Questions from Beginners MQL5 MT5 MetaTrader 5 - page 1488

[Sergey Gridnev]

In other words: call Comment only if the string passed to it has changed

[Maksim Burov]

Sergey Gridnev #:
If the information has not changed, do not call Comment

Information changes periodically.
For example, I want to see the position with the lowest opening price. Or to know the tick of the last closed position.
You can write everything in the print, but it is not convenient to look, you can miss. And so I can see where I have errors at once.

[Alexey Viktorov]

Maksim Burov #:

Googled it...
Cool type) where does he fit in with my problems))))))

On the forum find the thread "canvas is cool" or Latin spelt but I remember.

[Artyom Trishkin]

Maksim Burov #:

Googled it...
Cool type) where does he fit in with my problems))))))

[Maksim Burov]

Artyom Trishkin #:

Thank you. Read the thread, watched the video. It's pretty cool. But to me to this, as ... far)
I have everything more prosaic, why it starts to slow down, how to fix, and what affects).

[Artyom Trishkin]

Maksim Burov #:

Thank you. Read the thread, watched the video. It's pretty cool. But to me to this, as ... far)
I have everything more prosaic, why it starts to slow down, how to fix, and what affects).

Comment at each tick redraws the chart. Hence the brakes.

Do it on canvas. There you need to update only the kanvas. It is practically not necessary to redraw the chart.

[Maksim Burov]

Artyom Trishkin #:

Comment redraws the chart on every tick. Hence the brakes.

Do it on kanvas. There you need to update only the kanvas. It is practically not necessary to redraw the chart.

Thank you.

Do you have any examples?

[Alexey Viktorov]

Maksim Burov OBJ_BITMAP_LABEL and resources.

It is certainly not cartoons using iCanvas Nikolai Semko but better than using simple OBJ_LABELs

[Maksim Burov]

Alexey Viktorov #:

Take a look at this indicator

🙏

[Nikolai Semko]

Maksim Burov Comment in the EA code?
What options are there to fix this?
Does it affect the speed of optimisation?

You don't have to use kanvas.

For comment not to slow down the tester with visualisation, it is necessary that comment is not called more often than 30 milliseconds.

For example like this:

   static uint lastCalc= 0 ;
   uint cur= GetTickCount();
   if (cur-lastCalc> 30 ) {
      Comment("blablabla");
      lastCalc=cur; 
   }

Or use Print instead of Comment if it is important not to skip values.

If better visualisation of the output of any values is important, then kanvas is better.

https://www.mql5.com/ru/forum/277867/page8#comment_19186284