Initialization flicker when creating a document with an artboard or imported image

When creating a document with file -> new document, flickering occurs. This is because the editor first renders the artboard with a scale of 1 and no offset, before centring the viewport.

Ideally this first render should not be necessary. If it is kept however, there is no reason to blit it.

首先，使用画板或导入的图像，通过 File → New Document 复现文档创建过程，然后跟踪编辑器的初始渲染和视口居中流程。当初始的 scale-1、zero-offset 渲染被避免或不再被 blit，且创建过程不再闪烁时，工作即完成。

由索引模型根据 Issue 内容生成。