🚀 Launch 1.0.0+4

android/app/src/main/AndroidManifest.xml

@@ -1,6 +1,6 @@
 <manifest xmlns:android="http://schemas.android.com/apk/res/android">
     <application
-        android:label="simple_math_calc"
+        android:label="SimpleMathCalc"
         android:name="${applicationName}"
         android:icon="@mipmap/launcher_icon">
         <activity

lib/screens/calculator_home_page.dart

@@ -1,9 +1,9 @@
-import 'package:flutter/foundation.dart';
 import 'package:flutter/material.dart';
-import 'package:google_fonts/google_fonts.dart';
 import 'package:latext/latext.dart';
 import 'package:simple_math_calc/models/calculation_step.dart';
 import 'package:simple_math_calc/solver.dart';
+import 'package:fl_chart/fl_chart.dart';
+import 'package:math_expressions/math_expressions.dart' as math_expressions;
 import 'dart:math';
 
 class CalculatorHomePage extends StatefulWidget {
@@ -20,25 +20,141 @@ class _CalculatorHomePageState extends State<CalculatorHomePage> {
 
   CalculationResult? _result;
   bool _isLoading = false;
-  bool _isInputFocused = false;
+  double _zoomFactor = 1.0;
 
   @override
   void initState() {
     super.initState();
     _focusNode = FocusNode();
-    _focusNode.addListener(() {
-      setState(() {
-        _isInputFocused = _focusNode.hasFocus;
-      });
-    });
+    _controller.addListener(_onTextChanged);
   }
 
   @override
   void dispose() {
+    _controller.removeListener(_onTextChanged);
     _focusNode.dispose();
     super.dispose();
   }
 
+  void _onTextChanged() {
+    setState(() {});
+  }
+
+  /// 生成函数图表的点
+  List<FlSpot> _generatePlotPoints(String expression, double zoomFactor) {
+    try {
+      // 如果是方程，取左边作为函数
+      String functionExpr = expression;
+      if (expression.contains('=')) {
+        functionExpr = expression.split('=')[0].trim();
+      }
+
+      // 如果表达式不包含 x，返回空列表
+      if (!functionExpr.contains('x') && !functionExpr.contains('X')) {
+        return [];
+      }
+
+      // 预处理表达式，确保格式正确
+      functionExpr = functionExpr.replaceAll(' ', '');
+
+      // 在数字和变量之间插入乘号
+      functionExpr = functionExpr.replaceAllMapped(
+        RegExp(r'(\d)([a-zA-Z])'),
+        (match) => '${match.group(1)}*${match.group(2)}',
+      );
+
+      // 在变量和数字之间插入乘号 (如 x2 -> x*2)
+      functionExpr = functionExpr.replaceAllMapped(
+        RegExp(r'([a-zA-Z])(\d)'),
+        (match) => '${match.group(1)}*${match.group(2)}',
+      );
+
+      // 解析表达式
+      final parser = math_expressions.ShuntingYardParser();
+      final expr = parser.parse(functionExpr);
+
+      // 创建变量 x
+      final x = math_expressions.Variable('x');
+
+      // 根据缩放因子动态调整范围和步长
+      final range = 10.0 * zoomFactor;
+      final step = max(0.05, 0.2 / zoomFactor); // 缩放时步长更小，放大时步长更大
+
+      // 生成点
+      List<FlSpot> points = [];
+      for (double i = -range; i <= range; i += step) {
+        try {
+          final context = math_expressions.ContextModel()
+            ..bindVariable(x, math_expressions.Number(i));
+          final evaluator = math_expressions.RealEvaluator(context);
+          final y = evaluator.evaluate(expr);
+
+          if (y.isFinite && !y.isNaN) {
+            points.add(FlSpot(i, y.toDouble()));
+          }
+        } catch (e) {
+          // 跳过无法计算的点
+          continue;
+        }
+      }
+
+      // 如果没有足够的点，返回空列表
+      if (points.length < 2) {
+        debugPrint('Generated ${points.length} dots');
+        return [];
+      }
+
+      // 排序点按 x 值
+      points.sort((a, b) => a.x.compareTo(b.x));
+
+      debugPrint(
+        'Generated ${points.length} dots with zoom factor $zoomFactor',
+      );
+      return points;
+    } catch (e) {
+      debugPrint('Error generating plot points: $e');
+      return [];
+    }
+  }
+
+  /// 计算图表的数据范围
+  ({double minX, double maxX, double minY, double maxY}) _calculateChartBounds(
+    List<FlSpot> points,
+    double zoomFactor,
+  ) {
+    if (points.isEmpty) {
+      return (
+        minX: -10 * zoomFactor,
+        maxX: 10 * zoomFactor,
+        minY: -50 * zoomFactor,
+        maxY: 50 * zoomFactor,
+      );
+    }
+
+    double minX = points.first.x;
+    double maxX = points.first.x;
+    double minY = points.first.y;
+    double maxY = points.first.y;
+
+    for (final point in points) {
+      minX = min(minX, point.x);
+      maxX = max(maxX, point.x);
+      minY = min(minY, point.y);
+      maxY = max(maxY, point.y);
+    }
+
+    // 添加边距
+    final xPadding = (maxX - minX) * 0.1;
+    final yPadding = (maxY - minY) * 0.1;
+
+    return (
+      minX: minX - xPadding,
+      maxX: maxX + xPadding,
+      minY: minY - yPadding,
+      maxY: maxY + yPadding,
+    );
+  }
+
   void _solveEquation() {
     if (_controller.text.isEmpty) {
       return;
@@ -69,21 +185,23 @@ class _CalculatorHomePageState extends State<CalculatorHomePage> {
     }
   }
 
