bug#38109: 27.0.50; xpm image scaling doesn't work

[Emacs - Bugs mailing list]

I *think* scaling of xpm images used to work (maybe back when
ImageMagick did the scaling?) - but it doesn't now, e.g. if you go:

  (insert-image (create-image "/usr/src/emacs/etc/images/smilies/medium/wry.xpm" nil nil :scale 20.0))

a tiny 16x16 image is inserted. The expected result was a huge 320x320
image.

If I convert the image to png:

  convert /usr/src/emacs/etc/images/smilies/medium/wry.xpm /tmp/wry.gif

and insert it with:

  (insert-image (create-image "/tmp/wry.gif" nil nil :scale 20.0))

I do get a bug 320x320 pixel image in my buffer.

(Interestingly, if I convert it to PNG and insert it, I get a 320x320
pixel image, with the original small 16x16 graphics inside it, so
scaling seems to not work for PNG either, in a different way.)

This is what it looks like in emacs -Q:




In GNU Emacs 27.0.50 (build 1, x86_64-pc-linux-gnu, GTK+ Version 3.24.12)
 of 2019-10-31 built on tullinupnew
Repository revision: 058e293fddeaa7821f13055b451951360a135b0c
Repository branch: master
Windowing system distributor 'The X.Org Foundation', version 11.0.12004000
System Description: Debian GNU/Linux bullseye/sid

Recent messages:
Reading active file via nnml...done
Reading active file from archive via nnml...
Opening nnml server on archive...done
Reading active file from archive via nnml...done
Reading active file via nnir...done
Reading active file via nndraft...done
Opening nnml server...done
Registering 1 specific articles as ham using backend spam-use-move
Opening nntp server on gm...done
Mark set

Configured using:
 'configure --without-pop'

Configured features:
XPM JPEG TIFF GIF PNG RSVG SOUND GPM DBUS GSETTINGS GLIB NOTIFY INOTIFY
ACL LIBSELINUX GNUTLS LIBXML2 FREETYPE HARFBUZZ M17N_FLT LIBOTF XFT ZLIB
TOOLKIT_SCROLL_BARS GTK3 X11 XDBE XIM THREADS LIBSYSTEMD PDUMPER LCMS2
GMP

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--
 "Please don't "meh" the panopticon. You are                   Adam Sjøgren
  not making things better by doing that."                [hidden email]

[Emacs - Bugs mailing list]

I just updated my Emacs build to master HEAD now (previously was built
in mid-October), and the results are consitent no scaling for XPM, GIF
and PNG now, as can be seen in this image:

[Lars Ingebrigtsen]

Unknown <[hidden email]> writes:

> I just updated my Emacs build to master HEAD now (previously was built
> in mid-October), and the results are consitent no scaling for XPM, GIF
> and PNG now, as can be seen in this image:

Hm.  Odd.  When I try

(insert-image (create-image "/tmp/foo.png" nil nil :scale 10))

etc, I get the proper scaling with png and gif, but not with xpm.
(Running from HEAD with -Q.)

--
(domestic pets only, the antidote for overdose, milk.)
   bloggy blog: http://lars.ingebrigtsen.no

[Emacs - Bugs mailing list]

Lars writes:

>> I just updated my Emacs build to master HEAD now (previously was built
>> in mid-October), and the results are consitent no scaling for XPM, GIF
>> and PNG now, as can be seen in this image:
>
> Hm.  Odd.

Argh, I tested the wrong Emacs binary. How embarrasing. Ignore my second
email.

> I get the proper scaling with png and gif, but not with xpm. (Running
> from HEAD with -Q.)

I don't, the XPM is unscaled and the PNG is inserted on a large canvas
with the original image unscaled in the corner:

[Stephen Berman]

On Thu, 07 Nov 2019 22:11:14 +0100 Unknown <[hidden email]> wrote:

> I *think* scaling of xpm images used to work (maybe back when
> ImageMagick did the scaling?) - but it doesn't now, e.g. if you go:
>
>   (insert-image (create-image
> "/usr/src/emacs/etc/images/smilies/medium/wry.xpm" nil nil :scale 20.0))
>
> a tiny 16x16 image is inserted. The expected result was a huge 320x320
> image.
[...]
> Configured features:
> XPM JPEG TIFF GIF PNG RSVG SOUND GPM DBUS GSETTINGS GLIB NOTIFY INOTIFY
> ACL LIBSELINUX GNUTLS LIBXML2 FREETYPE HARFBUZZ M17N_FLT LIBOTF XFT ZLIB
> TOOLKIT_SCROLL_BARS GTK3 X11 XDBE XIM THREADS LIBSYSTEMD PDUMPER LCMS2
> GMP

On Thu, 07 Nov 2019 22:30:57 +0100 Unknown <[hidden email]> wrote:

> I just updated my Emacs build to master HEAD now (previously was built
> in mid-October), and the results are consitent no scaling for XPM, GIF
> and PNG now [...]

