[Qt-interest] Windows: Copy from Qt app into GIMP fails?

[Jason H]

Oh, my app is "unmaintained". And my app was  drop-target, not the initiator.


What I meant with the URL thing was use that as MIME type 
Content-type:application/url
etc.

Drag an image from Firefox to GIMP, and see how FF does it. Also, if you haven't 
already, make your app accept drops and log the mime data, and figure out which 
method works for GIMP, then drop on your app. 





----- Original Message ----
From: "Oliver.Knoll at comit.ch" <Oliver.Knoll at comit.ch>
To: qt-interest at trolltech.com
Sent: Wed, February 16, 2011 3:56:11 AM
Subject: Re: [Qt-interest] Windows: Copy from Qt app into GIMP fails?

On 2011-02-15 Jason Jason H wrote:

> I've only done limited clipboarding, but I'd say you need to find out what 
mime
> types GIMP accepts.

To my limited understanding of the Windows clipboard it stores it as "device 
independent bitmap" (BMP?). Simply calling 
http://doc.trolltech.com/4.7/qmimedata.html#setImageData should take care of all 
necessary encoding and properly setting the MIME data. And it does work for all 
applications I have tried so far - except GIMP :/

At least that's what I see within MS Word for example, when I choose "Paste 
Contents" ("Inhalte einfuegen" in my German Word version), it sais "Device 
independent bitmap" as the content of the clipboard, after I have copied the 
image data from my application.

> It should be that easy. I should take some kind image/??
> mime type. 

As a matter of fact in an earlier attempt I tried explicitly saving the image as 
PNG and setting the MIME data to 'image/png' (I also tried BMP) ("pseudo-code", 
might not actually compile, but you get the idea):

  QByteArray data;
  QBuffer buffer(data);
  buffer.open(QIODevice::Write)
  QImage image = ...;
  image.save(buffer, "PNG"); // save the image data as PNG
  QMimeData *mimeData = new QMimeData();
  mimeData->setData("image/png", data); // explicitly set MIME type to PNG

but same result, GIMP would say "No data to paste".


I do thing the error might actually be on the GIMP Windows clipboard 
implementation side, but somehow I have the feeling that it would not require 
much to "fix" it, either in my application code (maybe I really did miss 
something), or in the Qt clipboard implementation.

> As a failback, it probably accepts a URL, which could point to an on-
> disk copy of the image being dropped.

Hmmm, I just tried copying a file URL from within Windows File Explorer, and 
pasting to GIMP: does not work (same message: "No data to paste"). Anyway that 
would not work in my case, since the image data is generated in memory only.

Again, pasting image data from e.g. Firefox or MS Word into GIMP does work! Oh 
and by the way I am using the latest stable GIMP 2.6.11 (on all platforms, and 
yes, pasting from my app into GIMP on Mac and Linux /does/ work as well).


So for now I would be basically interested if anyone actually ever succeeded in 
pasting data from a Qt application (maybe also with an older Qt version, or an 
older GIMP installation maybe...) to GIMP on Windows. Or if you observe the same 
"bug" with your Qt image application.

Cheers, Oliver
--
Oliver Knoll
Dipl. Informatik-Ing. ETH
COMIT AG - ++41 79 520 95 22


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