Added quarter hour indicator to DayView and both half hour indicator and quarter hour indicator to WeekView.

lib/src/day_view/_internal_day_view_page.dart

@@ -93,7 +93,10 @@ class InternalDayViewPage<T extends Object?> extends StatelessWidget {
   final FullDayEventBuilder<T> fullDayEventBuilder;
 
   /// Flag to display half hours.
-  final bool showHalfHours;
+  final bool showHalfHours; 
+
+  /// Flag to display quarter hours.
+  final bool showQuarterHours;
 
   /// Settings for half hour indicator lines.
   final HourIndicatorSettings halfHourIndicatorSettings;
@@ -127,7 +130,8 @@ class InternalDayViewPage<T extends Object?> extends StatelessWidget {
     required this.fullDayEventBuilder,
     required this.scrollController,
     required this.dayDetectorBuilder,
-    required this.showHalfHours,
+    required this.showHalfHours, 
+    required this.showQuarterHours,
     required this.halfHourIndicatorSettings,
   }) : super(key: key);
 
@@ -178,6 +182,21 @@ class InternalDayViewPage<T extends Object?> extends StatelessWidget {
                           dashSpaceWidth:
                               halfHourIndicatorSettings.dashSpaceWidth,
                         ),
+                      ), 
+                     if (showQuarterHours)
+                      CustomPaint(
+                        size: Size(width, height),
+                        painter: QuarterHourLinePainter(
+                          lineColor: halfHourIndicatorSettings.color,
+                          lineHeight: halfHourIndicatorSettings.height,
+                          offset:
+                              timeLineWidth + halfHourIndicatorSettings.offset,
+                          minuteHeight: heightPerMinute,
+                          lineStyle: halfHourIndicatorSettings.lineStyle,
+                          dashWidth: halfHourIndicatorSettings.dashWidth,
+                          dashSpaceWidth:
+                              halfHourIndicatorSettings.dashSpaceWidth,
+                        ),
                       ),
                     dayDetectorBuilder(
                       width: width,

lib/src/day_view/day_view.dart

@@ -142,7 +142,7 @@ class DayView<T extends Object?> extends StatefulWidget {
   /// Defines offset of vertical line from hour line starts.
   final double verticalLineOffset;
 
-  /// Background colour of day view page.
+  /// Background color of day view page.
   final Color? backgroundColor;
 
   /// Scroll offset of day view page.
@@ -182,8 +182,12 @@ class DayView<T extends Object?> extends StatefulWidget {
   /// Display full day event builder.
   final FullDayEventBuilder<T>? fullDayEventBuilder;
 
+  /// Show half hour indicator
   final bool showHalfHours;
 
+  /// Show quarter hour indicator 
+  final bool showQuarterHours;
+
   /// Duration from where default day view will be visible
   /// By default it will be Duration(hours:0)
   final Duration startDuration;
@@ -226,6 +230,7 @@ class DayView<T extends Object?> extends StatefulWidget {
     this.pageViewPhysics,
     this.dayDetectorBuilder,
     this.showHalfHours = false,
+    this.showQuarterHours = false,
     this.halfHourIndicatorSettings,
     this.startDuration = const Duration(hours: 0),
   })  : assert(timeLineOffset >= 0,
@@ -426,6 +431,7 @@ class DayViewState<T extends Object?> extends State<DayView<T>> {
                             fullDayEventBuilder: _fullDayEventBuilder,
                             scrollController: _scrollController,
                             showHalfHours: widget.showHalfHours,
+                            showQuarterHours: widget.showQuarterHours,
                             halfHourIndicatorSettings:
                                 _halfHourIndicatorSettings,
                           ),

lib/src/painters.dart

@@ -147,6 +147,86 @@ class HalfHourLinePainter extends CustomPainter {
     }
   }
 
