A.M. Hoornweg

I'll see if I can concoct an example next week. It's hard to extract from my current program. I can tell you that it definitely happens in some forms of mine that have some panels with constraints and other panels with align=alClient, it causes these forms to "explode" when they are dragged between monitors. By trial and error I could stop it from happening by protecting WMDPICHANGED against recursions. procedure tMyForm.WMDPIChanged(var Msg: TWMDpi); begin inc(fChangingDPI); try if fChangingDPI = 1 then inherited else Msg.Result := 0; finally dec(fChangingDPI); end; end;

One observation: in unit Vcl.Forms there's an optimization in tCustomForm.WMDPICHanged which ensures that a form is only re-scaled when Message.YDPI is unequal to fCurrentPPI. Assuming that fCurrentPPI may not be perfectly reliable, I have removed that optimization just for testing. And bingo, my form now appears to re-scale properly every time. //unit vcl.forms.pas method tCustomForm.WMDPICHANGED if (* (Message.YDpi <> fCurrentppi) *) and Scaled then begin DoBeforeMonitorDpiChanged(fCurrentppi, Message.YDpi); OldPPI := fCurrentppi; ScaleForPPIRect(Message.YDpi, Message.ScaledRect); FCurrentPPI := Message.YDpi; fPixelsPerInch := FCurrentPPI; DoAfterMonitorDpiChanged(OldPPI, FCurrentPPI); end; Also I've found out that constraints may be problematic in Delphi. Normally, when a form is dragged to a new monitor having a different scaling factor and its center reaches the new monitor, Windows sends a wm_dpichanged message to the window's wndproc to inform it of the new resolution and also gives it a pointer to a rectangle containing a proposed new position and size. The form must then redraw itself using the proposed position and size to ensure that the scaled window is definitely on that new monitor. However, constraints in VCL components can enforce size limits to components and to the form itself. So it may very well be that after the positioning and resizing, the center of the form is suddenly back on the previous monitor ...

Hello all, I'm having some trouble debugging DLL's in Delphi 11, trouble which I did not have before in Delphi 10.4. My DLL is compiled in debug mode and has remote debugging symbols. If I specify the host executable (Run-> Parameters -> Debugger -> Host application) and execute the process, breakpoints will not fire in my DLL. But.... if I start the application manually and tell the debugger to attach to the process, breakpoints will fire in the DLL without any problems. This workaround works, but it is super uncomfortable and slows me down. Any idea how I can get the debugging situation back to normal?

It's been four months since this thread was created, still no bookmarks tool in sight 😞

Hello all, I have a tImagecollection with square transparent PNG images at 256x256 size which I want to downscale smoothly. The collection's interpolation mode is set to icIMModeHighQualityCubic. I notice that tVirtualImage gives much smoother image quality at 32x32 than tImage if I manually downscale the image using tImageCollection.GetBitmap(). I would very much like to get to the bottom of this. This is the code I use to manually extract and downscale an image from tImagecollection. Parameter "Targetimage" is just a TImage on some TPanel on a TForm. Am I doing something wrong? procedure LoadImageFromCollection(TargetImage: tImage; ImageName: string; Collection: TImageCollection; DesiredHeight: Integer); var tb: tbitmap; h,idx: Integer; begin idx := Collection.GetIndexByName(ImageName); if idx > -1 then begin h:=desiredHeight; if TargetImage.AlignWithMargins then h := h - TargetImage.Margins.Top - TargetImage.Margins.Bottom; TargetImage.Height := h; TargetImage.width := h; TargetImage.Transparent := True; tb := Collection.getbitmap(idx, h, h); try tb.AlphaFormat := afDefined; TargetImage.Picture.Bitmap.Assign(tb); finally tb.free; end; end; end;

Thank you! Now it works !

Hello all, I am using tImageCollection and tVirtualImageList inside a COM DLL to display some images on buttons etc. This COM DLL is an update to an existing version - the calling processes are existing programs, many of which were compiled with older Delphi versions. I'm observing a very strange phenomenon: the images on the buttons in the DLL are not displayed if the calling executable does not have a manifest. They are only displayed if the calling executable has a manifest. I find no reference in the Delphi documentation that tImageCollection has manifest requirements. Can anyone shed some light on this? My reason for asking: I cannot update the existing legacy applications with a new manifest - they are digitally signed and inserting a new manifest would break the signature..

Interesting! I'll take a good look at that, thanks for pointing it out!

Oww, that sounds like a pain. But I think it should be possible to just pack a manifest alongside an existing application, without embedding it and damaging the digital signature?

