Add documentation and make small fix

CHANGELOG.md

@@ -5,6 +5,7 @@
 * **BUGFIX** Allow to show title when axis diff is zero.
 * **IMPROVEMENT** Improve iteration over axis values logic (it solves some minor problems on showing titles when min, max values are below than 1.0).
 * **BREAKING** `LineTouchResponse` response now contains a list of `TouchLineBarSpot` instead of `LineBarSpot`. They are ordered based on their distance to the touch event and also contain that distance.
+* **IMPROVEMENT** Added `distanceCalculator` to `LineTouchData` which is used to calculate the distance between spots and touch events
 
 ## 0.41.0
 * **BUGFIX** Fix getNearestTouchedSpot. Previously it returned the first occurrence of a spot within the threshold, and not the nearest, #641, #645.

lib/src/chart/line_chart/line_chart_data.dart

@@ -1444,7 +1444,7 @@ class LineTouchData extends FlTouchData<LineTouchResponse> with EquatableMixin {
         getTouchedSpotIndicator =
             getTouchedSpotIndicator ?? defaultTouchedIndicators,
         touchSpotThreshold = touchSpotThreshold ?? 10,
-        distanceCalculator = distanceCalculator ?? xDistance,
+        distanceCalculator = distanceCalculator ?? _xDistance,
         handleBuiltInTouches = handleBuiltInTouches ?? true,
         getTouchLineStart = getTouchLineStart ?? defaultGetTouchLineStart,
         getTouchLineEnd = getTouchLineEnd ?? defaultGetTouchLineEnd,
@@ -1472,6 +1472,7 @@ class LineTouchData extends FlTouchData<LineTouchResponse> with EquatableMixin {
       getTouchedSpotIndicator:
           getTouchedSpotIndicator ?? this.getTouchedSpotIndicator,
       touchSpotThreshold: touchSpotThreshold ?? this.touchSpotThreshold,
+      distanceCalculator: distanceCalculator ?? this.distanceCalculator,
       getTouchLineStart: getTouchLineStart ?? this.getTouchLineStart,
       getTouchLineEnd: getTouchLineEnd ?? this.getTouchLineEnd,
       handleBuiltInTouches: handleBuiltInTouches ?? this.handleBuiltInTouches,
@@ -1512,7 +1513,7 @@ typedef CalculateTouchDistance = double Function(
     Offset touchPoint, Offset spotPixelCoordinates);
 
 /// Default distanceCalculator only considers distance on x axis
-double xDistance(Offset touchPoint, Offset spotPixelCoordinates) {
+double _xDistance(Offset touchPoint, Offset spotPixelCoordinates) {
   return ((touchPoint.dx - spotPixelCoordinates.dx)).abs();
 }
 

repo_files/documentations/line_chart.md

@@ -169,6 +169,7 @@ When you change the chart's state, it animates to the new state internally (usin
 |touchTooltipData|a [LineTouchTooltipData](#LineTouchTooltipData), that determines how show the tooltip on top of touched spots (appearance of the showing tooltip bubble)|LineTouchTooltipData|
 |getTouchedSpotIndicator| a callback that retrieves list of [TouchedSpotIndicatorData](#TouchedSpotIndicatorData) by the given list of [LineBarSpot](#LineBarSpot) for showing the indicators on touched spots|defaultTouchedIndicators|
 |touchSpotThreshold|the threshold of the touch accuracy|10|
+|distanceCalculator| a function to calculate the distance between a spot and a touch event| _xDistance|
 |handleBuiltInTouches| set this true if you want the built in touch handling (show a tooltip bubble and an indicator on touched spots) | true|
 |getTouchLineStart| controls where the line starts, default is bottom of the chart| defaultGetTouchLineStart|
 |getTouchLineEnd| controls where the line ends, default is the touch point| defaultGetTouchLineEnd|
@@ -212,10 +213,19 @@ When you change the chart's state, it animates to the new state internally (usin
 |spotIndex|index of the target [FlSpot](#FlSpot) inside [LineChartBarData](#LineChartBarData)|null|
 
 
+### TouchLineBarSpot
+|PropName|Description|default value|
+|:-------|:----------|:------------|
+|bar|the [LineChartBarData](#LineChartBarData) that contains a spot|null|
+|barIndex|index of the target [LineChartBarData](#LineChartBarData) inside [LineChartData](#LineChartData)|null|
+|spotIndex|index of the target [FlSpot](#FlSpot) inside [LineChartBarData](#LineChartBarData)|null|
+|distance|distance to the touch event|null|
+
+
 ### LineTouchResponse
 |PropName|Description|default value|
 |:-------|:----------|:------------|
-|lineBarSpots|a list of [LineBarSpot](#LineBarSpot)|null|
+|lineBarSpots|a list of [TouchLineBarSpot](#TouchLineBarSpot)|null|
 
 ### ShowingTooltipIndicators
 |PropName|Description|default value|