[Scilab-users] ?= GUI hel

Claus Futtrup cfuttrup at gmail.com
Fri Nov 29 21:21:05 CET 2019


Hi Stéphane

Lazy = not pretty.

... but you didn't answer my question. Which way do you personally 
prefer? ... and why?

Cheers,
Claus

On 29.11.2019 21:13, Stéphane Mottelet wrote:
> Hello again,
>
>> Le 29 nov. 2019 à 19:55, Claus Futtrup <cfuttrup at gmail.com> a écrit :
>>
>> 
>> Hi Stéphane
>>
>> >In "ge_fs=ge_fs" the lhs is a local copy and the rhs the variable in 
>> the calling context.
>>
>> I figured something like this was going on, but I don't find it 
>> logical. I read this as follows: The ge_r is a global handle, for 
>> which the function doesn't have write access. When you assign it to a 
>> local variable (it can be the same name, or a new name, I suppose), 
>> then suddenly this opens up for writing to it (so you can set the 
>> properties). Strange. I don't think even a hardcore programmer can 
>> find this to be "pretty code" ... it looks like a hack / a workaround 
>> to me.
>>
>
> No hack here. Please 
> see https://wiki.scilab.org/howto/global%20and%20local%20variables 
> <https://wiki.scilab.org/howto/global%20and%20local%20variables>
>
> Even the very orthodoxic Julia uses in some similar context  lazy 
> global variables.
>
> S.
>
>
>> I read your response just as - this is another way to do it - but 
>> which way do you personally prefer? ... and why? (maybe execution 
>> speed? ... or is there a benefit in flexibility that I cannot see?).
>>
>> Best regards,
>> Claus
>>
>> On 29.11.2019 19:21, Stéphane Mottelet wrote:
>>>
>>>
>>> Le 29/11/2019 à 19:17, Claus Futtrup a écrit :
>>>> Hi Stéphane
>>>>
>>>> Hm, you're right. This actually fixes the problem, but I do find it 
>>>> to be a strange "solution" that you write each of them to be equal 
>>>> with itself ... I prefer calling the set() function.
>>>
>>> In "ge_fs=ge_fs" the lhs is a local copy and the rhs the variable in 
>>> the calling context.
>>>
>>>>
>>>> Cheers,
>>>> Claus
>>>>
>>>> On 29.11.2019 19:05, Stéphane Mottelet wrote:
>>>>> To makeit work, just insert
>>>>>
>>>>> ge_r=ge_r;
>>>>> ge_fs=ge_fs;
>>>>> ge_hz=ge_hz;
>>>>>
>>>>> at the begining of function calc.
>>>>>
>>>>> My two cents...
>>>>>
>>>>> S.
>>>>>
>>>>>
>>>>> Le 29/11/2019 à 18:58, Claus Futtrup a écrit :
>>>>>> Hi Antoine
>>>>>>
>>>>>> >Not much progress because I never managed to get a minimal working example
>>>>>> I can repeat my example again and again. It never works. Please 
>>>>>> see it below.
>>>>>>
>>>>>> Do you agree. This consistently fails if you run it from Scinotes 
>>>>>> editor ... but if I copy e.g. ge_r.visible = "on" to the command 
>>>>>> line (not from within the calc function), then it shows up.
>>>>>>
>>>>>> /Claus
>>>>>>
>>>>>> // BAD_GUI_EXAMPLE.SCE
>>>>>> //
>>>>>> // Demo of how _NOT_ to build a simple GUI in Scilab.
>>>>>>
>>>>>> // Initialize variables
>>>>>> m  =  1;  // Moving mass 'm'(kilogram)
>>>>>> k  =  1;  // Stiffness, spring constant 'k'(Newton per meter)
>>>>>> fres  =  1;  // Resonance frequency (Hertz)
>>>>>>
>>>>>> function  calc()
>>>>>>      m  =  evstr(get(ge_m,"string"));  // get content in uicontrol ge_m
>>>>>>      k  =  evstr(get(ge_k,"string"));  // get content in uicontrol ge_k
>>>>>>      fres=sqrt(k/m)/(2*%pi);
>>>>>>      // putting GUI updates inside the calculation routine is not 
>>>>>> pretty code.
