🐛 Fix function graph
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@@ -32,10 +32,8 @@ class _GraphCardState extends State<GraphCard> {
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double? _manualY;
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/// 生成函数图表的点
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({List<FlSpot> leftPoints, List<FlSpot> rightPoints}) _generatePlotPoints(
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String expression,
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double zoomFactor,
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) {
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({List<FlSpot> leftPoints, List<FlSpot> rightPoints, bool shouldSplit})
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_generatePlotPoints(String expression, double zoomFactor) {
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try {
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// 使用solver准备函数表达式（展开因式形式）
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String functionExpr = _solverService.prepareFunctionForGraphing(
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@@ -44,7 +42,7 @@ class _GraphCardState extends State<GraphCard> {
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// 如果表达式不包含 x，返回空列表
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if (!functionExpr.contains('x') && !functionExpr.contains('X')) {
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return (leftPoints: [], rightPoints: []);
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return (leftPoints: [], rightPoints: [], shouldSplit: false);
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}
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// 预处理表达式，确保格式正确
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@@ -72,6 +70,18 @@ class _GraphCardState extends State<GraphCard> {
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final parser = Parser(functionExpr);
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final expr = parser.parse();
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// 检查函数在 x=0 处是否有垂直渐近线
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bool hasVerticalAsymptoteAtZero = false;
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try {
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final substituted = expr.substitute('x', DoubleExpr(0.0));
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final evaluated = substituted.evaluate();
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if (evaluated is DoubleExpr) {
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hasVerticalAsymptoteAtZero = !evaluated.value.isFinite;
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}
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} catch (e) {
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hasVerticalAsymptoteAtZero = true;
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}
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// 根据缩放因子动态调整范围和步长
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final range = 10.0 * zoomFactor;
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final step = max(0.01, 0.05 / zoomFactor); // 更小的步长以获得更好的分辨率
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@@ -79,6 +89,7 @@ class _GraphCardState extends State<GraphCard> {
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// 生成点
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List<FlSpot> leftPoints = [];
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List<FlSpot> rightPoints = [];
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List<FlSpot> allPoints = [];
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for (double i = -range; i <= range; i += step) {
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// 跳过 x = 0 以避免在 y=1/x 等函数中的奇点
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if (i.abs() < 1e-10) continue;
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@@ -91,10 +102,14 @@ class _GraphCardState extends State<GraphCard> {
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if (evaluated is DoubleExpr) {
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final y = evaluated.value;
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if (y.isFinite && y.abs() <= 100.0) {
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if (i < 0) {
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leftPoints.add(FlSpot(i, y));
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} else {
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rightPoints.add(FlSpot(i, y));
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final spot = FlSpot(i, y);
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allPoints.add(spot);
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if (hasVerticalAsymptoteAtZero) {
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if (i < 0) {
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leftPoints.add(spot);
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} else {
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rightPoints.add(spot);
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}
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}
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}
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}
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@@ -104,17 +119,30 @@ class _GraphCardState extends State<GraphCard> {
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}
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}
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// 排序点按 x 值
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leftPoints.sort((a, b) => a.x.compareTo(b.x));
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rightPoints.sort((a, b) => a.x.compareTo(b.x));
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if (hasVerticalAsymptoteAtZero) {
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// 排序点按 x 值
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leftPoints.sort((a, b) => a.x.compareTo(b.x));
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rightPoints.sort((a, b) => a.x.compareTo(b.x));
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debugPrint(
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'Generated ${leftPoints.length} left dots and ${rightPoints.length} right dots with zoom factor $zoomFactor',
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);
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return (leftPoints: leftPoints, rightPoints: rightPoints);
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debugPrint(
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'Generated ${leftPoints.length} left dots and ${rightPoints.length} right dots with zoom factor $zoomFactor (split due to asymptote)',
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);
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return (
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leftPoints: leftPoints,
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rightPoints: rightPoints,
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shouldSplit: true,
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);
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} else {
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// 不需要分割，直接返回所有点
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allPoints.sort((a, b) => a.x.compareTo(b.x));
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debugPrint(
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'Generated ${allPoints.length} dots with zoom factor $zoomFactor (no split)',
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);
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return (leftPoints: allPoints, rightPoints: [], shouldSplit: false);
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}
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} catch (e) {
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debugPrint('Error generating plot points: $e');
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return (leftPoints: [], rightPoints: []);
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return (leftPoints: [], rightPoints: [], shouldSplit: false);
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}
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}
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@@ -280,7 +308,11 @@ class _GraphCardState extends State<GraphCard> {
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height: 340,
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child: Builder(
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builder: (context) {
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final (:leftPoints, :rightPoints) = _generatePlotPoints(
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final (
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:leftPoints,
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:rightPoints,
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:shouldSplit,
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) = _generatePlotPoints(
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widget.expression,
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widget.zoomFactor,
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);
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@@ -383,26 +415,44 @@ class _GraphCardState extends State<GraphCard> {
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},
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),
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),
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lineBarsData: [
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if (leftPoints.isNotEmpty)
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LineChartBarData(
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spots: leftPoints,
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isCurved: true,
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color: Theme.of(context).colorScheme.primary,
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barWidth: 3,
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belowBarData: BarAreaData(show: false),
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dotData: FlDotData(show: false),
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),
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if (rightPoints.isNotEmpty)
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LineChartBarData(
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spots: rightPoints,
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isCurved: true,
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color: Theme.of(context).colorScheme.primary,
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barWidth: 3,
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belowBarData: BarAreaData(show: false),
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dotData: FlDotData(show: false),
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),
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],
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lineBarsData: shouldSplit
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? [
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if (leftPoints.isNotEmpty)
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LineChartBarData(
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spots: leftPoints,
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isCurved: true,
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color: Theme.of(
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context,
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).colorScheme.primary,
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barWidth: 3,
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belowBarData: BarAreaData(show: false),
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dotData: FlDotData(show: false),
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),
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if (rightPoints.isNotEmpty)
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LineChartBarData(
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spots: rightPoints,
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isCurved: true,
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color: Theme.of(
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context,
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).colorScheme.primary,
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barWidth: 3,
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belowBarData: BarAreaData(show: false),
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dotData: FlDotData(show: false),
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),
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]
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: [
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if (leftPoints.isNotEmpty)
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LineChartBarData(
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spots: leftPoints,
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isCurved: true,
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color: Theme.of(
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context,
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).colorScheme.primary,
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barWidth: 3,
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belowBarData: BarAreaData(show: false),
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dotData: FlDotData(show: false),
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),
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],
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minX: bounds.minX,
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maxX: bounds.maxX,
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minY: bounds.minY,
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