BorderedRectShape for the Flutter Graphic charting library

bordered_rect_shape.dart

// ignore_for_file: implementation_imports

import 'package:flutter/material.dart';
import 'package:graphic/graphic.dart';
import 'package:graphic/src/guide/axis/radial.dart';
import 'package:graphic/src/util/math.dart';

/// A rectangle or sector shape with border.
class BorderedRectShape extends RectShape {
  final double borderWidth;
  final Color borderColor;

  /// Creates a rectangle shape with border.
  BorderedRectShape({
    histogram = false,
    labelPosition = 1.0,
    borderRadius,
    this.borderWidth = 1.0,
    this.borderColor = Colors.black,
  }) : super(histogram: histogram, labelPosition: labelPosition, borderRadius: borderRadius);

  @override
  List<Figure> renderGroup(
    List<Aes> group,
    CoordConv coord,
    Offset origin,
  ) {
    final rst = <Figure>[];

    if (coord is RectCoordConv) {
      if (histogram) {
        // Histogram shape dosen't allow NaN value.

        // First item.
        Aes item = group.first;
        List<Offset> position = item.position;
        double bandStart = 0;
        double bandEnd = (group[1].position.first.dx + position.first.dx) / 2;
        rst.addAll(_renderRect(
          item,
          Rect.fromPoints(
            coord.convert(Offset(bandStart, position[1].dy)),
            coord.convert(Offset(bandEnd, position[0].dy)),
          ),
          coord.convert(position[0] + (position[1] - position[0]) * labelPosition),
          coord,
        ));
        // Middle items.
        for (var i = 1; i < group.length - 1; i++) {
          item = group[i];
          position = item.position;
          bandStart = (group[i].position.first.dx + group[i - 1].position.first.dx) / 2;
          bandEnd = (group[i + 1].position.first.dx + group[i].position.first.dx) / 2;
          rst.addAll(_renderRect(
            item,
            Rect.fromPoints(
              coord.convert(Offset(bandStart, position[1].dy)),
              coord.convert(Offset(bandEnd, position[0].dy)),
            ),
            coord.convert(position[0] + (position[1] - position[0]) * labelPosition),
            coord,
          ));
        }
        // Last item.
        item = group.last;
        position = item.position;
        bandStart = (position.first.dx + group[group.length - 2].position.first.dx) / 2;
        bandEnd = 1;
        rst.addAll(_renderRect(
          item,
          Rect.fromPoints(
            coord.convert(Offset(bandStart, position[1].dy)),
            coord.convert(Offset(bandEnd, position[0].dy)),
          ),
          coord.convert(position[0] + (position[1] - position[0]) * labelPosition),
          coord,
        ));
      } else {
        // Bar.

        for (var item in group) {
          bool nan = false;
          for (var point in item.position) {
            if (!point.dy.isFinite) {
              nan = true;
              break;
            }
          }
          if (nan) {
            continue;
          }

          final start = coord.convert(item.position[0]);
          final end = coord.convert(item.position[1]);
          final size = item.size ?? defaultSize;
          Rect rect;
          if (coord.transposed) {
            rect = Rect.fromLTRB(
              start.dx,
              start.dy - size / 2,
              end.dx,
              start.dy + size / 2,
            );
          } else {
            rect = Rect.fromLTRB(
              end.dx - size / 2,
              end.dy,
              end.dx + size / 2,
              start.dy,
            );
          }
          rst.addAll(_renderRect(
            item,
            rect,
            start + (end - start) * labelPosition,
            coord,
          ));
        }
      }
    } else if (coord is PolarCoordConv) {
      // All sector interval shapes dosen't allow NaN value.

      if (coord.transposed) {
        if (coord.dimCount == 1) {
          // Pie.

          for (var item in group) {
            final position = item.position;
            rst.addAll(_renderSector(
              item,
              coord.radiuses.last,
              coord.radiuses.first,
              coord.convertAngle(position[0].dy),
              coord.convertAngle(position[1].dy),
              true,
              coord.convert(Offset(
                labelPosition,
                (position[1].dy + position[0].dy) / 2,
              )),
              coord,
            ));
          }
        } else {
          // Race track.

          for (var item in group) {
            final position = item.position;
            final r = coord.convertRadius(position[0].dx);
            final halfSize = (item.size ?? defaultSize) / 2;
            rst.addAll(_renderSector(
              item,
              r - halfSize,
              r + halfSize,
              coord.convertAngle(position[0].dy),
              coord.convertAngle(position[1].dy),
              false,
              coord.convert(Offset(
                labelPosition,
                (position[1].dy - position[0].dy) / 2,
              )),
              coord,
            ));
            if (item.label != null && item.label!.haveText) {
              final labelAnchor = coord.convert(position[0] + (position[1] - position[0]) * labelPosition);
              final anchorOffset = labelAnchor - coord.center;
              rst.add(renderLabel(
                item.label!,
                labelAnchor,
                radialLabelAlign(anchorOffset) * -1,
              ));
            }
          }
        }
      } else {
        if (coord.dimCount == 1) {
          // Bull eye.

          for (var item in group) {
            rst.addAll(_renderSector(
              item,
              coord.convertRadius(item.position[1].dy),
              coord.convertRadius(item.position[0].dy),
              coord.angles.first,
              coord.angles.last,
              true,
              coord.convert(item.position[0] + (item.position[1] - item.position[0]) * labelPosition),
              coord,
            ));
          }
        } else {
          // Rose.

