Fix a regression: now again multi_cell() always renders a cell, even if "txt" is an empty string - close #349

Author: Lucas-C

CHANGELOG.md

@@ -10,6 +10,7 @@ and [PEP 440](https://www.python.org/dev/peps/pep-0440/).
 ## [2.5.2] - not released yet
 ### Fixed
 - a bug with string width calculation when Markdown is enabled - _cf._ [#351](https://github.com/PyFPDF/fpdf2/issues/351)
+- a regression: now again `multi_cell()` always renders a cell, even if `txt` is an empty string - _cf._ [#349](https://github.com/PyFPDF/fpdf2/issues/349)
 
 ## [2.5.1] - 2022-03-07
 ### Added

fpdf/fpdf.py

@@ -2302,6 +2302,7 @@ def _render_styled_cell_text(
 
             if self.fill_color != self.text_color:
                 s += " Q"
+                # cf. issue 348 & test_multi_cell_markdown_with_fill_color:
                 if style_changed:
                     s += f" /F{self.current_font['i']} {self.font_size_pt:.2f} Tf"
 
@@ -2327,7 +2328,7 @@ def _render_styled_cell_text(
         elif new_x == XPos.WCONT:
             self.x = s_start + s_width - self.c_margin
         elif new_x == XPos.CENTER:
-            self.x = (s_start + s_start + s_width) / 2.0
+            self.x = s_start + s_width / 2.0
         elif new_x == XPos.LMARGIN:
             self.x = self.l_margin
         elif new_x == XPos.RMARGIN:
@@ -2583,6 +2584,15 @@ def multi_cell(
                 maximum_allowed_emwidth
             )
 
+        if not text_lines:  # ensure we display at least one cell - cf. issue #349
+            text_lines = [
+                TextLine(
+                    "",
+                    text_width=0,
+                    number_of_spaces_between_words=0,
+                    justify=False,
+                )
+            ]
         for text_line_index, text_line in enumerate(text_lines):
             is_last_line = text_line_index == len(text_lines) - 1
 

test/fonts/test_font_remap.py

@@ -34,7 +34,7 @@ def test_subset_map():
 
 
 def test_emoji_glyph(tmp_path):
-    pdf = FPDF(font_cache_dir=tmp_path)
+    pdf = FPDF()
 
     font_file_path = HERE / "DejaVuSans.ttf"
     pdf.add_font("DejaVuSans", fname=str(font_file_path))
@@ -50,7 +50,7 @@ def test_emoji_glyph(tmp_path):
 
 
 def test_nb_replace(tmp_path):
-    pdf = FPDF(font_cache_dir=tmp_path)
+    pdf = FPDF()
 
     font_file_path = HERE / "DejaVuSans.ttf"
     pdf.add_font("DejaVuSans", fname=str(font_file_path))
@@ -66,7 +66,7 @@ def test_nb_replace(tmp_path):
 
 
 def test_two_mappings(tmp_path):
-    pdf = FPDF(font_cache_dir=tmp_path)
+    pdf = FPDF()
 
     font_file_path_1 = HERE / "DejaVuSans.ttf"
     font_file_path_2 = HERE / "DroidSansFallback.ttf"
@@ -84,7 +84,7 @@ def test_two_mappings(tmp_path):
 
 
 def test_thai_text(tmp_path):
-    pdf = FPDF(font_cache_dir=tmp_path)
+    pdf = FPDF()
     pdf.add_font("Waree", fname=HERE / "Waree.ttf")
     pdf.set_font("Waree")
     pdf.add_page()

test/text/multi_cell_with_empty_contents.pdf

@@ -230,3 +230,15 @@ def test_multi_cell_split_only():  # discussion 314
         "dolore sed ut",
     ]
     assert pdf.multi_cell(w=0, h=LINE_HEIGHT, txt=text, split_only=True) == expected
+
+
+def test_multi_cell_with_empty_contents(tmp_path):  # issue 349
+    pdf = fpdf.FPDF()
+    pdf.add_page()
+    pdf.set_font("helvetica", size=10)
+    for i in range(1, 5):
+        pdf.multi_cell(20, ln=3, txt=str(i))
+    pdf.ln(10)
+    for i in range(1, 5):
+        pdf.multi_cell(20, ln=3, txt=str(i) if i > 2 else "")
+    assert_pdf_equal(pdf, HERE / "multi_cell_with_empty_contents.pdf", tmp_path)