+  @override
+  bool shouldRepaint(covariant CustomPainter oldDelegate) {
+    return oldDelegate is HourLinePainter &&
+        (oldDelegate.lineColor != lineColor ||
+            oldDelegate.offset != offset ||
+            lineHeight != oldDelegate.lineHeight ||
+            minuteHeight != oldDelegate.minuteHeight);
+  }
+} 
+
+//using HalfHourIndicatorSettings for this too
+class QuarterHourLinePainter extends CustomPainter {
+  /// Color of quarter hour line
+  final Color lineColor;
+
+  /// Height of quarter hour line
+  final double lineHeight;
+
+  /// Offset of quarter hour line from left.
+  final double offset;
+
+  /// Height occupied by one minute of time stamp.
+  final double minuteHeight;
+
+  /// Style of the quarter hour line
+  final LineStyle lineStyle;
+
+  /// Line dash width when using the [LineStyle.dashed] style
+  final double dashWidth;
+
+  /// Line dash space width when using the [LineStyle.dashed] style
+  final double dashSpaceWidth;
+
+  /// Paint quarter hour lines
+  QuarterHourLinePainter({
+    required this.lineColor,
+    required this.lineHeight,
+    required this.offset,
+    required this.minuteHeight,
+    required this.lineStyle,
+    this.dashWidth = 4,
+    this.dashSpaceWidth = 4,
+  });
+
+  @override
+  void paint(Canvas canvas, Size size) {
+    final paint = Paint()
+      ..color = lineColor
+      ..strokeWidth = lineHeight;
+
+    for (var i = 0; i < Constants.hoursADay; i++) {
+      final dy1 = i * minuteHeight * 60 + (minuteHeight * 15);
+      final dy2 = i * minuteHeight * 60 + (minuteHeight * 45);
+
+      //for the 15 minute line
+      if (lineStyle == LineStyle.dashed) {
+        var startX = offset;
+        while (startX < size.width) {
+          canvas.drawLine(
+              Offset(startX, dy1), Offset(startX + dashWidth, dy1), paint);
+          startX += dashWidth + dashSpaceWidth;
+        }
+      } else {
+        canvas.drawLine(Offset(offset, dy1), Offset(size.width, dy1), paint);
+      }
+
+      // for the 45 minutes line
+      if (lineStyle == LineStyle.dashed) {
+        var startX = offset;
+        while (startX < size.width) {
+          canvas.drawLine(
+              Offset(startX, dy2), Offset(startX + dashWidth, dy2), paint);
+          startX += dashWidth + dashSpaceWidth;
+        }
+      } else {
+        canvas.drawLine(Offset(offset, dy2), Offset(size.width, dy2), paint);
+      }
+    }
+  }
+
   @override
   bool shouldRepaint(covariant CustomPainter oldDelegate) {
     return oldDelegate is HourLinePainter &&
@@ -157,6 +237,7 @@ class HalfHourLinePainter extends CustomPainter {
   }
 }
 
+
 /// Paints a single horizontal line at [offset].
 class CurrentTimeLinePainter extends CustomPainter {
   /// Color of time indicator.

lib/src/week_view/_internal_week_view_page.dart

@@ -37,6 +37,9 @@ class InternalWeekViewPage<T extends Object?> extends StatelessWidget {
   /// Settings for hour indicator lines.
   final HourIndicatorSettings hourIndicatorSettings;
 
+  /// Settings for half hour indicator lines. 
+  final HourIndicatorSettings halfHourIndicatorSettings;
+
   /// Flag to display live line.
   final bool showLiveLine;
 
@@ -111,6 +114,12 @@ class InternalWeekViewPage<T extends Object?> extends StatelessWidget {
   /// Display full day events.
   final FullDayEventBuilder<T> fullDayEventBuilder;
 
+  /// Flag to display half hours
+  final bool showHalfHours; 
+
+  /// Flag to display quarter hours 
+  final bool showQuarterHours; 
+
   /// A single page for week view.
   const InternalWeekViewPage({
     Key? key,
@@ -123,7 +132,8 @@ class InternalWeekViewPage<T extends Object?> extends StatelessWidget {
     required this.eventTileBuilder,
     required this.controller,
     required this.timeLineBuilder,
-    required this.hourIndicatorSettings,
+    required this.hourIndicatorSettings, 
+    required this.halfHourIndicatorSettings,
     required this.showLiveLine,
     required this.liveTimeIndicatorSettings,
     required this.heightPerMinute,
@@ -143,6 +153,8 @@ class InternalWeekViewPage<T extends Object?> extends StatelessWidget {
     required this.scrollConfiguration,
     required this.fullDayEventBuilder,
     required this.weekDetectorBuilder,
+    required this.showHalfHours, 
+    required this.showQuarterHours,
   }) : super(key: key);
 
   @override
@@ -225,6 +237,36 @@ class InternalWeekViewPage<T extends Object?> extends StatelessWidget {
                         showVerticalLine: showVerticalLine,
                       ),
                     ),
+                          if (showHalfHours)
+                      CustomPaint(
+                        size: Size(width, height),
+                        painter: HalfHourLinePainter(
+                          lineColor: halfHourIndicatorSettings.color,
+                          lineHeight: halfHourIndicatorSettings.height,
+                          offset:
+                              timeLineWidth + halfHourIndicatorSettings.offset,
+                          minuteHeight: heightPerMinute,
+                          lineStyle: halfHourIndicatorSettings.lineStyle,
+                          dashWidth: halfHourIndicatorSettings.dashWidth,
+                          dashSpaceWidth:
+                              halfHourIndicatorSettings.dashSpaceWidth,
+                        ),
+                      ), 
+                     if (showQuarterHours)
+                      CustomPaint(
+                        size: Size(width, height),
+                        painter: QuarterHourLinePainter(
+                          lineColor: halfHourIndicatorSettings.color,
+                          lineHeight: halfHourIndicatorSettings.height,
+                          offset:
+                              timeLineWidth + halfHourIndicatorSettings.offset,
+                          minuteHeight: heightPerMinute,
+                          lineStyle: halfHourIndicatorSettings.lineStyle,
+                          dashWidth: halfHourIndicatorSettings.dashWidth,
+                          dashSpaceWidth:
+                              halfHourIndicatorSettings.dashSpaceWidth,
+                        ),
+                      ),
                     if (showLiveLine && liveTimeIndicatorSettings.height > 0)
                       LiveTimeIndicator(
                         liveTimeIndicatorSettings: liveTimeIndicatorSettings,

