Make paragraph top margin trigger column break if necessary (#1216)

* fixing #1214

* Update CHANGELOG.md

CHANGELOG.md

@@ -36,6 +36,7 @@ This can also be enabled programmatically with `warnings.simplefilter('default',
 * line size calculation for fragments when [text shaping](https://py-pdf.github.io/fpdf2/TextShaping.html) is used
 * [`FPDF.write_html()`](https://py-pdf.github.io/fpdf2/fpdf/fpdf.html#fpdf.fpdf.FPDF.write_html): fixed incoherent indentation of long `<ul>` list entries - _cf._ [issue #1073](https://github.com/py-pdf/fpdf2/issues/1073) - thanks to @lcgeneralprojects
 * default values for `top_margin` and `bottom_margin` in `HTML2FPDF._new_paragraph()` calls are now correctly converted into chosen document units.
+* In [text_columns()](https://py-pdf.github.io/fpdf2/extColumns.html), paragraph top/bottom margins didn't correctly trigger column breaks; [issue #1214](https://github.com/py-pdf/fpdf2/issues/1214)
 ### Removed
 * an obscure and undocumented [feature](https://github.com/py-pdf/fpdf2/issues/1198) of [`FPDF.write_html()`](https://py-pdf.github.io/fpdf2/fpdf/fpdf.html#fpdf.fpdf.FPDF.write_html), which used to magically pass local variables as arguments.
 ### Changed

fpdf/text_region.py

@@ -524,10 +524,9 @@ def _render_column_lines(self, text_lines, top, bottom):
                     and self.pdf.y > self.pdf.t_margin
                 ):
                     self.pdf.y += cur_paragraph.top_margin
-                else:
-                    if self.pdf.y + text_line.height > bottom:
-                        last_line_height = prev_line_height
-                        break
+                if self.pdf.y + text_line.height > bottom:
+                    last_line_height = prev_line_height
+                    break
                 prev_line_height = last_line_height
                 last_line_height = text_line.height
                 col_left, col_right = self.current_x_extents(self.pdf.y, 0)

test/text_region/test_text_columns.py

@@ -307,30 +307,23 @@ def test_tcols_bad_uses():
     assert str(error.value) == expected_msg
 
 
-@pytest.mark.skip(reason="unfinished")
-def test_tcols_text_shaping(tmp_path):
+def test_tcols_break_top_margin(tmp_path):  # regression test for #1214
+    """Ensure that the top/bottom margins of a paragraph trigger
+    a column break.
+    """
     pdf = FPDF()
     pdf.add_page()
-    pdf.t_margin = 50
-    pdf.set_text_shaping(True)
-    pdf.set_font("Helvetica", "", 6)
-    tsfontpath = HERE.parent / "text_shaping"
-    pdf.add_font(
-        family="KFGQPC", fname=tsfontpath / "KFGQPC Uthmanic Script HAFS Regular.otf"
-    )
-    pdf.add_font(family="Mangal", fname=tsfontpath / "Mangal 400.ttf")
-    cols = pdf.text_columns(text_align="L", ncols=3, gutter=20)
-    with cols:
-        #        pdf.set_font("Times", "", 12)
-        #        cols.write(text=LOREM_IPSUM[:101])
-        pdf.set_font("KFGQPC", size=12)
-        cols.write(text=" مثال على اللغة العربية. محاذاة لليمين.")
-        pdf.set_font("Mangal", size=12)
-        cols.write(text="इण्टरनेट पर हिन्दी के साधन")
-    #        pdf.set_font("Helvetica", "", 12)
-    #        pdf.set_font("Times", "", 14)
-    #        cols.write(text=LOREM_IPSUM)
-    #        pdf.set_font("Courier", "", 16)
-    #        cols.write(text=LOREM_IPSUM)
+    pdf.set_font("Helvetica", "", 14)
+    pdf.set_top_margin(50)
+    pdf.set_auto_page_break(True, 50)
+    pdf.rect(pdf.l_margin, pdf.t_margin, pdf.epw, pdf.eph)
 
-    assert_pdf_equal(pdf, HERE / "tcols_text_shaping.pdf", tmp_path)
+    with pdf.text_columns(text_align="J", ncols=2) as cols:
+        for _ in range(3):
+            with cols.paragraph(
+                text_align="J",
+                bottom_margin=pdf.font_size * 5,
+                top_margin=pdf.font_size * 5,
+            ) as par:
+                par.write(text=LOREM_IPSUM)
+    assert_pdf_equal(pdf, HERE / "tcols_break_top_margin.pdf", tmp_path)