          // First item.
          Aes item = group.first;
          List<Offset> position = group.first.position;
          double bandStart = 0;
          double bandEnd = (group[1].position.first.dx + position.first.dx) / 2;
          rst.addAll(_renderSector(
            item,
            coord.convertRadius(position[1].dy),
            coord.convertRadius(position[0].dy),
            coord.convertAngle(bandStart),
            coord.convertAngle(bandEnd),
            true,
            coord.convert(position[0] + (position[1] - position[0]) * labelPosition),
            coord,
          ));
          // Middle items.
          for (var i = 1; i < group.length - 1; i++) {
            item = group[i];
            position = item.position;
            bandStart = (group[i].position.first.dx + group[i - 1].position.first.dx) / 2;
            bandEnd = (group[i + 1].position.first.dx + group[i].position.first.dx) / 2;
            rst.addAll(_renderSector(
              item,
              coord.convertRadius(position[1].dy),
              coord.convertRadius(position[0].dy),
              coord.convertAngle(bandStart),
              coord.convertAngle(bandEnd),
              true,
              coord.convert(position[0] + (position[1] - position[0]) * labelPosition),
              coord,
            ));
          }
          // Last item.
          item = group.last;
          position = item.position;
          bandStart = (position.first.dx + group[group.length - 2].position.first.dx) / 2;
          bandEnd = 1;
          rst.addAll(_renderSector(
            item,
            coord.convertRadius(position[1].dy),
            coord.convertRadius(position[0].dy),
            coord.convertAngle(bandStart),
            coord.convertAngle(bandEnd),
            true,
            coord.convert(position[0] + (position[1] - position[0]) * labelPosition),
            coord,
          ));
        }
      }
    }

    return rst;
  }

  /// Renders a rectangle interval item.
  ///
  /// It relaced [renderItem].
  List<Figure> _renderRect(
    Aes item,
    Rect rect,
    Offset labelAnchor,
    CoordConv coord,
  ) {
    assert(item.shape is BorderedRectShape);

    final path = Path();
    if (borderRadius != null) {
      path.addRRect(RRect.fromRectAndCorners(
        rect,
        topLeft: borderRadius!.topLeft,
        topRight: borderRadius!.topRight,
        bottomRight: borderRadius!.bottomRight,
        bottomLeft: borderRadius!.bottomLeft,
      ));
    } else {
      path.addRect(rect);
    }

    final rst = <Figure>[];

    rst.addAll(renderBasicItem(
      path,
      item,
      false,
      0,
      coord.region,
    ));

    if (item.label != null) {
      rst.add(renderLabel(
        item.label!,
        labelAnchor,
        labelPosition.equalTo(1) ? (coord.transposed ? Alignment.centerRight : Alignment.topCenter) : Alignment.center,
      ));
    }

    return rst;
  }

  /// Renders a sector interval item.
  ///
  /// It relaced [renderItem].
  List<Figure> _renderSector(
    Aes item,
    double r,
    double r0,
    double startAngle,
    double endAngle,
    bool haveLabel,
    Offset labelAnchor,
    PolarCoordConv coord,
  ) {
    assert(item.shape is BorderedRectShape);

    Path path;
    if (borderRadius != null) {
      path = Paths.rsector(
        center: coord.center,
        r: r,
        r0: r0,
        startAngle: startAngle,
        endAngle: endAngle,
        clockwise: true,
        topLeft: borderRadius!.topLeft,
        topRight: borderRadius!.topRight,
        bottomRight: borderRadius!.bottomRight,
        bottomLeft: borderRadius!.bottomLeft,
      );
    } else {
      path = Paths.sector(
        center: coord.center,
        r: r,
        r0: r0,
        startAngle: startAngle,
        endAngle: endAngle,
        clockwise: true,
      );
    }

    final rst = <Figure>[];

    rst.addAll(renderBasicItem(
      path,
      item,
      false,
      0,
      coord.region,
    ));

    rst.addAll(renderBasicItem(
      path,
      item.copyWith(color: borderColor),
      true,
      borderWidth,
      coord.region,
    ));

    if (haveLabel && item.label != null) {
      Alignment defaultAlign;
      if (labelPosition == 1) {
        // Calculate default alignment according to anchor's quadrant.
        final anchorOffset = labelAnchor - coord.center;
        defaultAlign = Alignment(
          anchorOffset.dx.equalTo(0) ? 0 : anchorOffset.dx / anchorOffset.dx.abs(),
          anchorOffset.dy.equalTo(0) ? 0 : anchorOffset.dy / anchorOffset.dy.abs(),
        );
      } else {
        defaultAlign = Alignment.center;
      }
      rst.add(renderLabel(
        item.label!,
        labelAnchor,
        defaultAlign,
      ));
    }

    return rst;
  }
}

extension AesCopyWith on Aes {
  Aes copyWith({Color? color}) {
    return Aes(
      index: index,
      position: position,
      shape: shape,
      color: color ?? this.color,
      gradient: gradient,
      elevation: elevation,
      label: label,
      size: size,
    );
  }
}