Touch interface development

Benedict Yappy yappy.benedict at gmail.com
Mon Jul 7 02:15:48 UTC 2014


Hi Plasma developers,

I'm a new linux and KDE (Sabayon) user on a touch-enabled laptop (Ideapad
Flex 14), and also learning to code (could use some tutor :p). My
touchscreen was recognized well.
I'd like to discuss/ask about the current development/implementation of
touch support.
I have tried Plasma Active, but I still need to use my laptop as a
full-fledged desktop where touch is simply an additional input device.

I found that my touchscreen is treated like a desktop mouse taken to the
screen with immediate switching of cursor position. Such approach has some
notable drawbacks compared with touch interface in other platform:
1. High accuracy necessary to register a double click. Double click in
touch devices is prone to mevement of the pointer. Some tolerance in double
is necessary for proper smooth operation. In android, single press is
launching.
2. Touching and dragging is equivalent to click and dragging, which moves
an item, not scroll the screen. To scroll purely using touch screen, touch
users had to resort to dragging the scrollbar.
3. Long pressing does nothing different with holding a click.

Although applications are still not developed to be touch friendly, I
believe some compromise can be made to accomodate touch users.
As touchpad is treated differently with desktop mice, maybe touch screen
can be made as a separate input device. Such then, two options are
available:
ANDROID behaviour:
1. Single press = launching, equivalent to double click using mouse.
2. Long pressing = right click, with added option to start multi-select (as
in file browser, like holding shift in a computer).
3. Pressing and dragging = scrolling, much like using hand tool in
scrolling a PDF document in Okular.

WINDOWS 8 behaviour:
1. Single press = selecting, equivalent to single left click using mouse.
2. Long press = right click
3. Double press = double click using mouse. However, some there are some
tolerance area of the pointer. In Windows, the tolerance area is marked
with an unconfigurable box. We can improve by adding a touch tolerance area
which can be adjusted (for instanwce, 8px tolerance area).
4. Pressing and dragging = scrolling, much like using hand tool in
scrolling a PDF document in Okular.

Only implementing these ideas looks simple and straightforward, but can
help touch users very much.
I think implementing the Windows 8 will be simpler (hence adopted by the
giant company?). A new KCM might even be implemented to switch between
options, much like the breath of options available selection behavior in
Krusader.
Is there chance that these ideas of touch improvements being implemented?

Regards,


Benedct.
PS. I apologize if I email in inappropriate section, please direct me.
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