TListBox and TStringList and LoadFromFile Data Display Issue

[Aruna]

Ps: Tested the "Linux only" on Windows 

Lol.. haha.. oh well I thought it should work seamlessly across platforms that is why I went with the captured data in a text file. So right now all it does when you click a button is load a text file on disk into the TListView so yes it should work on any platform the way it is right now. But once I figure out how to execute an external command through the code then I will have to put in checks as shown below. And then we have loads of fun! 

Code: Pascal  [Select][+][-]

1. {$IFDEF Windows}
2.      giveKodeZwergAHardTime();
3.  {$ENDIF Windows}
4.  
5.   {$IFDEF Unix}  
6.     {$IFDEF Darwin}
7.       // Running on a Mac??
8.     {$ENDIF Darwin}
9.  
10.     {$IFDEF Linux}
11.       doNotGiveKodeZwergAHardTime();
12.     {$ENDIF Linux}
13.  
14.     {$IFDEF FreeBSD}
15.      // do something
16.     {$ENDIF FreeBSD}
17.  
18.   {$ENDIF Unix}

The above was shamelessly lifted from https://wiki.freepascal.org/Executing_External_Programs

[Aruna]

There are lots of comments in the main unit of the project.
Have fun.

Hello @wp I have a small request for you. That function you wrote would you mind commenting on things for me, please? Thank you.

Code: Pascal  [Select][+][-]

1. function GetTextHeight(AFont: TFont): Integer;
2. var
3.   bmp: TBitmap;
4.   tm: TLCLTextMetric; // FTW is a TextMetric (scratching my head here)
5. begin
6.   bmp := TBitmap.Create;
7.   try
8.     bmp.SetSize(1, 1);
9.     bmp.Canvas.Font.Assign(AFont);
10.     bmp.Canvas.GetTextMetrics(tm);
11.     Result := abs(tm.Height);
12.   finally
13.     bmp.Free;
14.   end;
15. end;                        

[wp]

The function extracts the font height from the font metric data which is a record defined - I think - in unit Graphics. (there is another metric in units LCLIntf, LCLType). In order to fill this record you need a valid canvas to which the font under investigation is assigned. Controls have a valid canvas only during the paint cycle, and some widgetset even crash your application when the canvas is accessed outside the paint cycle. To avoid this I created a bitmap since it has a canvas that is always accessible. To allocate some memory for the bitmap I set its size to just 1x1 pixel - that's enough to get a valid canvas, and I don't do any painting so that its real size is unimportant. Then I assign the font to the canvas and extract the text metric. The font height usually is a negative number to indicate that it is measured in pixels (not 100% sure...) - therefore I use the abs() function to make it positive.

If you want to learn more about font metrics you are welcome to check out my "FontInspector": https://github.com/wp-xyz/LazSamples/tree/master/graphics/font%20inspector

[KodeZwerg]

But once I figure out how to execute an external command through the code then I will have to put in checks as shown below. And then we have loads of fun! 

It is as easy as open a webpage and read it 

[Aruna]

The function extracts the font height from the font metric data which is a record defined - I think - in unit Graphics. (there is another metric in units LCLIntf, LCLType). In order to fill this record you need a valid canvas to which the font under investigation is assigned. Controls have a valid canvas only during the paint cycle, and some widgetset even crash your application when the canvas is accessed outside the paint cycle. To avoid this I created a bitmap since it has a canvas that is always accessible. To allocate some memory for the bitmap I set its size to just 1x1 pixel - that's enough to get a valid canvas, and I don't do any painting so that its real size is unimportant. Then I assign the font to the canvas and extract the text metric. The font height usually is a negative number to indicate that it is measured in pixels (not 100% sure...) - therefore I use the abs() function to make it positive.

If you want to learn more about font metrics you are welcome to check out my "FontInspector": https://github.com/wp-xyz/LazSamples/tree/master/graphics/font%20inspector

I was wondering about that 1 x 1 and that is when I thought I must ask you and now it makes a whole lot of sense. Very clever. Thank you very much I am constantly learning and this makes me very content and happy.

[KodeZwerg]

But once I figure out how to execute an external command through the code then I will have to put in checks as shown below. And then we have loads of fun! 

It is as easy as open a webpage and read it 

Ohh, just now I see you already found that link.
Please open a new thread when you having questions about executing programs or want info about how-to for other platforms, I can just help for Windows systems