Support table columns with percentage width #206

Author: onizet

src/Html2OpenXml/Expressions/Table/TableColExpression.cs

@@ -23,21 +23,33 @@ namespace HtmlToOpenXml.Expressions;
 /// </summary>
 sealed class TableColExpression(IHtmlTableColumnElement node) : TableElementExpressionBase(node)
 {
+    private const int MaxTablePortraitWidth = 9622;
+    private const int MaxTableLandscapeWidth = 12996;
     private readonly IHtmlTableColumnElement colNode = node;
+    private double? percentWidth;
 
 
     /// <inheritdoc/>
-    public override IEnumerable<OpenXmlElement> Interpret (ParsingContext context)
+    public override IEnumerable<OpenXmlElement> Interpret(ParsingContext context)
     {
         ComposeStyles(context);
 
         var column = new GridColumn();
         var width = styleAttributes!.GetUnit("width");
-        if (width.IsValid && width.IsFixed)
+        if (width.IsValid)
         {
-            // This value is specified in twentieths of a point.
-            // If this attribute is omitted, then the last saved width of the grid column is assumed to be zero.
-            column.Width = Math.Round( width.ValueInPoint * 20 ).ToString(CultureInfo.InvariantCulture);
+            if (width.IsFixed)
+            {
+                // This value is specified in twentieths of a point.
+                // If this attribute is omitted, then the last saved width of the grid column is assumed to be zero.
+                column.Width = Math.Round(width.ValueInPoint * 20).ToString(CultureInfo.InvariantCulture);
+            }
+            else if (width.Type == UnitMetric.Percent)
+            {
+                var maxWidth = context.IsLandscape ? MaxTableLandscapeWidth : MaxTablePortraitWidth;
+                percentWidth = Math.Max(0, Math.Min(100, width.Value));
+                column.Width = Math.Ceiling(maxWidth / 100d * percentWidth.Value).ToString(CultureInfo.InvariantCulture);
+            }
         }
 
         if (colNode.Span == 0)
@@ -51,4 +63,18 @@ public override IEnumerable<OpenXmlElement> Interpret (ParsingContext context)
 
         return elements;
     }
+
+    public override void CascadeStyles(OpenXmlElement element)
+    {
+        base.CascadeStyles(element);
+
+        if (percentWidth.HasValue && element is TableCell cell &&
+            cell.TableCellProperties?.TableCellWidth is null)
+        {
+            cell.TableCellProperties!.TableCellWidth = new() {
+                Type = TableWidthUnitValues.Pct,
+                Width = ((int) (percentWidth.Value * 50)).ToString(CultureInfo.InvariantCulture)
+            };
+        }
+    }
 }

test/HtmlToOpenXml.Tests/TableTests.cs

@@ -522,8 +522,8 @@ public void Colstyle_ReturnsStyleAppliedOnCell()
             Assert.Multiple(() =>
             {
                 Assert.That(columns.Count(), Is.EqualTo(2));
-                //Assert.That(columns.First().Width?.Value, Is.EqualTo("1500"));
-                //Assert.That(columns.Last().Width?.Value, Is.EqualTo("750"));
+                Assert.That(columns.First().Width?.Value, Is.EqualTo("1500"));
+                Assert.That(columns.Last().Width?.Value, Is.EqualTo("750"));
             });
 
             var cells = elements[0].GetFirstChild<TableRow>()?.Elements<TableCell>();
@@ -683,5 +683,47 @@ public void Width_ReturnsRefineTableWidth(string width, string expectedUnit, str
                 Assert.That(tableWidth?.Width?.Value, Is.EqualTo(expectedValue));
             });
         }
+
+        public void ColWithPercentWidth_ReturnsRefineTableWidth()
+        {
+            var elements = converter.Parse(@"<table style='width: 75%'>
+                <colgroup><col style='width: 13.185%;'><col style='width: 86.9293%;'></colgroup>
+                <tbody>
+                    <tr>
+                        <td>Cell 1</td>
+                        <td>Cell 2</td>
+                    </tr>
+                </tbody>
+                </table>");
+
+            Assert.That(elements, Has.Count.EqualTo(1));
+            Assert.That(elements, Has.All.TypeOf<Table>());
+            var tableWidth = elements[0].GetFirstChild<TableProperties>()?.TableWidth;
+            Assert.That(tableWidth, Is.Not.Null);
+            Assert.Multiple(() =>
+            {
+                Assert.That(tableWidth?.Type?.Value, Is.EqualTo(TableWidthUnitValues.Pct));
+                Assert.That(tableWidth?.Width?.Value, Is.EqualTo("3750"));
+            });
+
+            var columns = elements[0].GetFirstChild<TableGrid>()?.Elements<GridColumn>();
+            Assert.That(columns, Is.Not.Null);
+            Assert.Multiple(() =>
+            {
+                Assert.That(columns.Count(), Is.EqualTo(2));
+                Assert.That(columns.First().Width?.Value, Is.EqualTo("1269"));
+                Assert.That(columns.Last().Width?.Value, Is.EqualTo("8365"));
+            });
+
+            var cells = elements[0].GetFirstChild<TableRow>()?.Elements<TableCell>();
+            Assert.That(cells, Is.Not.Null);
+            Assert.Multiple(() =>
+            {
+                Assert.That(cells.Count(), Is.EqualTo(2));
+                // width on cell are on 5000 basis
+                Assert.That(cells.First().TableCellProperties?.TableCellWidth?.Width?.Value, Is.EqualTo("659"));
+                Assert.That(cells.Last().TableCellProperties?.TableCellWidth?.Width?.Value, Is.EqualTo("4346"));
+            });
+        }
     }
 }