>>>>>>      ge_r.visible  =  "on";
>>>>>>      ge_fs.visible  =  "on";        // THIS DOESN'T WORK
>>>>>>      ge_hz.visible  =  "on";
>>>>>> // set(ge_r,"Visible","on"); // THIS WORKS
>>>>>> // set(ge_fs,"Visible","on");
>>>>>> // set(ge_hz,"Visible","on");
>>>>>>      // update global variables
>>>>>>      [m,k,fres]=return(m,k,fres);
>>>>>> endfunction
>>>>>>
>>>>>> function  goodbye()
>>>>>>      close(ge);  // Close GUI window
>>>>>>      printf("Resulting fres: %f Hertz\n",fres);
>>>>>>      abort  // Print result in console (e.g. for copy/paste), then kill the app
>>>>>> endfunction
>>>>>>
>>>>>> ge  =  scf();  // GUI Example, Initialize and 'set current figure'
>>>>>> as  =  ge.axes_size;  // read size of window, as = [width height]
>>>>>> ge.figure_name  =  "GUI Example";  // Change window header
>>>>>>
>>>>>> uicontrol("style","text","string","Moving mass :","position",  ..
>>>>>>            [10  as(2)-35  80  20],"background",[1  1  1]);  // white background
>>>>>>            // position properties has four parameters = x,y,width,height
>>>>>>            // y-position counts from lower left corner, so we subtract from 'as'
>>>>>> ge_m  =  uicontrol("style","edit","string",string(m),  ..
>>>>>>            "position",[100  as(2)-35  80  20]);
>>>>>> uicontrol("style","text","string","kg ","position",  ..
>>>>>>            [200  as(2)-35  30  20],"background",[1  1  1]);
>>>>>>
>>>>>> uicontrol("style","text","string","Stiffness :","position",  ..
>>>>>>            [10  as(2)-60  80  20],"background",[1  1  1]);
>>>>>> ge_k  =  uicontrol("style","edit","string",string(k),  ..
>>>>>>            "position",[100  as(2)-60  80  20]);
>>>>>> uicontrol("style","text","string","N/m ","position",  ..
>>>>>>            [200  as(2)-60  30  20],"background",[1  1  1]);
>>>>>>
>>>>>> uicontrol("style","pushbutton","string","Calculate",  ..
>>>>>>            "position",[10  as(2)-85  80  20],"callback","calc");
>>>>>>
>>>>>> ge_r  =  uicontrol("style","text","string","Result :","position",  ..
>>>>>>            [10  as(2)-110  80  20],"visible","off");  // keep these hidden for a start
>>>>>> ge_fs  =  uicontrol("style","text","string",string(fres),  ..
>>>>>>            "position",[100  as(2)-110  80  20],"visible","off");
>>>>>> ge_hz  =  uicontrol("style","text","string","Hz ","position",  ..
>>>>>>            [200  as(2)-110  30  20],"visible","off");
>>>>>>
>>>>>> uicontrol("style","pushbutton","string","Exit",  ..
>>>>>>            "position",[10  as(2)-135  80  20],"callback","goodbye");
>>>>>>
>>>>>> On 29.11.2019 10:20, Antoine Monmayrant wrote:
>>>>>>> Le Jeudi, Novembre 28, 2019 19:40 CET, Claus Futtrup<cfuttrup at gmail.com>  a écrit:
>>>>>>>   
>>>>>>>> Hi Antoine
>>>>>>>>
>>>>>>>> Also, you should better use get(a, 'propertyName') or set(a, 'propertyName', value) instead of a.propertyName and a.propertyName=value in your callbacks.
>>>>>>>>
>>>>>>>>
>>>>>>>> I see what you mean. I just now had trouble turning visibility on/off,
>>>>>>>> but using set(), it works fine. Thanks for the tip.
>>>>>>> It's something quite weird, maybe a race condition.
>>>>>>> I've seen it when using 'a.prop' or 'a.prop=value' syntax in either a callback function or in a for loop.
>>>>>>> When you repeatedly use this syntax, scilab tends to forget that 'a' exists and that it's a handle with different properties.
>>>>>>> The initial bug report is here:http://bugzilla.scilab.org/show_bug.cgi?id=15786
>>>>>>> Not much progress because I never managed to get a minimal working example (it's an Heisenbug).
