iOS & macOS Charting Documentation - SciChart iOS & macOS Charts SDK v4.x

SCIXabcdCreationModifier

The SCIXabcdCreationModifier is a custom gesture modifier used for interactive creation of XABCD annotations on a SciChart surface.

It enables users to place five key points (X → A → B → C → D) using touch gestures, with real-time visual feedback during placement.

Overview

The modifier handles the full lifecycle of XABCD annotation creation:

Sequential point placement via touch interaction
Real-time dragging feedback for each point
Automatic completion after the final point (D)
Immediate reset for continuous drawing

Once completed, the annotation remains on the chart and a callback is triggered.

Interaction Behavior

The creation flow follows a structured sequence:

Per Point Interaction (X → A → B → C → D)

Gesture	Behavior
Touch Down	Places the current point at the touch location
Drag	Moves the point dynamically in real-time
Touch Up	Locks the point and advances to the next one

Completion

After placing point D, the annotation is finalized
The SCIAnnotationCreationModifierBase.annotationCreationCompletionListener callback is invoked
The modifier resets immediately, ready for a new annotation

Xabcd Annotation

Retrieving Annotation Points After Drawing Completion

After an annotation drawing is completed, you can retrieve its underlying points using: -[ISCITradingAnnotation getBaseDataValues] -[ISCITradingAnnotation getBasePoints] Both methods return the annotation’s defining points, but in different coordinate spaces.

-[ISCITradingAnnotation getBaseDataValues]

X and Y values correspond to the chart’s actual data coordinates
Independent of pixel resolution or screen scaling
Useful for storing, analysis, or reloading annotations

-[ISCITradingAnnotation getBasePoints]

X and Y values correspond to screen pixels
Useful for rendering overlays or UI alignment

Usage Example

// Create a new XABCD creation modifier instance
SCIXabcdCreationModifier *modifier = [SCIXabcdCreationModifier new];

// Set the stroke (outline) style for the XABCD annotation lines
modifier.annotationStroke = [[SCISolidPenStyle alloc] initWithColorCode:0xFFE97064 thickness:2];

// Set the fill style for the annotation 
modifier.annotationFill = [[SCISolidBrushStyle alloc] initWithColorCode:0x55AAAA00];

// Callback triggered when the user completes placing all 5 points (X, A, B, C, D)
// Provides access to the fully created annotation object
__weak typeof(self) weakSelf = self;
modifier.annotationCreationCompletionListener = ^(id _Nonnull         createdAnnotation, SCIAnnotationCreationType type) {
    __strong typeof(weakSelf) strongSelf = weakSelf;
    if (!strongSelf) return;
            
    NSLog(@“XABCD annotation created: %@ type %@”, createdAnnotation, SCIAnnotationTypeName(type));
            
    if (![createdAnnotation isKindOfClass:[SCIXabcdAnnotation class]]) return;
            
    SCIXabcdAnnotation *xabcd = (SCIXabcdAnnotation *)createdAnnotation;
    NSArray *points = [xabcd getBaseDataValues];

    // Get data points
    // Index mapping: 0 = X, 1 = A, 2 = B, 3 = C, 4 = D
    NSLog(@“[XABCD] X: date=%@  price=%@”, points[0].x, points[0].y);
    NSLog(@“[XABCD] A: date=%@  price=%@”, points[1].x, points[1].y);
};

// Add the modifier to the chart surface
[self.surface.chartModifiers add:modifier];

// Create a new XABCD creation modifier instance
let modifier = SCIXabcdCreationModifier()

// Set the stroke (outline) style for the XABCD annotation lines
modifier.annotationStroke = SCISolidPenStyle(color: 0xFFE97064, thickness: 2)

// Set the fill style for the annotation
modifier.annotationFill = SCISolidBrushStyle(color: 0x55AAAA00)

// Callback triggered when all points (X, A, B, C, D) are placed
// Gives access to the completed annotation object
modifier.annotationCreationCompletionListener  = { [weak self] createdAnnotation, type in
    guard self != nil else { return }
                
    print(“Annotation created: \(createdAnnotation), type: \(SCIAnnotationTypeName(type))”)
                
    guard let xabcd = createdAnnotation as? SCIXabcdAnnotation else { return }
    let arrPoints = xabcd.getBaseDataValues()
                
    // Get data points
    // Index mapping: 0 = X, 1 = A, 2 = B, 3 = C, 4 = D
    print(“XABCD point X: \(arrPoints[0].x), \(arrPoints[0].y)”)
    print(“XABCD point A: \(arrPoints[1].x), \(arrPoints[1].y)”)
}

// Add the modifier to the chart surface 
surface.chartModifiers.add(modifier)

The SCIXabcdCreationModifier can be configured using the properties and method listed in the table below:

Field	Description
`SCIXabcdCreationModifier.annotationStroke`	Defines the stroke style for newly created annotations.
`SCIXabcdCreationModifier.annotationFill`	Defines the fill style for newly created annotations.
`SCIXabcdCreationModifier.isDragging`	Indicates whether the user is actively dragging a point.
`SCIXabcdCreationModifier.activePointIndex`	Represents the index of the point currently being placed.
`-[SCIXabcdCreationModifier reset]`	Cancels and removes any in-progress annotation.

NOTE: The xAxisId and yAxisId must be supplied if you have axis with non-default Axis Ids, e.g. in multi-axis scenario.

Best Practices

Disable conflicting gesture modifiers during drawing for better UX
Use CompletionListener to validate or store annotations
Call -[SCIXabcdCreationModifier reset] when switching tools or exiting drawing mode
Customize stroke/fill for better visual distinction
Call cancel when switching tools or modes

Notes

The modifier automatically resets after completing point D
Only one annotation is created per interaction cycle
Designed for real-time financial charting and harmonic pattern visualization