fix(line): use curveMonotone

[pearmini]

Smooth Line

close: #5541

当 y 方向的数据连续为 0 的时候，曲线超出坐标轴。

解决办法

使用 curveMonotoneX 和 curveMonotoneY 作为默认的曲线生成器。

案例

export function mockLineCloseX(): G2Spec {
  return {
    type: 'line',
    data: [
      { x: 0, y: 0 },
      { x: 0.02, y: 0.8 },
      { x: 1, y: 1 },
    ],
    encode: { x: 'x', y: 'y' },
    style: { shape: 'smooth' },
  };
}

export function mockLineZeroY(): G2Spec {
  return {
    type: 'line',
    coordinate: { transform: [{ type: 'transpose' }] },
    data: [
      { date: '2-1', close: 1 },
      { date: '2-2', close: 10 },
      { date: '2-3', close: 0 },
      { date: '2-4', close: 0 },
      { date: '2-5', close: 12 },
    ],
    encode: { x: 'date', y: 'close' },
    style: { shape: 'smooth' },
  };
}

export function mockLineCloseX(): G2Spec {
  return {
    type: 'line',
    data: [
      { x: 0, y: 0 },
      { x: 0.02, y: 0.8 },
      { x: 1, y: 1 },
    ],
    encode: { x: 'x', y: 'y' },
    style: { shape: 'smooth' },
  };
}

[ai-qing-hai]

line close curveCatmullRom , use curveMonotoneY/curveMonotoneX

[coveralls]

Pull Request Test Coverage Report for Build 6779796068

• 4 of 4 (100.0%) changed or added relevant lines in 1 file are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage increased (+0.001%) to 88.237%

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Totals
Change from base Build 6769567652:	0.001%
Covered Lines:	10021
Relevant Lines:	10992

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💛 - Coveralls