Posted by jpluimers on 2019/09/17
I forgot who pointed me to this, but it will be useful the next time I need to do image export/import in .NET or GDI+ [WayBack] Using Image Encoders and Decoders in Managed GDI+ | Microsoft Docs.
GDI+ has built-in encoders and decoders that support the following file types:
- BMP
- GIF
- JPEG
- PNG
- TIFF
GDI+ also has built-in decoders that support the following file types:
- WMF
- EMF
- ICON
–jeroen
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Posted by jpluimers on 2019/09/17
Sometimes your toolbox can already things you forgot it could: [Archive.is] GExperts Help.
Via:
–jeroen
Posted in Delphi, Development, GExperts, Software Development | Leave a Comment »
Posted by jpluimers on 2019/09/17
Since about a decade, TThread has a few overloaded [WayBack] Synchronize methods which all allow some specified synchronised method to run in the context of the main thread:
Any exceptions raised in that methods are caught using [WayBack] System.AcquireExceptionObject and re-raised in the calling thread.
If that happens, you loose a piece of the stack information. I knew that, but found out the hard way that it does because I had to hunt for bugs through inherited code written by people that did not know.
This was part of the stack trace that code would show during an exception:
Exception EAccessViolation at $004D732F: Access violation at address $00409174 in module ''.....exe''.
Read of address 80808080
StackTrace:
(000D632F){.....exe} [004D732F] System.Classes.TThread.Synchronize$qqrp41System.Classes.TThread.TSynchronizeRecordo (Line 14975, "System.Classes.pas" + 40) + $0
(000D6430){.....exe} [004D7430] System.Classes.TThread.Synchronize$qqrxp22System.Classes.TThreadynpqqrv$v (Line 15007, "System.Classes.pas" + 9) + $A
(005D6E61){.....exe} [009D7E61] IdSync.DoThreadSync$qqrp18Idthread.TIdThreadynpqqrv$v (Line 281, "IdSync.pas" + 21) + $6
(005D6E87){.....exe} [009D7E87] IdSync.TIdSync.SynchronizeMethod$qqrynpqqrv$v (Line 326, "IdSync.pas" + 2) + $8
Exception EAccessViolation at $00409174: Access violation at address $00409174 in module ''.....exe''. Read of address $80808080 with StackTrace
(00008174){.....exe} [00409174] System.@IsClass$qqrxp14System.TObjectp17System.TMetaClass + $C
The first exception has a different address than the one in the exception message.
Which means that you miss the whole stack path to the _IsClass call (the underlying method implementing the as keyword) that the actual exception was initiated at.
And yes: the $80808080 is the FastMM4 marker for freed memory, so this was a use-after-free scenario.
A simple wrapper like this using a central logging facility gave much more insight in the actual cause:
procedure RunLoggedMethod(AMethod: TMethod);
begin
try
AMethod();
except
on E: Exception do
begin
Logger.LogExceptionDuringMethod(E, AMethod);
raise; // mandatory to stay compatible with the old un-logged code
end;
end;
end;
Then call it like this inside a thread descendant:
Synchronize(RunLoggedMethod(MethodToRunInMainThread));
The old code was like this:
Synchronize(MethodToRunInMainThread);
This was quite easy to change, as I already had boiler code around exported DLL functions that had a similar construct (without the raise; as exceptions cannot pass DLL boundaries unless very specific circumstances hold).
Similar methods are needed to encapsulate procedure TIdSync.Synchronize(), procedure TIdSync.SynchronizeMethod, procedure TIdThread.Synchronize(Method: TThreadMethod) and [WayBack] Queue overloads:
–jeroen
Posted in Conference Topics, Conferences, Delphi, Development, Event, Software Development | 1 Comment »
Posted by jpluimers on 2019/09/13
Interesting approach on how a free app got itself free translations: Case Study on engaging users to become app translators
Source: [WayBack] Crowdsourcing App-Translation with in-app message – Christoph Wiesner – Medium
The app: Visual Timer – Countdown
Platforms used:
Via:
–jeroen
Posted in Android Devices, Development, internatiolanization (i18n) and localization (l10), Power User, Software Development | Leave a Comment »
Posted by jpluimers on 2019/09/13
Enjoy your day and [WayBack] Good Questions — Geek&Poke; [WayBack] The art of programming — Geek&Poke
–jeroen
Related: Happy Day of the Programmer! 2018
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Posted by jpluimers on 2019/09/12
[WayBack] What went wrong with the IT industry? Well, maybe the same as what happened in other industries that deal with complexity. We maybe beat ourselves up to… – James Coplien – Google+ is on my list of videos to watch.
–jeroen
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Posted by jpluimers on 2019/09/12
For my link archive: [WayBack] Delphi / Stefan Glienke: I looked into IntroSort … and the Microsoft implementation … Here is my current implementation
[WayBack] Delphi IntroSort by Stefan Glienke
–jeroen
https://bitbucket.org/snippets/sglienke/64LG6b/introsort
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Posted by jpluimers on 2019/09/12
For my link archive.
Full text at: [WayBack] … why the Delphi language does not allow parameterless constructors… – David Heffernan – Google+
Abstract:
+Stefan Glienke deleted his post about parameterless record constructors, presumably due to all the off topic comments.
…
.net at CLR level does allow parameterless constructors on structs. But the C# language bans them: https://msdn.microsoft.com/en-us/library/saxz13w4.aspx
Jon Skeet posted an answer on SO way back in 2008 on this topic: http://stackoverflow.com/a/333840/ From that answer:
—-
The CLR allows value types to have parameterless constructors, but C# doesn’t. I believe this is because it would introduce an expectation that the constructor would be called when it wouldn’t. For instance, consider this:
MyStruct[] foo = new MyStruct[1000];…
—-My guess is that Embarcadero decided to ban parameterless constructors on Delphi records for the same reason. Or perhaps they just copied the rules from C# without realising that the CLR supported parameterless struct constructors.
References:
--jeroen
Posted in .NET, C#, Delphi, Development, Jon Skeet, Software Development | Tagged: 1029 | Leave a Comment »
Posted by jpluimers on 2019/09/11
An interesting question from a while back: [WayBack] delphi – Should a descendant class’ method’s variable that is identical to Self, have access to its ancestor’s protected methods? – Stack Overflow
In unit A:
TParent = class protected function DoSomething: TParent; end;In unit B:
TChild = class(TParent) public procedure DoAnotherThing; end; implementation procedure TChild.DoAnotherThing; begin DoSomething.DoSomething end;…
This won’t compile, throwing a
cannot access protected symbol TParent.DoSomething
The kicker here is that the error message makes you think you are operating in Self context, but you are not as you are calling DoSomething.DoSomething where only the first DoSomething is in your Self context, but the second .DoSomethingis in the context of any TParent instance trying to access a public identifier.
Stefan Glienke posted [WayBack] a more elaborate answer explaining some workarounds.
–jeroen
Posted in Conference Topics, Conferences, Delphi, Development, Event, Software Development | Leave a Comment »
Posted by jpluimers on 2019/09/10
Oh boy:
Ditch IDEs like Intellij and glorified text editors like Eclipse, and switch to a real IDE, MS Paint.
It wraps around MS Paint.
You can get it at [WayBack] MS Paint IDE and source code at [WayBack] GitHub – RubbaBoy/MSPaintIDE: Programming in MS Paint.
A long thread discussing it, including a tutorial: [WayBack] Resource – Programming in MS Paint [UPDATED] | SpigotMC – High Performance Minecraft
–jeroen
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The Wiert Corner - irregular stream of stuff 