nowplaying: Create a custom Label for displaying tags

This Label supports setting a prefix that is applied to the displayed
string and setting a font size in pixels.

Signed-off-by: Anna Schumaker <Anna@NoWheyCreamery.com>

emmental/gsetup.py

@@ -6,6 +6,7 @@ import sqlite3
 import gi
 import xdg.BaseDirectory
 
+gi.require_version("Pango", "1.0")
 gi.require_version("Gdk", "4.0")
 gi.require_version("Gtk", "4.0")
 gi.require_version("Adw", "1")
@@ -56,6 +57,9 @@ def print_versions():
     __print_version("GStreamer", gi.repository.Gst.version().major,
                     gi.repository.Gst.version().minor,
                     gi.repository.Gst.version().micro)
+    __print_version("Pango", gi.repository.Pango.VERSION_MAJOR,
+                    gi.repository.Pango.VERSION_MINOR,
+                    gi.repository.Pango.VERSION_MICRO)
     __print_version("SQLite", sqlite3.sqlite_version_info[0],
                     sqlite3.sqlite_version_info[1],
                     sqlite3.sqlite_version_info[2])

emmental/nowplaying/label.py

@@ -0,0 +1,36 @@
+# Copyright 2022 (c) Anna Schumaker.
+"""A Gtk.Label set up for displaying nowplaying tags."""
+from gi.repository import GObject
+from gi.repository import Gtk
+from gi.repository import Pango
+
+
+class Label(Gtk.Label):
+    """A Gtk.Label wrapped in a ScrolledWindow for displaying tags."""
+
+    prefix = GObject.Property(type=str)
+    size = GObject.Property(type=int)
+
+    def __init__(self, prefix="", **kwargs):
+        """Initialize our Label."""
+        super().__init__(prefix=prefix, xalign=0, **kwargs)
+        self.connect("notify::size", self.__set_size)
+
+    @GObject.Property(type=str)
+    def text(self) -> str:
+        """Get the text set to the label (without any prefix)."""
+        return self.get_text()[len(self.prefix):]
+
+    @text.setter
+    def text(self, text: str) -> None:
+        """Set text to the label (adding any prefix)."""
+        text = f"{self.prefix}{text}" if text else ""
+        self.set_text(text)
+
+    def __set_size(self, label: Gtk.Label, param) -> None:
+        # Note that we have to create a new Pango.AttrList here because
+        # Gtk.Label.get_attributes() returns a COPY of the AttrList, so
+        # any modifications won't take effect.
+        attrlist = Pango.AttrList.new()
+        attrlist.insert(Pango.attr_size_new_absolute(self.size * Pango.SCALE))
+        self.set_attributes(attrlist)

tests/nowplaying/test_label.py

@@ -0,0 +1,62 @@
+# Copyright 2022 (c) Anna Schumaker.
+"""Tests our modified Gtk.Label."""
+import unittest
+import emmental.nowplaying.label
+from gi.repository import GLib
+from gi.repository import Gtk
+from gi.repository import Pango
+
+
+class TestLabel(unittest.TestCase):
+    """Test case for our custom Label."""
+
+    def setUp(self, prefix=""):
+        """Set up common variables."""
+        self.label = emmental.nowplaying.label.Label(prefix=prefix)
+
+    def test_init(self):
+        """Test that the label is configured correctly."""
+        self.assertIsInstance(self.label, Gtk.Label)
+
+        self.assertIsNone(self.label.get_attributes())
+        self.assertEqual(self.label.get_xalign(), 0)
+
+        label = emmental.nowplaying.label.Label(visible=False)
+        self.assertFalse(label.get_visible())
+
+    def test_set_text(self):
+        """Test setting label text."""
+        self.assertEqual(self.label.text, "")
+        self.assertEqual(self.label.get_text(), "")
+
+        for text in ["Test Text", ""]:
+            with self.subTest(text=text):
+                self.label.text = text
+                self.assertEqual(self.label.text, text)
+                self.assertEqual(self.label.get_text(), text)
+
+    def test_prefix(self):
+        """Test the prefix property."""
+        self.setUp(prefix="Prefix ")
+        self.assertEqual(self.label.prefix, "Prefix ")
+
+        self.assertEqual(self.label.text, "")
+        self.assertEqual(self.label.get_text(), "")
+
+        for text in ["Test Text", ""]:
+            with self.subTest(text=text):
+                self.label.text = text
+                self.assertEqual(self.label.text, text)
+                self.assertEqual(self.label.get_text(),
+                                 "Prefix Test Text" if len(text) else "")
+
+    def test_size(self):
+        """Test the size property."""
+        self.assertEqual(self.label.size, 0)
+        expected = f"0 {GLib.MAXUINT} absolute-size"
+
+        for size in [42, 20]:
+            with self.subTest(size=size):
+                self.label.size = size
+                self.assertEqual(self.label.get_attributes().to_string(),
+                                 f"{expected} {size * Pango.SCALE}")

tests/test_gsetup.py

@@ -15,6 +15,7 @@ class TestGSetup(unittest.TestCase):
         self.assertEqual(gi.get_required_version("Gtk"), "4.0")
         self.assertEqual(gi.get_required_version("Adw"), "1")
         self.assertEqual(gi.get_required_version("Gst"), "1.0")
+        self.assertEqual(gi.get_required_version("Pango"), "1.0")
 
     def test_adw(self):
         """Check that libadwaita style has been set."""