MonthLabelBuilder is an enum containing static methods for building month labels for heatmap displays. It intelligently places month labels at the start of each month while maintaining minimum spacing to prevent overcrowding.
Methods
build
public static func build(from weeks: [HeatmapWeek]) -> [MonthLabel]
Array of heatmap weeks to generate labels for. Each week contains a start date used to determine the month.
MonthLabel objects, each containing:
label: Three-letter month abbreviation (“Jan”, “Feb”, etc.)weekIndex: The index of the week where this label should be displayed
Labeling Rules:
- A label is placed when the month changes from the previous week
- Labels must be at least 3 weeks apart (except for the first label at index 0)
- Month abbreviations are in English (“en_US” locale)
- Format: “MMM” (e.g., “Jan”, “Feb”, “Mar”)
Example:
import Foundation
let weeks: [HeatmapWeek] = [
HeatmapWeek(start: date("2024-01-01"), values: [...]),
HeatmapWeek(start: date("2024-01-08"), values: [...]),
HeatmapWeek(start: date("2024-01-15"), values: [...]),
HeatmapWeek(start: date("2024-02-05"), values: [...]),
HeatmapWeek(start: date("2024-02-12"), values: [...]),
// ... more weeks
]
let labels = MonthLabelBuilder.build(from: weeks)
// Returns:
// [
// MonthLabel(label: "Jan", weekIndex: 0),
// MonthLabel(label: "Feb", weekIndex: 3),
// // ... more labels
// ]
// Using in a SwiftUI view
struct HeatmapHeader: View {
let weeks: [HeatmapWeek]
var body: some View {
let labels = MonthLabelBuilder.build(from: weeks)
HStack(spacing: 2) {
ForEach(weeks.indices, id: \.self) { index in
let label = labels.first { $0.weekIndex == index }
Text(label?.label ?? "")
.font(.caption2)
.frame(width: 12)
}
}
}
}
// Example: Short month spanning only 2 weeks
let weeks = [
HeatmapWeek(start: date("2024-01-01"), ...), // Label: "Jan" at index 0
HeatmapWeek(start: date("2024-01-08"), ...),
HeatmapWeek(start: date("2024-02-01"), ...), // Feb starts, but only 1 week gap - skipped
HeatmapWeek(start: date("2024-03-01"), ...), // Label: "Mar" at index 3 (3 weeks from Jan)
]
let labels = MonthLabelBuilder.build(from: weeks)
// Returns: [MonthLabel("Jan", 0), MonthLabel("Mar", 3)]
// Note: "Feb" is skipped due to insufficient gap