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3. Using The Software

Dr GEO doesn't have menu or icon in the way we use on IBM PC. Instead of this it has contextual menu icons and menus. I took this inspiration from the greatest (pesonnal point of view) but quite unknown Acorn RISC OS, as used on Acorn Risc PC station and Acorn Network Computers. The idea behind this is to make appear the icons or menus only when you need them and at the place where the cursor is placed.

The left button performs an action (ie : creates an object or selects a specified menu). We name it the ACTION BUTTON. The right button generaly calls up the vertical icons menu. Passing the cursor over the icon changes their appearance.

Pressing the left button opens a horizontal sub-menu. We name it the MENU BUTTON.

From the vertical icons menu you can enter inside 5 sub-menus.

3.1 The Menus

To create a specified object (ie a line) in a particular position you may need to select some other objects (ie 2 points). When you pass over an object Dr GEO shows a text bubble with its name. The bubble is displayed only if this object can be use for the creation of the new object (ie Dr GEO shows the name of the point you pass over but not the names of line, circle, etc.) This item is very useful in the creation of an object. Some objects can be created by several different methods but Dr GEO always shows you if a specified object can be use in the creation of another one. If there is more than one possible object that might be selected at a point Dr Geo shows ??? in a bubble. Click on that to see a list of possible objects. Once you select an object it blinks. If you click over it again you unselect it and it stops blinking.

The Point Menu

Within this menu you can create points with various properties. The horizontal menu offers the following options.

Free Point

A free point can be totally free or free to move on an other object (ie a line, a segment, etc.) You can create a point by a left click. If the mouse is over an object the point will belong to this object.

Middle Point

Create the middle of a segment : select a segment.

Create the middle of two points : select two points.

Intersection Point

Create one/several points as the instersection of 2 objects: select the two objects for which you want the intersection.

Coordinate Point

Create a point defined by its coordinates: select 2 numbers to perform this.

The Line Menu

From this group of menu you can create lines, half-lines, segments, vectors and circles by selecting two points.

Line

Create a line through two selected points.

Halfline

The first selected point is the halfline origin. The second point will be on the halfline.

Segment

Create a segment defined from two selected points.

Vector

Create a vector from two points : the first point is the origin.

Circle

Create a circle by :

Locus

Create a locus from two points: one point must be a free point on an object (line, half-line, etc.),the second point should be dependent upon the other point to produce an interesting locus. If not the locus will be reduced to the second point.

The Transform Menu

From this group of menus you can create parallel & perpendicular lines. Also there are geometric transformations : axial & central symmetry,translation and rotation.

A Parallel

Create a parallel line by:

A Perpendicular

Create a perpendicular line by:

Axial Symmetry

Computerize the transformation of a point, line, half line, segment, circle by an axial symmetry by selecting a line and another object (point, line, etc.): the first selected line is always the axial symmetry axis.

Central Symmetry

Computerize the transformation of a point, line, half line, segment, circle by a central symmetry by electing a point and another object (point, line, etc.): the first selected point is always the central symmetry center.

Translation Transformation

Computerize the transformation of a point, line, half line, segment, circle by a translation by selecting a vector and another object (point, line, etc.).

Rotation Transformation

Computerize the transformation of a point, line, half line, segment, circle by a rotation by selecting a point, an angle (geometrical or oriented) and another object (point, line, etc.) : the first selected point is alway the rotation center, the selected angle is the rotation angle.

The Number Menu

You can create number:

The Macro-Construction Menu

A macro-construction can repeat a construction sequence. It has several input and output objects. To understand the macro-construction you need to understand what is a proposition figure. Here an example:

   point A ------+ 
     |           | 
+----+           +- C' middle -------- segment [CC'] ------+ 
|                |  of [AB]          |                     | 
|  point B ------|                   |                     +-G intersection 
|                |                 +-+-+                   | of [AA'] & [CC'] 
|                +- A' middle -----+ | +-- segment [AA'] --+ 
|                |  of [BC]          | | 
|  point C-------+                   | | 
|     |                              | | 
|     +------------------------------+ | 
+--------------------------------------+ 

This show the creation process of the gravity center of three points. We call this a construction tree. After performing this construction we can build a macro-construction. Such a macro-construction should apply to three points (the input objects) this creation process and output the gravity center (the output object) of the three input points. Once a macro-construction is recorded, it can be execute, save or delete. Just read the following section to know how to manipulate macro-construction.

Features

Multi input object (memory limited). Multi output object (memory limited). Any number of macro-construction in Dr Geo (memory limited). The macro-construction can be named with up 8 characters. The macro-construction has a 5*30 text field for information (not appear yet). The macro-construction can be saved, loaded or deleted in the macro-construction menu. The macro-construction names and the macro-construction filenames are the same plus mac extension : macro-construction Gravity will be save as gravity.mac.

Limitations

Macro-construction can't be constructed if a human decision object appears in the macro-construction tree (moveable point on a line, etc.) however a human decison object can be chosen as an input object. Also a locus can't be involved in any part of macro-construction.

How To Build A Macro-Construction ?

  1. select the input objects and press enter
  2. select the output objects and press enter
  3. enter the name of the macro-construction. Remember you should use the same name to save the macro-construction
NB: Dr Geo informs you if the macro-construction is invalid. This means that the output object can't be constructed from the input object. May be you have forgotten some input object.

How To Play A Macro-Construction ?

  1. in the list double click on the chosen macro-construction
  2. select the input objects (same order as you created the macro-construction)
  3. the macro-construction executes as soon as you have selected all the parameters
NB: Dr Geo will display info bubble only on interesting object regarding the macro-construction

How To Save A Macro ?

  1. in the save menu (save fileselector)
  2. enter the macro name plus mac extension (to save center macro type center.mac)
NB: forgetting the mac extension, Dr Geo will save the current figure with a geo extension

How To Load A Macro ?

  1. in the load menu (load selector)
  2. select a file with the mac extension
  3. the macro with the same filename appears in the play macro menu

The Tools Menu

Move A Point

Move a free point : to give dynamism to the figure. Move a number or an equation. Also in this menu an object can be renamed : press a shift key and click on the object. In the case there is a conflict, the bubble will show ???. Click with the left mouse button. A menu will appear with selectable objects. Choose the desired object by clicking. Click again to move it.

Drawing Options

With this menu you can change the appearance of an object.

  1. select an object with the action button.
  2. a set-up window appears with the selected object drawing set-up, you can change :
    1. the width/size of object : the four straight lines. The first dot line means invisible object.
    2. the color
    3. the point aspect : cross, round or square.
  3. apply the style change by selecting again the object with the menu button. You can also apply this style to other objects.
  4. you can move the set-up window with the move bar on the top.
  5. you can close the window with the close button.

Set-Up Option

With set-up box you can:

Erase An Object

With the action button select the object to delete. Dr Geo asks you to confirm.

Save Option

With this option you can save:

Read Option

With this option you can read:

New Figure

Form there you can start again with a blank figure. All unsaved objects are be lost.

Quit Dr Geo.


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