Method scrollDown

packages/fairygui/src/scroll/ScrollPane.ts:357–363

* Scroll down * 向下滚动

(ratio: number = 1, bAnimate?: boolean)

     * 向下滚动
     */
    public scrollDown(ratio: number = 1, bAnimate?: boolean): void {
        if (this.pageMode) {
            this.setPosY(this._scrollY + this._viewHeight * ratio, bAnimate ?? false);
        } else {
            this.setPosY(this._scrollY + this.scrollStep * ratio, bAnimate ?? false);
        }
    }

    /**
     * Scroll left