Cf. NEWS:

 ** Emacs now supports resizing and rotating images without ImageMagick.
 All modern systems support this feature.  (On GNU and Unix systems,
 Cairo drawing or the XRender extension to X11 is required for this to
 be available; the configure script will test for it and, if found,
 enable scaling.)

I'm not sure about XRender; I think my X has it, but I only get scaling
(also of XPM and PNG images) with the Cairo build.

Steve Berman

[Lars Ingebrigtsen]

Adam Sjøgren <[hidden email]> writes:

> I don't, the XPM is unscaled and the PNG is inserted on a large canvas
> with the original image unscaled in the corner:

I made two PNGs from wry.xpm.

file /tmp/wry*.png
/tmp/wry2.png: PNG image data, 13 x 14, 8-bit/color RGBA, non-interlaced
/tmp/wry.png:  PNG image data, 13 x 14, 2-bit colormap, non-interlaced

With the colormap png, I see the same as you -- no scaling, but a large
canvas.  With the non-colormap one, I get the proper scaling, too.

Odder and odder.

--
(domestic pets only, the antidote for overdose, milk.)
   bloggy blog: http://lars.ingebrigtsen.no

[Emacs - Bugs mailing list]

Lars writes:

> I made two PNGs from wry.xpm.
>
> file /tmp/wry*.png
> /tmp/wry2.png: PNG image data, 13 x 14, 8-bit/color RGBA, non-interlaced
> /tmp/wry.png:  PNG image data, 13 x 14, 2-bit colormap, non-interlaced
>
> With the colormap png, I see the same as you -- no scaling, but a large
> canvas.  With the non-colormap one, I get the proper scaling, too.

Interesting; the files I tested with:

  $ file wry.*
  wry.gif: GIF image data, version 89a, 16 x 16
  wry.png: PNG image data, 16 x 16, 4-bit colormap, non-interlaced

So that's consistent with what you see. Perhaps testing was done with
RGB(A) images, and not with colormaps/palettes.

--
 "Please don't "meh" the panopticon. You are                   Adam Sjøgren
  not making things better by doing that."                [hidden email]

[Eli Zaretskii]

> Date: Thu, 07 Nov 2019 22:11:14 +0100
> From: Adam Sjøgren via "Bug reports for GNU Emacs,
>  the Swiss army knife of text editors" <[hidden email]>
>
> I *think* scaling of xpm images used to work (maybe back when
> ImageMagick did the scaling?) - but it doesn't now, e.g. if you go:
>
>   (insert-image (create-image "/usr/src/emacs/etc/images/smilies/medium/wry.xpm" nil nil :scale 20.0))
>
> a tiny 16x16 image is inserted. The expected result was a huge 320x320
> image.

You need to build either with XRender support (should be automatic if
you have it installed) or with ImageMagick.  Does config.h define
HAVE_XRENDER to 1?

[Eli Zaretskii]

> From: Lars Ingebrigtsen <[hidden email]>
> Date: Thu, 07 Nov 2019 22:49:13 +0100
> Cc: [hidden email]
>
> Hm.  Odd.  When I try
>
> (insert-image (create-image "/tmp/foo.png" nil nil :scale 10))
>
> etc, I get the proper scaling with png and gif, but not with xpm.
> (Running from HEAD with -Q.)

Maybe there's some X-specific problem.  I see no problem on
MS-Windows.

[Emacs - Bugs mailing list]

Eli writes:

> You need to build either with XRender support (should be automatic if
> you have it installed) or with ImageMagick.  Does config.h define
> HAVE_XRENDER to 1?

