bug#68452: w32-use-native-image-API makes weird behavior

[Jinsong Zhao]

On 2024/1/15 11:34, Eli Zaretskii wrote:
> > Date: Mon, 15 Jan 2024 10:30:26 +0800
> > Cc: 68452@debbugs.gnu.org
> > From: Jinsong Zhao <jszhao@yeah.net>
> >
> > On 2024/1/15 0:34, Eli Zaretskii wrote:
> > > > Date: Sun, 14 Jan 2024 21:52:00 +0800
> > > > From: Jinsong Zhao <jszhao@yeah.net>
> > > >
> > > > I am not a skilled Emacs user. I mainly use Emacs as a front end for Maxima 
> > > > with the help of
> > > > imaxima. imaxima converts Maxima output into PNG image, which are then 
> > > > displayed in Emacs. I am
> > > > using Windows 10.
> > > >
> > > > It works fine on Emacs 28.2, when I type an expression, e.g. q^2 = 1; and 
> > > > return, Emacs 28.2
> > > > immediately displays the resulting PNG image.
> > > >
> > > > If I use Emacs 29.1, however, all I get after returning is an empty square. And 
> > > > if I type another
> > > > expression and return, a blank square appears. At the same time, the first 
> > > > empty square was
> > > > replaced by a PNG image of the first expression. That's weird.
> > > >
> > > > I saw the following messages in the *Messages* buffer:
> > > >
> > > > Processing Maxima output...done
> > > > Unable to load image (image :type png :file 
> > > > c:/Users/Jinso/AppData/Local/Temp/imaximatU5Y9B/1 :
> > > > scale 1.001595744680851 :ascent center :mask (heuristic (color-values 
> > > > imaxima-bg-color)) :
> > > > transform-smoothing t) [35 times]
> > > > Process imaxima finished
> > > >
> > > > After (setq w32-use-native-image-API nil), imaxima has the same behaviour on 
> > > > Emacs 28.2 and
> > > > 29.1.
> > >
> > > Thanks, but we'd need an example of such a PNG image to investigate.
> > > Can you send one such image, which works with w32-use-native-image-API
> > > nil, but not when it is non-nil?
> > >
> > > In any case, it is perfectly okay to reset w32-use-native-image-API to
> > > nil if the native image APIs fail to process an image you want to see.
> > > That's why we support both modes.
> >
> > Thanks for the reply.
> >
> > The PNG image is created on the fly by imaxima, a front end for Maxima.
> > I think it's a normal PNG image file, actually converted from a ps file
> > by ghostscript. I also tried to use JPEG, it's the same.
>
> Well, we cannot do anything with this bug report unless we have an
> example of an image to work with.  So please find a way to ask imaxima
> to save the image on a file, and then send it.

I could provide the PNG files, please see the attachments.

File "1" and "2" are PNG files that were displayed in Emacs.

File "11.png" and "33.png" are the screenshots with 
w32-use-native-image-API set to nil after the first and second input.

File "22.png" and "44.png" are the screenshots with 
w32-use-native-image-API set to non-nil after the first and second input.

I don't know if I am clear.

Best wishes,
Jinsong

1
Description: PNG image

2
Description: PNG image

11.png
Description: PNG image

33.png
Description: PNG image

22.png
Description: PNG image

44.png
Description: PNG image