-  void _insertSymbol(String symbol) {
-    final text = _controller.text;
-    final selection = _controller.selection;
-    final newText = text.replaceRange(selection.start, selection.end, symbol);
-    _controller.text = newText;
-    _controller.selection = TextSelection.collapsed(
-      offset: selection.start + symbol.length,
-    );
+  void _zoomIn() {
+    setState(() {
+      _zoomFactor = (_zoomFactor * 0.8).clamp(0.1, 10.0);
+    });
+  }
+
+  void _zoomOut() {
+    setState(() {
+      _zoomFactor = (_zoomFactor * 1.25).clamp(0.1, 10.0);
+    });
   }
 
   @override
   Widget build(BuildContext context) {
     return Scaffold(
       appBar: AppBar(
-        title: const Text('方程与表达式计算器'),
+        title: const Text('计算器'),
         centerTitle: false,
         leading: const Icon(Icons.calculate_outlined),
       ),
@@ -105,12 +223,10 @@ class _CalculatorHomePageState extends State<CalculatorHomePage> {
                       floatingLabelAlignment: FloatingLabelAlignment.center,
                       hintText: '例如: 2x^2 - 8x + 6 = 0',
                     ),
-                    keyboardType: kIsWeb
-                        ? TextInputType.numberWithOptions(
+                    keyboardType: TextInputType.numberWithOptions(
                       signed: true,
                       decimal: true,
-                          )
-                        : TextInputType.number,
+                    ),
                     onSubmitted: (_) => _solveEquation(),
                   ),
                 ),
@@ -128,7 +244,6 @@ class _CalculatorHomePageState extends State<CalculatorHomePage> {
                 ? const Center(child: Text('请输入方程开始计算'))
                 : buildResultView(_result!),
           ),
-          if (_isInputFocused) _buildToolbar(),
         ],
       ),
     );
@@ -239,155 +354,107 @@ class _CalculatorHomePageState extends State<CalculatorHomePage> {
             ),
           ),
         ),
-      ],
-    );
-  }
-
-  Widget _buildToolbar() {
-    return Material(
-      elevation: 8,
+        const SizedBox(height: 16),
+        Card(
           child: Padding(
-        padding: const EdgeInsets.symmetric(horizontal: 8.0, vertical: 8),
+            padding: const EdgeInsets.all(16.0),
             child: Column(
-          mainAxisSize: MainAxisSize.min,
               children: [
                 Row(
-              mainAxisAlignment: MainAxisAlignment.spaceEvenly,
-              spacing: 8,
+                  mainAxisAlignment: MainAxisAlignment.spaceBetween,
                   children: [
-                Expanded(
-                  child: Tooltip(
-                    message: '左括号',
-                    child: FilledButton.tonal(
-                      onPressed: () => _insertSymbol('('),
-                      child: Text('(', style: GoogleFonts.robotoMono()),
+                    Padding(
+                      padding: const EdgeInsets.only(left: 4),
+                      child: Text(
+                        '函数图像',
+                        style: Theme.of(context).textTheme.titleMedium,
                       ),
                     ),
-                ),
-                Expanded(
-                  child: Tooltip(
-                    message: '右括号',
-                    child: FilledButton.tonal(
-                      onPressed: () => _insertSymbol(')'),
-                      child: Text(')', style: GoogleFonts.robotoMono()),
-                    ),
-                  ),
-                ),
-                Expanded(
-                  child: Tooltip(
-                    message: '幂符号',
-                    child: FilledButton.tonal(
-                      onPressed: () => _insertSymbol('^'),
-                      child: Text('^', style: GoogleFonts.robotoMono()),
-                    ),
-                  ),
-                ),
-                Expanded(
-                  child: Tooltip(
-                    message: '平方',
-                    child: FilledButton.tonal(
-                      onPressed: () => _insertSymbol('^2'),
-                      child: Text('²', style: GoogleFonts.robotoMono()),
-                    ),
-                  ),
-                ),
-                Expanded(
-                  child: Tooltip(
-                    message: '未知数',
-                    child: FilledButton.tonal(
-                      onPressed: () => _insertSymbol('x'),
-                      child: Text('x', style: GoogleFonts.robotoMono()),
-                    ),
-                  ),
-                ),
-                Expanded(
-                  child: Tooltip(
-                    message: '未知数二号',
-                    child: FilledButton.tonal(
-                      onPressed: () => _insertSymbol('y'),
-                      child: Text('y', style: GoogleFonts.robotoMono()),
-                    ),
-                  ),
-                ),
-              ],
-            ),
-            const SizedBox(height: 8),
                     Row(
-              mainAxisAlignment: MainAxisAlignment.spaceEvenly,
-              spacing: 8,
+                      mainAxisAlignment: MainAxisAlignment.center,
                       children: [
-                Expanded(
-                  child: Tooltip(
-                    message: '加法',
-                    child: FilledButton.tonal(
-                      onPressed: () => _insertSymbol('+'),
-                      child: Text('+', style: GoogleFonts.robotoMono()),
-                    ),
-                  ),
-                ),
-                Expanded(
