Basic Drawing - 4

Rotating & Scaling a Line.-

It has been already explained how to move a line (more specifically, how to translate a line) and how to modify it by changing one of its defining points. The good news is that the process explained is exactly the same for all the geometrical objects available in Metagraf. In this paragraph it will be explained how to rotate and how to scale objects.
There are two ways of performing this actions: the quick one and the precise one.
For using the quick rotation/scaling of an object it should be activated the control ON state for transformations. This is done by clicking the bottom-right button of Metagraf's screen, near the small gray window with the "Ctrl OFF" label.

Clicking this button will change this small window to the one that can be seen below:


If an object was already selected or a new one is selected in this state, in the center of the object one vertical and one horizontal blue lines will be apparent, being the object of red color as corresponding to its selected state. See next figure:


The circles at the extreme of this lines correspond to points that can be selected with the mouse cursor. The vertical line serves for scaling the object and the horizontal for rotating it.
Pressing the mouse left button with the cursor over one of this points, if the button is not released, dragging the mouse will move the point and the scale or angle will be accordingly modified. If the button is released, the control will be transferred to the arrow-keys of the keyboard in the same way as explained before.
In this situation, the points will not change its aspect but if anyone is selected the color of the object will change from red to purple.
The angle rotated will be the angle that the rotation line will have with the horizontal, and the real value of the rotation will be visible in the big bottom "Text" window, as shown in the next figure:



In the next paragraph it will be explained how to made this kind of transformations in a less intuitive but more precise way.
It should be mentioned that the "Ctrl ON" state can be deactivated by clicking once more the button used to activate it or, more simply, just by clicking the right-mouse button. Also, for those using a mouse with three buttons, clicking the center button activates this state.
It is recommended to deactivate this state once it has been used.




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Madrid, January 2006