refactor: make TabPosition opened and use TabRow to manage TabIndicator

flexiui-core/src/commonMain/kotlin/com/highcapable/flexiui/component/Tab.kt

@@ -19,7 +19,7 @@
  *
  * This file is created by fankes on 2023/11/9.
  */
-@file:Suppress("unused")
+@file:Suppress("unused", "MemberVisibilityCanBePrivate")
 
 package com.highcapable.flexiui.component
 
@@ -102,25 +102,7 @@ fun TabRow(
     modifier: Modifier = Modifier,
     colors: TabColors = Tab.colors,
     style: TabStyle = Tab.style,
-    tabs: @Composable () -> Unit
+    indicator: @Composable TabRow.() -> Unit = { TabIndicator(modifier = Modifier.tabIndicatorOffset()) },
-) {
-    TabRow(
-        selectedTabIndex = selectedTabIndex,
-        modifier = modifier,
-        colors = colors,
-        style = style,
-        pagerState = null,
-        tabs = tabs
-    )
-}
-
-@Composable
-fun TabRow(
-    selectedTabIndex: Int = 0,
-    modifier: Modifier = Modifier,
-    colors: TabColors = Tab.colors,
-    style: TabStyle = Tab.style,
-    pagerState: PagerState?,
     tabs: @Composable () -> Unit
 ) {
     TabStyleBox(modifier, colors, style) {
@@ -145,7 +127,7 @@ fun TabRow(
                     placeable.placeRelative(x = index * tabAverageWidth, y = 0)
                 }
                 subcompose(TabSlots.Indicator) {
-                    TabIndicator(selectedTabIndex, colors, style, pagerState, tabPositions)
+                    indicator(TabRow(selectedTabIndex, colors, style, tabPositions))
                 }.forEach {
                     it.measure(Constraints.fixed(tabRowWidth, tabRowHeight)).placeRelative(x = 0, y = 0)
                 }
@@ -161,27 +143,7 @@ fun ScrollableTabRow(
     colors: TabColors = Tab.colors,
     style: TabStyle = Tab.style,
     scrollState: ScrollState = rememberScrollState(),
-    tabs: @Composable () -> Unit
+    indicator: @Composable TabRow.() -> Unit = { TabIndicator(modifier = Modifier.tabIndicatorOffset()) },
-) {
-    ScrollableTabRow(
-        selectedTabIndex = selectedTabIndex,
-        modifier = modifier,
-        colors = colors,
-        style = style,
-        pagerState = null,
-        scrollState = scrollState,
-        tabs = tabs
-    )
-}
-
-@Composable
-fun ScrollableTabRow(
-    selectedTabIndex: Int = 0,
-    modifier: Modifier = Modifier,
-    colors: TabColors = Tab.colors,
-    style: TabStyle = Tab.style,
-    pagerState: PagerState?,
-    scrollState: ScrollState = rememberScrollState(),
     tabs: @Composable () -> Unit
 ) {
     TabStyleBox(modifier, colors, style) {
@@ -214,7 +176,7 @@ fun ScrollableTabRow(
                     tabLeft += placeables.width
                 }
                 subcompose(TabSlots.Indicator) {
-                    TabIndicator(selectedTabIndex, colors, style, pagerState, tabPositions)
+                    indicator(TabRow(selectedTabIndex, colors, style, tabPositions))
                 }.forEach {
                     it.measure(Constraints.fixed(layoutWidth, layoutHeight)).placeRelative(x = 0, y = 0)
                 }
@@ -271,23 +233,6 @@ fun Tab(
     }
 }
 
