From ba60de41c75cfefe712f7e8fccd7f730ed8461cf Mon Sep 17 00:00:00 2001
From: Oleh <pelmenstar1@gmail.com>
Date: Thu, 22 Jun 2023 23:24:07 +0300
Subject: [PATCH 1/7] Move logic related to rendering and managing weekday row
 state out of RangeCalendarGridView. Move logic of extracting weekdays out of
 CalendarResources

---
 .../rangecalendar/WeekdayDataTests.kt         |  29 +++++
 .../rangecalendar/CalendarResources.kt        |  60 +++--------
 .../rangecalendar/RangeCalendarGridView.kt    | 100 +++---------------
 .../RangeCalendarPagerAdapter.kt              |   2 -
 .../pelmenstar1/rangecalendar/WeekdayData.kt  |  67 ++++++++++++
 .../rangecalendar/WeekdayMeasureHelper.kt     |  20 ++++
 .../pelmenstar1/rangecalendar/WeekdayRow.kt   |  79 ++++++++++++++
 7 files changed, 229 insertions(+), 128 deletions(-)
 create mode 100644 library/src/androidTest/java/com/github/pelmenstar1/rangecalendar/WeekdayDataTests.kt
 create mode 100644 library/src/main/java/com/github/pelmenstar1/rangecalendar/WeekdayData.kt
 create mode 100644 library/src/main/java/com/github/pelmenstar1/rangecalendar/WeekdayMeasureHelper.kt
 create mode 100644 library/src/main/java/com/github/pelmenstar1/rangecalendar/WeekdayRow.kt

diff --git a/library/src/androidTest/java/com/github/pelmenstar1/rangecalendar/WeekdayDataTests.kt b/library/src/androidTest/java/com/github/pelmenstar1/rangecalendar/WeekdayDataTests.kt
new file mode 100644
index 0000000..0f1f093
--- /dev/null
+++ b/library/src/androidTest/java/com/github/pelmenstar1/rangecalendar/WeekdayDataTests.kt
@@ -0,0 +1,29 @@
+package com.github.pelmenstar1.rangecalendar
+
+import android.os.Build
+import androidx.test.ext.junit.runners.AndroidJUnit4
+import org.junit.Test
+import org.junit.runner.RunWith
+import java.util.Locale
+import kotlin.test.assertContentEquals
+
+@RunWith(AndroidJUnit4::class)
+class WeekdayDataTests {
+    @Suppress("UNCHECKED_CAST")
+    @Test
+    fun getTest() {
+        val locale = Locale.ENGLISH
+        val data = WeekdayData.get(locale)
+
+        val expectedWeekdays: Array<String> = if (Build.VERSION.SDK_INT >= 24) {
+            arrayOf(
+                "Mon", "Tue", "Wed", "Thu", "Fri", "Sat", "Sun",
+                "M", "T", "W", "T", "F", "S", "S",
+            )
+        } else {
+            arrayOf("Mon", "Tue", "Wed", "Thu", "Fri", "Sat", "Sun")
+        }
+
+        assertContentEquals(expectedWeekdays, data.weekdays as Array<String>)
+    }
+}
\ No newline at end of file
diff --git a/library/src/main/java/com/github/pelmenstar1/rangecalendar/CalendarResources.kt b/library/src/main/java/com/github/pelmenstar1/rangecalendar/CalendarResources.kt
index 47a43be..3873e41 100644
--- a/library/src/main/java/com/github/pelmenstar1/rangecalendar/CalendarResources.kt
+++ b/library/src/main/java/com/github/pelmenstar1/rangecalendar/CalendarResources.kt
@@ -3,7 +3,7 @@ package com.github.pelmenstar1.rangecalendar
 import android.annotation.SuppressLint
 import android.content.Context
 import android.content.res.ColorStateList
-import android.icu.text.DateFormatSymbols
+import android.graphics.Paint
 import android.os.Build
 import com.github.pelmenstar1.rangecalendar.utils.darkerColor
 import com.github.pelmenstar1.rangecalendar.utils.getColorFromAttribute
@@ -23,7 +23,7 @@ internal class CalendarResources(context: Context) {
     val disabledTextColor: Int
 
     val weekdayTextSize: Float
-    val weekdays: Array<String>
+    val defaultWeekdayData: WeekdayData
 
     val dayNumberTextSize: Float
 
@@ -47,7 +47,8 @@ internal class CalendarResources(context: Context) {
         colorPrimary = context.getColorFromAttribute(androidx.appcompat.R.attr.colorPrimary)
         colorPrimaryDark = colorPrimary.darkerColor(0.4f)
         textColor = getTextColor(context)
-        colorControlNormal = context.getColorStateListFromAttribute(androidx.appcompat.R.attr.colorControlNormal)
+        colorControlNormal =
+            context.getColorStateListFromAttribute(androidx.appcompat.R.attr.colorControlNormal)
         outMonthTextColor = colorControlNormal.getColorForState(ENABLED_STATE, 0)
         disabledTextColor = colorControlNormal.getColorForState(EMPTY_STATE, 0)
         hoverColor = getHoverColor(context)
@@ -64,52 +65,28 @@ internal class CalendarResources(context: Context) {
         // First element in getShortWeekDays() is empty and actual items start from 1
         // It's better to copy them to another array where elements start from 0
         val locale = context.getLocaleCompat()
-        val shortWeekdays: Array<String>
-        var narrowWeekdays: Array<String>? = null
 
-        if (Build.VERSION.SDK_INT >= 24) {
-            val symbols = DateFormatSymbols.getInstance(locale)
-            shortWeekdays = symbols.shortWeekdays
+        defaultWeekdayData = WeekdayData.get(locale)
+        val weekdays = defaultWeekdayData.weekdays
 
-            narrowWeekdays = symbols.getWeekdays(
-                DateFormatSymbols.FORMAT,
-                DateFormatSymbols.NARROW
-            )
-        } else {
-            shortWeekdays = java.text.DateFormatSymbols.getInstance(locale).shortWeekdays
-        }
-
-        val weekdaysLength = if (Build.VERSION.SDK_INT >= 24) 14 else 7
-
-        @Suppress("UNCHECKED_CAST")
-        weekdays = arrayOfNulls<String?>(weekdaysLength) as Array<String>
-        System.arraycopy(shortWeekdays, 1, weekdays, 0, 7)
+        defaultWeekdayWidths = FloatArray(weekdays.size)
 
-        if (narrowWeekdays != null) {
-            System.arraycopy(narrowWeekdays, 1, weekdays, 7, 7)
+        val defaultWeekdayPaint = Paint().apply {
+            textSize = weekdayTextSize
+            typeface = null
         }
 
-        defaultWeekdayWidths = FloatArray(weekdaysLength)
-        defaultShortWeekdayRowHeight = computeWeekdayWidthAndMaxHeight(SHORT_WEEKDAYS_OFFSET)
+        defaultShortWeekdayRowHeight = WeekdayMeasureHelper.computeWeekdayWidthAndMaxHeight(
+            weekdays, WeekdayData.SHORT_WEEKDAYS_OFFSET, defaultWeekdayPaint, defaultWeekdayWidths
+        )
+
         defaultNarrowWeekdayRowHeight = if (Build.VERSION.SDK_INT >= 24) {
-            computeWeekdayWidthAndMaxHeight(NARROW_WEEKDAYS_OFFSET)
+            WeekdayMeasureHelper.computeWeekdayWidthAndMaxHeight(
+                weekdays, WeekdayData.NARROW_WEEKDAYS_OFFSET, defaultWeekdayPaint, defaultWeekdayWidths
+            )
         } else Float.NaN
     }
 
-    private fun computeWeekdayWidthAndMaxHeight(offset: Int): Float {
-        var maxHeight = -1
-
-        getTextBoundsArray(weekdays, offset, offset + 7, weekdayTextSize, typeface = null) { i, width, height ->
-            if (height > maxHeight) {
-                maxHeight = height
-            }
-
-            defaultWeekdayWidths[i + offset] = width.toFloat()
-        }
-
-        return maxHeight.toFloat()
-    }
-
     companion object {
         val DAYS = arrayOf(
             "1", "2", "3", "4", "5", "6", "7", "8", "9", "10",
@@ -123,9 +100,6 @@ internal class CalendarResources(context: Context) {
         private val ENABLED_STATE = intArrayOf(android.R.attr.state_enabled)
         private val EMPTY_STATE = IntArray(0)
 
