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packages/idraw/lib/components/coordinate_pro.dart

@@ -0,0 +1,164 @@
+import 'package:flutter/material.dart';
+import 'dart:ui' as ui;
+
+/// create by 张风捷特烈 on 2020/5/1
+/// contact me by email 1981462002@qq.com
+/// 说明:
+@immutable
+class Coordinate {
+  final double step;
+  final double strokeWidth;
+  final Color axisColor;
+  final Color gridColor;
+  final TextPainter _textPainter = TextPainter(textDirection: TextDirection.ltr);
+
+  Coordinate(
+      {this.step = 20,
+      this.strokeWidth = .5,
+      this.axisColor = Colors.blue,
+      this.gridColor = Colors.grey});
+
+  final Paint _gridPaint = Paint();
+  final Path _gridPath = Path();
+
+  void paint(Canvas canvas, Size size) {
+    canvas.save();
+    canvas.translate(size.width / 2, size.height / 2);
+    _drawGridLine(canvas, size);
+    _drawAxis(canvas, size);
+    _drawText(canvas, size);
+    canvas.restore();
+  }
+
+
+
+  void _drawAxis(Canvas canvas, Size size) {
+    _gridPaint
+      ..color = Colors.blue
+      ..strokeWidth = 1.5;
+    canvas.drawLine(
+        Offset(-size.width / 2, 0), Offset(size.width / 2, 0), _gridPaint);
+    canvas.drawLine(
+        Offset(0, -size.height / 2), Offset(0, size.height / 2), _gridPaint);
+    canvas.drawLine(Offset(0, size.height / 2),
+        Offset(0 - 7.0, size.height / 2 - 10), _gridPaint);
+    canvas.drawLine(Offset(0, size.height / 2),
+        Offset(0 + 7.0, size.height / 2 - 10), _gridPaint);
+    canvas.drawLine(
+        Offset(size.width / 2, 0), Offset(size.width / 2 - 10, 7), _gridPaint);
+    canvas.drawLine(
+        Offset(size.width / 2, 0), Offset(size.width / 2 - 10, -7), _gridPaint);
+  }
+
+  void _drawGridLine(Canvas canvas, Size size) {
+    _gridPaint
+      ..style = PaintingStyle.stroke
+      ..strokeWidth = .5
+      ..color = Colors.grey;
+
+    for (int i = 0; i < size.width / 2 / step; i++) {
+      _gridPath.moveTo(step * i, -size.height / 2 );
+      _gridPath.relativeLineTo(0, size.height);
+
+      _gridPath.moveTo(-step * i, -size.height / 2 );
+      _gridPath.relativeLineTo(0, size.height);
+    }
+
+    for (int i = 0; i < size.height / 2 / step; i++) {
+      _gridPath.moveTo(-size.width / 2,step * i );
+      _gridPath.relativeLineTo(size.width,0 );
+
+      _gridPath.moveTo(-size.width / 2,-step * i,  );
+      _gridPath.relativeLineTo(size.width,0 );
+    }
+
+    canvas.drawPath(_gridPath, _gridPaint);
+  }
+
+  void _drawAxisText(Canvas canvas, String str,
+      {Color color = Colors.black, bool? x = false}) {
+    TextSpan text = TextSpan(
+        text: str,
+        style: TextStyle(
+          fontSize: 11,
+          color: color,
+        ));
+
+    _textPainter.text = text;
+    _textPainter.layout(); // 进行布局
+    Size size = _textPainter.size;
+    Offset offset = Offset.zero;
+    if (x == null) {
+      offset = Offset(-size.width*1.5, size.width*0.7);
+    } else if (x) {
+      offset = Offset(-size.width / 2, size.height / 2);
+    } else {
+      offset = Offset(size.height / 2, -size.height / 2 + 2);
+    }
+    _textPainter.paint(canvas, offset);
+  }
+
+  void _drawText(Canvas canvas, Size size) {
+    // y > 0 轴 文字
+    canvas.save();
+    for (int i = 0; i < size.height / 2 / step; i++) {
+      if (step < 30 && i.isOdd || i == 0) {
+        canvas.translate(0, step);
+        continue;
+      } else {
+        var str = (i * step).toInt().toString();
+        _drawAxisText(canvas, str, color: Colors.green);
+      }
+      canvas.translate(0, step);
+    }
+    canvas.restore();
+
+    // x > 0 轴 文字
+    canvas.save();
+    for (int i = 0; i < size.width / 2 / step; i++) {
+      if (i == 0) {
+        _drawAxisText(canvas, "O", color: Colors.black, x: null);
+        canvas.translate(step, 0);
+        continue;
+      }
+      if (step < 30 && i.isOdd) {
+        canvas.translate(step, 0);
+        continue;
+      } else {
+        var str = (i * step).toInt().toString();
+        _drawAxisText(canvas, str, color: Colors.green, x: true);
+      }
+      canvas.translate(step, 0);
+    }
+    canvas.restore();
+
+    // y < 0 轴 文字
+    canvas.save();
+    for (int i = 0; i < size.height / 2 / step; i++) {
+      if (step < 30 && i.isOdd || i == 0) {
+        canvas.translate(0, -step);
+        continue;
+      } else {
+        var str = (-i * step).toInt().toString();
+        _drawAxisText(canvas, str, color: Colors.green);
+      }
+
+      canvas.translate(0, -step);
+    }
+    canvas.restore();
+
+    // x < 0 轴 文字
+    canvas.save();
+    for (int i = 0; i < size.width / 2 / step; i++) {
+      if (step < 30 && i.isOdd || i == 0) {
+        canvas.translate(-step, 0);
+        continue;
+      } else {
+        var str = (-i * step).toInt().toString();
+        _drawAxisText(canvas, str, color: Colors.green, x: true);
+      }
+      canvas.translate(-step, 0);
+    }
+    canvas.restore();
+  }
+}