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Anders Melander

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Anders Melander last won the day on March 10

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  • Delphi-Version
    Delphi 10.2 Tokyo

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  1. Anders Melander

    Check for override

    Are you saying that it wasn't worth it back when the change was made or that it isn't worth it anymore (i.e. today)? IMO the change was definitely worth it at the time because it didn't break backward compatibility and AFAIR didn't introduce new problems. They could have marked the old methods deprecated at some point and eventually retired it completely. AFAIK the change didn't introduce any new problems in older TStream descendants with 2+Gb files - it just made them possible going forward. If you have examples of bugs then I'd love to hear of them.
  2. Anders Melander

    Check for override

    Good thing you're not in charge of the RTL then. IRL backward compatibility matters.
  3. Anders Melander

    Check for override

    You're missing the point. The purpose was to provide backward compatibility for existing descendants of TStream - not existing code using TStream.
  4. Anders Melander

    Check for override

    ...or just see TStream.Seek(Longint, Word) in classes.pas.
  5. Anders Melander

    Trouble with (very) simple XML-parsing

    Why do you have this test? I would think that the second variant (LDocument.getElementsByTagName) would be good enough... I also think it would be safer if you used XPath or specified the path in your search criteria: LDocument.getElementsByTagName('/BkToCstmrStmt/Stmt/Acct/Id/IBAN');
  6. Anders Melander

    Right Process for Changing an Application's Icon?

    A word of warning to those (I'm counting 50 since yesterday) that downloaded this version: If your resources contains bitmaps that were created by older versions of Delphi (or rather applications built with older versions of Delphi) then the resource editor might corrupt them on save. It appears that a bug was introduced in TBitmap between Delphi 2009 and 10.2. Here's the short version: The format of a windows bitmap is basically 1) Header, 2) Color table, 3) Pixel data. For bitmaps with PixelFormat>pf8bit the color table is optional. The Header specifies the number of colors in the color table (the TBitmapInfoHeader.biClrUsed field). Older versions of Delphi sometimes saved bitmaps in pf24bit/pf32bit format with a color table and the corresponding value in the biClrUsed field. This was unnecessary but harmless and perfectly legal according to the bitmap specs. Here's an example of what such a bitmap might look like: [File header] [Bitmap header, biClrUsed=16, biBitCount=32] [Pixel data] These bitmaps can be read by newer versions of Delphi, but when the bitmaps are written again they become corrupt. Delphi keeps the value in the biClrUsed field but fails to write the corresponding color table. The result is that the pixel data ends up at the wrong file offset. Here's an example of a corrupt bitmap: [File header] [Bitmap header, biClrUsed=16, biBitCount=32] [Pixel data] The reason why this is a problem for the resource editor is that it is built with Delphi 10.2. I have a fix for the problem but I'm not ready to release a new version with the fix. Here's the fix btw: // Fix for bug in TBitmap. // Saving bitmap with PixelFormat>pf8bit with biClrUsed>0 fails to save the color table // leading to a corrupt bitmap. type TBitmapColorTableBugFixer = class helper for TBitmap type TBitmapImageCracker = class(TBitmapImage); public function FixColorTable: boolean; end; function TBitmapColorTableBugFixer.FixColorTable: boolean; begin if (TBitmapImageCracker(FImage).FDIB.dsBmih.biBitCount > 8) and (TBitmapImageCracker(FImage).FDIB.dsBmih.biClrUsed <> 0) then begin TBitmapImageCracker(FImage).FDIB.dsBmih.biClrUsed := 0; Result := True; end else Result := False; end; The problem appears to be the same one reported here: Setting TBitmap.PixelFormat can lead to later image corruption or EReadError
  7. Anders Melander

    Right Process for Changing an Application's Icon?

    Only because I've just uploaded a new version 🙂. It's been gone for at least 5 years. My ISP keeps flagging it as a virus (probably because it's built with Delphi) and taking it offline.
  8. Anders Melander

    Right Process for Changing an Application's Icon?

    It's my own. You can get it here: http://melander.dk/download/ResourceEditor20190309a.zip
  9. Anders Melander

    Right Process for Changing an Application's Icon?

    1) I don't know of any "approved process" apart from specifying an icon in the project options and, as you have discovered, that doesn't always work. Here's why: The default icon to use as the application icon is determined by Windows. Delphi has no control over it. Windows simply selects "the first icon" as the default application icon. The order of icons are determined by their resource ID/name (AFAIR this is only true for Delphi because Delphi sorts the resources at link time (which is actually a good thing as the alternative would means we had no control over what icon got selected (as we have no control over the order))). The Delphi project icon is always named (by Delphi) "MAINICON". If you add another icon to the project, and the name of that icon is sorted before MAINICON, then this icon will be ordered before MAINICON and will be selected by Windows as the application icon. For this reason I usually name my application icon "A" and add it as an external resource file to my projects. This way I don't have to worry about what other icons there might be added by 3rd parties (or other developers) and what their names are. The MAINICON I just ignore or load with the same icon as the "A" icon. 2) The icon size used for the forms depends on the size of the windows caption area, which depends on scaling/zoom, font sizes and so on. The icon is selected by Windows from the different sizes available in your application icon (or whatever icon you have associated with the form). -- See also: forms.pas (search for WM_SETICON and WM_GETICON)
  10. Then you shouldn't have mentioned it. If you post something as an example of a lock free implementation and it's clearly not thread safe, then I think it's fair that people are warned about that fact.
  11. You have a problem so you decide to use threads. you problems.2 have Now
  12. If you can live with FIFO LIFO/FILO/stack semantics then you can use Windows SLists. They're lock free and can be used with multiple readers and writers.
  13. There's at least one race condition. Stopped reading once I spotted it: if InterlockedDecrement(FActiveWriters) = 0 then FActiveWritersZeroEvent.SetEvent;
  14. Anders Melander

    How to identify problem remotely

    MadExcept: Main thread freeze checking http://help.madshi.net/HowToUseMadExcept.htm
  15. Anders Melander

    Version Control System

    I'd recommend SVN or GIT - and since someone dared to mention it, I'd also like to warn against TFS. It's an abomination and just a tiny improvement over VSS. In my experience the learning curve, if coming from VSS, is much smaller for SVN than for GIT. IMO the DVCS aspect of GIT is mostly hype since nobody uses it that way, but it does make it easy to work with local feature branches. If you need your source hosted in the cloud I think GIT is the best solution. There are SVN hosting solutions but in my experience they aren't very good. I personally prefer SVN as it matches the way I think better. I do use GIT but I really have to think hard about what I'm doing every time I need to do something with it. I can picture what I want to do in my head but have a hard time translating that to the available actions. For SVN I use TortoiseSVN and for GIT TortoiseGIT. I also have SourceTree v1 (v2 is a bad joke) but it's really slow to work with - and buggy. I didn't know there was a newer version, so I'll check that out.
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