Use the scaled font for wrapped text line spacing

Tests/test_imagetext.py

@@ -1,5 +1,7 @@
 from __future__ import annotations
 
+from typing import AnyStr
+
 import pytest
 
 from PIL import Image, ImageDraw, ImageFont, ImageText, features
@@ -170,6 +172,29 @@ def test_wrap_height() -> None:
     assert text.text == "Text does\nnot fit"
 
 
+@skip_unless_feature("freetype2")
+@pytest.mark.parametrize(
+    "data",
+    (
+        "A\n\nB",
+        b"A\n\nB",
+        "A\n\n\nB",
+        b"A\n\n\nB",
+        "A\n \nB",
+        b"A\n \nB",
+    ),
+)
+def test_wrap_height_blank_line(layout_engine: ImageFont.Layout, data: AnyStr) -> None:
+    font = ImageFont.truetype(FONT_PATH, 10, layout_engine=layout_engine)
+    text = ImageText.Text(data, font)
+
+    wrapped = text.wrap(100, int(font.getbbox("A")[3]))
+
+    assert text.text == data[:1]
+    assert wrapped is not None
+    assert wrapped.text == data[2:]
+
+
 def test_wrap_scaling_unsupported() -> None:
     font = ImageFont.load_default_imagefont()
     text = ImageText.Text("Hello World!", font)
@@ -231,3 +256,39 @@ def test_wrap_grow() -> None:
     assert text.wrap(50, 50, ("grow", 18)) is None
     assert isinstance(text.font, ImageFont.FreeTypeFont)
     assert text.font.size == 16
+
+
+@skip_unless_feature("freetype2")
+@pytest.mark.parametrize("scaling, size", (("grow", 10), ("shrink", 60)))
+@pytest.mark.parametrize(
+    "data, width, spacing, stroke_width",
+    (
+        ("A\nB", 400, 4, 0),
+        ("A\n\nB", 400, 6, 2),
+        ("A B C D", 40, 4, 0),
+    ),
+)
+def test_wrap_scaling_height(
+    layout_engine: ImageFont.Layout,
+    scaling: str,
+    size: int,
+    data: str,
+    width: int,
+    spacing: int,
+    stroke_width: int,
+) -> None:
+    font = ImageFont.truetype(FONT_PATH, size, layout_engine=layout_engine)
+    text = ImageText.Text(data, font, spacing=spacing)
+    text.stroke(stroke_width)
+
+    assert text.wrap(width, 50, scaling) is None
+    assert text.get_bbox()[2] <= width
+    assert text.get_bbox()[3] <= 50
+
+    assert isinstance(text.font, ImageFont.FreeTypeFont)
+    larger = ImageText.Text(
+        data, text.font.font_variant(size=text.font.size + 1), spacing=spacing
+    )
+    larger.stroke(stroke_width)
+    assert larger.wrap(width) is None
+    assert larger.get_bbox()[3] > 50

docs/releasenotes/13.1.0.rst

@@ -49,6 +49,17 @@ TODO
 Other changes
 =============
 
+Scaling multiline text to a height limit
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+:py:meth:`~PIL.ImageText.Text.wrap` now measures line spacing using the scaled
+font when growing or shrinking text. Previously, growing multiline text could
+exceed the height limit, and shrinking could select a smaller font than needed
+or fail to find a font size that fits.
+
+Wrapping also stops at a blank line that exceeds the height limit, preserving the
+remaining text. This avoids ``RuntimeError: raqm_layout() failed`` when using RAQM.
+
 Resizing I;16B and I;16N images
 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 

src/PIL/ImageText.py

@@ -52,7 +52,8 @@ def __init__(
                     break
                 for i, line in enumerate(newlines):
                     if i != 0 and not self.add_line(emptystring):
-                        break
+                        self.remaining_text: AnyStr = input_text[self.position :]
+                        return
                     self.position += len(line)
                     word = word[len(line) :]
                 line = emptystring
@@ -80,12 +81,12 @@ def __init__(
         else:
             if line:
                 self.add_line(line)
-        self.remaining_text: AnyStr = input_text[self.position :]
+        self.remaining_text = input_text[self.position :]
 
     def add_line(self, line: AnyStr) -> bool:
         lines = self.lines + [line]
         if self.height is not None:
-            last_line_y = self.text._split(lines=lines)[-1].y
+            last_line_y = self.text._split(lines=lines, font=self.font)[-1].y
             last_line_height = self.text._get_bbox(line, self.font)[3]
             if last_line_y + last_line_height > self.height:
                 return False
@@ -331,6 +332,7 @@ def _split(
         anchor: str | None = None,
         align: str = "left",
         lines: list[str] | list[bytes] | None = None,
+        font: ImageFont.BaseImageFont | None = None,
     ) -> list[_Line]:
         if anchor is None:
             anchor = "lt" if self.direction == "ttb" else "la"
@@ -351,9 +353,10 @@ def _split(
             msg = "anchor not supported for multiline text"
             raise ValueError(msg)
 
+        font = font or self.font
         fontmode = self._get_fontmode()
         line_spacing = (
-            self.font.getbbox(
+            font.getbbox(
                 "A",
                 fontmode,
                 None,
@@ -376,7 +379,7 @@ def _split(
             widths = []
             max_width: float = 0
             for line in lines:
-                line_width = self.font.getlength(
+                line_width = font.getlength(
                     line, fontmode, self.direction, self.features, self.language
                 )
                 widths.append(line_width)
@@ -420,7 +423,7 @@ def _split(
                             left -= max_width
 
                         word_widths = [
-                            self.font.getlength(
+                            font.getlength(
                                 word,
                                 fontmode,
                                 self.direction,