General How to.-
In Metagraf, all the objects (geometrical shapes) are created in the same way:
The "name of the game" is click and drag. It will be explained in what follows.
In Metagraf there are two basic modes or states that have a visual correspondence with the cursor (mouse cursor): mode edit and mode insert.
When beginning Metagraf, it is in mode edit. The cursor is the usual "hand cursor". If the left-button-mouse is clicked when the cursor is in the drawing screen, nothing happens. If it is clicked and, without releasing the pressure, dragged, a red rectangle will appear on the screen. This rectangle will disappear as soon as the button is released.
To begin drawing (creating an object), some object-button on the tool-bar at left or some item corresponding to Objects on the Menu bar, should be clicked. The mouse cursor will change to a "cross-hair" one with a rectangle below, at right, with a small icon of the object selected. The center of the cross-hair correspond to the active point of the cursor.
The state or mode has been changed to insert mode, and now everything should be carefully done. (The insert mode is the "dangerous one" as will be seen.)
An object has been selected and the mode has been changed automatically to insert. This is shown by the shape of the mouse-cursor. To come back to the edit mode, without doing anything (Oh! this not the object wanted!), just clicking the right-mouse button once will do.
All the geometrical objects in Metagraf (with the sole exception of the Point) are created in the same way. Being in insert-mode, the mouse-cursor over the drawing-screen, the left-button-mouse should be clicked and without releasing the pressure, dragged.
If the object selected is a simple one defined by two points: right-line, rectangle, ellipse, circle, regular polygon, round-rectangle or spiral, releasing the mouse-button will finish the process and the mode will change safely to edit-mode.
If the object is a composite one, as polyline, all curves, arc, irregular polygons, etc., releasing the mouse-button will maintain the insert-mode as more points should be clicked to define the object. This points are clicked always with the left-mouse-button, just pressing and releasing in each point. Once the object created is satisfactory, the right-mouse-button should be pressed once to come back to the edit-mode.
If the object is the Point-object, just clicking and releasing without dragging, will create a point.
If in Insert-mode, to create an object different from a Point, the left-mouse-button is clicked and released without dragging, a problem can arise. Metagraf has been told that some object is going to be created, and this object needs the dragging operation. So, when trying to recreate this object, it will not be found in its correct form, and Metagraf can refuse to work in these conditions. There is a way to control that all objects have been created in due form, and correct any mistakes. More on that, later on.
Finally an object will be on the screen, perhaps not in the exact place or with the exact shape wanted, but as will be seeing, this is very simple to correct.
Madrid, January 2006 |
|