-        const val SHORT_WEEKDAYS_OFFSET = 0
-        const val NARROW_WEEKDAYS_OFFSET = 7
-
         fun getDayText(day: Int) = DAYS[day - 1]
 
         @SuppressLint("PrivateResource")
diff --git a/library/src/main/java/com/github/pelmenstar1/rangecalendar/RangeCalendarGridView.kt b/library/src/main/java/com/github/pelmenstar1/rangecalendar/RangeCalendarGridView.kt
index a0f6e76..94017ad 100644
--- a/library/src/main/java/com/github/pelmenstar1/rangecalendar/RangeCalendarGridView.kt
+++ b/library/src/main/java/com/github/pelmenstar1/rangecalendar/RangeCalendarGridView.kt
@@ -244,15 +244,9 @@ internal class RangeCalendarGridView(
     private var onAnimationEnd: (() -> Unit)? = null
     private var animationHandler: (() -> Unit)? = null
 
-    var isFirstDaySunday = false
     private val touchHelper: TouchHelper
 
-    private var weekdayType = WeekdayType.SHORT
-
-    private var isWeekdayMeasurementsDirty = false
-
-    private var weekdayWidths: FloatArray = cr.defaultWeekdayWidths
-    private var maxWeekdayHeight: Float = cr.defaultShortWeekdayRowHeight
+    private val weekdayRow: WeekdayRow
 
     private var isDayNumberMeasurementsDirty = false
     private var dayNumberSizes = cr.defaultDayNumberSizes
@@ -332,6 +326,14 @@ internal class RangeCalendarGridView(
         cellHoverPaint = Paint(Paint.ANTI_ALIAS_FLAG).apply {
             style = Paint.Style.FILL
         }
+
+        weekdayRow = WeekdayRow(
+            cr.defaultShortWeekdayRowHeight,
+            cr.defaultNarrowWeekdayRowHeight,
+            cr.defaultWeekdayWidths,
+            cr.defaultWeekdayData,
+            weekdayPaint
+        )
     }
 
     private inline fun updateUIState(block: () -> Unit) =
@@ -437,7 +439,7 @@ internal class RangeCalendarGridView(
         weekdayPaint.textSize = size
 
         if (size != cr.weekdayTextSize) {
-            isWeekdayMeasurementsDirty = true
+            weekdayRow.onMeasurementsChanged()
         }
 
         onGridTopChanged()
@@ -539,20 +541,8 @@ internal class RangeCalendarGridView(
         // There is no narrow weekdays before API < 24, so we need to resolve it
         val type = _type.resolved()
 
-        if (weekdayType != type) {
-            weekdayType = type
-
-            // If weekdays measurements are from calendar resources then we can use precomputed values and don't make them "dirty"
-            if (weekdayWidths === cr.defaultWeekdayWidths) {
-                maxWeekdayHeight = if (type == WeekdayType.SHORT) {
-                    cr.defaultShortWeekdayRowHeight
-                } else {
-                    cr.defaultNarrowWeekdayRowHeight
-                }
-            } else {
-                // Widths and max height needs to be precomputed if they are not from calendar resources.
-                isWeekdayMeasurementsDirty = true
-            }
+        if (weekdayRow.type != type) {
+            weekdayRow.type = type
 
             onGridTopChanged()
             invalidate()
@@ -1259,66 +1249,7 @@ internal class RangeCalendarGridView(
     }
 
     private fun drawWeekdayRow(c: Canvas) {
-        if (isWeekdayMeasurementsDirty) {
-            isWeekdayMeasurementsDirty = false
-
-            measureWeekdays()
-        }
-
-        var x = cr.hPadding + columnWidth * 0.5f
-
-        val offset = if (weekdayType == WeekdayType.SHORT)
-            CalendarResources.SHORT_WEEKDAYS_OFFSET
-        else
-            CalendarResources.NARROW_WEEKDAYS_OFFSET
-
-        val startIndex = if (isFirstDaySunday) 0 else 1
-
-        // If widths are from calendar resources, then we do not need any widths-offset to get the size,
-        // because it contains both short and narrow (if API level >= 24) weekday widths.
-        // But if the widths are recomputed, not from calendar resources,
-        // then it contains either short or narrow (if API level >= 24) weekday widths and
-        // we need to shift the index.
-        val widthsOffset = if (weekdayWidths === cr.defaultWeekdayWidths) 0 else offset
-
-        for (i in offset + startIndex until offset + 7) {
-            drawWeekday(c, i, widthsOffset, x)
-
-            x += columnWidth
-        }
-
-        if (!isFirstDaySunday) {
-            drawWeekday(c, offset, widthsOffset, x)
-        }
-    }
-
-    private fun drawWeekday(c: Canvas, index: Int, widthsOffset: Int, midX: Float) {
-        val textX = midX - weekdayWidths[index - widthsOffset] * 0.5f
-        val textY = maxWeekdayHeight
-
-        c.drawText(cr.weekdays[index], textX, textY, weekdayPaint)
-    }
-
-    private fun measureWeekdays() {
-        val offset = if (weekdayType == WeekdayType.SHORT) 0 else 7
-
-        var maxHeight = -1
-
-        // If weekdays are from calendar resources,
-        // then create new array to not overwrite the resources' one.
-        if (weekdayWidths === cr.defaultWeekdayWidths) {
-            weekdayWidths = FloatArray(7)
-        }
-
-        weekdayPaint.getTextBoundsArray(cr.weekdays, offset, offset + 7) { i, width, height ->
-            if (height > maxHeight) {
-                maxHeight = height
-            }
-
-            weekdayWidths[i] = width.toFloat()
-        }
-
-        maxWeekdayHeight = maxHeight.toFloat()
+        weekdayRow.draw(c, cr.hPadding, columnWidth)
     }
 
     private fun drawHover(c: Canvas) {
@@ -1483,12 +1414,15 @@ internal class RangeCalendarGridView(
         updateGradientBoundsIfNeeded()
         updateSelectionStateConfiguration()
 
+        // Height of the view depends on gridTop()
+        requestLayout()
+
         // y-axis of entries depends on type of weekday, so we need to refresh accessibility info
         touchHelper.invalidateRoot()
     }
 
     private fun gridTop(): Float {
-        return maxWeekdayHeight + cr.weekdayRowMarginBottom
+        return weekdayRow.height + cr.weekdayRowMarginBottom
     }
 
     // It'd be better if cellRoundRadius() returns round radius that isn't greater than half of cell size.
diff --git a/library/src/main/java/com/github/pelmenstar1/rangecalendar/RangeCalendarPagerAdapter.kt b/library/src/main/java/com/github/pelmenstar1/rangecalendar/RangeCalendarPagerAdapter.kt
index 3b94d76..7eeed5f 100644
--- a/library/src/main/java/com/github/pelmenstar1/rangecalendar/RangeCalendarPagerAdapter.kt
+++ b/library/src/main/java/com/github/pelmenstar1/rangecalendar/RangeCalendarPagerAdapter.kt
@@ -1,6 +1,5 @@
 package com.github.pelmenstar1.rangecalendar
 