-                  child: Tooltip(
-                    message: '减法',
-                    child: FilledButton.tonal(
-                      onPressed: () => _insertSymbol('-'),
-                      child: Text('-', style: GoogleFonts.robotoMono()),
-                    ),
-                  ),
-                ),
-                Expanded(
-                  child: Tooltip(
-                    message: '乘法',
-                    child: FilledButton.tonal(
-                      onPressed: () => _insertSymbol('*'),
-                      child: Text('*', style: GoogleFonts.robotoMono()),
-                    ),
-                  ),
-                ),
-                Expanded(
-                  child: Tooltip(
-                    message: '除法',
-                    child: FilledButton.tonal(
-                      onPressed: () => _insertSymbol('/'),
-                      child: Text('/', style: GoogleFonts.robotoMono()),
-                    ),
-                  ),
-                ),
-                Expanded(
-                  child: Tooltip(
-                    message: '小数点',
-                    child: FilledButton.tonal(
-                      onPressed: () => _insertSymbol('.'),
-                      child: Text('.', style: GoogleFonts.robotoMono()),
-                    ),
-                  ),
-                ),
-                Expanded(
-                  child: Tooltip(
-                    message: '等于号',
-                    child: FilledButton.tonal(
-                      onPressed: () => _insertSymbol('='),
-                      child: Text('=', style: GoogleFonts.robotoMono()),
-                    ),
-                  ),
-                ),
-              ],
-            ),
-            if (!kIsWeb) const SizedBox(height: 8),
-            if (!kIsWeb)
-              Row(
-                children: [
-                  Expanded(
-                    child: FilledButton.icon(
-                      icon: const Icon(Icons.keyboard_hide),
-                      onPressed: () => _focusNode.unfocus(),
-                      label: Text('收起键盘'),
+                        IconButton(
+                          onPressed: _zoomIn,
+                          icon: Icon(Icons.zoom_in),
+                          tooltip: '放大',
+                          padding: EdgeInsets.zero,
+                          visualDensity: VisualDensity.compact,
                         ),
+                        IconButton(
+                          onPressed: _zoomOut,
+                          icon: Icon(Icons.zoom_out),
+                          tooltip: '缩小',
+                          padding: EdgeInsets.zero,
+                          visualDensity: VisualDensity.compact,
                         ),
                       ],
                     ),
                   ],
                 ),
+                const SizedBox(height: 24),
+                SizedBox(
+                  height: 340,
+                  child: Builder(
+                    builder: (context) {
+                      final points = _generatePlotPoints(
+                        _controller.text,
+                        _zoomFactor,
+                      );
+                      final bounds = _calculateChartBounds(points, _zoomFactor);
+
+                      return LineChart(
+                        LineChartData(
+                          gridData: FlGridData(show: true),
+                          titlesData: FlTitlesData(
+                            leftTitles: AxisTitles(
+                              sideTitles: SideTitles(
+                                showTitles: true,
+                                reservedSize: 40,
                               ),
+                            ),
+                            bottomTitles: AxisTitles(
+                              sideTitles: SideTitles(
+                                showTitles: true,
+                                reservedSize: 30,
+                              ),
+                            ),
+                            topTitles: AxisTitles(
+                              sideTitles: SideTitles(showTitles: false),
+                            ),
+                            rightTitles: AxisTitles(
+                              sideTitles: SideTitles(showTitles: false),
+                            ),
+                          ),
+                          borderData: FlBorderData(
+                            show: true,
+                            border: Border.all(
+                              color: Theme.of(context).colorScheme.outline,
+                            ),
+                          ),
+                          lineBarsData: [
+                            LineChartBarData(
+                              spots: points,
+                              isCurved: true,
+                              color: Theme.of(context).colorScheme.primary,
+                              barWidth: 3,
+                              belowBarData: BarAreaData(show: false),
+                              dotData: FlDotData(show: false),
+                            ),
+                          ],
+                          minX: bounds.minX,
+                          maxX: bounds.maxX,
+                          minY: bounds.minY,
+                          maxY: bounds.maxY,
+                        ),
+                      );
+                    },
+                  ),
+                ),
+              ],
+            ),
+          ),
+        ),
+      ],
     );
   }
 }

