弧形是沿著指定矩形范围内的椭圆形周围所描绘的。

The arc is traced along the perimeter of the ellipse bounded by the specified rectangle.

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因此，抓住你的矩形选框工具(中)在图像上点击右键并选择颜色范围。

So grab your Rectangular Marquee Tool (m) right click on the image and select Color Range.

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同时，其切割范围也受到限制，一般仅限于切割规则的矩形件和一维的型材和棒材等，不能切割异形件。

At the same time, its scope of cutting also restricted, generally limited to cut rules and one dimensional rectangular pieces of profiles and rod, can not cutting profiled.

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