-import android.util.Log
 import android.util.SparseArray
 import android.view.ViewGroup
 import androidx.recyclerview.widget.RecyclerView
@@ -876,7 +875,6 @@ internal class RangeCalendarPagerAdapter(
         val gridView = holder.calendar
 
         gridView.ym = ym
-        gridView.isFirstDaySunday = false
         gridView.onSelectionListener = createRedirectSelectionListener(ym)
         gridView.selectionGate = createRedirectSelectionGate(ym)
 
diff --git a/library/src/main/java/com/github/pelmenstar1/rangecalendar/WeekdayData.kt b/library/src/main/java/com/github/pelmenstar1/rangecalendar/WeekdayData.kt
new file mode 100644
index 0000000..f7d65f6
--- /dev/null
+++ b/library/src/main/java/com/github/pelmenstar1/rangecalendar/WeekdayData.kt
@@ -0,0 +1,67 @@
+package com.github.pelmenstar1.rangecalendar
+
+import android.icu.text.DateFormatSymbols
+import android.os.Build
+import java.util.Calendar
+import java.util.Locale
+
+class WeekdayData(val weekdays: Array<out String>) {
+    companion object {
+        const val SHORT_WEEKDAYS_OFFSET = 0
+        const val NARROW_WEEKDAYS_OFFSET = 7
+
+        fun get(locale: Locale): WeekdayData {
+            return WeekdayData(weekdays = getWeekdays(locale))
+        }
+
+        fun getOffsetByWeekdayType(type: WeekdayType): Int {
+            return if (type == WeekdayType.SHORT) {
+                SHORT_WEEKDAYS_OFFSET
+            } else {
+                NARROW_WEEKDAYS_OFFSET
+            }
+        }
+
+        @Suppress("UNCHECKED_CAST")
+        private fun getWeekdays(locale: Locale): Array<out String> {
+            val resultArrayLength: Int
+            val shortWeekdays: Array<String>
+            var narrowWeekdays: Array<String>? = null
+
+            if (Build.VERSION.SDK_INT >= 24) {
+                val symbols = DateFormatSymbols.getInstance(locale)
+                shortWeekdays = symbols.shortWeekdays
+
+                narrowWeekdays = symbols.getWeekdays(
+                    DateFormatSymbols.FORMAT,
+                    DateFormatSymbols.NARROW
+                )
+                resultArrayLength = 14
+            } else {
+                shortWeekdays = java.text.DateFormatSymbols.getInstance(locale).shortWeekdays
+                resultArrayLength = 7
+            }
+
+            // Cast to array with non-null elements because in the end the array won't have any null elements.
+            val weekdays = arrayOfNulls<String>(resultArrayLength) as Array<String>
+
+            copyAndFixWeekdaysOrder(shortWeekdays, weekdays, offset = SHORT_WEEKDAYS_OFFSET)
+
+            if (narrowWeekdays != null) {
+                copyAndFixWeekdaysOrder(narrowWeekdays, weekdays, offset = NARROW_WEEKDAYS_OFFSET)
+            }
+
+            return weekdays
+        }
+
+        // In format that DateFormatSymbols returns, Sunday is the first day of the week and 0 element is null, then goes Sun, Mon, Tue, ...
+        // But it's better for logic when first day of week is Monday and the elements start from 0 element.
+        // The method copies elements from source to dest with some reordering.
+        private fun copyAndFixWeekdaysOrder(source: Array<out String>, dest: Array<String>, offset: Int) {
+            System.arraycopy(source, 2, dest, offset, 6)
+
+            // Sunday is the last day of week
+            dest[offset + 6] = source[Calendar.SUNDAY]
+        }
+    }
+}
\ No newline at end of file
diff --git a/library/src/main/java/com/github/pelmenstar1/rangecalendar/WeekdayMeasureHelper.kt b/library/src/main/java/com/github/pelmenstar1/rangecalendar/WeekdayMeasureHelper.kt
new file mode 100644
index 0000000..5f8501d
--- /dev/null
+++ b/library/src/main/java/com/github/pelmenstar1/rangecalendar/WeekdayMeasureHelper.kt
@@ -0,0 +1,20 @@
+package com.github.pelmenstar1.rangecalendar
+
+import android.graphics.Paint
+import com.github.pelmenstar1.rangecalendar.utils.getTextBoundsArray
+
+object WeekdayMeasureHelper {
+    fun computeWeekdayWidthAndMaxHeight(weekdays: Array<out String>, offset: Int, paint: Paint, outWidths: FloatArray): Float {
+        var maxHeight = -1
+
+        paint.getTextBoundsArray(weekdays, offset, offset + 7) { i, width, height ->
+            if (height > maxHeight) {
+                maxHeight = height
+            }
+
+            outWidths[i + offset] = width.toFloat()
+        }
+
+        return maxHeight.toFloat()
+    }
+}
\ No newline at end of file
diff --git a/library/src/main/java/com/github/pelmenstar1/rangecalendar/WeekdayRow.kt b/library/src/main/java/com/github/pelmenstar1/rangecalendar/WeekdayRow.kt
new file mode 100644
index 0000000..bd9b79f
--- /dev/null
+++ b/library/src/main/java/com/github/pelmenstar1/rangecalendar/WeekdayRow.kt
@@ -0,0 +1,79 @@
+package com.github.pelmenstar1.rangecalendar
+
+import android.graphics.Canvas
+import android.graphics.Paint
+
+internal class WeekdayRow(
+    private val defaultShortWeekdayRowHeight: Float,
+    private val defaultNarrowWeekdayRowHeight: Float,
+    private val defaultWeekdayWidths: FloatArray,
+    private val weekdayData: WeekdayData,
+    private val textPaint: Paint
+) {
+    private var weekdayWidths: FloatArray = defaultWeekdayWidths
+
+    /**
+     * Height of the row, in pixels.
+     */
+    var height: Float = defaultShortWeekdayRowHeight
+        private set
+
+    /**
+     * Gets or sets type of weekdays in the row. In setter the value should be "resolved" (via [WeekdayType.resolved])
+     */
+    var type = WeekdayType.SHORT
+        set(value) {
+            if (field != value) {
+                field = value
+
+                // If we're still using defaultWeekdayWidths, it means that text size of weekday haven't been changed and
+                // we can use default measurements.
+                if (weekdayWidths === defaultWeekdayWidths) {
+                    height = if (value == WeekdayType.SHORT)
+                        defaultShortWeekdayRowHeight
+                    else
+                        defaultNarrowWeekdayRowHeight
+                } else {
+                    onMeasurementsChanged()
+                }
+            }
+        }
+
+    /**
+     * The method should be called when some measurements might be changed.
+     */
+    fun onMeasurementsChanged() {
+        val offset = WeekdayData.getOffsetByWeekdayType(type)
+
+        // If weekdayWidths is default one, create a new array not to overwrite default one.
+        if (weekdayWidths === defaultWeekdayWidths) {
+            // If we can't use precomputed widths, we re-compute them only for specified weekday type, so length is 7.
+            weekdayWidths = FloatArray(7)
+        }
+
+        height = WeekdayMeasureHelper.computeWeekdayWidthAndMaxHeight(
+            weekdayData.weekdays, offset, textPaint, weekdayWidths
+        )
+    }
+
+    fun draw(c: Canvas, x: Float, columnWidth: Float) {
+        var midX = x + columnWidth * 0.5f
+
+        val offset = WeekdayData.getOffsetByWeekdayType(type)
+        val widthsOffset = if (weekdayWidths === defaultWeekdayWidths) offset else 0
+
+        val weekdays = weekdayData.weekdays
+        val textY = height
+
+        for (i in 0 until 7) {
+            val text = weekdays[i + offset]
+            val width = weekdayWidths[i + widthsOffset]
+
+            val textX = midX - width * 0.5f
+
+            c.drawText(text, textX, textY, textPaint)
+
+            midX += columnWidth
+        }
+    }
+}
\ No newline at end of file

From 76d4616fa15575b756f07707cedf882efad8ecbe Mon Sep 17 00:00:00 2001
From: Oleh <pelmenstar1@gmail.com>
Date: Thu, 22 Jun 2023 23:36:15 +0300
Subject: [PATCH 2/7] Allow customizing typeface of weekday text

---
 .../pelmenstar1/rangecalendar/RangeCalendarGridView.kt |  7 +++++++
 .../rangecalendar/RangeCalendarPagerAdapter.kt         | 10 ++++++++--
 .../pelmenstar1/rangecalendar/RangeCalendarView.kt     | 10 ++++++++++
 3 files changed, 25 insertions(+), 2 deletions(-)

diff --git a/library/src/main/java/com/github/pelmenstar1/rangecalendar/RangeCalendarGridView.kt b/library/src/main/java/com/github/pelmenstar1/rangecalendar/RangeCalendarGridView.kt
index 94017ad..8a67d1f 100644
--- a/library/src/main/java/com/github/pelmenstar1/rangecalendar/RangeCalendarGridView.kt
+++ b/library/src/main/java/com/github/pelmenstar1/rangecalendar/RangeCalendarGridView.kt
@@ -445,6 +445,13 @@ internal class RangeCalendarGridView(
         onGridTopChanged()
     }
 
