XE5 > RIO

[#ifdef 12]

Hi everyone! Need your help with old one sample* from Christen Blom-Dahl:

    objc_msgSend((FStillImageOutput as ILocalObject).GetObjectID,
                 sel_getUid('addObserver:forKeyPath:options:context:'),
                 FVideoCaptureDelegate.GetObjectID,
                 (NSSTR('capturingStillImage') as ILocalObject).GetObjectID,
                 NSKeyValueObservingOptionNew,
                 (FAVCaptureStillImageIsCapturingStillImageContext as ILocalObject).GetObjectID);

* article + listing

 

 

 

I have an error message "Too many actual parameters", of course. And don't know what should I do now in Delphi 10.3.3. Found a similar question but it is unanswered too.

 

Any suggestions?

[David Heffernan 2345]

The error message tells you that you are supplying more arguments to a function call than expected. 

 

Look at the declaration of the function in question. Look at the list of parameters. Look at the arguments you pass. Where is the mismatch? 

[#ifdef 12]

Ok, I'll try in other words: how to split (or merge) correctly that too big objc-message for success send? I see where mismatch is (the Macapi.ObjCRuntime is not so far) but don't understand what should I do with it.

[Gustav Schubert 25]

I am looking at Macapi.ObjCRuntime.
There is a function objc_msgSendP2.
What if you declare objc_msgSendP4?

 

There are 5 calls to objc-msgSend in the uFMain unit.
Three take two params, these do compile?
One takes 4 Params, should be objc_msgSendP2?
One takes 6 params, which should be objc_msgSendP4?
 

[#ifdef 12]

15 hours ago, Gustav Schubert said:

I am looking at Macapi.ObjCRuntime.
There is a function objc_msgSendP2.
What if you declare objc_msgSendP4?

 

There are 5 calls to objc-msgSend in the uFMain unit.
Three take two params, these do compile?
One takes 4 Params, should be objc_msgSendP2?
One takes 6 params, which should be objc_msgSendP4?
 

Thanks a lot for suggestion! I'll see which variant is right the best for me :)

[#ifdef 12]

I think Christen Blom-Dahl is in da house but not sure

Edited December 10, 2019 by #ifdef

[Gustav Schubert 25]

const
  libImageIO = '/System/Library/Frameworks/ImageIO.framework/ImageIO';

function objc_msgSendP4(
  theReceiver: Pointer;
  theSelector: Pointer;
  P1: Pointer;
  P2: Pointer;
  P3: LongWord; // ?
  P4: Pointer): Pointer; cdecl; overload; external libobjc name _PU + 'objc_msgSend';

You could find out if it is a long word or an Integer and if it works ...

[Dave Nottage 557]

If FStillImageOutput is a AVCaptureStillImageOutput, you could do this:

  AVCaptureStillImageOutput = interface(iOSapi.AVFoundation.AVCaptureStillImageOutput)
    ['{A1669519-9901-489E-BDD1-A0E697C8C6CB}']
    procedure addObserver(observer: NSObject; forKeyPath: NSString; options: NSKeyValueObservingOptions; context: Pointer); cdecl; 
  end;
  TAVCaptureStillImageOutput = class(TOCGenericImport<AVCaptureStillImageOutputClass, AVCaptureStillImageOutput>)
  end;

  ...

  TAVCaptureStillImageOutput.Wrap(FStillImageOutput).addObserver(FVideoCaptureDelegate, NSObjectToID(StrToNSStr('capturingStillImage')), NSKeyValueObservingOptionNew, NSObjectToID(FAVCaptureStillImageIsCapturingStillImageContext));

NSObjectToID comes from Macapi.Helpers

Edited December 10, 2019 by Dave Nottage

[Gustav Schubert 25]

Yes, this compiles - with small changes - and looks much better.

 

  AVCaptureStillImageOutput = interface(iOSapi.AVFoundation.AVCaptureStillImageOutput)
    ['{A1669519-9901-489E-BDD1-A0E697C8C6CB}']
    procedure addObserver(observer: Pointer; forKeyPath: NSString; options: NSKeyValueObservingOptions; context: Pointer); cdecl;
    procedure captureStillImageAsynchronouslyFromConnection(connection: AVCaptureConnection; completionHandler: TAVCaptureCompletionHandler); cdecl;
  end;
  TAVCaptureStillImageOutput = class(TOCGenericImport<AVCaptureStillImageOutputClass, AVCaptureStillImageOutput>)
  end;

//    objc_msgSendP4((FStillImageOutput as ILocalObject).GetObjectID,
//                 sel_getUid('addObserver:forKeyPath:options:context:'),
//                 FVideoCaptureDelegate.GetObjectID,
//                 (StrToNSStr('capturingStillImage') as ILocalObject).GetObjectID,
//                 NSKeyValueObservingOptionNew,
//                 (FAVCaptureStillImageIsCapturingStillImageContext as ILocalObject).GetObjectID);

    TAVCaptureStillImageOutput.Wrap(FStillImageOutput).addObserver(
        FVideoCaptureDelegate.GetObjectID,
        StrToNSStr('capturingStillImage'),
        NSKeyValueObservingOptionNew,
        NSObjectToID(FAVCaptureStillImageIsCapturingStillImageContext));

{
[stillImageOutput
   addObserver:self
   forKeyPath:@"capturingStillImage"
   options:NSKeyValueObservingOptionNew
   context:AVCaptureStillImageIsCapturingStillImageContext];
}

Source Link.

[Dave Nottage 557]

Thanks for the changes.. but does it work? 😉

[Gustav Schubert 25]

I don't know if it works, I am just learning - how to code against the api, I only compile and read some interesting code. It is for the original poster to test it out, waiting ...

[Christen Blom-Dahl 7]

Sorry for my late answer (I've been very busy for some months). This code was compiled against Delphi XE5 and the iOS RTL has changed a lot since then. 

Nonetheless the code is a good sample that should run with minor adjustments.

 

Regards

Edited March 16, 2020 by Christen Blom-Dahl

[Christen Blom-Dahl 7]

With newer versions of Delphi you should define the function:

function objc_msgSendP4(theReceiver: Pointer; theSelector: Pointer; P1,P2,P3,P4: Pointer): Pointer; cdecl; overload;
  external libobjc name _PU + 'objc_msgSend';

And then you can use it as follows:

 

    objc_msgSendP4((FStillImageOutput as ILocalObject).GetObjectID,
                   sel_getUid('addObserver:forKeyPath:options:context:'),
                   FVideoCaptureDelegate.GetObjectID,
                   (StrToNSStr('capturingStillImage') as ILocalObject).GetObjectID,
                   Pointer(NSKeyValueObservingOptionNew),
                   (FAVCaptureStillImageIsCapturingStillImageContext as ILocalObject).GetObjectID);

Nonetheless, the best solution is the one posted by Gustav some posts ago. objc_msgSend should be avoided if possible.

 

Regards

Edited March 16, 2020 by Christen Blom-Dahl