Editing the lines

Edit lines

The IDA Editor provides the following types of line-type elements: point sets, lines, polygons, curves, regions, and plot lines (see Shapes).

A special mode is used for line editing. In this mode all mouse events are interpreted as input for the line. All other graphical objects are unavailable. There is no possibility to edit two lines at the same time (even in different windows).

There are two editing methods for lines, polygons and plot lines: isotropic and orthogonal (Manhattan-style).

The isotropic method (with Control key pressed): for lines with an arbitrary direction of the segments.

The orthogonal method (with Shift key pressed): for lines with horizontal or vertical segments only.

The default method (with neither Shift nor Control pressed) depends on the context. When editing pure graphical elements, the default method is the isotropic. For connection lines the default method is initially orthogonal, but this setting may be changed in the Preferences dialog.

The curves, regions, and point sets are always edited in isotropic mode.

To start editing

Insert a new line (see Insert new element)

or Move the mouse cursor over an existing line, press the right mouse button and select Edit from the pop-up menu

or Double-click on the line

To end the editing mode

Press Enter (this accepts all changes)

or Press Esc (this cancels all changes)

or Press the right mouse button and select any item from the pop-up menu:

• Done: accept all changes;
• Cancel: rejects all changes.

To add a vertex

1. Move the cursor to the desired location. The cursor must be a cross.
2. Press the left mouse button
3. If required, drag the inserted point to a desired position.
4. Release the mouse button

While editing a line or a curve, the first inserted vertex will be added to the nearest endpoint. The subsequent vertices are added to the same end. To change the side, click the endpoint with right mouse button and select "Add points to this side" from menu

For polygons and regions, the point is inserted into the nearest segment.

For plot lines, the points are sorted in increasing order of the x-coordinate.

When using the orthogonal method, the previous vertex is moved in order to ensure the Manhattan-style of the new segment. If the previous segment is oblique, one extra vertex may be inserted. For polygons, the orthogonal insertion is possible on an existing segment only (see the next section).

See also To start a new contour.

To add a vertex inside a segment

1. Isotropic method or oblique segment
   1. Move the cursor to the segment (the cursor will change shape to a cross with a point inside).
   2. Press the left mouse button. A new vertex will divide the pointed segment.
   3. If required, drag the new vertex to the desired position.
   4. Release the button.
2. Orthogonal method and horizontal or vertical segment
   1. Move the cursor to the segment (the cursor will change shape to  or ),
   2. Click on the left mouse button. A new vertex will divide the pointed segment.

To move a vertex

1. Move the cursor to the vertex until the cursor changes to an arrow.
2. Press the left mouse button and drag the vertex.
3. Release the button.

You must drag at least at the distance equal to the size of the sensitive point. Otherwise your action will be considered as clicking and the point will be deleted (see To delete a vertex)

To cancel moving, click the Esc key before releasing the mouse button.

When the orthogonal method is being used, the vertical and horizontal segments adjacent to the moving vertex are also moved. Extra vertices may be inserted. The oblique adjacent segments are changed as in the isotropic method.

To move a segment (only for orthogonal method and horizontal/vertical segment)

1. Move the cursor to the segment until it changes shape to  or ).
2. Press the left mouse button.
3. Drag the segment.
4. Release the button.

To delete a vertex

1. Move the cursor to the vertex until the cursor changes to an arrow
2. Click on the left mouse button.

If the option "Delete point without confirmation" is checked in the Preferences dialog (category Form, Edit tab), the points is removed. Otherwise (this is the default setting) a menu is displayed. Choose "Remove point" to finish the operation.

By holding in the DEL key, the option "Delete point without confirmation" is temporary enabled which allows vertexes to be deleted by a single left click.

To align a vertex

To align a corner so that the adjacent sides become vertical or horizontal,

1. Move the cursor to the vertex until the cursor changes to an arrow
2. Click on the right mouse button (if the option "Delete point without confirmation" in Preferences dialog (category Form, Edit tab) is not checked, the left button may also be used);
3. In the menu, select the appropriate alignment option.

To start a new contour

Lines, curves, polygons and regions may consist of several contours. To start drawing new contour,

1. Move the cursor to the place where the contour should be started.
2. Click the left mouse button with Alt key pressed
   or click the right mouse button and select "Start new contour" from menu.

To change the shape of a curve or a region

Curves and regions may contain vertices of three types: auto points (this is the default type), smooth points, and corners.

To change the point type, click the point with the right mouse button and select the desired point type from the shortcut menu.

The shape of a segment of a curve between two vertices is controlled by two auxiliary control points attached to the ends of the segment.

For auto vertices, the position of the attached control points are calculated automatically (from the position of the adjacent vertices) and are not shown on the screen.

For smooth vertices and corners, the attached control points are shown on the screen (in editing mode only). The user may change the shape of the curve by dragging these points. In case of a smooth vertex the two control points are always symmetric relative to the vertex; in case of a corner the control points may be dragged independently.