Using QCAD Simple API most effectively and successfully? [SOLVED]

[Joseph1916]

To All:

I'm new to programming since the late 1970's and early 1980's..... I could use tip's on the QCAD's Simple API, such as how it is being used for development?

I'm getting feedback that executing with the ECMAScript shell one line at a time is effective.
The below links was helpful:

[url]https://www.freecodecamp.org/news/objec ... rogramming[/url]
[url]https://dmitripavlutin.com/javascript-c ... ete-guide/[/url]


Joseph1916

[andrew]

Please refer to our scripting tutorials at:
https://qcad.org/en/tutorial-script-programming

Feel free to post back if you have questions. Please be as specific as possible, so we can help effectively.

[Joseph1916]

[attachment=3]Header.png[/attachment][attachment=3]Header.png[/attachment]

OS: Ubuntu Linux 22.04
QCAD Version: 3.28.1


I have included 4 attachments dealing with the *.ui file type. I am assuming they appear above and in reverse order. The 4 reflect the content of ExMyMinimal.ui. This file executed on my Ubuntu Linux 22.04 fine.

I am intending to use this format as a template for *.iu files when needing widgets, custom widgets to obtain a functional GUI.

Should that work? Add any comments......

Another post to you will be about the associated ExMyMinimal.js file.

Jsseph1916

[Joseph1916]

Andrew;
This posting deals with the content of ExMyMinimal.js file. Line 1-57 inclusively. Again they might be in reverse order.
Line 1-10 sets up the functions required structure with include files and main function call

[attachment=3]js_function_declaratiom.png[/attachment]

the use of the term "prototype" is of interest to me, as it appears multiple times......
the same is true of the term "this" .......


[attachment=2]js_prototype.png[/attachment]
The reserved term "var" appears in in some of my snippets. Considering the work being done, that is not many variables !!


[attachment=1]js_vavable_assignment_+.png[/attachment]

[attachment=0]js.initialize_slot.png[/attachment]

ends with an initialization call, amazing !

I hope this makes some sense. Trying to learn this new world we all have, almost with each passing day....

Thank You !!

Joseph1916
I will be out tomorrow..

[CVH]

Joseph1916,
You are probably following this tutorial:
https://qcad.org/en/tutorial-interactive-script-actions
It is fully explained step by step, If you read carefully and understand each step then the final code make sense.

May I remark that adding screenshots is not helping, using a code panel is the proper way.
Code may be tens to several hundreds lines long.
We can't copy/paste and test/correct code from a picture.

Indeed these attachments are listed below and seemingly in reverse order.
But these sentences in your post tells me that you tried to insert them inline with your text.

Code: Select all

[attachment=3]js_function_declaratiom.png[/attachment]

Why they don't occur inline is a mystery for me.
Where they inserted, removed and re-inserted?
BTW: The above is a code panel otherwise the forum thinks that I am also inserting a picture inline in my reply.

Correct, var is the most common way to declare variables.
One should always declare variables.
Remark that event and preview in ExMyMinimal.prototype.pickCoordinate = function(event, preview) {...}
are also declared variable names of arguments that are passed on to the pickCoordinate function.

Variables have block scope meaning that the exists within the function block from { to }.
Outside that block they have no meaning, leaving the block they do not retain their value and if unused for a while they are removed by what is called a Garbage Collector. (Otherwise the memory will quickly be filled with unused variables )

Considering the work being done, that is not many variables !!

Indeed, the power of the intensive QCAD API.
With a document, an operation and a circle shape we add a circle entity to the drawing.
Previewing or actually casting it is handled in the pickCoordinate function.
Remark that the pickCoordinate and getOperation functions are called by QCAD on regular basis to update the screen.

In the last step of the tutorial we add a basic Option Toolbar UI, read the value on change and add a circle with this radius.
To create basic to complex UI files for the Option Toolbar or for a dialog I can advise Qt Designer.
One tiny mistake/typo in the XML file and it won't work, seemingly without a clear reason, not debug-able.

About prototype and this:
this is in fact your class.
this.pos is practically the same as a variable but it is called an object.
An object of your class with the name 'pos'.
With a subtle difference: It is passed by reference and not by value.

prototype is harder to explain but what interest us is that the class objects are shared among all class members.
this.radius in slotRadiusChanged{...} is the same thing as in getOperation{...}. Both are 'prototyped'.

Because of ExMyMinimal.prototype = new EAction(); the meaning of this can also be EAction ...
... this.updatePreview(); executes https://github.com/qcad/qcad/blob/maste ... n.js#L1711
... and this.applyOperation(); executes https://github.com/qcad/qcad/blob/maste ... n.js#L1753

Remark then for example that the pickCoordinate function of the EAction class does nothing:
https://github.com/qcad/qcad/blob/maste ... n.js#L1784
Without a tool, your tool, running one can click wherever one wants in the drawing.
Picking coordinates (and moving the cursor) does nothing at all.
Once your tool is running then it previews the circle or adds the circle to the drawing.
ExMyMinimal.prototype.pickCoordinate {} overwrites the standard behavior.

ends with an initialization call, amazing !

Mostly the order has no meaning, we tend to end with the initialization or include it as a separate script file.

This is how QCAD retrieves all tool scripts and initialize them on startup.
It looks for sub folders in the 'scripts' folder. See: https://github.com/qcad/qcad/tree/master/scripts
In each folder it looks for the *.js file with the same name as the folder.
This is the main tool script file to implement.
In that file it looks for the init function or it looks for a *Init.js file again with the same prefix as the folder name.

It may be that in your QCAD installation the 'script' folder is fairly empty compared with GitHub.
All standard tool scripts also come in compiled form
Not to worry, everything on GitHub is there and more when it is QCAD Pro or QCAD/CAM.


Finally, nothing here is QCAD Simple API.
This is mentioned in the Shell tutorial under 'Running commands': https://qcad.org/en/tutorial-the-script-shell
And an overview of the Simple API functions: https://www.qcad.org/doc/qcad/latest/de ... imple.html
One can write simple code for the Shell or for an Addon but ... Interactive ... That requires the tutorial mentioned at the beginning.
addCircle(cx,cy, radius) will add a circle entity at (cx, cy) without using a cursor, without a preview.

Regards,
CVH

[Joseph1916]

Having Internet problems. I will be back when I figure out the issue. Uncovered Internet provider has shut me down now till Saturday August 12th. As of now I only have cell phone connection. I have to make do till Saturday my time.

The Internet provider now informs me not till 11:59 pm of August 12th.

I am beside. Myself. Hope to be online soon.

[Joseph1916]

I see at this point I was not familiar enough with the use of other tools I already have at my disposal. Or have not gained enough knowledge about QCAD.

I WILL continue exploring Scripting to fully appreciate the Simple API.

I note l have been reading on Javascript and becoming pretty sure I will not require C++. Everything can be done with Javascript. With the use of QCAD "Simple" API .

I am going to post "SOLVED" to this thread.
Read the Documentation and comprehend them !!

Joseph1916