Draft Circle/zh-cn

描述
底图圆形工具通过用户输入的两个点（中心点与半径），或通过拾取切线，或上述若干组合来在当前的工作平面上创建一个圆形. 它将根据Draft Tray中的Draft Linestyle来创建圆形.

此工具与Draft Arc工具的工作方式很相似，区别在于前者创建的是一个完整的圆周. 要绘制椭圆形请使用Draft Ellipse工具.



如何使用

 * 1) 点击按钮，或先后按下、键.
 * 2) 在3D视图中单击第一个点，或输入一个coordinate并按下按钮.
 * 3) 在3D视图中单击第二个点，或输入一个半径值.

通过双击树状视图（tree view）中的元素或点击按钮即可编辑对应圆形. 届时，您就可将中心点与半径点移动到预定的新位置.

创建圆形之后，通过将其第一角度（first angle）与最后角度（last angle）两个属性设置为不同值，便可以将它转换为一条弧.

Options

 * The primary use of the circle tool is by picking two points, the centre and a point on the circumference.
 * By pressing, you can select a tangent instead of picking a point. You can therefore construct several types of circles by selecting one, two or three tangents.
 * To enter coordinates manually, simply enter the numbers, then press between each X, Y and Z component. You can press the  button when you have entered the desired values to insert the point.
 * Press or click the checkbox to toggle continue mode. If continue mode is on, the Circle tool will restart after you finish the circle, allowing you to draw another one without pressing the tool button again.
 * Press or click the checkbox to toggle filled mode. If filled mode is on, the circle will create a filled face ; if not, the circle will not make a face.
 * Hold while drawing to force snapping your point to the nearest snap location, independently of the distance.
 * Hold while drawing to constrain your second point horizontally or vertically in relation to the first one.
 * Press or the  button to abort the current command.

属性
圆形对象享有Draft Arc中的所有属性，但是有些属性仅对圆形而言才有意义.

Data

 * : specifies the starting angle of the circle; normally 0&#176;.
 * : specifies the ending angle of the circle; normally 0&#176;.
 * : specifies the radius of the circle.
 * : specifies if the Circle makes a face or not. If it is a face is created, otherwise only the circumference is considered part of the object. This property only works if the shape is a full circumference.
 * For it to be a full circle and  should have the same value; otherwise, a Draft Arc is displayed. The values 0&#176; and 360&#176; aren't considered the same, so if these two values are used, the circle will not form a face.

View

 * : specifies a Draft Pattern with which to fill the face of the circle. This property only works if is, and if  is "Flat Lines".
 * : specifies the size of the Draft Pattern.

脚本
Draft API 与 FreeCAD Scripting Basics.

通过下列函数就可以在macros与Python控制台中使用圆形工具：


 * Creates a object with given  in millimeters.
 * can also be a, whose attribute must be a.
 * If a is given, it is used; otherwise the shape is created at the origin.
 * If is, the circle will make a face, that is, it will appear filled.
 * If and  are given in degrees, and have different values, they are used and the object appears as a Draft Arc.

示例：