lib/solver.dart

@@ -277,10 +277,9 @@ class SolverService {
 
     final deltaDouble = delta.toDouble();
     if (deltaDouble > 0) {
-      // Keep sqrt symbolic instead of evaluating to decimal
-      final sqrtDeltaStr = _formatSqrtExpression(delta.toDouble());
-      final x1Expr = _formatQuadraticRoot(-b, sqrtDeltaStr, 2 * a, true);
-      final x2Expr = _formatQuadraticRoot(-b, sqrtDeltaStr, 2 * a, false);
+      // Pass delta directly to maintain precision
+      final x1Expr = _formatQuadraticRoot(-b, delta, 2 * a, true);
+      final x2Expr = _formatQuadraticRoot(-b, delta, 2 * a, false);
 
       steps.add(
         CalculationStep(
@@ -319,8 +318,9 @@ class SolverService {
         ),
       );
 
-      // Keep sqrt symbolic for complex roots
-      final sqrtNegDeltaStr = _formatSqrtExpression(-delta.toDouble());
+      // For complex roots, we need to handle -delta
+      final negDelta = -delta;
+      final sqrtNegDeltaStr = _formatSqrtFromRational(negDelta);
       final realPart = -b / (2 * a);
       final imagPartExpr = _formatImaginaryPart(sqrtNegDeltaStr, 2 * a);
 
@@ -1079,76 +1079,166 @@ ${b1}y &= ${c1 - a1 * x.toDouble()}
 
   int gcd(int a, int b) => b == 0 ? a : gcd(b, a % b);
 
-  /// 格式化平方根表达式，保持符号形式
-  String _formatSqrtExpression(double value) {
-    if (value == 0) return '0';
+  /// 格式化 Rational 值的平方根表达式，保持符号形式
+  String _formatSqrtFromRational(Rational value) {
+    if (value == Rational.zero) return '0';
 
     // 处理负数（用于复数根）
-    if (value < 0) {
-      return '\\sqrt{${(-value).toInt()}}';
+    if (value < Rational.zero) {
+      return '\\sqrt{${(-value).toBigInt()}}';
     }
 
-    // 检查是否为完全平方数
-    final sqrtValue = sqrt(value);
-    final rounded = sqrtValue.round();
-    if ((sqrtValue - rounded).abs() < 1e-10) {
-      return rounded.toString();
-    }
+    // 尝试将 Rational 转换为完全平方数的形式
+    // 例如: 4/9 -> 2/3, 9/4 -> 3/2, 25/16 -> 5/4 等
 
