In this rather long article, I want to reveal several alternative methods that you can use to your benefit when composing math artwork in the Math-o-mir software. These methods are not that obvious and you may easily miss them if nobody tells you where to look.

  • Use the hash key ‘#’ to enter fraction lines
  • Use the Alt+Spacebar keystroke to select objects
  • Use the Ctrl key when hand-drawing
  • Use the dot (period) key to enter functions


Using the hash key ‘#’ to enter fraction lines

To enter fraction lines you can either use the double slash-key ‘//’ keystroke or the hash-key ‘#’ keystroke. If you type many fractions you will benefit if you learn to use both methods appropriately.

The double slash ‘//’ method is easy to explain: by hitting the slash key twice, the empty fraction element will be created and the cursor will automatically move into its numerator. This method, however, has two disadvantages: 1) you obviously need to press more than one key to create the fraction symbol; and 2) the sequence feels ‘wrong’ because when writing simple fractions with pencil, you would first write down the numerator, and just then draw the fraction line below it.

For example, to type a/b fraction using the ‘//’ method, you would use following keystroke sequence: //a<enter>b

To make simple fraction typing faster and more natural, I  also implemented the hash-key ‘#’ method. When you hit the hash-key, the fraction element will be created and the element just left of the cursor will be moved into its numerator. The cursor will automatically move into the denominator.  Therefore to type the a/b fraction, you now need to use following keystroke sequence: a#b. This looks more natural, and also saves few keystrokes.

The ‘#’ method is only beneficial if you are typing fractions with simple numerators. You can, theoretically, hit the # key more than once to put more than one element into the numerator, but the advantage is lost. For fractions that have many elements numerator, I would suggest the ‘//’ method.

In fact, instead of the ‘#’ key you can also use the grave-accent key ‘`’ for the same purpose (it is much easier to type the grave-accent key then the hash key on some keyboards).


Using the Alt+Spacebar keystroke to select objects

When you work with mouse you can select objects by dragging a selection frame over them. This can be annoying when you want to select only one object, especially if other objects are overlapping with the target so that you cannot select just the wanted one.

To select an object, equation or drawing, you can point it with the mouse pointer and then hit the Alt+Spacebar keystroke. The object will be added to the selection (unless it is already selected in which case it will be removed from the selection).

In fact, there is more… if you hit the Alt+spacebar while the mouse is pointing at empty area, the last created object will be selected (hit the Alt+spacebar several times to select several last-created objects). This works even in the hand-drawing mode and may be handy if you want to change the line thickness or the color of the object you just painted.

The major disadvantage of the Alt+Spacebar selection method is that it cannot be used while the keyboard typing mode is active because Alt+Spacebar is then used to toggle between text and math typing modes.


Using the Ctrl key when hand-drawing

When you are drawing and your mouse pointer is pencil-shaped, you cannot do much editing on already existing objects. For example, you cannot move them nor resize them. But if you press and hold the Ctrl key, you will temporarily exit the hand-drawing mode (the pencil-pointer will revert into arrow-pointer) and you will be able to access already existing objects.

But there is even more… when the Ctrl key is down, you can edit nodes of hand drawings. Drawing with mouse is hard and very often you will need to correct your drawings – then just press and hold the Ctrl key and edit drawings at the node level (btw, to add a new node, hit the spacebar key while you are mouse-pointing at a drawing).

The node-editing feature is really useful as you can convert some basic shapes into completely different form. For example, to draw an irregular triangle, you can draw a rectangle using the rectangle-drawing tool and then node-edit it to remove one node (btw, you remove a node by dragging the node at a nearby node to join them into one single node).


Using the dot (period) key to enter functions

If, like most users, you only care about writing your formulas, you can generously type “f of x” simply as: f(x). However, then the Math-o-mir will regard the ‘f’ as any other variable and will not be aware that ‘f’ is actually a function.

But if you care about structure of your formulas you will want to tell the Math-o-mir that the ‘f’ is a function. You will generally do this by casting a function-generating command like \f (or \sin, or \cos, or \log, or \whatever) that will generate the function object. The Math-o-mir will show its gratitude by rendering this function name in a serif font with greenish color to make distinction between functions and regular variables.

However, a much faster way to enter a function would be by hitting the dot key just after the function name. For example you can type ‘f.’ to enter the ‘f’ function (or ‘sin.’ to enter the sine function…). The dot key is used as a converter key that converts variable(s) into function. The dot key is easy to type on most keyboards and if you type many functions you will see much benefit if you adopt this method.

There is one disadvantage when using the dot key to generate functions: you can only convert single-letter functions (like ‘f’, ‘g’, ‘y’…) or those multi-letter functions that are considered standard (like ‘sin’, ‘cos’, ‘ch’, ‘log’…).