[core/output] Add generic pango support

Allow any piece of a theme that specifies a set of attributes (default,
cycles, states, widgets) to use pango *instead* of the usual attributes.

If pango is present, this will have precedence.

A practical example of this can be found in the powerline-pango theme,
which is added solely for demonstration purposes.

fixes #531

core/output.py

@@ -74,21 +74,59 @@ class i3(object):
             return []
         attr = self.__common_attributes(module, widget)
         attr.update({
-            'full_text': self.__theme.separator(),
-            'color': self.__theme.bg(widget),
-            'background': self.__theme.bg('previous'),
             '_decorator': True,
         })
+        pango = self.__theme.pango(widget)
+        prev_pango = self.__theme.pango('previous') or {}
+        if pango:
+            pango = dict(pango)
+            if 'bgcolor' in pango:
+                pango['fgcolor'] = pango['bgcolor']
+                del pango['bgcolor']
+            if 'background' in pango:
+                pango['foreground'] = pango['background']
+                del pango['background']
+            if 'bgcolor' in prev_pango:
+                pango['bgcolor'] = prev_pango['bgcolor']
+            if 'background' in prev_pango:
+                pango['background'] = prev_pango['background']
+
+            attr.update({
+                'full_text': self.__pango(self.__theme.separator(), pango),
+                'markup': 'pango'
+            })
+        else:
+            attr.update({
+                'full_text': self.__theme.separator(),
+                'color': self.__theme.bg(widget),
+                'background': self.__theme.bg('previous'),
+            })
         return [attr]
 
+    def __pango(self, text, attributes):
+        result = '<span'
+        for key, value in attributes.items():
+            result = '{} {}="{}"'.format(result, key, value)
+        result = '{}>{}</span>'.format(result, text)
+        return result
+
     def __main(self, module, widget, text):
         attr = self.__common_attributes(module, widget)
         attr.update({
-            'full_text': self.__decorate(module, widget, text),
-            'color': self.__theme.fg(widget),
-            'background': self.__theme.bg(widget),
             'min_width': self.__decorate(module, widget, widget.get('theme.minwidth')),
         })
+        pango = self.__theme.pango(widget)
+        if pango:
+            attr.update({
+                'full_text': self.__pango(self.__decorate(module, widget, text), pango),
+                'markup': 'pango'
+            })
+        else:
+            attr.update({
+                'full_text': self.__decorate(module, widget, text),
+                'color': self.__theme.fg(widget),
+                'background': self.__theme.bg(widget),
+            })
         if (self.__config.debug()):
             attr.update({
                 '__state': ", ".join(module.state(widget))

core/theme.py

@@ -44,6 +44,7 @@ class Theme(object):
             ('border-right', 0),
             ('padding', ''),
             ('prefix', ''), ('suffix', ''),
+            ('pango', None),
         ]:
             setattr(self, attr.replace('-', '_'), lambda widget=None, default=default, attr=attr: self.__get(widget, attr, default))
 

doc/HOWTO_THEME.md

@@ -0,0 +1,3 @@
+# How to write themes
+
+## TODO: Pango support!

themes/powerline-pango.json

@@ -0,0 +1,70 @@
+{
+	"icons": [ "awesome-fonts" ],
+	"defaults": {
+		"separator-block-width": 0,
+		"critical": {
+			"pango": {
+				"foreground": "#ffffff",
+				"background": "#ff0000"
+			}
+		},
+		"warning": {
+			"pango": {
+				"foreground": "#d75f00",
+				"background": "#ffd700"
+			}
+		},
+		"default_separators": false
+	},
+	"cycle": [
+		{
+			"pango": {
+				"foreground": "#ffd700",
+				"background": "#d75f00"
+			}
+		},
+		{
+			"pango": {
+				"foreground": "#ffffff",
+				"background": "#0087af"
+			}
+		}
+	],
+	"dnf": {
+		"good": {
+			"fg": "#494949",
+			"bg": "#41db00"
+		}
+	},
+	"apt": {
+		"good": {
+			"fg": "#494949",
+			"bg": "#41db00"
+		}
+	},
+	"battery": {
+		"charged": {
+			"fg": "#494949",
+			"bg": "#41db00"
+		},
+		"AC": {
+			"fg": "#494949",
+			"bg": "#41db00"
+		}
+	},
+    "pomodoro": {
+        "paused": {
+            "fg": "#d75f00",
+            "bg": "#ffd700"
+        },
+        "work": {
+            "fg": "#ffd700",
+            "bg": "#d75f00"
+        },
+        "break": {
+            "fg": "#494949",
+            "bg": "#41db00"
+        }
+    }
+
+}