[Gambas-user] painting graph to image continuously

[wally]

On Thursday 16 December 2010 18:03:21 Fabien Bodard wrote:
> if you want us to help you ... please be more explicit on what you want to 
do !
> 
> first why do you want to resize the drawing area ????(for scrolling ?)
> 
> are you sure you have understand all the capabilities of a drawing
> area ?  do you know the _draw event ?
> 
> 
> waht i've understand is :
> 
> you want like for an array draw on an image... resizing it with
> preserve of the last draw, and add a new draw.
> 
> if it's that ..; i think there is many things you have not understand
> ... tell me
> 
> 
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Fabian,

i just want to do something like an ECG. Drawing a graph from continuously
received data from SerialPort. Exactly i read data from the ADC of an Arduino 
uC via the Serialport and want to draw this graph. Behind the Arduino ADC
is a HPLC Detector and to take a spectrogram may last up to an hour.
I store the data during receive to file for further external math processing.
But i need a visual control whats going on. 
Using an Image to paint and resize as needed works nice.
But the DrawingArea do something like copy stuff to new (via resized) area
instead of just increase width. Maybe i need to repaint always or to buffer 
the recently drawn stuff before resizing.

My last attachments contains a picture file with 4 circles. 3 of thes circles 
are created by simply resizing the drawingArea. see attached simple 
short code please. 

I do not know whats going on internally and i do not know where to find
more information and further reading on it.
 
> if it's that ..; i think there is many things you have not understand
> ... tell me

agree, thats the reason i post here

> are you sure you have understand all the capabilities of a drawing
> area ?  do you know the _draw event ?
   
where did you find your knowledge on this. If i need to read all the qt4 and 
GTK stuff i might programm directly in C/C++. I have choosen Gambas for rapid 
apps devel. 

i try to attach a xcapture,of the DrawingArea behavior, It should explain 
whats my problem. If it's not allowed to attach a 1MB file i may send to 
your email.

(2nd trial: message body too big, i send again without attachment)

cheers wally