Do not justify a single word

Tests/test_imagefont.py

@@ -267,6 +267,18 @@ def test_render_multiline_text_align(
     assert_image_similar_tofile(im, f"Tests/images/multiline_text{ext}.png", 0.01)
 
 
+def test_render_multiline_text_align_justify_single_word(
+    font: ImageFont.FreeTypeFont,
+) -> None:
+    im = Image.new("RGB", (185, 65))
+    draw = ImageDraw.Draw(im)
+    draw.multiline_text(
+        (0, 0), "hey you\nyou are awesome\nthis", font=font, align="justify"
+    )
+
+    assert_image_equal_tofile(im, "Tests/images/multiline_text_justify_single_word.png")
+
+
 def test_unknown_align(font: ImageFont.FreeTypeFont) -> None:
     im = Image.new(mode="RGB", size=(300, 100))
     draw = ImageDraw.Draw(im)

src/PIL/ImageDraw.py

@@ -772,24 +772,26 @@ class ImageDraw:
 
             if align == "justify" and width_difference != 0:
                 words = line.split(" " if isinstance(text, str) else b" ")
-                word_widths = [
+                if len(words) > 1:
-                    self.textlength(
+                    word_widths = [
-                        word,
+                        self.textlength(
-                        font,
+                            word,
-                        direction=direction,
+                            font,
-                        features=features,
+                            direction=direction,
-                        language=language,
+                            features=features,
-                        embedded_color=embedded_color,
+                            language=language,
-                    )
+                            embedded_color=embedded_color,
-                    for word in words
+                        )
-                ]
+                        for word in words
-                width_difference = max_width - sum(word_widths)
+                    ]
-                for i, word in enumerate(words):
+                    width_difference = max_width - sum(word_widths)
-                    parts.append(((left, top), word))
+                    for i, word in enumerate(words):
-                    left += word_widths[i] + width_difference / (len(words) - 1)
+                        parts.append(((left, top), word))
-            else:
+                        left += word_widths[i] + width_difference / (len(words) - 1)
-                parts.append(((left, top), line))
+                    top += line_spacing
+                    continue
 
+            parts.append(((left, top), line))
             top += line_spacing
 
         return font, anchor, parts