Method markDirty

packages/fairygui/src/text/DynamicFont.ts:334–347

* Mark a region as dirty * 标记区域为脏

(x: number, y: number, width: number, height: number)

     * 标记区域为脏
     */
    private markDirty(x: number, y: number, width: number, height: number): void {
        this._dirty = true;

        if (!this._dirtyRegion) {
            this._dirtyRegion = { x, y, width, height };
        } else {
            const r = this._dirtyRegion;
            const newX = Math.min(r.x, x);
            const newY = Math.min(r.y, y);
            const newWidth = Math.max(r.x + r.width, x + width) - newX;
            const newHeight = Math.max(r.y + r.height, y + height) - newY;
            this._dirtyRegion = { x: newX, y: newY, width: newWidth, height: newHeight };
        }
    }

    /**
     * Upload texture to GPU