off screen drawing

QNX Newsgroups (Archives) qdn.public.qnx4.photon
1

Hi,

I have to play around with some off screen drawing to see if I can get the
desired functionality for one specific feature in our App. We are trying to
draw a map with several aircraft positions and tracks not to mention wind
barbs along the tracks.

Are there any white papers/documentation on this? Any thing at all to help
a “poor” developer :slight_smile:?

I’m using the karaoke example from the /usr/free section of the QNX ftp site
and I have some specific questions.

I understand that you can draw in the memory context from anywhere. I also
understand that you can only draw on a PtRaw widget from inside the draw
function.

In the example the drawing is done in the animate_iteration() function,
which gets called by a PtTimer. I can’t figure out for sure how the display
is getting updated by the PgDrawImagemx() function? How does the image link
up to the PtLabel widget?

If you have an example with several PtRaw widgets and you want to draw
different data on each widget from a memory context, how is this done?

TIA

Augie

2

Hi Augie,
I wrote an app. for IFR approach pumping NMEA0183 messages from GPS into the
PtRaw widget for visualisation. I use this app. to support my VFR flights
and it is of course not FAA appr. but it is quite easy…if you are
interrested contact me by email.
cheers, Peter pw@dolphin.de

“Augie Henriques” <augiehenriques@hotmail.com> schrieb im Newsbeitrag
news:a5obji$3e9$1@inn.qnx.com…

Hi,

I have to play around with some off screen drawing to see if I can get the
desired functionality for one specific feature in our App. We are trying
to
draw a map with several aircraft positions and tracks not to mention wind
barbs along the tracks.

Are there any white papers/documentation on this? Any thing at all to
help
a “poor” developer > :slight_smile:> ?

I’m using the karaoke example from the /usr/free section of the QNX ftp
site
and I have some specific questions.

I understand that you can draw in the memory context from anywhere. I
also
understand that you can only draw on a PtRaw widget from inside the draw
function.

In the example the drawing is done in the animate_iteration() function,
which gets called by a PtTimer. I can’t figure out for sure how the
display
is getting updated by the PgDrawImagemx() function? How does the image
link
up to the PtLabel widget?

If you have an example with several PtRaw widgets and you want to draw
different data on each widget from a memory context, how is this done?

TIA

Augie