-    // 寻找最大的完全平方数因子
-    int maxSquareFactor = 1;
-    int intValue = value.toInt();
-    for (int i = 2; i * i <= intValue; i++) {
-      if (intValue % (i * i) == 0) {
-        maxSquareFactor = i * i;
-      }
-    }
+    // 首先简化分数
+    final simplified = value;
 
-    final coefficient = sqrt(maxSquareFactor).round();
-    final remaining = intValue ~/ maxSquareFactor;
+    // 检查分子和分母是否都是完全平方数
+    final numerator = simplified.numerator;
+    final denominator = simplified.denominator;
 
-    if (remaining == 1) {
-      return coefficient == 1
-          ? '\\sqrt{$intValue}'
-          : '$coefficient\\sqrt{$remaining}';
-    } else if (coefficient == 1) {
-      return '\\sqrt{$remaining}';
+    // 寻找分子和分母的平方根因子
+    BigInt sqrtNumerator = _findSquareRootFactor(numerator);
+    BigInt sqrtDenominator = _findSquareRootFactor(denominator);
+
+    // 计算剩余的分子和分母
+    final remainingNumerator = numerator ~/ (sqrtNumerator * sqrtNumerator);
+    final remainingDenominator =
+        denominator ~/ (sqrtDenominator * sqrtDenominator);
+
+    // 构建结果
+    String result = '';
+
+    // 处理系数部分
+    if (sqrtNumerator > BigInt.one || sqrtDenominator > BigInt.one) {
+      if (sqrtNumerator > sqrtDenominator) {
+        final coeff = sqrtNumerator ~/ sqrtDenominator;
+        if (coeff > BigInt.one) {
+          result += '$coeff';
+        }
+      } else if (sqrtDenominator > sqrtNumerator) {
+        // 这会导致分母，需要用分数表示
+        final coeffNum = sqrtNumerator;
+        final coeffDen = sqrtDenominator;
+        if (coeffNum == BigInt.one) {
+          result += '\\frac{1}{$coeffDen}';
         } else {
-      return '$coefficient\\sqrt{$remaining}';
+          result += '\\frac{$coeffNum}{$coeffDen}';
         }
       }
+    }
+
+    // 处理根号部分
+    if (remainingNumerator == BigInt.one &&
+        remainingDenominator == BigInt.one) {
+      // 没有根号部分
+      if (result.isEmpty) {
+        return '1';
+      }
+    } else if (remainingNumerator == remainingDenominator) {
+      // 根号部分约分后为1
+      if (result.isEmpty) {
+        return '1';
+      }
+    } else {
+      // 需要根号
+      String sqrtContent = '';
+      if (remainingDenominator == BigInt.one) {
+        sqrtContent = '$remainingNumerator';
+      } else {
+        sqrtContent = '\\frac{$remainingNumerator}{$remainingDenominator}';
+      }
+
+      if (result.isEmpty) {
+        result = '\\sqrt{$sqrtContent}';
+      } else {
+        result += '\\sqrt{$sqrtContent}';
+      }
+    }
+
+    return result.isEmpty ? '1' : result;
+  }
+
+  /// 寻找一个大整数的平方根因子
+  BigInt _findSquareRootFactor(BigInt n) {
+    if (n <= BigInt.one) return BigInt.one;
+
+    BigInt factor = BigInt.one;
+    BigInt i = BigInt.two;
+
+    while (i * i <= n) {
+      BigInt count = BigInt.zero;
+      while (n % (i * i) == BigInt.zero) {
+        n = n ~/ (i * i);
+        count += BigInt.one;
+      }
+      if (count > BigInt.zero) {
+        factor = factor * i;
+      }
+      i += BigInt.one;
+    }
+
+    return factor;
+  }
 
   /// 格式化二次方程的根：(-b ± sqrt(delta)) / (2a)
   String _formatQuadraticRoot(
     double b,
-    String sqrtExpr,
+    Rational delta,
     double denominator,
     bool isPlus,
   ) {
-    final sign = isPlus ? '+' : '-';
-    final bStr = b == 0
-        ? ''
-        : b > 0
-        ? '${b.toInt()}'
-        : '(${b.toInt()})';
+    final denomInt = denominator.toInt();
     final denomStr = denominator == 2 ? '2' : denominator.toString();
 
