[Ipe-discuss] pen issues of Ipe 7.0.12

Otfried Cheong otfried at ipe.airpost.net
Wed Nov 24 02:25:09 CET 2010


On 11/24/2010 02:54 AM, Gerhard Mesenich wrote:

> 4) menu item 'Fit page width'
>
> Page width is missing in the menu and on the edit toolbar.

It's only missing because I don't have a good icon for it.  If you send 
me one that I can reuse, I'll implement it.

> Handwriting works well, but speed is marginal on slow computers.
 > ...
> So in the future going to a fixed point
> binary data and an optimized picture storage format for the Pen-Tool
> only should be considered.

These have nothing to do with handwriting speed.  The handwriting 
sampling rate is so slow that even my ARM handheld can handle double 
arithmetic at that rate easily.

The problem is the redrawing:  The Ink tool is written in Lua. For every 
new point, it updates the stroke shape, a Lua data structure.  This data 
structure is then converted to a C++ data structure from scratch, and 
then a screen update is requested.  This causes the entire Ipe drawing 
to be copied from a background pixmap to the screen, and then the stroke 
is redrawn on top of it.

For ink strokes, it would suffice to simply add new segments to the 
existing image.  I will see if I can implement that (it would require a 
completely new interface to the canvas).

> If time allows, it would be nice if you could fix the first 3-4 issues
> before the next release.

And how much would you pay for that?

Since I do not have a tablet, you should not expect too much specific 
table support in the near or mid-term future.  I have no plans for Ipe 
to become a substitute for Xournal.   The only eraser that I will likely 
implement is to erase entire strokes.

One interim possibility would be to treat eraser events (which I believe 
are implemented on many tablets as pen events with the side button 
pressed, although there also seem to be tablets where the opposite 
(broader) side of the pen is used) as normal pen events with the 
Ctrl-Key held, giving you faster access to some functions.

Currently eraser events are ignored - drawing with the pen's side button 
pressed should do nothing.  Can somebody confirm that?

Cheers,
  Otfried




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