lib/src/week_view/week_view.dart

@@ -85,6 +85,9 @@ class WeekView<T extends Object?> extends StatefulWidget {
   /// Settings for hour indicator settings.
   final HourIndicatorSettings? hourIndicatorSettings;
 
+  /// Settings for half hour and quarter hour indicator settings.
+  final HourIndicatorSettings? halfHourIndicatorSettings;
+
   /// Settings for live time indicator settings.
   final HourIndicatorSettings? liveTimeIndicatorSettings;
 
@@ -175,14 +178,20 @@ class WeekView<T extends Object?> extends StatefulWidget {
   final MinuteSlotSize minuteSlotSize;
 
   /// Style for WeekView header.
-  final HeaderStyle headerStyle;
+  final HeaderStyle headerStyle;  
 
   /// Option for SafeArea.
   final SafeAreaOption safeAreaOption;
 
   /// Display full day event builder.
   final FullDayEventBuilder<T>? fullDayEventBuilder;
 
+  ///Show half hour indicator 
+  final bool showHalfHours; 
+
+  ///Show quarter hour indicator 
+  final bool showQuarterHours;
+
   /// Main widget for week view.
   const WeekView({
     Key? key,
@@ -198,6 +207,7 @@ class WeekView<T extends Object?> extends StatefulWidget {
     this.maxDay,
     this.initialDay,
     this.hourIndicatorSettings,
+    this.halfHourIndicatorSettings,
     this.timeLineBuilder,
     this.timeLineWidth,
     this.liveTimeIndicatorSettings,
@@ -224,6 +234,8 @@ class WeekView<T extends Object?> extends StatefulWidget {
     this.headerStyle = const HeaderStyle(),
     this.safeAreaOption = const SafeAreaOption(),
     this.fullDayEventBuilder,
+    this.showHalfHours = false, 
+    this.showQuarterHours = false,
   })  : assert((timeLineOffset) >= 0,
             "timeLineOffset must be greater than or equal to 0"),
         assert(width == null || width > 0,
@@ -258,7 +270,8 @@ class WeekViewState<T extends Object?> extends State<WeekView<T>> {
 
   late EventArranger<T> _eventArranger;
 
-  late HourIndicatorSettings _hourIndicatorSettings;
+  late HourIndicatorSettings _hourIndicatorSettings; 
+  late HourIndicatorSettings _halfHourIndicatorSettings;
   late HourIndicatorSettings _liveTimeIndicatorSettings;
 
   late PageController _pageController;
@@ -418,6 +431,7 @@ class WeekViewState<T extends Object?> extends State<WeekView<T>> {
                             eventTileBuilder: _eventTileBuilder,
                             heightPerMinute: widget.heightPerMinute,
                             hourIndicatorSettings: _hourIndicatorSettings,
+                            halfHourIndicatorSettings: _halfHourIndicatorSettings,
                             dates: dates,
                             showLiveLine: widget.showLiveTimeLineInAllDays ||
                                 _showLiveTimeIndicator(dates),
@@ -433,6 +447,8 @@ class WeekViewState<T extends Object?> extends State<WeekView<T>> {
                             minuteSlotSize: widget.minuteSlotSize,
                             scrollConfiguration: _scrollConfiguration,
                             fullDayEventBuilder: _fullDayEventBuilder,
+                            showHalfHours: widget.showHalfHours, 
+                            showQuarterHours: widget.showQuarterHours,
                           ),
                         );
                       },
@@ -510,6 +526,13 @@ class WeekViewState<T extends Object?> extends State<WeekView<T>> {
     _weekTitleWidth =
         (_width - _timeLineWidth - _hourIndicatorSettings.offset) /
             _totalDaysInWeek;
+
+    _halfHourIndicatorSettings = widget.halfHourIndicatorSettings ?? 
+      HourIndicatorSettings(
+          height: widget.heightPerMinute,
+          color: Constants.defaultBorderColor,
+          offset: 5,
+        );
   }
 
   void _calculateHeights() {