Image on shift register slowing down the program

[mam1nej]

Hello Everyone,

I am trying to add a beam tracking feature to a program that controls a laser, reads its beam position and plots it.

The beam tracking option is supposed to give the previous beam positions as well as the current one.

I was able to get it running by using a shift register to carry the image on one of the program threads:

I think the code is self explanatory so let me descrive the problem I am running to:

After about 30 min of execusion, the program responsiveness becomes very low and the image refresh rate seems to be the problem. When I wired the shift register the wasy I did, I though the image that was carried was a kind of a pixel array, but it looks like its size is getting bigger and bigger the longer I keep adding those back beam position squares.

I kind of lie this simple approach but I am wondering if there is a better way of handeling the picture: should I convert to bmp then import it as background ? is there a function that converts from and to a bitmap array ?

Thanks in advance

Regards,

AJ

[Ben]

If memory serves me...

You can cast (use type cast) the picture data to a string and what you will find is something that looks like old-school "HPGL" (HP graphing Language) ... commands strings like move pen to, pen down, draw arc, etc.

So wha you are doing is building a longer and longer set of draw commands.

Toss the SR and set the picture function "Erase first" to false. The Picture will act like the pixel array you wanted.

Ben

[MikaelH]

Check the size of that picture wire.
Type cast to String and use "StringLength", I think you're adding to many drawing elements on that picture.
Maybe check if you've already drawn a point at that location and is so, ignore that.
And you're running the look without a delay, is that okay?

[mam1nej]

Thanks for the reply MikaelH.

I do have a delay in the real loop, I just made a mini-version of it to explain what I was doing.

The idea of filtering same location points is good. I will definetly add that.

I am still wondering if I can convert the picture to an arra after drawign the point, pass that through the shift register, and import it as background image for the next point ?

[mam1nej]

Thanks for the reply Ben,

If I remove the SR and start a new picture every time, the resulting picture will only display the current position, I will be loosing the history carried by the SR. Does it make sens ?

[MikaelH]

I would keep all data in an array, and then redraw the picture control from scratch after you've updated the array with new data.

[daveTW]

Hello Mikael,

your approach is what Ben already described. Since the blue wire, containing the picture, is basically a string, containing drawing commands which are executed by the picture indicator, you don't need to hold a separate array of coordinates. They are held in the picture wire!

And to explain Ben's hint again: Uncheck the "Erase first" item in the context menu of the picture indicator (on the front panel). See attached image:

This Picture is created with the following code:

[mam1nej]

Got it !!!

Thanks for the help , Ben, Michael and Dave.

[mam1nej]

The only tradeoff in this case is that I can't display the current position cursor in floating ( and in different color)

I will find a work around it.

[daveTW]

What do you mean with floating?

And for the different color: What about storing the very last position and drawing the point again with black and painting the current position with the different color.