+    fun setWeekdayTypeface(typeface: Typeface?) = updateUIState(weekdayPaint.typeface, typeface) {
+        weekdayPaint.typeface = typeface
+        weekdayRow.onMeasurementsChanged()
+
+        onGridTopChanged()
+    }
+
     fun setInMonthTextColor(color: Int) = updateUIState(inMonthTextColor, color) {
         inMonthTextColor = color
     }
diff --git a/library/src/main/java/com/github/pelmenstar1/rangecalendar/RangeCalendarPagerAdapter.kt b/library/src/main/java/com/github/pelmenstar1/rangecalendar/RangeCalendarPagerAdapter.kt
index 7eeed5f..9f18295 100644
--- a/library/src/main/java/com/github/pelmenstar1/rangecalendar/RangeCalendarPagerAdapter.kt
+++ b/library/src/main/java/com/github/pelmenstar1/rangecalendar/RangeCalendarPagerAdapter.kt
@@ -1,5 +1,6 @@
 package com.github.pelmenstar1.rangecalendar
 
+import android.graphics.Typeface
 import android.util.SparseArray
 import android.view.ViewGroup
 import androidx.recyclerview.widget.RecyclerView
@@ -137,7 +138,7 @@ internal class RangeCalendarPagerAdapter(
 
     private val gridInfo = YearMonthGridInfo()
     private val styleData = IntArray(20)
-    private val styleObjData = arrayOfNulls<Any>(7)
+    private val styleObjData = arrayOfNulls<Any>(8)
 
     private var onSelectionListener: RangeCalendarView.OnSelectionListener? = null
     var selectionGate: RangeCalendarView.SelectionGate? = null
@@ -164,6 +165,9 @@ internal class RangeCalendarPagerAdapter(
         initStyle(STYLE_CELL_HEIGHT, cr.cellSize)
         initStyle(STYLE_CLICK_ON_CELL_SELECTION_BEHAVIOR, ClickOnCellSelectionBehavior.NONE)
 
+        // typefaces
+        initStyle(STYLE_WEEKDAY_TYPEFACE, Typeface.DEFAULT_BOLD)
+
         // animations
         initStyle(
             STYLE_COMMON_ANIMATION_DURATION,
@@ -204,7 +208,7 @@ internal class RangeCalendarPagerAdapter(
         initStyle(type, data.ordinal)
     }
 
-    private fun initStyle(type: Int, data: Any) {
+    private fun initStyle(type: Int, data: Any?) {
         styleObjData[type - STYLE_OBJ_START] = data
     }
 
@@ -325,6 +329,7 @@ internal class RangeCalendarPagerAdapter(
                 STYLE_SELECTION_FILL -> setSelectionFill(data.value())
                 STYLE_SELECTION_MANAGER -> setSelectionManager(data.value())
                 STYLE_CELL_ACCESSIBILITY_INFO_PROVIDER -> setCellAccessibilityInfoProvider(data.value())
+                STYLE_WEEKDAY_TYPEFACE -> setWeekdayTypeface(data.value())
             }
         }
     }
@@ -1033,6 +1038,7 @@ internal class RangeCalendarPagerAdapter(
         const val STYLE_SELECTION_FILL = 35
         const val STYLE_SELECTION_MANAGER = 36
         const val STYLE_CELL_ACCESSIBILITY_INFO_PROVIDER = 37
+        const val STYLE_WEEKDAY_TYPEFACE = 38
 
         // Precomputed value
         private const val PAGES_BETWEEN_ABS_MIN_MAX = 786432
diff --git a/library/src/main/java/com/github/pelmenstar1/rangecalendar/RangeCalendarView.kt b/library/src/main/java/com/github/pelmenstar1/rangecalendar/RangeCalendarView.kt
index 41cc5b2..e2ade50 100644
--- a/library/src/main/java/com/github/pelmenstar1/rangecalendar/RangeCalendarView.kt
+++ b/library/src/main/java/com/github/pelmenstar1/rangecalendar/RangeCalendarView.kt
@@ -5,6 +5,7 @@ import android.content.Context
 import android.content.res.Configuration
 import android.content.res.TypedArray
 import android.graphics.Rect
+import android.graphics.Typeface
 import android.os.Build
 import android.os.Parcelable
 import android.util.AttributeSet
@@ -892,6 +893,15 @@ class RangeCalendarView @JvmOverloads constructor(
             adapter.setStyleFloat({ STYLE_WEEKDAY_TEXT_SIZE }, size)
         }
 
+    /**
+     * Gets or sets a typeface of weekday. Pass null to clear previous typeface.
+     */
+    var weekdayTypeface: Typeface?
+        get() = adapter.getStyleObject { STYLE_WEEKDAY_TYPEFACE }
+        set(value) {
+            adapter.setStyleObject({ STYLE_WEEKDAY_TYPEFACE }, value)
+        }
+
     /**
      * Gets or sets a background color of cell which appears when user hovers under a cell
      * (when a pointer is registered to be down).

From 0932aff5f9e31ef446c2f789f917b2e751ea5c20 Mon Sep 17 00:00:00 2001
From: Oleh <pelmenstar1@gmail.com>
Date: Fri, 23 Jun 2023 00:04:00 +0300
Subject: [PATCH 3/7] Allow customizing weekdays

---
 .../rangecalendar/RangeCalendarGridView.kt    | 11 +++--
 .../RangeCalendarPagerAdapter.kt              |  3 ++
 .../rangecalendar/RangeCalendarView.kt        | 27 ++++++++++++-
 .../pelmenstar1/rangecalendar/WeekdayRow.kt   | 40 ++++++++++++++-----
 4 files changed, 65 insertions(+), 16 deletions(-)

diff --git a/library/src/main/java/com/github/pelmenstar1/rangecalendar/RangeCalendarGridView.kt b/library/src/main/java/com/github/pelmenstar1/rangecalendar/RangeCalendarGridView.kt
index 8a67d1f..1c67926 100644
--- a/library/src/main/java/com/github/pelmenstar1/rangecalendar/RangeCalendarGridView.kt
+++ b/library/src/main/java/com/github/pelmenstar1/rangecalendar/RangeCalendarGridView.kt
@@ -437,10 +437,7 @@ internal class RangeCalendarGridView(
 
     fun setWeekdayTextSize(size: Float) = updateUIState(weekdayPaint.textSize, size) {
         weekdayPaint.textSize = size
-
-        if (size != cr.weekdayTextSize) {
-            weekdayRow.onMeasurementsChanged()
-        }
+        weekdayRow.onMeasurementsChanged()
 
         onGridTopChanged()
     }
@@ -452,6 +449,12 @@ internal class RangeCalendarGridView(
         onGridTopChanged()
     }
 
+    fun setCustomWeekdays(weekdays: Array<out String>?) = updateUIState(weekdayRow.weekdays, weekdays) {
+        weekdayRow.weekdays = weekdays
+
+        onGridChanged()
+    }
+
     fun setInMonthTextColor(color: Int) = updateUIState(inMonthTextColor, color) {
         inMonthTextColor = color
     }
diff --git a/library/src/main/java/com/github/pelmenstar1/rangecalendar/RangeCalendarPagerAdapter.kt b/library/src/main/java/com/github/pelmenstar1/rangecalendar/RangeCalendarPagerAdapter.kt
index 9f18295..19e2f25 100644
--- a/library/src/main/java/com/github/pelmenstar1/rangecalendar/RangeCalendarPagerAdapter.kt
+++ b/library/src/main/java/com/github/pelmenstar1/rangecalendar/RangeCalendarPagerAdapter.kt
@@ -190,6 +190,7 @@ internal class RangeCalendarPagerAdapter(
         // other stuff
         initStyle(STYLE_VIBRATE_ON_SELECTING_CUSTOM_RANGE, true)
         initStyle(STYLE_SHOW_ADJACENT_MONTHS, true)
+        initStyle(STYLE_WEEKDAYS, null)
     }
 
     private fun initStyle(type: Int, data: Boolean) {
@@ -330,6 +331,7 @@ internal class RangeCalendarPagerAdapter(
                 STYLE_SELECTION_MANAGER -> setSelectionManager(data.value())
                 STYLE_CELL_ACCESSIBILITY_INFO_PROVIDER -> setCellAccessibilityInfoProvider(data.value())
                 STYLE_WEEKDAY_TYPEFACE -> setWeekdayTypeface(data.value())
+                STYLE_WEEKDAYS -> setCustomWeekdays(data.value())
             }
         }
     }
@@ -1039,6 +1041,7 @@ internal class RangeCalendarPagerAdapter(
         const val STYLE_SELECTION_MANAGER = 36
         const val STYLE_CELL_ACCESSIBILITY_INFO_PROVIDER = 37
         const val STYLE_WEEKDAY_TYPEFACE = 38
+        const val STYLE_WEEKDAYS = 39
 
