src/chart/gauge/PointerPath.ts

/*
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements.  See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership.  The ASF licenses this file
* to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance
* with the License.  You may obtain a copy of the License at
*
*   http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing,
* software distributed under the License is distributed on an
* "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
* KIND, either express or implied.  See the License for the
* specific language governing permissions and limitations
* under the License.
*/

import Path, { PathProps } from 'zrender/src/graphic/Path';

class PointerShape {
    angle = 0;
    width = 10;
    r = 10;
    x = 0;
    y = 0;
}

interface PointerPathProps extends PathProps {
    shape?: Partial<PointerShape>
}

export default class PointerPath extends Path<PointerPathProps> {

    readonly type = 'pointer';

    shape: PointerShape;

    constructor(opts?: PointerPathProps) {
        super(opts);
    }

    getDefaultShape() {
        return new PointerShape();
    }

    buildPath(ctx: CanvasRenderingContext2D, shape: PointerShape) {
        const mathCos = Math.cos;
        const mathSin = Math.sin;

        const r = shape.r;
        const width = shape.width;
        let angle = shape.angle;
        const x = shape.x - mathCos(angle) * width * (width >= r / 3 ? 1 : 2);
        const y = shape.y - mathSin(angle) * width * (width >= r / 3 ? 1 : 2);

        angle = shape.angle - Math.PI / 2;
        ctx.moveTo(x, y);
        ctx.lineTo(
            shape.x + mathCos(angle) * width,
            shape.y + mathSin(angle) * width
        );
        ctx.lineTo(
            shape.x + mathCos(shape.angle) * r,
            shape.y + mathSin(shape.angle) * r
        );
        ctx.lineTo(
            shape.x - mathCos(angle) * width,
            shape.y - mathSin(angle) * width
        );
        ctx.lineTo(x, y);
    }
}