fix ios line gradient crash and LineChart popup IOOBE

compose-charts/src/commonMain/kotlin/ir/ehsannarmani/compose_charts/LineChart.kt

@@ -264,8 +264,11 @@ fun LineChart(
             val properties = line.popupProperties ?: popupProperties
             if (!properties.enabled) return@forEachIndexed
 
+            if (line.values.isEmpty()) return@forEachIndexed
+            val pathData = linesPathData.getOrNull(dataIndex) ?: return@forEachIndexed
+            if (pathData.xPositions.isEmpty()) return@forEachIndexed
+
             val positionX = position.x.coerceIn(0f, size.width.toFloat())
-            val pathData = linesPathData[dataIndex]
 
             val isSingleValue =  line.values.count() == 1
 

compose-charts/src/commonMain/kotlin/ir/ehsannarmani/compose_charts/extensions/line_chart/Gradient.kt

@@ -1,10 +1,11 @@
 package ir.ehsannarmani.compose_charts.extensions.line_chart
 
-import androidx.compose.ui.geometry.Offset
 import androidx.compose.ui.geometry.Size
-import androidx.compose.ui.graphics.*
+import androidx.compose.ui.graphics.Brush
+import androidx.compose.ui.graphics.Color
+import androidx.compose.ui.graphics.Path
+import androidx.compose.ui.graphics.TileMode
 import androidx.compose.ui.graphics.drawscope.DrawScope
-import androidx.compose.ui.graphics.drawscope.drawIntoCanvas
 
 internal fun DrawScope.drawLineGradient(
     path: Path,
@@ -13,25 +14,25 @@ internal fun DrawScope.drawLineGradient(
     progress: Float,
     size: Size? = null,
     startOffset: Float,
-    endOffset: Float
+    endOffset: Float,
 ) {
     val _size = size ?: this.size
-    drawIntoCanvas {
-        val p = Path()
-        p.addPath(path)
-        p.lineTo(endOffset, _size.height)
-        p.lineTo(startOffset, _size.height)
-        p.close()
-        val paint = Paint()
-        paint.shader = LinearGradientShader(
-            Offset(0f, 0f),
-            Offset(0f, _size.height),
-            listOf(
+    val filled = Path().apply {
+        addPath(path)
+        lineTo(endOffset, _size.height)
+        lineTo(startOffset, _size.height)
+        close()
+    }
+    drawPath(
+        path = filled,
+        brush = Brush.verticalGradient(
+            colors = listOf(
                 color1.copy(alpha = color1.alpha * progress),
                 color2.copy(alpha = color2.alpha * progress),
             ),
-            tileMode = TileMode.Mirror
-        )
-        it.drawPath(p, paint)
-    }
-}
+            startY = 0f,
+            endY = _size.height,
+            tileMode = TileMode.Mirror,
+        ),
+    )
+}