>>>>>>>
>>>>>>> Antoine
>>>>>>>
>>>>>>>> Best regards,
>>>>>>>> Claus
>>>>>>>>
>>>>>>>> On 28.11.2019 17:47, Antoine Monmayrant wrote:
>>>>>>>>> Le Jeudi, Novembre 28, 2019 17:05 CET, Claus Futtrup<cfuttrup at gmail.com>  a écrit:
>>>>>>>>>    
>>>>>>>>>> Hi Antoine, et al.
>>>>>>>>>>
>>>>>>>>>> Your reply is very helpful, so I think you got the right question :-)
>>>>>>>>>>
>>>>>>>>>> 1) Good point that I can use callback on every uicontrol. This would be
>>>>>>>>>> suitable for a simple example (like gui_example.sce) ... but for heavy
>>>>>>>>>> calculations, it might be more practical with a CALC button. P.S. The
>>>>>>>>>> correct equation for the resonance frequency is fres=sqrt(k/m)/(2*%pi);
>>>>>>>>> You are right.
>>>>>>>>> Also, the trick to disable the callback function/ reenable it is key for sliders that tend to generate an avalanche of call to the function when one moves the cursor.
>>>>>>>>>
>>>>>>>>>> 2) I see what you mean, so not having an empty space, but "show" the
>>>>>>>>>> whole she-bang from the beginning. I didn't want to do that (just
>>>>>>>>>> deleting the IF-statement), but it could be the best solution in the end
>>>>>>>>>> (rather than the inline GUI updates), if nothing better shows up. This
>>>>>>>>>> was somehow the "core" of my question. Maybe I ask for too much.
>>>>>>>>> I think you can achieve what you want by setting ".visible='off'" for all the uicontrols you don't want to show initialy. You can then set  ".visible='on'" after the first call to the callback (or at each call if you are lazy).
>>>>>>>>>
>>>>>>>>>> 3) I will look into this. Thanks for the tip.
>>>>>>>>> Also, you should better use get(a, 'propertyName') or set(a, 'propertyName', value) instead of a.propertyName and a.propertyName=value in your callbacks.
>>>>>>>>> I have found that this latter syntax is causing a lot of bug if your callback get called really often. I still don't know why.
>>>>>>>>>
>>>>>>>>>> 4) I will also look into this. My problem is the steep learning curve.
>>>>>>>>>> If you look at the Scilab tutorials you have the good-old Openeering
>>>>>>>>>> LHY_Tutorial - it's incredibly complicated and long. Is LHY_Tutorial
>>>>>>>>>> using the Model-Viewer-Controller approach? - Maybe the
>>>>>>>>>> Model-Viewer-Controller could be presented in a _simple_ tutorial - is
>>>>>>>>>> it possible?
>>>>>>>>> Hmm, that would be a good idea.
>>>>>>>>> I'll see whether I can put something together.
>>>>>>>>> The thing is, MVC approach looks rather silly and overengineered on a small example.
>>>>>>>>>
>>>>>>>>>> I appreciate gui_example.sce with just about 70 lines of code, two
>>>>>>>>>> inputs and one output. I think something like it could help a lot of
>>>>>>>>>> people ... and it's not 250 lines of code to get a GUI up and running,
>>>>>>>>>> if you know what I mean. The gui_example shows a few differences, like
>>>>>>>>>> white versus grey background, editable boxes, etc. In the outputs,
>>>>>>>>>> because of the default grey background, you can see the dimensions of
>>>>>>>>>> the grid / text-boxes, and gui_example has two buttons. It looks
>>>>>>>>>> operational and easy to expand for new users.
>>>>>>>>>>
>>>>>>>>>> Cheers,
>>>>>>>>>> Claus
>>>>>>>>>>
>>>>>>>>>> On 28.11.2019 08:57, Antoine Monmayrant wrote:
>>>>>>>>>>> Hello Claus,
>>>>>>>>>>>
>>>>>>>>>>> I've been playing a bit with GUIs for teaching, so maybe I can help.
>>>>>>>>>>> The issue is that I don't get what your problem is exactly here, so I my answer might be a bit off-topic.
>>>>>>>>>>> Do not hesitate to rephrase your issue, I'll try a more focused answer.