It does:

  asjo@tullinup:/usr/src/emacs$ grep HAVE_XRENDER src/config.h
  #define HAVE_XRENDER 1

and ImageMagick isn't defined:

  asjo@tullinup:/usr/src/emacs$ grep HAVE_IMAGEMAGICK src/config.h
  /* #undef HAVE_IMAGEMAGICK */
  /* #undef HAVE_IMAGEMAGICK7 */

[Alan Third]

On Thu, Nov 07, 2019 at 11:12:31PM +0100, Adam Sjøgren via Bug reports for GNU Emacs, the Swiss army knife of text editors wrote:

> Lars writes:
>
> > I made two PNGs from wry.xpm.
> >
> > file /tmp/wry*.png
> > /tmp/wry2.png: PNG image data, 13 x 14, 8-bit/color RGBA, non-interlaced
> > /tmp/wry.png:  PNG image data, 13 x 14, 2-bit colormap, non-interlaced
> >
> > With the colormap png, I see the same as you -- no scaling, but a large
> > canvas.  With the non-colormap one, I get the proper scaling, too.
>
> Interesting; the files I tested with:
>
>   $ file wry.*
>   wry.gif: GIF image data, version 89a, 16 x 16
>   wry.png: PNG image data, 16 x 16, 4-bit colormap, non-interlaced
>
> So that's consistent with what you see. Perhaps testing was done with
> RGB(A) images, and not with colormaps/palettes.

OK, that makes sense. Check out the comment and code at line 2593 of
image.c:

    /* FIXME: Do we need to handle all possible bit depths?
       XRenderFindStandardFormat supports PictStandardARGB32,
       PictStandardRGB24, PictStandardA8, PictStandardA4,
       PictStandardA1, and PictStandardNUM (what is this?!).
   
       XRenderFindFormat may support more, but I don't
       understand the documentation.  */
    format = XRenderFindStandardFormat (display,
                                        depth == 32 ? PictStandardARGB32
                                        : depth == 24 ? PictStandardRGB24
                                        : PictStandardA8);
    *picture = XRenderCreatePicture (display, *pixmap, format, 0, &attr);

There should be an error message somewhere telling you that Emacs
doesn’t support scaling with that bit depth.

I guess it should be simple enough to add 4 and 1 bit to the above
which I hope would cover some of the above cases...
--
Alan Third

[Alan Third]

On Fri, Nov 08, 2019 at 07:34:07PM +0000, Alan Third wrote:
> On Thu, Nov 07, 2019 at 11:12:31PM +0100, Adam Sjøgren via Bug reports for GNU Emacs, the Swiss army knife of text editors wrote:
>
> I guess it should be simple enough to add 4 and 1 bit to the above
> which I hope would cover some of the above cases...

Although I don’t understand why the png displays unscaled in a big
canvas. We must have missed a check against the Picture member to
prevent it resizing if there is no Picture.

This is at the top of image_set_transform:

    # if !defined USE_CAIRO && defined HAVE_XRENDER
      if (!img->picture)
        return;
    # endif

which should prevent any attempt to scale right at the start... I’m
really not sure what’s going on there.
--
Alan Third

[Emacs - Bugs mailing list]

Alan writes:

[...]

> There should be an error message somewhere telling you that Emacs
> doesn’t support scaling with that bit depth.

Indeed there is for the:

  /tmp/wry.png: PNG image data, 16 x 16, 4-bit colormap, non-interlaced

image. But not for the .xpm. Ah, but xpm doesn't go through
image_create_x_image_and_pixmap_1(), so that explains that.

> I guess it should be simple enough to add 4 and 1 bit to the above
> which I hope would cover some of the above cases...

Yes, with this patch:

diff --git a/src/image.c b/src/image.c
index 870f008b14..bb76e9db60 100644
--- a/src/image.c
+++ b/src/image.c
@@ -2585,7 +2585,7 @@ image_create_x_image_and_pixmap_1 (struct frame *f, int width, int height, int d
     {
       if (depth <= 0)
  depth = DefaultDepthOfScreen (FRAME_X_SCREEN (f));
-      if (depth == 32 || depth == 24 || depth == 8)
+      if (depth == 32 || depth == 24 || depth == 8 || depth == 4 || depth == 1)
         {
           XRenderPictFormat *format;
           XRenderPictureAttributes attr;
@@ -2600,12 +2600,16 @@ image_create_x_image_and_pixmap_1 (struct frame *f, int width, int height, int d
           format = XRenderFindStandardFormat (display,
                                               depth == 32 ? PictStandardARGB32
                                               : depth == 24 ? PictStandardRGB24
-                                              : PictStandardA8);
+                                              : depth ==  8 ? PictStandardA8
+                                              : depth ==  4 ? PictStandardA4
+                                              : PictStandardA1);
           *picture = XRenderCreatePicture (display, *pixmap, format, 0, &attr);
         }
       else
         {
-          image_error ("Specified image bit depth is not supported by XRender");
+          Lisp_Object depth_err;
+          XSETINT(depth_err, depth);
+          image_error ("Specified image bit depth (%d) is not supported by XRender", depth_err);
           *picture = 0;
         }
     }

the error in *Messages* doesn't appear.

