Fixing texts alignments in RTL (Arabic, Persian, ...)

core/src/main/java/com/alamkanak/weekview/CanvasExtensions.kt

@@ -16,6 +16,19 @@ internal fun Canvas.draw(staticLayout: StaticLayout) {
     staticLayout.draw(this)
 }
 
+internal fun Canvas.drawRtl(staticLayout: StaticLayout) {
+    staticLayout.text.split("\n").forEachIndexed { index, text ->
+        val textPaint = staticLayout.paint
+        val xPos: Int = staticLayout.width / 2
+        drawText(
+            text,
+            xPos.toFloat(),
+            ((staticLayout.height / 2) * (index + 1) - (textPaint.descent() + textPaint.ascent()) / 2),
+            textPaint
+        )
+    }
+}
+
 internal fun Canvas.drawVerticalLine(
     horizontalOffset: Float,
     startY: Float,

core/src/main/java/com/alamkanak/weekview/EventChipDrawer.kt

@@ -137,11 +137,7 @@ internal class EventChipDrawer(
     ) {
         val bounds = eventChip.bounds
 
-        val horizontalOffset = if (viewState.isLtr) {
-            bounds.left + viewState.eventPaddingHorizontal
-        } else {
-            bounds.right - viewState.eventPaddingHorizontal
-        }
+        val horizontalOffset = bounds.left + viewState.eventPaddingHorizontal
 
         val verticalOffset = if (eventChip.event.isAllDay) {
             (bounds.height() - textLayout.height) / 2f

core/src/main/java/com/alamkanak/weekview/HeaderRenderer.kt

@@ -173,11 +173,16 @@ private class DateLabelsDrawer(
         val key = date.toEpochDays()
         val textLayout = dateLabelLayouts[key]
 
+        val offset = if (textLayout.text.toString().isArabic()) 0f else viewState.dayWidth / 2f
         withTranslation(
-            x = startPixel + viewState.dayWidth / 2f,
+            x = startPixel + offset,
             y = viewState.headerPadding,
         ) {
-            draw(textLayout)
+            if (textLayout.text.toString().isArabic()) {
+                drawRtl(textLayout)
+            } else {
+                draw(textLayout)
+            }
         }
     }
 }

core/src/main/java/com/alamkanak/weekview/TextExtensions.kt

@@ -43,11 +43,21 @@ internal fun CharSequence.semibold() = SpannableString(this).apply {
 
 internal fun ViewState.getTextPaint(event: ResolvedWeekViewEntity): TextPaint {
     val textPaint = TextPaint(if (event.isAllDay) allDayEventTextPaint else eventTextPaint)
-    textPaint.textAlign = if (isLtr) Paint.Align.LEFT else Paint.Align.RIGHT
+    textPaint.textAlign = Paint.Align.LEFT
 
     val textColor = event.style.textColor
     if (textColor != null) {
         textPaint.color = textColor
     }
     return textPaint
 }
+
+internal fun String.isArabic(): Boolean {
+    var i = 0
+    while (i < this.length) {
+        val c = this.codePointAt(i)
+        if (c in 0x0600..0x06E0) return true
+        i += Character.charCount(c)
+    }
+    return false
+}

core/src/main/java/com/alamkanak/weekview/TimeColumnRenderer.kt

@@ -1,6 +1,7 @@
 package com.alamkanak.weekview
 
 import android.graphics.Canvas
+import android.text.Layout
 import android.text.StaticLayout
 import android.util.SparseArray
 
@@ -89,7 +90,8 @@ internal class TimeColumnRenderer(
         val textLayouts = mutableListOf<StaticLayout>()
 
         for (hour in displayedHours) {
-            val textLayout = timeFormatter(hour).toTextLayout(timeColumnTextPaint, width = Int.MAX_VALUE)
+            val alignment = if (timeFormatter(hour).isArabic()) Layout.Alignment.ALIGN_OPPOSITE else Layout.Alignment.ALIGN_NORMAL
+            val textLayout = timeFormatter(hour).toTextLayout(timeColumnTextPaint, width = Int.MAX_VALUE, alignment = alignment)
             textLayouts += textLayout
             timeLabelLayouts.put(hour, textLayout)
         }