>>>>>>>>>>>
>>>>>>>>>>> Anywya, here is how I think your code could be improved:
>>>>>>>>>>>
>>>>>>>>>>> (1) You can use 'calc' as the callback for all of the editable text field so that your result gets shown right away, without having to press a button.
>>>>>>>>>>> (2) You should populate all the uicontrols of your gui first, then only update the displayed values, the visibility of the uicontrols, etc inside your calc function. (ie no more creating a uicontrol inside a callback)
>>>>>>>>>>> (3) The 'tag' property of any uicontrol together with 'findobj()' are really nice to get/set the properties of each existing uicontrol.
>>>>>>>>>>> (4) You can rely on a proper Model-View-Controler approach (or any other well established method to avoid mixing gui stuff with calculation stuff).
>>>>>>>>>>>
>>>>>>>>>>> I attached a small gui I use to illustrate optical anti-reflection coating.
>>>>>>>>>>> It is far from perfect (I did not implement a proper model-view-controler for example).
>>>>>>>>>>> But you can see how I tried to separate the different parts of the code an how I use findobj/tag/get/set,  etc.
>>>>>>>>>>>
>>>>>>>>>>> Hope it helps,
>>>>>>>>>>>
>>>>>>>>>>> Antoine
>>>>>>>>>>>     
>>>>>>>>>>> Le Mercredi, Novembre 27, 2019 19:21 CET, Claus Futtrup<cfuttrup at gmail.com>  a écrit:
>>>>>>>>>>>     
>>>>>>>>>>>> Hi there
>>>>>>>>>>>>
>>>>>>>>>>>> I'm trying to build a GUI. For simplicity on the forum, I've built a
>>>>>>>>>>>> really simple example of what I'm trying to do. How can I make the
>>>>>>>>>>>> "conditional" GUI output work and not have it inside the calc function?
>>>>>>>>>>>> ... or, how would you do it? Thanks.
>>>>>>>>>>>>
>>>>>>>>>>>> Best regards, Claus.
>>>>>>>>>>>>
>>>>>>>>>>>> // GUI_EXAMPLE.SCE
>>>>>>>>>>>> //
>>>>>>>>>>>> // Demo of how to build a simple GUI in Scilab.
>>>>>>>>>>>> // Real simple, with two input variables and one output.
>>>>>>>>>>>> // The example uses the basic mechanical example of a mass and a spring as
>>>>>>>>>>>> // input parameters and calculates the resonance frequency of the mechanical
>>>>>>>>>>>> // system.
>>>>>>>>>>>>
>>>>>>>>>>>> // Initialize variables
>>>>>>>>>>>> m  =  1;  // Moving mass 'm'(kilogram)
>>>>>>>>>>>> k  =  1;  // Stiffness, spring constant 'k'(Newton per meter)
>>>>>>>>>>>> fres  =  1;  // Resonance frequency (Hertz)
>>>>>>>>>>>> show_result  =  %f;
>>>>>>>>>>>>
>>>>>>>>>>>> function  calc()
>>>>>>>>>>>>         m  =  evstr(get(ge_m,"string"));  // get content in uicontrol ge_m
>>>>>>>>>>>>         k  =  evstr(get(ge_k,"string"));  // get content in uicontrol ge_k
>>>>>>>>>>>>         fres  =  sqrt(m  *  k);
>>>>>>>>>>>>         // putting GUI updates inside the calculation routine is not pretty code.
>>>>>>>>>>>>         uicontrol("style","text","string","Result :","position",  ..
>>>>>>>>>>>>                   [10  as(2)-110  80  20]);
>>>>>>>>>>>>         uicontrol("style","text","string",string(fres),  ..
>>>>>>>>>>>>                   "position",[100  as(2)-110  80  20]);
>>>>>>>>>>>>         uicontrol("style","text","string","Hz ","position",  ..
