twm's blog

Playing around with ImageMagick I found that somebody already wrote a Pascal/Delphi import unit for it called PascalMagick. Unfortunately it has been integrated into freepascal which means Delphi support no longer has any priority.

So, the first thing to do was getting it to compile with Delphi.
It requires the ctypes unit from freepascal which did not compile because of an {$if …} that was terminated with an ${endif} rather than ${ifend} (line 107, newer versions fo Delphi won’t complain about this any more).

Then I opened one of the examples. There is a DPR file with an associated DPROJ file, but unfortunately that file was not a Delphi project file but some XML stuff. I renamed the LPR file (Lazarus Project) to DPR and it loaded into Delphi 2007.

Compiling worked too, but when I started it, I immediately got a System Exception with some cryptic error message. Half an hour later I knew the cause: The DLL could not be loaded, because there is an {$IFDEF Windows} around the MagickExport and WandExport constants (ImagageMagick.pas line 45). Delphi does not by default define this symbol. So I added it and the DLL still could not be found. WTF? Turned out that the DLL name was wrong. It’s now CORE_RL_MagickWand_.dll rather than CORE_RL_Wand_.dll. After that change the example program actually worked.

But I did not want to do the simple stuff but was interested in writing code that does what ‘magick -distort Perspective’ does. And I could not find anything in those units and include files that looked promising. Google finally turned up the MagickDistortImage function which is simply missing from import unit. So I added it:

type
  TMagickDistortImage = function(wand: PMagickWand; Method: DistortMethod; NumOfArgs: Integer;
        arguments: PDouble; bestfit: MagickBooleanType): MagickBooleanType; cdecl;

var
    MagickDistortImage: TMagickDistortImage;

  MagickDistortImage := GetProcAddress('MagickDistortImage');

But which values can be passed to the Method parameter? Again, it took me a while to find that enum declaration in C, so I converted it to Delphi:

type
  DistortMethod = (
    UndefinedDistortion,
    AffineDistortion, AffineProjectionDistortion, ScaleRotateTranslateDistortion,
    PerspectiveDistortion, PerspectiveProjectionDistortion,
    BilinearForwardDistortion,
    BilinearDistortion = BilinearForwardDistortion,
    BilinearReverseDistortion, PolynomialDistortion, ArcDistortion, PolarDistortion,
    DePolarDistortion, Cylinder2PlaneDistortion, Plane2CylinderDistortion, BarrelDistortion,
    BarrelInverseDistortion, ShepardsDistortion, ResizeDistortion, SentinelDistortion);

That’s how far I have come by now. I’ll put this here in case somebody else is as desparately looking for these declarations as I was for the last few hours.

As I mentioned before, Embarcadero will turn off Code Central which will result in a wealth of Delphi code and tools vanishing from the face of the earth.

I have just saved two more entries for posterity:

• Code Template Script examples [Archive.org]
  

  Code Template example for seeding a live template point with the clipboard contents. Also an example that modifies the ‘var’ code template allowing for initialization of the variable being declared.

  There are 2 templates included. A replacement for the var template and a new template called clippy that takes what is on the clipboard and surrounds it with a try…finally block.

  download link and

• Code Template Basics – NewBucketList [archive.is]
  

  Code Template for Creating Code Template Basics – Delphi2006 by Adam Markowitz. NewBucketList code template is used as the example.

  download link

both by Adam Markowitz a former Borland Employee.

The Delphi Wiki has some more live templates.