[LyX/master] Use inkscape as fallback png->eps converter

[Juergen Spitzmueller]

commit 5aefad462b850708012eea42cff0145452a1cb6b
Author: Juergen Spitzmueller <spitz at lyx.org>
Date:   Fri May 15 14:38:30 2026 +0200

    Use inkscape as fallback png->eps converter
    
    if ImageMagick is not available or IM policy does not allow for this
    conversion
---
 lib/configure.py | 29 ++++++++++++++++++++++++++++-
 1 file changed, 28 insertions(+), 1 deletion(-)

diff --git a/lib/configure.py b/lib/configure.py
index 8561a51b7f..bad14f34c2 100644
--- a/lib/configure.py
+++ b/lib/configure.py
@@ -1247,12 +1247,39 @@ def checkConverterEntries():
             removeFiles(['mock.eps'])
             #needs empty record otherwise default converter will be issued
             addToRC(r'''\converter eps        png        ""	""
-\converter png        eps        ""	""
 \converter jpg        tiff        "convert $$i $$o"	""
 \converter png        tiff        "convert $$i $$o"	""''')
             logger.info('ImageMagick seems to ban conversions from EPS. Disabling direct EPS->PNG.')
             pdftopng.append('pdftoppm -r 72 -png -singlefile $$i >  $$o')
     #
+    # Same for png to eps
+    _, cmd = checkProg('a PNG -> EPS converter', ['magick', 'convert'])
+    have_png2eps = False
+    if cmd:
+        from PIL import Image
+        img = Image.new('RGB', (5, 5))
+        img.save("mock.png", "PNG")
+        try:
+            subprocess.check_call([cmd, "mock.png", "mock.eps"])
+            removeFiles(['mock.eps', 'mock.png'])
+            rc_entry = r'\converter png        eps        "%s $$i[0] $$o"	""'
+            addToRC(rc_entry % cmd)
+            have_png2eps = True
+        except:
+            removeFiles(['mock.png'])
+            #needs empty record otherwise default converter will be issued
+            addToRC(r'''\converter png        eps        ""	""''')
+            logger.info('ImageMagick seems to ban conversions to EPS. Disabling direct PNG->EPS.')
+            
+    if not have_png2eps:
+        #try inkscape instead.
+        if inkscape_stable:
+            checkProg('an alternative PNG -> EPS converter', [inkscape_cl + ' $$i --export-area-drawing --export-filename=$$o'],
+                rc_entry = [ r'\converter png        eps        "%%"	""'])
+        else:
+            checkProg('an alternative PNG -> EPS converter', [inkscape_cl + ' --file=$$i --export-area-drawing --without-gui --export-eps=$$o'],
+                rc_entry = [ r'\converter png        eps        "%%"	""'])
+    #
     # PDF -> PNG: sips (mac), IM convert (windows, linux), pdftoppm (linux with IM ban)
     # sips:Define a converter from pdf6 to png for Macs where pdftops is missing.
     # The converter utility sips allows to force the dimensions of the resulting