file suppresses warnings about this. Accessing this property will return default(bool) (false).
ReadData side effects are implicit: Setting UnitType, TimeUnitType, SelectedFilter, or Filter silently sets ReadData = true. Callers must be aware that these property changes have side effects beyond the property value itself.
Historical comment FB 13120: The comment // FB 13120 does not need to set SelectedFilter any more since it's not using enum and // FB 13120 use filter class instead of cfc filter enum reference a past bug/feature (likely FogBugz case 13120) where filter handling was refactored from an enum to a class-based approach.

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