[Zhihao Yuan & I] use convert is dvipng doesn't work. Fixes #5935

src/common/latex.py

@@ -115,11 +115,16 @@ def latex_to_image(str_):
     result = None
     exitcode = 0
 
-    try:
-        bg_str, fg_str = gajim.interface.get_bg_fg_colors()
-    except:
-        # interface may not be available when we test latext at startup
-        bg_str, fg_str = 'rgb 1.0 1.0 1.0', 'rgb 0.0 0.0 0.0'
+    def fg_str(fmt):
+        try:
+            return [{'hex' : '+level-colors', 'tex' : '-fg'}[fmt],
+                gajim.interface.get_fg_color(fmt)]
+        except KeyError:
+            # interface may not be available when we test latex at startup
+            return []
+        except AttributeError:
+            # interface may not be available when we test latext at startup
+            return ['-fg', 'rgb 0.0 0.0 0.0']
 
     # filter latex code with bad commands
     if check_blacklist(str_):
@@ -138,9 +143,13 @@ def latex_to_image(str_):
     if exitcode == 0:
         # convert dvi to png
         latex_png_dpi = gajim.config.get('latex_png_dpi')
-        exitcode = try_run(['dvipng', '-bg', bg_str, '-fg', fg_str, '-T',
-                        'tight', '-D', latex_png_dpi, tmpfile + '.dvi', '-o',
-                        tmpfile + '.png'])
+        exitcode = try_run(['dvipng'] + fg_str('tex') + ['-T', 'tight', '-D',
+            latex_png_dpi, tmpfile + '.dvi', '-o', tmpfile + '.png'])
+
+        if exitcode:
+            # dvipng failed, try convert
+            exitcode = try_run(['convert'] + fg_str('hex') + ['-trim',
+                '-density', latex_png_dpi, tmpfile + '.dvi', tmpfile + '.png'])
 
     # remove temp files created by us and TeX
     extensions = ['.tex', '.log', '.aux', '.dvi']

src/features_window.py

@@ -92,8 +92,8 @@ class FeaturesWindow:
                         _('Requires python2.5.')),
                 _('LaTeX'): (self.latex_available,
                         _('Transform LaTeX expressions between $$ $$.'),
-                        _('Requires texlive-latex-base and dvipng. You have to set \'use_latex\' to True in the Advanced Configuration Editor.'),
-                        _('Requires texlive-latex-base and dvipng (All is in MikTeX). You have to set \'use_latex\' to True in the Advanced Configuration Editor.')),
+                        _('Requires texlive-latex-base and (dvipng or ImageMagick). You have to set \'use_latex\' to True in the Advanced Configuration Editor.'),
+                        _('Requires texlive-latex-base and (dvipng or ImageMagick) (All is in MikTeX). You have to set \'use_latex\' to True in the Advanced Configuration Editor.')),
                 _('End to End message encryption'): (self.pycrypto_available,
                         _('Encrypting chat messages.'),
                         _('Requires python-crypto.'),

src/gui_interface.py

@@ -2704,6 +2704,19 @@ class Interface:
         fg_str = format_gdkcolor(style.text[gtk.STATE_NORMAL])
         return (bg_str, fg_str)
 
+    def get_fg_color(self, fmt='hex'):
+        def format_gdkcolor (c):
+            if fmt == 'tex':
+                return ' '.join([str(s) for s in 
+                    ('rgb', c.red_float, c.green_float, c.blue_float)])
+            elif fmt == 'hex':
+                return str(c)
+
+        # get foreground style color and create string
+        dummy = gtk.Invisible()
+        dummy.ensure_style()
+        return format_gdkcolor(dummy.get_style().text[gtk.STATE_NORMAL])
+
     def read_sleepy(self):
         """
         Check idle status and change that status if needed