+    // Format sqrt(delta) symbolically using the Rational value
+    final sqrtExpr = _formatSqrtFromRational(delta);
+
     if (b == 0) {
       // 简化为 ±sqrt(delta)/denominator
       if (denominator == 2) {
-        return isPlus
-            ? '\\frac{\\sqrt{${sqrtExpr.replaceAll('\\sqrt{', '').replaceAll('}', '')}}}{2}'
-            : '-\\frac{\\sqrt{${sqrtExpr.replaceAll('\\sqrt{', '').replaceAll('}', '')}}}{2}';
+        return isPlus ? '\\frac{$sqrtExpr}{2}' : '-\\frac{$sqrtExpr}{2}';
       } else {
         return isPlus
-            ? '\\frac{\\sqrt{${sqrtExpr.replaceAll('\\sqrt{', '').replaceAll('}', '')}}}{$denomStr}'
-            : '-\\frac{\\sqrt{${sqrtExpr.replaceAll('\\sqrt{', '').replaceAll('}', '')}}}{$denomStr}';
+            ? '\\frac{$sqrtExpr}{$denomStr}'
+            : '-\\frac{$sqrtExpr}{$denomStr}';
       }
     } else {
       // 完整的表达式：(-b ± sqrt(delta))/denominator
+      final bInt = b.toInt();
+
+      // Check if b is divisible by denominator for simplification
+      if (bInt % denomInt == 0) {
+        // Can simplify: b/denominator becomes integer
+        final simplifiedB = bInt ~/ denomInt;
+
+        if (simplifiedB == 0) {
+          // Just the sqrt part with correct sign
+          return isPlus ? '$sqrtExpr' : '-$sqrtExpr';
+        } else if (simplifiedB == 1) {
+          // +1 * sqrt part
+          return isPlus ? '1 + $sqrtExpr' : '1 - $sqrtExpr';
+        } else if (simplifiedB == -1) {
+          // -1 * sqrt part
+          return isPlus ? '-1 + $sqrtExpr' : '-1 - $sqrtExpr';
+        } else if (simplifiedB > 0) {
+          // Positive coefficient
+          return isPlus
+              ? '$simplifiedB + $sqrtExpr'
+              : '$simplifiedB - $sqrtExpr';
+        } else {
+          // Negative coefficient
+          final absB = (-simplifiedB).toString();
+          return isPlus ? '-$absB + $sqrtExpr' : '-$absB - $sqrtExpr';
+        }
+      } else {
+        // Cannot simplify, use fraction form
+        final bStr = b > 0 ? '${bInt}' : '(${bInt})';
+        final signStr = isPlus ? '+' : '-';
         final numerator = b > 0
-          ? '-$bStr $sign \\sqrt{${sqrtExpr.replaceAll('\\sqrt{', '').replaceAll('}', '')}}'
-          : '(${b.toInt()}) $sign \\sqrt{${sqrtExpr.replaceAll('\\sqrt{', '').replaceAll('}', '')}}';
+            ? '-$bStr $signStr $sqrtExpr'
+            : '(${bInt}) $signStr $sqrtExpr';
 
         if (denominator == 2) {
           return '\\frac{$numerator}{2}';
@@ -1157,6 +1247,7 @@ ${b1}y &= ${c1 - a1 * x.toDouble()}
         }
       }
     }
+  }
 
   /// 格式化复数根的虚部：sqrt(-delta)/(2a)
   String _formatImaginaryPart(String sqrtExpr, double denominator) {
@@ -1256,33 +1347,6 @@ ${b1}y &= ${c1 - a1 * x.toDouble()}
     return coeffs;
   }
 
-  /// 规范化系数字符串
-  String _normalizeCoefficientString(String coeff) {
-    if (coeff.isEmpty || coeff == '+') return '1';
-    if (coeff == '-') return '-1';
-
-    // 处理类似 "2sqrt(3)" 的情况
-    coeff = coeff.replaceAll(' ', ''); // 移除空格
-
-    // 检查是否是纯数字
-    final numValue = double.tryParse(coeff);
-    if (numValue != null) {
-      return coeff;
-    }
-
-    // 检查是否包含 sqrt
-    if (coeff.contains('sqrt(') || coeff.contains('\\sqrt{')) {
-      // 如果前面没有数字系数，默认为 1
-      if (coeff.startsWith('sqrt(') || coeff.startsWith('\\sqrt{')) {
-        return coeff.startsWith('-') ? coeff : '1' + coeff;
-      }
-      // 如果前面有数字，保持原样
-      return coeff;
-    }
-
-    return coeff;
-  }
-
   /// 合并系数，保持符号形式
   String _combineCoefficients(String? existing, String newCoeff) {
     if (existing == null || existing == '0') return newCoeff;

