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Swift Charts: chartScrollTargetBehavior fails to snap to a day unit
I am working on a scrollable chart that displays days on the horizontal axis. As the user scrolls, I always want them to be able to snap to a specific day. I implemented the following steps described in this WWDC23 session to achieve this. I have set the chartScrollTargetBehavior to .valueAligned(matching: DateComponents(hour: 0)) I have set the x value unit on the BarMark to Calendar.Component.day I ended up with the chart code that looks like this: Chart(dates, id: \.self) { date in BarMark( x: .value("Date", date, unit: Calendar.Component.day), y: .value("Number", 1) ) .annotation { Text(date.formatted(.dateTime.day())) .font(.caption2) } } .chartXAxis { AxisMarks(format: .dateTime.day()) } .chartScrollableAxes(.horizontal) .chartScrollTargetBehavior(.valueAligned(matching: DateComponents(hour: 0))) .chartXVisibleDomain(length: fifteenDays) .chartScrollPosition(x: $selection) However, this fails to work reliably. There is often a situation where the chart scroll position lands on, for instance, Oct 20, 11:56 PM, but the chart snaps to Oct 21. I attempted to solve this problem by introducing an intermediate binding between a state value and a chart selection. This binding aims to normalize the selection always to be the first moment of any given date. But this hasn't been successful. private var selectionBinding: Binding<Date> { Binding { Calendar.current.startOfDay(for: selection) } set: { newValue in self.selection = Calendar.current.startOfDay(for: newValue) } } It's also worth mentioning that this issue also exists in Apple's sample project on Swift Charts. How would you approach solving this? How can I find a way to make the chart scroll position blind to time values and only recognize whole days? Here's the minimal reproducible example project for your reference.
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