Work Area

The Work Area is used to display all the geometric objects created with GEObject, and some popup menus that allow the creation and the manipulation of these objects.
All possible actions in this area of GEObject window are controlled by the left botton of the mouse.
When the user clicks, a popup menu appears; by dragging the mouse up and down, you select the desired option, and confirm it by releasing the button.

In the Status Bar some messages give informations about possible actions.

Two objects appear here: the default popup menu, which can be enlarged using the Creation Method and the Interaction Method.

Class Popup Menu

Available primitive geometric objects

The Creation Popup lets you to create new geometric objects.
It appears when you click in the Work Area, in every point of the screen where there aren't objects.
Some entries in this popup have a sub-popup; they are distinguished from the others by a little square in the corner.

Point

Allows the creation of a point in the Work Area; it's possible to do it in two ways:

• With X and Y
  puts the new point where you click
• With point segment
  if you have a segment, you can create a point near to another as long as the segment is and in the same direction; moving one extreme of the segment, the new point will move, too, thus the distance will remaine equal to the segment length, and the direction will be according to the segment direction

Line

Allows to create a line in the Work Area; this option asks the user for two points, and draws the line which passes through them.

Halfline

Allows to create a halfline in the Work Area; this option asks the user for two points, and draws the halfline which passes through them, starting from the first one created.

Segment

Allows to create a segment in the Work Area; it's possible to do it in two ways:

• With two points
  the program asks the user for two points, and draws the segment which connects them
• With point segment
  if you still have a segment, you can create another one equal in lenght and in direction, simply choosing this option; moving the first segment, the new one will change as the first does

Circle

Allows to create a circle in the Work Area; it's possible to do it in three ways:

• With center point
  the program asks the user for two points: the center of the circle, and one circumference point
• With three points
  the program asks the user for three points, and then draws the circle connecting them
• With pt two pts
  the program asks to the user one point as center of the circle, and two other points: the distance between them will be the circle-radius

Arc

Allows the creation of an arc in the Work Area; the program asks the user for three points, and then draws an arc which has center in the first point, radius long as the distance from the first point to the second, in the anticlockwise direction, starting from the second point, and finishing on the intersection between the circle and the halfline starting in the first point and passing from the third (which is not displayed).

Angle

Allows to create an angle in the Work Area; the program asks the user for three points, and then draws an angle which has vertex in the first point, in the anticlockwise direction, and two sides that are segments connecting the first point with the second one and the first point with the third one

GenericObj

Allows to create a generic object (not necessarly connected) clicking over some already existent object; to stop this option, clik twice over the last object selected; it's useful also to define some new classes in the popup.

Polygon

Allows to create new polygons; simply click on the Work Area in the positions where you want to have vertexes, to stop the mode, click twice in the last point.

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Interaction Methods Popup Menu

The Interaction Methods Popup allows the manipulation of geometric objects.
It appears when you click over an existent object.
If at the same point of the screen there is more than one object, a little popup with the objects's names appears, making it possible to choose the desired object.
Every geometric object has its own Interaction Methods Popup; there are some entries that are the same for all kinds of objects, and some that aren't.

Translate

Move the object in the Work Area, simply dragging the mouse.
The points of the translating objects, appear white, while dragging, and return to be black when you click to stop the Translation Mode.

Hide

Hide the geometric object selected.
The object is still existent, and it's possible to make it visible in every moment, using the Window/Unhide Object.

Hide Name

Hide the name of the geometric object selected.
This name doesen't reappear using the Window/Name ON/OFF; to make it visible again, the user has to select this option again.

Set Name

Change the name of the selected geometric object.
Write the new name in the dialog box appears.

A Point On

Insert a point on the geometric object.
The position of the new point is decided randomly.

Intersect

When two geometric objects intersect one another, this option allows to make new points in the intersection points.
The user has to select the second object in the intersection.

Movable Point On

Put a moveable point over the object, using two other as control for the movement.
The program asks for two points, so that the object is between them (if the object is a circle, just one point out of the circumference is needed, because the other is by default the center); a new point is created in the intersection between the object and the segment connecting those points (that is not shown); moving one of the two points given, the new point will move on the object.

Orthogonal Line

Allows to draw the line orthogonal to the geometric object, in a point selected.

Set Footsteps (only for points)

Allows the point to leave a footstep when translated.
It's possible to cancel the trace, using the option Window/ Cancel Footsteps in the Menubar

Set Anchor (only for points)

Anchor the point in its position.
When this option is selected, a little anchor is shown near to the point, that is immoveable.
If the the point is in a construction, anchoring it means that every movement and translation of the construction, will be affected from the obligation, and the constuction will be deformed in accordance to the position of the anchored point.
To cancel the anchor, reselect this option

Set Coincident (only for points)

Allows to make two points coincident.
Useful when doing an inverse construction

Set Forced to exist (only for points)

If a point is the result of an intersection from two objetcs, force it to exist means to put constraint on the two objects in their movements: they will not move in ways that imply the disappearing of the point (i.e. they cannot be divided).
This option is useful for simulation of physical constraint.

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