>>>>>>>>>>>>                   [200  as(2)-110  30  20]);
>>>>>>>>>>>>         show_result  =  %t;
>>>>>>>>>>>>         // update global variables
>>>>>>>>>>>>         [m,k,fres,show_result]=return(m,k,fres,show_result);
>>>>>>>>>>>> endfunction
>>>>>>>>>>>>
>>>>>>>>>>>> function  goodbye()
>>>>>>>>>>>>         close(ge);  // Close GUI window
>>>>>>>>>>>>         printf("Resulting fres: %f Hertz\n",fres);
>>>>>>>>>>>>         abort  // Print result in console (e.g. for copy/paste), then kill the app
>>>>>>>>>>>> endfunction
>>>>>>>>>>>>
>>>>>>>>>>>> ge  =  scf();  // GUI Example, Initialize and 'set current figure'
>>>>>>>>>>>> as  =  ge.axes_size;  // read size of window, as = [width height]
>>>>>>>>>>>> ge.figure_name  =  "GUI Example";  // Change window header
>>>>>>>>>>>>
>>>>>>>>>>>> uicontrol("style","text","string","Moving mass :","position",  ..
>>>>>>>>>>>>               [10  as(2)-35  80  20],"background",[1  1  1]);  // white background
>>>>>>>>>>>>               // position properties has four parameters = x,y,width,height
>>>>>>>>>>>>               // y-position counts from lower left corner, so we subtract from 'as'
>>>>>>>>>>>> ge_m  =  uicontrol("style","edit","string",string(m),  ..
>>>>>>>>>>>>               "position",[100  as(2)-35  80  20]);
>>>>>>>>>>>> uicontrol("style","text","string","kg ","position",  ..
>>>>>>>>>>>>               [200  as(2)-35  30  20],"background",[1  1  1]);
>>>>>>>>>>>>
>>>>>>>>>>>> uicontrol("style","text","string","Stiffness :","position",  ..
>>>>>>>>>>>>               [10  as(2)-60  80  20],"background",[1  1  1]);
>>>>>>>>>>>> ge_k  =  uicontrol("style","edit","string",string(k),  ..
>>>>>>>>>>>>               "position",[100  as(2)-60  80  20]);
>>>>>>>>>>>> uicontrol("style","text","string","N/m ","position",  ..
>>>>>>>>>>>>               [200  as(2)-60  30  20],"background",[1  1  1]);
>>>>>>>>>>>>
>>>>>>>>>>>> uicontrol("style","pushbutton","string","Calculate",  ..
>>>>>>>>>>>>               "position",[10  as(2)-85  80  20],"callback","calc");
>>>>>>>>>>>>
>>>>>>>>>>>> // How do I make this "conditional"output show up in my GUI?
>>>>>>>>>>>> if  show_result  then  // If "Calculate"button was pushed at least once ...
>>>>>>>>>>>>         uicontrol("style","text","string","Result :","position",  ..
>>>>>>>>>>>>                   [10  as(2)-110  80  20]);
>>>>>>>>>>>>         uicontrol("style","text","string",string(fres),  ..
>>>>>>>>>>>>                   "position",[100  as(2)-110  80  20]);
>>>>>>>>>>>>         uicontrol("style","text","string","Hz ","position",  ..
>>>>>>>>>>>>                   [200  as(2)-110  30  20]);
>>>>>>>>>>>> end
>>>>>>>>>>>>
>>>>>>>>>>>> uicontrol("style","pushbutton","string","Exit",  ..
>>>>>>>>>>>>               "position",[10  as(2)-135  80  20],"callback","goodbye");
>>>>>>>>>>>>
>>>>>>>>>>>>
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>>>>> -- 
>>>>> Stéphane Mottelet
>>>>> Ingénieur de recherche
>>>>> EA 4297 Transformations Intégrées de la Matière Renouvelable
>>>>> Département Génie des Procédés Industriels
>>>>> Sorbonne Universités - Université de Technologie de Compiègne
>>>>> CS 60319, 60203 Compiègne cedex
>>>>> Tel : +33(0)344234688
>>>>> http://www.utc.fr/~mottelet
>>>>>
>>>>> _______________________________________________
>>>>> users mailing list
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>>>>> http://lists.scilab.org/mailman/listinfo/users
>>>>
>>>>
>>>>
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>>> -- 
>>> Stéphane Mottelet
>>> Ingénieur de recherche
>>> EA 4297 Transformations Intégrées de la Matière Renouvelable
>>> Département Génie des Procédés Industriels
>>> Sorbonne Universités - Université de Technologie de Compiègne
>>> CS 60319, 60203 Compiègne cedex
>>> Tel : +33(0)344234688
>>> http://www.utc.fr/~mottelet
>>>
>>> _______________________________________________
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>>> http://lists.scilab.org/mailman/listinfo/users
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