         // Precomputed value
         private const val PAGES_BETWEEN_ABS_MIN_MAX = 786432
diff --git a/library/src/main/java/com/github/pelmenstar1/rangecalendar/RangeCalendarView.kt b/library/src/main/java/com/github/pelmenstar1/rangecalendar/RangeCalendarView.kt
index e2ade50..5c80215 100644
--- a/library/src/main/java/com/github/pelmenstar1/rangecalendar/RangeCalendarView.kt
+++ b/library/src/main/java/com/github/pelmenstar1/rangecalendar/RangeCalendarView.kt
@@ -902,6 +902,25 @@ class RangeCalendarView @JvmOverloads constructor(
             adapter.setStyleObject({ STYLE_WEEKDAY_TYPEFACE }, value)
         }
 
+    /**
+     * Gets or sets array of weekdays. Length of the array should be exactly 7. First day of week is expected to be Monday.
+     *
+     * Note that the getter returns a reference to weekdays, not a copy, thus that array should not be modified in any way.
+     * If you want to update weekdays, make a copy with changes and use setter.
+     *
+     * Pass `null` to use localized weekdays. Note that if you do that, the getter will return localized weekdays, not `null`.
+     */
+    var weekdays: Array<out String>?
+        get() = adapter.getStyleObject { STYLE_WEEKDAYS }
+        set(value) {
+            if (value != null && value.size != 7) {
+                throw IllegalArgumentException("Length of the array should be 7")
+            }
+
+            // Copy the array because the caller might be it later.
+            adapter.setStyleObject({ STYLE_WEEKDAYS }, value?.copyOf())
+        }
+
     /**
      * Gets or sets a background color of cell which appears when user hovers under a cell
      * (when a pointer is registered to be down).
@@ -969,13 +988,17 @@ class RangeCalendarView @JvmOverloads constructor(
         }
 
     /**
-     * Gets or sets weekday type. Should be [WeekdayType.SHORT] or [WeekdayType.NARROW].
+     * Gets or sets weekday type.
+     *
      * If [WeekdayType.SHORT], then weekdays will be: Mo, Tue, Wed, Thu, Fri.
      * If [WeekdayType.NARROW], then weekdays will be: M, T, W, T, F.
      * Note:
-     * - Narrow weekdays is dependent on user locale and are not always one-letter.
+     * - Narrow weekdays depend on user locale and are not always one-letter.
      * - **If API level is less than 24, [WeekdayType.NARROW] won't work.**
      *
+     * Changing weekday type when custom weekdays array was set (via [weekdays]) won't have any effect, even though when
+     * `null` value is passed to the setter of [weekdays], the latest value of [weekdayType] will be used.
+     *
      * @throws IllegalArgumentException if type is not one of [WeekdayType] constants
      */
     var weekdayType: WeekdayType
diff --git a/library/src/main/java/com/github/pelmenstar1/rangecalendar/WeekdayRow.kt b/library/src/main/java/com/github/pelmenstar1/rangecalendar/WeekdayRow.kt
index bd9b79f..ea064d4 100644
--- a/library/src/main/java/com/github/pelmenstar1/rangecalendar/WeekdayRow.kt
+++ b/library/src/main/java/com/github/pelmenstar1/rangecalendar/WeekdayRow.kt
@@ -7,11 +7,14 @@ internal class WeekdayRow(
     private val defaultShortWeekdayRowHeight: Float,
     private val defaultNarrowWeekdayRowHeight: Float,
     private val defaultWeekdayWidths: FloatArray,
-    private val weekdayData: WeekdayData,
+    private val localizedWeekdayData: WeekdayData,
     private val textPaint: Paint
 ) {
     private var weekdayWidths: FloatArray = defaultWeekdayWidths
 
+    private var isCustomWeekdays = false
+    private var weekdayData = localizedWeekdayData
+
     /**
      * Height of the row, in pixels.
      */
@@ -26,19 +29,36 @@ internal class WeekdayRow(
             if (field != value) {
                 field = value
 
-                // If we're still using defaultWeekdayWidths, it means that text size of weekday haven't been changed and
-                // we can use default measurements.
-                if (weekdayWidths === defaultWeekdayWidths) {
-                    height = if (value == WeekdayType.SHORT)
-                        defaultShortWeekdayRowHeight
-                    else
-                        defaultNarrowWeekdayRowHeight
-                } else {
-                    onMeasurementsChanged()
+                // Changing the type when custom weekdays are used should have no effect
+                if (!isCustomWeekdays) {
+                    // If we're still using defaultWeekdayWidths, it means that text size of weekday haven't been changed and
+                    // we can use default measurements.
+                    if (weekdayWidths === defaultWeekdayWidths) {
+                        height = if (value == WeekdayType.SHORT)
+                            defaultShortWeekdayRowHeight
+                        else
+                            defaultNarrowWeekdayRowHeight
+                    } else {
+                        onMeasurementsChanged()
+                    }
                 }
             }
         }
 
+    var weekdays: Array<out String>?
+        get() = weekdayData.weekdays
+        set(value) {
+            weekdayData = if (value == null) {
+                localizedWeekdayData
+            } else {
+                WeekdayData(value)
+            }
+
+            isCustomWeekdays = value != null
+
+            onMeasurementsChanged()
+        }
+
     /**
      * The method should be called when some measurements might be changed.
      */

From 67e16029d01510a97891ce8479db74563e422173 Mon Sep 17 00:00:00 2001
From: Oleh <pelmenstar1@gmail.com>
Date: Fri, 23 Jun 2023 00:20:06 +0300
Subject: [PATCH 4/7] Add rangeCalendar_weekdays attribute

---
 README.md                                      | 10 ++++++++--
 .../rangecalendar/RangeCalendarView.kt         | 18 +++++++++++++-----
 library/src/main/res/values/attrs.xml          |  1 +
 3 files changed, 22 insertions(+), 7 deletions(-)

diff --git a/README.md b/README.md
index 3617ba5..c53aa48 100644
--- a/README.md
+++ b/README.md
@@ -276,11 +276,17 @@ observer.register() // The observer should be registered manually.
         <td>rangeCalendar_weekdayType</td>
         <td>
             Type of weekday. <br/> 
-            Format of weekdays is very dependent on locale. In example, English locale is used.
+            Format of weekdays depends on locale. In example, English locale is used.
             <ul>
                 <li>shortName (WeekdayType.SHORT) - weekdays will look like Mob, Tue, Wed. </li>
                 <li>narrowName (WeekdayType.NARROW) - weekdays will look like M, T, W,. </li>
-            </ul>
+            </ul> 
+        </td>
+    </tr>
+    <tr>
+        <td>rangeCalendar_weekdays</td>  
+        <td>
+            Custom weekdays. The value should be a string array, whose length is 7.
         </td>
     </tr>
     <tr>
diff --git a/library/src/main/java/com/github/pelmenstar1/rangecalendar/RangeCalendarView.kt b/library/src/main/java/com/github/pelmenstar1/rangecalendar/RangeCalendarView.kt
index 5c80215..a92d7a3 100644
--- a/library/src/main/java/com/github/pelmenstar1/rangecalendar/RangeCalendarView.kt
+++ b/library/src/main/java/com/github/pelmenstar1/rangecalendar/RangeCalendarView.kt
@@ -115,12 +115,14 @@ class RangeCalendarView @JvmOverloads constructor(
         fun onPageChanged(year: Int, month: Int)
     }
 
