Improving fix for issue #389

Author: Lucas-C

fpdf/fpdf.py

@@ -2859,11 +2859,6 @@ def multi_cell(
         # If width is 0, set width to available width between margins
         if w == 0:
             w = self.w - self.r_margin - self.x
-        if w <= 2 * self.c_margin:
-            raise FPDFException(
-                "Not enough horizontal space to render cell."
-                " Consider introducing a line break or using x_pos=XPos.LEFT in your previous call."
-            )
         maximum_allowed_emwidth = (w - 2 * self.c_margin) * 1000 / self.font_size
 
         # Calculate text length

fpdf/line_break.py

@@ -1,5 +1,7 @@
 from typing import NamedTuple, Any, Union, Sequence
 
+from .errors import FPDFException
+
 SOFT_HYPHEN = "\u00ad"
 HYPHEN = "\u002d"
 SPACE = " "
@@ -208,6 +210,7 @@ def __init__(
         self.print_sh = print_sh
         self.fragment_index = 0
         self.character_index = 0
+        self.char_index_for_last_forced_manual_break = None
 
     def _get_character_width(self, character: str, style: str = ""):
         if character == SOFT_HYPHEN and not self.print_sh:
@@ -217,6 +220,8 @@ def _get_character_width(self, character: str, style: str = ""):
 
     # pylint: disable=too-many-return-statements
     def get_line_of_given_width(self, maximum_width: float, wordsplit: bool = True):
+        char_index_for_last_forced_manual_break = self.char_index_for_last_forced_manual_break
+        self.char_index_for_last_forced_manual_break = None
 
         if self.fragment_index == len(self.styled_text_fragments):
             return None
@@ -259,6 +264,11 @@ def get_line_of_given_width(self, maximum_width: float, wordsplit: bool = True):
                 if not wordsplit:
                     line_full = True
                     break
+                if char_index_for_last_forced_manual_break == self.character_index:
+                    raise FPDFException(
+                        "Not enough horizontal space to render a single character"
+                    )
+                self.char_index_for_last_forced_manual_break = self.character_index
                 return current_line.manual_break()
 
             current_line.add_character(

test/text/test_line_break.py

@@ -1,5 +1,8 @@
+from fpdf import FPDFException
 from fpdf.line_break import Fragment, MultiLineBreak, TextLine
 
+import pytest
+
 
 def test_no_fragments():
     """
@@ -34,11 +37,10 @@ def test_width_calculation():
     assert multi_line_break.get_line_of_given_width(0) == TextLine(
         fragments=[], text_width=0, number_of_spaces_between_words=0, justify=False
     )
-    # the first character has width of 2 units. request of 1 unit line returns
-    # an empty line
-    assert multi_line_break.get_line_of_given_width(1) == TextLine(
-        fragments=[], text_width=0, number_of_spaces_between_words=0, justify=False
-    )
+    # the first character has width of 2 units.
+    # request of 1 unit line raises an exception
+    with pytest.raises(FPDFException):
+        multi_line_break.get_line_of_given_width(1)
     # get other characters one by one
     assert multi_line_break.get_line_of_given_width(2) == TextLine(
         fragments=[Fragment.from_string("a", "normal", False)],

test/text/test_multi_cell.py

@@ -314,3 +314,13 @@ def test_multi_cell_with_zero_horizontal_space():  # issue #389
     pdf.multi_cell(w=0, h=5, txt="test")
     with pytest.raises(FPDFException):
         pdf.multi_cell(w=0, h=5, txt="test")
+
+
+def test_multi_cell_with_limited_horizontal_space():  # issue #389
+    pdf = FPDF()
+    pdf.add_page()
+    pdf.set_font("Helvetica", "", 10)
+    pdf.multi_cell(w=pdf.epw - 2 * pdf.c_margin - 1, h=5, txt="test")
+    assert pdf.x == pdf.l_margin + pdf.epw - 2 * pdf.c_margin - 1
+    with pytest.raises(FPDFException):
+        pdf.multi_cell(w=0, h=5, txt="test")