The problem isn't tImageList related - the DLL used tImageList in the past without problems or manifest requirements until I replaced it with tImageCollection & tVirtualImageList. Also, the operating system is Windows 10, so comctl32 on the system is most certainly the current version. By the way, with a properly manifested application, the new icons display correctly even on Windows XP which is vintage so I don't think it's a matter of an outdated comctl32. ( edit: I compiled the test application under Delphi 11 fixpack 1 with {$SETPEOSVERSION 5.1} {$SETPESUBSYSVERSION 5.1} to make it work on XP).

Sure. Until that time, I'll just stick with Windows 10 in the VM.

One simple workaround is to run Delphi inside a VMWare VM and to configure that VM so, that its resolution is 1920x1080 and "stretched". That way Delphi will run at a resolution of 2K even though the monitor really has a much higher resolution. As for DPI awareness in compiled Delphi applications themselves, I have a whole bunch of workarounds to make things work better. The key for me was to inherit every TForm from a common ancestor and to override some virtual methods in that ancestor (DoBeforeMonitorDPIChanged, DoAfterMonitorDPIChanged, Loaded, Docreate and some more ...) to fix the most egregious bugs. That way any form derived from that common ancestor behaves much better.

That workaround is well known, but it'll probably cease working when the first updates of Windows 11 appear. In that case one would be stuck with a possibly buggy initial version.

Some things (like Per-Monitor DPI-awareness V2) are really awkward to test through Remote Debugging. Delphi 11 still has tons of issues regarding DPI Awareness, for which I had to devise workarounds until Embarcadero hopefully gets it right. I expect some improvements to this feature in Windows 11 and it would be really nice to be able to debug it natively rather than remotely.

I have no desire to switch to a different virtualization product. My appreciation of VMWare far exceeds any desire for Windows 11.

That's not an option. VMWare workstation is essential to me, also because of compatibility with ESXI. (I don't know if other virtualizers that use "passthrough" TPM's don't have the same problem, because in that case the TPM also dies if the host breaks)

Will that work on a new hardware? I mean, will VMWare Workstation boot a recent backup, if I exchange my notebook for a new one?

A virtual HDD encrypted by VMWare would not be recoverable anymore indeed. [edit] I make weekly backups of my VM's on an external HDD. If they were cryptographically tied to my notebook's hardware, they would become worthless if my notebook broke.

Hello all, I have a question regarding dynamic methods in Delphi that handle Windows messages. The documentation is not clear about this. Suppose I declare a Windows message handler in my form like procedure WMNCCreate (var Message: TWMNCCreate); message WM_NCCREATE; with a trivial implementation like procedure WMNCCreate(var Message: TWMNCCreate); begin inherited; end; how is the inherited() call resolved by Delphi? Is it resolved by method name or by message number? In other words, does inherited() call an ancestor's method having the name WMNCCreate, or does it call any method that handles message number WM_NCCreate regardless of the method's name ?

Ah, I've overlooked that! Thanks! One of the reasons I asked is because many of these message handlers in Vcl.Forms are declared private. But apparently, the keyword "private" is meaningless for message methods if they're resolved by number.

Hello all, it is *extremely* annoying that Delphi 11 writes a property "PixelsPerInch" into dfm files of type tDatamodule and tService. Such objects are totally non-visual so what the heck ? This property cause runtime errors when such projects are compiled with Delphi 10 or older. I now have to manually strip it from each and every data module using Notepad!

Would it not be necessary to change the DFM file too (change "object" into "inherited") because of this inheritance?

I like the idea, but it would require changing existing projects. Existing datamodules, services and frames would need to inherit from new classes. Maybe it would be more elegant to write a patching unit for older Delphi versions that hooks into the dfm reader and ignores PixelsPerInch.

AFAIK there is no property "scaled" in tService and tDatamodule, so why would the designer need to know PixelsPerInch if it's not supposed to do any scaling? There's "Width" and "Height" so it can still create the window big enough to display the placed components. As a workaround, I've written a command line application that detects if a DFM is tdatamodule or a tservice and if so, removes the "pixelsperinch" property. Maybe I should do the same for tFrame because I intend to always use 96 dpi in design mode. The tool is now integrated in my Finalbuilder build scripts and so far it looks promising. If it is error-free, I may use it inside a pre-commit hook in SVN as well.

Hello World, I just had a pleasant surprise - when I build a certain x64 project of mine, the executable is noticeably smaller under Delphi 11 Alexandria (6.5 MB) than under Delphi 10.4.2 Sydney (7.3 MB). Embarcadero must have done some serious optimizations. (Edit) the project is compiled with {$WEAKLINKRTTI ON}.