+    // Kotlin says that there's redundant qualitifer in RangeCalendarPagerAdapter.getStyle() but it's wrong.
+    @Suppress("RemoveRedundantQualifierName")
     private class ExtractAttributesScope(
         private val calendarView: RangeCalendarView,
         private val attrs: TypedArray
     ) {
         fun color(@StyleableRes index: Int, styleType: Int) {
-            extract(
+            extractPrimitive(
                 index, styleType,
                 ::PackedInt,
                 extract = { getColor(index, 0) }
@@ -128,7 +130,7 @@ class RangeCalendarView @JvmOverloads constructor(
         }
 
         fun dimension(@StyleableRes index: Int, styleType: Int) {
-            extract(
+            extractPrimitive(
                 index, styleType,
                 ::PackedInt,
                 extract = { getDimension(index, 0f) }
@@ -136,7 +138,7 @@ class RangeCalendarView @JvmOverloads constructor(
         }
 
         fun int(@StyleableRes index: Int, styleType: Int) {
-            extract(
+            extractPrimitive(
                 index, styleType,
                 ::PackedInt,
                 extract = { getInteger(index, 0) }
@@ -144,7 +146,7 @@ class RangeCalendarView @JvmOverloads constructor(
         }
 
         fun boolean(@StyleableRes index: Int, styleType: Int) {
-            extract(
+            extractPrimitive(
                 index, styleType,
                 ::PackedInt,
                 extract = { getBoolean(index, false) }
@@ -171,7 +173,7 @@ class RangeCalendarView @JvmOverloads constructor(
             getStyle: RangeCalendarPagerAdapter.Companion.() -> Int
         ) = boolean(index, RangeCalendarPagerAdapter.getStyle())
 
-        private inline fun <T> extract(
+        private inline fun <T> extractPrimitive(
             @StyleableRes index: Int,
             styleType: Int,
             createPacked: (T) -> PackedInt,
@@ -423,6 +425,12 @@ class RangeCalendarView @JvmOverloads constructor(
                     }
                 }
 
+                // weekdays should be set via setter because additional checks should be made.
+                if (a.hasValue(R.styleable.RangeCalendarView_rangeCalendar_weekdays)) {
+                    val resId = a.getResourceId(R.styleable.RangeCalendarView_rangeCalendar_weekdays, 0)
+
+                    weekdays = resources.getStringArray(resId)
+                }
             }
         } finally {
             a.recycle()
diff --git a/library/src/main/res/values/attrs.xml b/library/src/main/res/values/attrs.xml
index 73f3f3e..226bca0 100644
--- a/library/src/main/res/values/attrs.xml
+++ b/library/src/main/res/values/attrs.xml
@@ -18,6 +18,7 @@
             <enum name="shortName" value="0"/>
             <enum name="narrowName" value="1"/>
         </attr>
+        <attr name="rangeCalendar_weekdays" format="reference"/>
         <attr name="rangeCalendar_clickOnCellSelectionBehavior" format="enum">
             <enum name="none" value="0"/>
             <enum name="clear" value="1"/>

From 244a036024913cc57a8690c158f6c46df2f47952 Mon Sep 17 00:00:00 2001
From: Oleh <pelmenstar1@gmail.com>
Date: Fri, 23 Jun 2023 15:40:24 +0300
Subject: [PATCH 5/7] Do not precompute text sizes of weekdays. Refactor the
 logic

---
 .../rangecalendar/WeekdayDataTests.kt         | 38 ++++++++----
 .../rangecalendar/CalendarResources.kt        | 39 ++----------
 .../rangecalendar/RangeCalendarGridView.kt    | 13 +---
 .../pelmenstar1/rangecalendar/WeekdayData.kt  | 60 ++++++++-----------
 .../rangecalendar/WeekdayMeasureHelper.kt     | 16 ++---
 .../pelmenstar1/rangecalendar/WeekdayRow.kt   | 60 +++++--------------
 6 files changed, 84 insertions(+), 142 deletions(-)

diff --git a/library/src/androidTest/java/com/github/pelmenstar1/rangecalendar/WeekdayDataTests.kt b/library/src/androidTest/java/com/github/pelmenstar1/rangecalendar/WeekdayDataTests.kt
index 0f1f093..6bf25d2 100644
--- a/library/src/androidTest/java/com/github/pelmenstar1/rangecalendar/WeekdayDataTests.kt
+++ b/library/src/androidTest/java/com/github/pelmenstar1/rangecalendar/WeekdayDataTests.kt
@@ -6,24 +6,42 @@ import org.junit.Test
 import org.junit.runner.RunWith
 import java.util.Locale
 import kotlin.test.assertContentEquals
+import kotlin.test.assertSame
 
 @RunWith(AndroidJUnit4::class)
 class WeekdayDataTests {
     @Suppress("UNCHECKED_CAST")
+    private fun assertContentEquals(expected: Array<out String>?, actual: Array<out String>?) {
+        // Pass null message to make Kotlin use the right method.
+        assertContentEquals(expected as Array<String>?, actual as Array<String>?, message = null)
+    }
+
     @Test
     fun getTest() {
-        val locale = Locale.ENGLISH
-        val data = WeekdayData.get(locale)
-
-        val expectedWeekdays: Array<String> = if (Build.VERSION.SDK_INT >= 24) {
-            arrayOf(
-                "Mon", "Tue", "Wed", "Thu", "Fri", "Sat", "Sun",
-                "M", "T", "W", "T", "F", "S", "S",
-            )
+        val data = WeekdayData.get(Locale.ENGLISH)
+
+        val expectedShortWeekdays = arrayOf("Mon", "Tue", "Wed", "Thu", "Fri", "Sat", "Sun")
+        val expectedNarrowWeekdays = if (Build.VERSION.SDK_INT >= 24) {
+            arrayOf( "M", "T", "W", "T", "F", "S", "S")
         } else {
-            arrayOf("Mon", "Tue", "Wed", "Thu", "Fri", "Sat", "Sun")
+            null
         }
 
-        assertContentEquals(expectedWeekdays, data.weekdays as Array<String>)
+        assertContentEquals(expectedShortWeekdays, data.shortWeekdays)
+        assertContentEquals(expectedNarrowWeekdays, data.narrowWeekdays)
+    }
+
+    @Test
+    fun getWeekdaysTest() {
+        val data = WeekdayData.get(Locale.ENGLISH)
+
+        val actualShortWeekdays = data.getWeekdays(WeekdayType.SHORT)
+        assertSame(data.shortWeekdays, actualShortWeekdays)
+
+        if (Build.VERSION.SDK_INT >= 24) {
+            val actualNarrowWeekdays = data.getWeekdays(WeekdayType.NARROW)
+
+            assertSame(data.narrowWeekdays, actualNarrowWeekdays)
+        }
     }
 }
\ No newline at end of file
diff --git a/library/src/main/java/com/github/pelmenstar1/rangecalendar/CalendarResources.kt b/library/src/main/java/com/github/pelmenstar1/rangecalendar/CalendarResources.kt
index 3873e41..5fdfbeb 100644
--- a/library/src/main/java/com/github/pelmenstar1/rangecalendar/CalendarResources.kt
+++ b/library/src/main/java/com/github/pelmenstar1/rangecalendar/CalendarResources.kt
@@ -3,8 +3,6 @@ package com.github.pelmenstar1.rangecalendar
 import android.annotation.SuppressLint
 import android.content.Context
 import android.content.res.ColorStateList
-import android.graphics.Paint
-import android.os.Build
 import com.github.pelmenstar1.rangecalendar.utils.darkerColor
 import com.github.pelmenstar1.rangecalendar.utils.getColorFromAttribute
 import com.github.pelmenstar1.rangecalendar.utils.getColorStateListFromAttribute
@@ -27,17 +25,9 @@ internal class CalendarResources(context: Context) {
 
     val dayNumberTextSize: Float
 
-    // Can only be used when text size is default one (dayNumberTextSize)
+    // It's a precomputed text sizes for day numbers using default system font and dayNumberTextSize
     val defaultDayNumberSizes: PackedSizeArray
 
-    /*
-     * These are precomputed values for default weekdayTextSize and cannot be used for another text size.
-     */
-    val defaultWeekdayWidths: FloatArray
-    val defaultShortWeekdayRowHeight: Float
-    val defaultNarrowWeekdayRowHeight: Float
-    /* ----- */
-
     val weekdayRowMarginBottom: Float
     val colorControlNormal: ColorStateList
 
