Function giveSymbol

src/component/timeline/SliderTimelineView.ts:772–833

* Create symbol or update symbol * opt: basic position and event handlers

(
    hostModel: Model<TimelineDataItemOption | TimelineCheckpointStyle>,
    itemStyleModel: Model<TimelineDataItemOption['itemStyle'] | TimelineCheckpointStyle>,
    group: graphic.Group,
    opt: PathProps,
    symbol?: TimelineSymbol,
    callback?: {
        onCreate?: (symbol: TimelineSymbol) => void
        onUpdate?: (symbol: TimelineSymbol) => void
    }
)

 * opt: basic position and event handlers
 */
function giveSymbol(
    hostModel: Model<TimelineDataItemOption | TimelineCheckpointStyle>,
    itemStyleModel: Model<TimelineDataItemOption['itemStyle'] | TimelineCheckpointStyle>,
    group: graphic.Group,
    opt: PathProps,
    symbol?: TimelineSymbol,
    callback?: {
        onCreate?: (symbol: TimelineSymbol) => void
        onUpdate?: (symbol: TimelineSymbol) => void
    }
) {
    const color = itemStyleModel.get('color');

    if (!symbol) {
        const symbolType = hostModel.get('symbol');
        symbol = createSymbol(symbolType, -1, -1, 2, 2, color);
        symbol.setStyle('strokeNoScale', true);
        group.add(symbol);
        callback && callback.onCreate(symbol);
    }
    else {
        symbol.setColor(color);
        group.add(symbol); // Group may be new, also need to add.
        callback && callback.onUpdate(symbol);
    }

    // Style
    const itemStyle = itemStyleModel.getItemStyle(['color']);
    symbol.setStyle(itemStyle);

    // Transform and events.
    opt = merge({
        rectHover: true,
        z2: 100
    }, opt, true);

    const symbolSize = normalizeSymbolSize(hostModel.get('symbolSize'));

    opt.scaleX = symbolSize[0] / 2;
    opt.scaleY = symbolSize[1] / 2;

    const symbolOffset = normalizeSymbolOffset(hostModel.get('symbolOffset'), symbolSize);
    if (symbolOffset) {
        opt.x = (opt.x || 0) + symbolOffset[0];
        opt.y = (opt.y || 0) + symbolOffset[1];
    }

    const symbolRotate = hostModel.get('symbolRotate');
    opt.rotation = (symbolRotate || 0) * Math.PI / 180 || 0;

    symbol.attr(opt);

    // FIXME
    // (1) When symbol.style.strokeNoScale is true and updateTransform is not performed,
    // getBoundingRect will return wrong result.
    // (This is supposed to be resolved in zrender, but it is a little difficult to
    // leverage performance and auto updateTransform)
    // (2) All of ancesters of symbol do not scale, so we can just updateTransform symbol.