pubspec.lock

@@ -145,6 +145,14 @@ packages:
       url: "https://pub.dev"
     source: hosted
     version: "1.0.8"
+  equatable:
+    dependency: transitive
+    description:
+      name: equatable
+      sha256: "567c64b3cb4cf82397aac55f4f0cbd3ca20d77c6c03bedbc4ceaddc08904aef7"
+      url: "https://pub.dev"
+    source: hosted
+    version: "2.0.7"
   fake_async:
     dependency: transitive
     description:
@@ -169,6 +177,14 @@ packages:
       url: "https://pub.dev"
     source: hosted
     version: "7.0.1"
+  fl_chart:
+    dependency: "direct main"
+    description:
+      name: fl_chart
+      sha256: "00b74ae680df6b1135bdbea00a7d1fc072a9180b7c3f3702e4b19a9943f5ed7d"
+      url: "https://pub.dev"
+    source: hosted
+    version: "0.66.2"
   flutter:
     dependency: "direct main"
     description: flutter

pubspec.yaml

@@ -16,7 +16,7 @@ publish_to: "none" # Remove this line if you wish to publish to pub.dev
 # https://developer.apple.com/library/archive/documentation/General/Reference/InfoPlistKeyReference/Articles/CoreFoundationKeys.html
 # In Windows, build-name is used as the major, minor, and patch parts
 # of the product and file versions while build-number is used as the build suffix.
-version: 1.0.0+3
+version: 1.0.0+4
 
 environment:
   sdk: ^3.9.2
@@ -40,6 +40,7 @@ dependencies:
   go_router: ^16.2.1
   url_launcher: ^6.3.2
   rational: ^2.2.3
+  fl_chart: ^0.66.1
 
 dev_dependencies:
   flutter_test:

test/solver_test.dart

@@ -54,5 +54,56 @@ void main() {
         true,
       );
     });
+
+    test('二次方程根的简化', () {
+      final result = solver.solve('x^2 - 4x - 5 = 0');
+      debugPrint('Result for x^2 - 4x - 5 = 0: ${result.finalAnswer}');
+      // 这个方程的根应该是 x = (4 ± √(16 + 20))/2 = (4 ± √36)/2 = (4 ± 6)/2
+      // 所以 x1 = (4 + 6)/2 = 5, x2 = (4 - 6)/2 = -1
+      expect(
+        (result.finalAnswer.contains('x_1 = 5') &&
+                result.finalAnswer.contains('x_2 = -1')) ||
+            (result.finalAnswer.contains('x_1 = -1') &&
+                result.finalAnswer.contains('x_2 = 5')),
+        true,
+        reason: '方程 x^2 - 4x - 5 = 0 的根应该被正确简化',
+      );
+    });
+
+    test('二次方程精确度改进', () {
+      final result = solver.solve('x^2 - 2x - 1 = 0');
+      debugPrint('Result for x^2 - 2x - 1 = 0: ${result.finalAnswer}');
+      // 这个方程的根应该是 x = (2 ± √(4 + 4))/2 = (2 ± √8)/2 = (2 ± 2√2)/2 = 1 ± √2
+      // 验证结果包含正确的根格式
+      expect(
+        result.finalAnswer.contains('x_1') &&
+            result.finalAnswer.contains('x_2'),
+        true,
+        reason: '方程应该有两个根',
+      );
+      expect(
+        result.finalAnswer.contains('1 +') ||
+            result.finalAnswer.contains('1 -'),
+        true,
+        reason: '根应该以 1 ± √2 的形式出现',
+      );
+    });
+
+    test('无实数解的二次方程', () {
+      final result = solver.solve('x(55-3x+2)=300');
+      debugPrint('Result for x(55-3x+2)=300: ${result.finalAnswer}');
+      // 这个方程展开后为 -3x² + 57x - 300 = 0，判别式为负数，应该无实数解
+      expect(
+        result.steps.any((step) => step.formula.contains('无实数解')),
+        true,
+        reason: '方程应该被识别为无实数解',
+      );
+      expect(
+        result.finalAnswer.contains('x_1') &&
+            result.finalAnswer.contains('x_2'),
+        true,
+        reason: '应该提供复数根',
+      );
+    });
   });
 }