@@ -62,29 +52,7 @@ internal class CalendarResources(context: Context) {
         // Compute text size of numbers in [0; 31]
         defaultDayNumberSizes = getTextBoundsArray(DAYS, dayNumberTextSize)
 
-        // First element in getShortWeekDays() is empty and actual items start from 1
-        // It's better to copy them to another array where elements start from 0
-        val locale = context.getLocaleCompat()
-
-        defaultWeekdayData = WeekdayData.get(locale)
-        val weekdays = defaultWeekdayData.weekdays
-
-        defaultWeekdayWidths = FloatArray(weekdays.size)
-
-        val defaultWeekdayPaint = Paint().apply {
-            textSize = weekdayTextSize
-            typeface = null
-        }
-
-        defaultShortWeekdayRowHeight = WeekdayMeasureHelper.computeWeekdayWidthAndMaxHeight(
-            weekdays, WeekdayData.SHORT_WEEKDAYS_OFFSET, defaultWeekdayPaint, defaultWeekdayWidths
-        )
-
-        defaultNarrowWeekdayRowHeight = if (Build.VERSION.SDK_INT >= 24) {
-            WeekdayMeasureHelper.computeWeekdayWidthAndMaxHeight(
-                weekdays, WeekdayData.NARROW_WEEKDAYS_OFFSET, defaultWeekdayPaint, defaultWeekdayWidths
-            )
-        } else Float.NaN
+        defaultWeekdayData = WeekdayData.get(context.getLocaleCompat())
     }
 
     companion object {
@@ -96,7 +64,8 @@ internal class CalendarResources(context: Context) {
         )
 
         private val SINGLE_INT_ARRAY = IntArray(1)
-        private val HOVER_STATE = intArrayOf(android.R.attr.state_hovered, android.R.attr.state_enabled)
+        private val HOVER_STATE =
+            intArrayOf(android.R.attr.state_hovered, android.R.attr.state_enabled)
         private val ENABLED_STATE = intArrayOf(android.R.attr.state_enabled)
         private val EMPTY_STATE = IntArray(0)
 
diff --git a/library/src/main/java/com/github/pelmenstar1/rangecalendar/RangeCalendarGridView.kt b/library/src/main/java/com/github/pelmenstar1/rangecalendar/RangeCalendarGridView.kt
index 1c67926..8dda2c0 100644
--- a/library/src/main/java/com/github/pelmenstar1/rangecalendar/RangeCalendarGridView.kt
+++ b/library/src/main/java/com/github/pelmenstar1/rangecalendar/RangeCalendarGridView.kt
@@ -33,10 +33,7 @@ import kotlin.math.min
 
 // It will never be XML layout, so there's no need to match conventions
 @SuppressLint("ViewConstructor")
-internal class RangeCalendarGridView(
-    context: Context,
-    val cr: CalendarResources
-) : View(context) {
+internal class RangeCalendarGridView(context: Context, val cr: CalendarResources) : View(context) {
     interface OnSelectionListener {
         fun onSelectionCleared()
         fun onSelection(range: CellRange)
@@ -327,13 +324,7 @@ internal class RangeCalendarGridView(
             style = Paint.Style.FILL
         }
 
-        weekdayRow = WeekdayRow(
-            cr.defaultShortWeekdayRowHeight,
-            cr.defaultNarrowWeekdayRowHeight,
-            cr.defaultWeekdayWidths,
-            cr.defaultWeekdayData,
-            weekdayPaint
-        )
+        weekdayRow = WeekdayRow(cr.defaultWeekdayData, weekdayPaint)
     }
 
     private inline fun updateUIState(block: () -> Unit) =
diff --git a/library/src/main/java/com/github/pelmenstar1/rangecalendar/WeekdayData.kt b/library/src/main/java/com/github/pelmenstar1/rangecalendar/WeekdayData.kt
index f7d65f6..785d49d 100644
--- a/library/src/main/java/com/github/pelmenstar1/rangecalendar/WeekdayData.kt
+++ b/library/src/main/java/com/github/pelmenstar1/rangecalendar/WeekdayData.kt
@@ -5,27 +5,17 @@ import android.os.Build
 import java.util.Calendar
 import java.util.Locale
 
-class WeekdayData(val weekdays: Array<out String>) {
-    companion object {
-        const val SHORT_WEEKDAYS_OFFSET = 0
-        const val NARROW_WEEKDAYS_OFFSET = 7
+/**
+ * Saves weekdays in short format and in narrow format (if possible). [narrowWeekdays] is always non-null when API level >= 24
+ */
+class WeekdayData(val shortWeekdays: Array<out String>, val narrowWeekdays: Array<out String>?) {
+    fun getWeekdays(type: WeekdayType): Array<out String> {
+        return if (type == WeekdayType.SHORT) shortWeekdays else narrowWeekdays!!
+    }
 
+    companion object {
         fun get(locale: Locale): WeekdayData {
-            return WeekdayData(weekdays = getWeekdays(locale))
-        }
-
-        fun getOffsetByWeekdayType(type: WeekdayType): Int {
-            return if (type == WeekdayType.SHORT) {
-                SHORT_WEEKDAYS_OFFSET
-            } else {
-                NARROW_WEEKDAYS_OFFSET
-            }
-        }
-
-        @Suppress("UNCHECKED_CAST")
-        private fun getWeekdays(locale: Locale): Array<out String> {
-            val resultArrayLength: Int
-            val shortWeekdays: Array<String>
+            var shortWeekdays: Array<String>
             var narrowWeekdays: Array<String>? = null
 
             if (Build.VERSION.SDK_INT >= 24) {
@@ -36,32 +26,32 @@ class WeekdayData(val weekdays: Array<out String>) {
                     DateFormatSymbols.FORMAT,
                     DateFormatSymbols.NARROW
                 )
-                resultArrayLength = 14
+
+                shortWeekdays = fixWeekdaysOrder(shortWeekdays)
+                narrowWeekdays = fixWeekdaysOrder(narrowWeekdays)
             } else {
                 shortWeekdays = java.text.DateFormatSymbols.getInstance(locale).shortWeekdays
-                resultArrayLength = 7
+                shortWeekdays = fixWeekdaysOrder(shortWeekdays)
             }
 
-            // Cast to array with non-null elements because in the end the array won't have any null elements.
-            val weekdays = arrayOfNulls<String>(resultArrayLength) as Array<String>
-
-            copyAndFixWeekdaysOrder(shortWeekdays, weekdays, offset = SHORT_WEEKDAYS_OFFSET)
-
-            if (narrowWeekdays != null) {
-                copyAndFixWeekdaysOrder(narrowWeekdays, weekdays, offset = NARROW_WEEKDAYS_OFFSET)
-            }
-
-            return weekdays
+            return WeekdayData(shortWeekdays, narrowWeekdays)
         }
 
+
         // In format that DateFormatSymbols returns, Sunday is the first day of the week and 0 element is null, then goes Sun, Mon, Tue, ...
         // But it's better for logic when first day of week is Monday and the elements start from 0 element.
-        // The method copies elements from source to dest with some reordering.
-        private fun copyAndFixWeekdaysOrder(source: Array<out String>, dest: Array<String>, offset: Int) {
-            System.arraycopy(source, 2, dest, offset, 6)
+        // The method creates a new array with fixed order.
+        @Suppress("UNCHECKED_CAST")
+        private fun fixWeekdaysOrder(source: Array<out String>): Array<String> {
+            // In the end, weekdays will contain only non-null elements
+            val weekdays = arrayOfNulls<String>(7) as Array<String>
+
+            System.arraycopy(source, 2, weekdays, 0, 6)
 
             // Sunday is the last day of week
-            dest[offset + 6] = source[Calendar.SUNDAY]
+            weekdays[6] = source[Calendar.SUNDAY]
+
+            return weekdays
         }
     }
 }
\ No newline at end of file
diff --git a/library/src/main/java/com/github/pelmenstar1/rangecalendar/WeekdayMeasureHelper.kt b/library/src/main/java/com/github/pelmenstar1/rangecalendar/WeekdayMeasureHelper.kt
index 5f8501d..b19f94b 100644
--- a/library/src/main/java/com/github/pelmenstar1/rangecalendar/WeekdayMeasureHelper.kt
+++ b/library/src/main/java/com/github/pelmenstar1/rangecalendar/WeekdayMeasureHelper.kt
@@ -2,17 +2,19 @@ package com.github.pelmenstar1.rangecalendar
 
 import android.graphics.Paint
 import com.github.pelmenstar1.rangecalendar.utils.getTextBoundsArray
+import kotlin.math.max
 
 object WeekdayMeasureHelper {
-    fun computeWeekdayWidthAndMaxHeight(weekdays: Array<out String>, offset: Int, paint: Paint, outWidths: FloatArray): Float {
+    fun computeWidthsAndMaxHeight(
+        weekdays: Array<out String>,
+        paint: Paint,
+        outWidths: FloatArray
+    ): Float {
         var maxHeight = -1
 