However the png-image is still not scaled, and still shown in the larger
canvas.

I apparently haven't got Cairo enabled in my build, maybe that's a
problem?

  asjo@tullinup:/usr/src/emacs$ grep CAIRO src/config.h
  /* #undef USE_CAIRO */

An observation: when displaying the colormapped .png,
image_create_x_image_and_pixmap_1() is called twice, the first time
depth is <= 0, and the second time it isn't.

[Lars Ingebrigtsen]

Eli Zaretskii <[hidden email]> writes:

>> Hm.  Odd.  When I try
>>
>> (insert-image (create-image "/tmp/foo.png" nil nil :scale 10))
>>
>> etc, I get the proper scaling with png and gif, but not with xpm.
>> (Running from HEAD with -Q.)
>
> Maybe there's some X-specific problem.  I see no problem on
> MS-Windows.

Did you try with the test images I posted?  The problem is that png
images with a colormap aren't scaled, but rgb (etc) ones are.

--
(domestic pets only, the antidote for overdose, milk.)
   bloggy blog: http://lars.ingebrigtsen.no

[Lars Ingebrigtsen]

Alan Third <[hidden email]> writes:

> OK, that makes sense. Check out the comment and code at line 2593 of
> image.c:
>
>     /* FIXME: Do we need to handle all possible bit depths?
>        XRenderFindStandardFormat supports PictStandardARGB32,
>        PictStandardRGB24, PictStandardA8, PictStandardA4,
>        PictStandardA1, and PictStandardNUM (what is this?!).
>
>        XRenderFindFormat may support more, but I don't
>        understand the documentation.  */
>     format = XRenderFindStandardFormat (display,
>                                         depth == 32 ? PictStandardARGB32
>                                         : depth == 24 ? PictStandardRGB24
>                                         : PictStandardA8);
>     *picture = XRenderCreatePicture (display, *pixmap, format, 0, &attr);

But isn't that about the depth of the screen, not the number of bits in
the image?

--
(domestic pets only, the antidote for overdose, milk.)
   bloggy blog: http://lars.ingebrigtsen.no

[Lars Ingebrigtsen]

Adam Sjøgren <[hidden email]> writes:

>> There should be an error message somewhere telling you that Emacs
>> doesn’t support scaling with that bit depth.
>
> Indeed there is for the:
>
>   /tmp/wry.png: PNG image data, 16 x 16, 4-bit colormap, non-interlaced
>
> image. But not for the .xpm. Ah, but xpm doesn't go through
> image_create_x_image_and_pixmap_1(), so that explains that.

Where do you get the error message?

--
(domestic pets only, the antidote for overdose, milk.)
   bloggy blog: http://lars.ingebrigtsen.no

[Emacs - Bugs mailing list]

Lars writes:

> Where do you get the error message?

In the *Messages* buffer.

[Emacs - Bugs mailing list]

Alan writes:

> Although I don’t understand why the png displays unscaled in a big
> canvas. We must have missed a check against the Picture member to
> prevent it resizing if there is no Picture.
>
> This is at the top of image_set_transform:
>
>     # if !defined USE_CAIRO && defined HAVE_XRENDER
>       if (!img->picture)
>         return;
>     # endif
>
> which should prevent any attempt to scale right at the start... I’m
> really not sure what’s going on there.

This is what stops the .xpm from being scaled, I think. At least I see
image_set_transform() being called for the .xpm, and that if() is hit
and it returns early.

The colormapped .png, however, passes by that if() and the entire
function is executed.

[Lars Ingebrigtsen]

Adam Sjøgren <[hidden email]> writes:

> Lars writes:
>
>> Where do you get the error message?
>
> In the *Messages* buffer.

Hm.  I don't get any on saying

(insert-image (create-image "/tmp/wry.png" nil nil :scale 10))

Do I have to switch error reporting to verbose somehow?

--
(domestic pets only, the antidote for overdose, milk.)
   bloggy blog: http://lars.ingebrigtsen.no

[Emacs - Bugs mailing list]

Lars writes:

>>> Where do you get the error message?
>>
>> In the *Messages* buffer.
>
> Hm.  I don't get any on saying
>
> (insert-image (create-image "/tmp/wry.png" nil nil :scale 10))
>
> Do I have to switch error reporting to verbose somehow?

I may have confused myself.

I get the error in *Messages* the _first_ time I display the .gif.

I only get the error in *Messages* on the .xpm, if it is the first image
I try to insert.

I don't get it on either .png's now (so I maybe have been cross-eyed
when I said I did previously).

This is not for kids.