[fpc-pascal] Talkback and detecting touch events

Thomas Young tygraphics at icloud.com
Tue Sep 17 19:16:06 CEST 2019

Years ago I had a career as a technical illustrator. First analog then digital. Perhaps the following code I developed back around 1992 might be helpful to you.

H = Horizontal coordinate on picture plane.

V = Vertical coordinate on picture plane.

XYZ = 3D coordinate.

distance = "camera" distance from the model:
a range of values [0..15000] (logrithmic).

height = "camera" height from 0 ground plane.

H := scale * (X * distance / (Y + distance)) + H_offset;
V := scale * ((Z - height) * D / (Y + distance)) + Y_offset;

Thomas Young
Sent from my iPhone

> On Sep 17, 2019, at 11:20 AM, Mgr. Janusz Chmiel <janusz.chmiel at volny.cz> wrote:
> Please would somebody of us try to tell Me, if Android API functions can detect how many fingers have been used to touch The display even while Talkback screen reader work ane Explore by touch service is communicating with display?
> I do not want to use graphical mode, since it require that Talkback screen reader must be turned off. One developer, who have used Java language used some technique, which could detect how many fingers have been used to shift from down to up. If one or two. Thank you very much for yours tips how to detect this specific touch events when Talkback is running.
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