-        paint.getTextBoundsArray(weekdays, offset, offset + 7) { i, width, height ->
-            if (height > maxHeight) {
-                maxHeight = height
-            }
-
-            outWidths[i + offset] = width.toFloat()
+        paint.getTextBoundsArray(weekdays, start = 0, end = 7) { i, width, height ->
+            maxHeight = max(maxHeight, height)
+            outWidths[i] = width.toFloat()
         }
 
         return maxHeight.toFloat()
diff --git a/library/src/main/java/com/github/pelmenstar1/rangecalendar/WeekdayRow.kt b/library/src/main/java/com/github/pelmenstar1/rangecalendar/WeekdayRow.kt
index ea064d4..2067623 100644
--- a/library/src/main/java/com/github/pelmenstar1/rangecalendar/WeekdayRow.kt
+++ b/library/src/main/java/com/github/pelmenstar1/rangecalendar/WeekdayRow.kt
@@ -4,21 +4,16 @@ import android.graphics.Canvas
 import android.graphics.Paint
 
 internal class WeekdayRow(
-    private val defaultShortWeekdayRowHeight: Float,
-    private val defaultNarrowWeekdayRowHeight: Float,
-    private val defaultWeekdayWidths: FloatArray,
     private val localizedWeekdayData: WeekdayData,
     private val textPaint: Paint
 ) {
-    private var weekdayWidths: FloatArray = defaultWeekdayWidths
-
     private var isCustomWeekdays = false
-    private var weekdayData = localizedWeekdayData
+    private val currentWidths = FloatArray(7)
 
     /**
      * Height of the row, in pixels.
      */
-    var height: Float = defaultShortWeekdayRowHeight
+    var height: Float = Float.NaN
         private set
 
     /**
@@ -31,63 +26,40 @@ internal class WeekdayRow(
 
                 // Changing the type when custom weekdays are used should have no effect
                 if (!isCustomWeekdays) {
-                    // If we're still using defaultWeekdayWidths, it means that text size of weekday haven't been changed and
-                    // we can use default measurements.
-                    if (weekdayWidths === defaultWeekdayWidths) {
-                        height = if (value == WeekdayType.SHORT)
-                            defaultShortWeekdayRowHeight
-                        else
-                            defaultNarrowWeekdayRowHeight
-                    } else {
-                        onMeasurementsChanged()
-                    }
+                    _weekdays = localizedWeekdayData.getWeekdays(value)
+
+                    onMeasurementsChanged()
                 }
             }
         }
 
+    private var _weekdays: Array<out String> = localizedWeekdayData.shortWeekdays
+
     var weekdays: Array<out String>?
-        get() = weekdayData.weekdays
+        get() = _weekdays
         set(value) {
-            weekdayData = if (value == null) {
-                localizedWeekdayData
-            } else {
-                WeekdayData(value)
-            }
-
+            _weekdays = value ?: localizedWeekdayData.getWeekdays(type)
             isCustomWeekdays = value != null
 
             onMeasurementsChanged()
         }
 
-    /**
-     * The method should be called when some measurements might be changed.
-     */
-    fun onMeasurementsChanged() {
-        val offset = WeekdayData.getOffsetByWeekdayType(type)
-
-        // If weekdayWidths is default one, create a new array not to overwrite default one.
-        if (weekdayWidths === defaultWeekdayWidths) {
-            // If we can't use precomputed widths, we re-compute them only for specified weekday type, so length is 7.
-            weekdayWidths = FloatArray(7)
-        }
+    init {
+        onMeasurementsChanged()
+    }
 
-        height = WeekdayMeasureHelper.computeWeekdayWidthAndMaxHeight(
-            weekdayData.weekdays, offset, textPaint, weekdayWidths
-        )
+    fun onMeasurementsChanged() {
+        height = WeekdayMeasureHelper.computeWidthsAndMaxHeight(_weekdays, textPaint, currentWidths)
     }
 
     fun draw(c: Canvas, x: Float, columnWidth: Float) {
         var midX = x + columnWidth * 0.5f
 
-        val offset = WeekdayData.getOffsetByWeekdayType(type)
-        val widthsOffset = if (weekdayWidths === defaultWeekdayWidths) offset else 0
-
-        val weekdays = weekdayData.weekdays
         val textY = height
 
         for (i in 0 until 7) {
-            val text = weekdays[i + offset]
-            val width = weekdayWidths[i + widthsOffset]
+            val text = _weekdays[i]
+            val width = currentWidths[i]
 
             val textX = midX - width * 0.5f
 

From 8da5f8d6fb124904aa0f5e44071cf568af38f506 Mon Sep 17 00:00:00 2001
From: Oleh <pelmenstar1@gmail.com>
Date: Fri, 23 Jun 2023 17:46:59 +0300
Subject: [PATCH 6/7] Add weekdays section to README.md

---
 README.md | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

diff --git a/README.md b/README.md
index c53aa48..a534355 100644
--- a/README.md
+++ b/README.md
@@ -204,6 +204,21 @@ observer.setLifecycle(lifecycle) // If we want to unregister the observer on des
 observer.register() // The observer should be registered manually.
 ```
 
+## Weekdays
+
+By default, the calendar will use localized weekdays in 'short' format. The format of localized weekdays can be changed via `weekdayType`. Currently there's only two options:
+
+- WeekdayType.SHORT. If user locale is English, weekdays will look like: Mon, Tue, Wed, Thu, Fri, Sat, Sun
+- WeekdayType.NARROW. If user locale is English, weekdays will look like: M, T, W, T, F, S, S. **This option only works when API level >= 24. If API level is lower, weekdays in 'short' format will be used.
+
+If you want to change weekdays, it can be done via `weekdays`. 
+
+```kotlin
+rangeCalendarView.weekdays = arrayOf("0", "1", "2", "3", "4", "5", "6")
+```
+
+If you want back to using localized weekdays, pass null to `weekdays`.
+
 ## Other
 
 - `getVibrateOnSelectingCustomRange()/setVibrateOnSelectingCustomRange()` to get or set whether the device should

From 039d97de9f3a284d853e147b18d3f539322513ba Mon Sep 17 00:00:00 2001
From: Oleh <pelmenstar1@gmail.com>
Date: Fri, 23 Jun 2023 17:49:16 +0300
Subject: [PATCH 7/7] Fix README.md

---
 README.md | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/README.md b/README.md
index a534355..6335d6f 100644
--- a/README.md
+++ b/README.md
@@ -208,10 +208,10 @@ observer.register() // The observer should be registered manually.
 
 By default, the calendar will use localized weekdays in 'short' format. The format of localized weekdays can be changed via `weekdayType`. Currently there's only two options:
 
-- WeekdayType.SHORT. If user locale is English, weekdays will look like: Mon, Tue, Wed, Thu, Fri, Sat, Sun
-- WeekdayType.NARROW. If user locale is English, weekdays will look like: M, T, W, T, F, S, S. **This option only works when API level >= 24. If API level is lower, weekdays in 'short' format will be used.
+- `WeekdayType.SHORT`. If user locale is English, weekdays will look like: Mon, Tue, Wed, Thu, Fri, Sat, Sun
+- `WeekdayType.NARROW`. If user locale is English, weekdays will look like: M, T, W, T, F, S, S. **This option only works when API level >= 24. If API level is lower, weekdays in 'short' format will be used.**
 
-If you want to change weekdays, it can be done via `weekdays`. 
+If you want to change weekdays, it can be done via `weekdays`:
 
 ```kotlin
 rangeCalendarView.weekdays = arrayOf("0", "1", "2", "3", "4", "5", "6")