-@Composable
-private fun TabIndicator(
-    selectedTabIndex: Int,
-    colors: TabColors,
-    style: TabStyle,
-    pagerState: PagerState?,
-    tabPositions: List<TabPosition>
-) {
-    val indicatorModifier = pagerState?.let { Modifier.pagerTabIndicatorOffset(it, tabPositions, style.indicatorWidth) }
-        ?: Modifier.tabIndicatorOffset(tabPositions[selectedTabIndex], style.indicatorWidth)
-    Box(
-        modifier = Modifier.then(indicatorModifier)
-            .height(style.indicatorHeight)
-            .background(colors.indicatorColor, style.indicatorShape)
-    )
-}
-
 @Composable
 private fun TabStyleBox(
     modifier: Modifier,
@@ -311,16 +256,42 @@ private fun rememberScrollableTabData(scrollState: ScrollState): ScrollableTabDa
     return remember(scrollState, coroutineScope) { ScrollableTabData(scrollState, coroutineScope) }
 }
 
-private fun Modifier.tabIndicatorOffset(
+@Immutable
-    currentTabPosition: TabPosition,
+data class TabPosition(val left: Dp, val width: Dp, val tabWidth: Dp) {
-    indicatorWidth: Dp
+
-) = composed(
+    val right get() = left + width
+
+    fun calculateCenter(currentWidth: Dp) = left + width / 2 - currentWidth / 2
+}
+
+@Stable
+class TabRow internal constructor(
+    val selectedTabIndex: Int,
+    val colors: TabColors,
+    val style: TabStyle,
+    val tabPositions: List<TabPosition>
+) {
+
+    @Composable
+    fun TabIndicator(
+        modifier: Modifier = Modifier,
+        color: Color = colors.indicatorColor,
+        height: Dp = style.indicatorHeight,
+        shape: Shape = style.indicatorShape
+    ) {
+        Box(modifier.height(height).background(color, shape))
+    }
+
+    fun Modifier.tabIndicatorOffset(
+        currentTabPosition: TabPosition = tabPositions[selectedTabIndex],
+        indicatorWidth: Dp = style.indicatorWidth
+    ) = composed(
         inspectorInfo = debugInspectorInfo {
             name = "tabIndicatorOffset"
             properties["currentTabPosition"] = currentTabPosition
             properties["indicatorWidth"] = indicatorWidth
         }
-) {
+    ) {
         val currentWidth = indicatorWidth.orElse() ?: currentTabPosition.tabWidth
         val animatedWidh by animateDpAsState(
             targetValue = currentWidth,
@@ -334,20 +305,20 @@ private fun Modifier.tabIndicatorOffset(
             .wrapContentSize(Alignment.BottomStart)
             .offset(x = animatedOffsetX)
             .width(animatedWidh)
-}
+    }
 
-private fun Modifier.pagerTabIndicatorOffset(
+    fun Modifier.pagerTabIndicatorOffset(
         pagerState: PagerState,
-    tabPositions: List<TabPosition>,
+        tabPositions: List<TabPosition> = this@TabRow.tabPositions,
-    indicatorWidth: Dp
+        indicatorWidth: Dp = style.indicatorWidth
-) = composed(
+    ) = composed(
         inspectorInfo = debugInspectorInfo {
             name = "pagerTabIndicatorOffset"
             properties["pagerState"] = pagerState
             properties["tabPositions"] = tabPositions
             properties["indicatorWidth"] = indicatorWidth
         }
-) {
+    ) {
         layout { measurable, constraints ->
             // If there are no pages, nothing to show.
             if (tabPositions.isEmpty()) return@layout layout(constraints.maxWidth, 0) {}
@@ -386,6 +357,7 @@ private fun Modifier.pagerTabIndicatorOffset(
             val measureHeight = maxOf(placeable.height, constraints.minHeight)
             layout(measureWidth, measureHeight) { placeable.placeRelative(movableOffsetX, offsetY) }
         }
+    }
 }
 
 @Stable
@@ -433,14 +405,6 @@ private class ScrollableTabData(private val scrollState: ScrollState, private va
         }
 }
 
-@Immutable
-private data class TabPosition(val left: Dp, val width: Dp, val tabWidth: Dp) {
-
-    val right get() = left + width
-
-    fun calculateCenter(currentWidth: Dp) = left + width / 2 - currentWidth / 2
-}
-
 @Stable
 private enum class TabSlots { Tabs, TabsAverage, Indicator }