Method makeBtn

src/component/timeline/SliderTimelineView.ts:543–570

(
            position: number[],
            iconName: ControlName,
            onclick: () => void,
            willRotate?: boolean
        )

        );

        function makeBtn(
            position: number[],
            iconName: ControlName,
            onclick: () => void,
            willRotate?: boolean
        ) {
            if (!position) {
                return;
            }
            const iconSize = parsePercent(
                retrieve2(timelineModel.get(['controlStyle', iconName + 'BtnSize' as any]), controlSize),
                controlSize
            );
            const rect = [0, -iconSize / 2, iconSize, iconSize];
            const btn = makeControlIcon(timelineModel, iconName + 'Icon' as ControlIconName, rect, {
                x: position[0],
                y: position[1],
                originX: controlSize / 2,
                originY: 0,
                rotation: willRotate ? -rotation : 0,
                rectHover: true,
                style: itemStyle,
                onclick: onclick
            });
            btn.ensureState('emphasis').style = hoverStyle;
            group.add(btn);
            enableHoverEmphasis(btn);
        }
    }

    private _renderCurrentPointer(