[Ipe-discuss] Ipe on Tablet-PCs

[Gerhard Mesenich]

Hi there,

I am a German engineer using Ipe on a Tablet-PC (HP2710p) and would like
to share my thoughts and observations for such use. With some mostly
minor improvements Ipe could become an excellent program for taking
engineering notes and to make sketches, drawings and presentations
covering almost all needs in that field.

Background:

Tablet-PCs in slate mode usually only have an electromagnetic pen with a
side-button and a pressure sensitive tip. In addition the pen usually
also has a second opposite pressure sensitive tip, which is intended as
eraser. Personally I almost never use the eraser-tip because of the
cumbersome flipping action. There is also an On-Screen-Keyboard, which
is somewhat cumbersome to use and should mostly be avoided.

With such limited input Ipe currently becomes very difficult to use.
Technically a pen-computer is basically just a screen with a pressure
sensitive 2-button mouse, but with almost perfect fine-control.

To overcome these limitations I am now using Ipe with a Bluetooth
Mini-Keyboard seen here:

http://www.irxon.com/english/products/kb850_e.htm

This setup works quite well, but leads to problems due to the
international layout on the native German operating system (winXP) where
the required language switch and the additional hardware is a nuisance.
For decent pen-computing Ipe requires some relatively simple enhancements:


Handwriting:

Handwriting itself works very well already (Freehand-Lines). This is the
preferred and fastest method for note-taking and drawing annotation. It
could be enhanced by implementing pressure sensitivity (Line-width); but
personally I rarely use it and don't consider pressure sensitivity
essential in the engineering field.

Missing but most essential is a good eraser function. This is the most
serious deficiency of Ipe for such use.

Eraser:

The eraser should be able to work in two different modes:
Freehand-eraser and Stroke-Eraser, invoked with two additional toolbar
buttons.

In Freehand mode the Eraser function should best be invoked with the
side button of the pen (same as the left mouse button), which allows the
most intuitive and fastest work flow.

The Stroke-Eraser would mostly be used on shapes and full words. Both of
these eraser functions are essential.

Very nice to have would be a universal Freehand-Eraser working on shapes
too. Arcs could then be just drawn as circles and the superfluous parts
be erased. Polylines could be broken up with the eraser and be moved
independently. Such way rather sophisticated drawings could easily be
drawn with very few basic shapes. Such a universal function would
probably be too difficult to implement right away, but should definitely
be considered in the future.


Pen user interface:

Edit-Toolbar:

Totally missing is an Edit-Toolbar, which is essential for pen-input.
Beside the usual standard set (copy, cut, paste, delete, undo, redo,
pan, zoom in/out/page-width/full-page) it should have the essential
Modifier-Keys for Ipe: ctrl, shift, alt and the necessary combinations.

Such way all basic Ipe functions could easily be reached with the pen.
Nice to have would also be a button to directly invoke an
On-Screen-Keyboard, which is usually part of all operating systems. That
way there is no need to worry about all kinds of different
multi-platform input methods.

Pen-Interface example:

A good example for a very good and intuitive pen interface is xournal:

http://xournal.sourceforge.net/

Xournal is an excellent notetaking and pdf-annotation program, but lacks
almost all serious drawing functions, which are often needed. For Ipe
the Edit-Icons could probably be just taken from there, if the author
consents (also Open-Source).


Context Menu:

Another good way to make the Edit functions reachable could probably be
through the context menu. It could be made two-level-type; with the
basic edit functions on the first level, or alternatively on top of the
standard context menu. Such way it could hopefully be implemented with
a simple Lua-script, so that experimentation with different input
strategies could be easy.


Summary:

Ipe needs a good eraser function and an Edit-Toolbar and/or a context
menu to make it usable with Pen-Computers. A configurable toolbar would
be the best.

Apart from that Ipe has already almost everything needed for a good
standard drawing program for such purpose. With a few and relatively
simple enhancements Ipe can serve for notetaking, engineering-sketches,
publication-drawings and full presentations. The program is already
intuitive to use; with little effort I was able to make some nice
drawings of excellent quality much faster than with anything else I know.

Thanks in advance for consideration and an already great program!

Regards,
Gerhard Mesenich