QTextDocument: add css-styling of table cell borders to HTML import/export

Supported style attributes:

<table>
style: supports "border-collapse: collapse" and "border-color".
border: width of the outer border
bordercolor: basic color for all borders

<tr>
style: not supported

<td>/</th>
style: supports the "border", "border-[top|left|bottom|right]]"
       shorthand styles and the "border-width", "border-color"
       and "border-style" (and the top/left/bottom/right variants)
       attributes

<table border=1 style="border-collapse: collapse"> will render
a simple 1px table grid.

Notes:

The QTextDocument table model is much simpler than the HTML table model.
It basically only has <table> and <td> support. So the HTML parser is
forced to map markup and styling to the QTextDocument model which
is not without loss.

In other words: While QTextDocument -> HTML -> QTextDocument should
preserve the QTextDocument structure, HTML -> QTextDocument -> HTML
does not preserve the HTML DOM at all.

So for now the HTML importer and writer only support border styles on
the <td> and <th> nodes. In future updates, the HTML parser might be
enhanced to map <tr> and <table> CSS styles to the cells.

Change-Id: If9e7312fa6cbf270cf8f7b3c72ba1fa094107517
Reviewed-by: Shawn Rutledge <shawn.rutledge@qt.io>

1 files changed, 26 insertions, 0 deletions

diff --git a/src/gui/text/qtextdocumentfragment.cpp b/src/gui/text/qtextdocumentfragment.cpp
index 8ad1300e6c..778493d4bc 100644
--- a/src/gui/text/qtextdocumentfragment.cpp
+++ b/src/gui/text/qtextdocumentfragment.cpp
@@ -986,6 +986,7 @@ QTextHtmlImporter::Table QTextHtmlImporter::scanTable(int tableNodeIdx)
         tableFmt.setColumns(table.columns);
         tableFmt.setColumnWidthConstraints(columnWidths);
         tableFmt.setHeaderRowCount(tableHeaderRowCount);
+        tableFmt.setBorderCollapse(node.borderCollapse);
         fmt = tableFmt;
     }
 
@@ -1061,6 +1062,31 @@ QTextHtmlImporter::ProcessNodeResult QTextHtmlImporter::processBlockNode()
                     fmt.setLeftPadding(leftPadding(currentNodeIdx));
                 if (rightPadding(currentNodeIdx) >= 0)
                     fmt.setRightPadding(rightPadding(currentNodeIdx));
+                if (tableCellBorder(currentNodeIdx, QCss::TopEdge) > 0)
+                    fmt.setTopBorder(tableCellBorder(currentNodeIdx, QCss::TopEdge));
+                if (tableCellBorder(currentNodeIdx, QCss::RightEdge) > 0)
+                    fmt.setRightBorder(tableCellBorder(currentNodeIdx, QCss::RightEdge));
+                if (tableCellBorder(currentNodeIdx, QCss::BottomEdge) > 0)
+                    fmt.setBottomBorder(tableCellBorder(currentNodeIdx, QCss::BottomEdge));
+                if (tableCellBorder(currentNodeIdx, QCss::LeftEdge) > 0)
+                    fmt.setLeftBorder(tableCellBorder(currentNodeIdx, QCss::LeftEdge));
+                if (tableCellBorderStyle(currentNodeIdx, QCss::TopEdge) != QTextFrameFormat::BorderStyle_None)
+                    fmt.setTopBorderStyle(tableCellBorderStyle(currentNodeIdx, QCss::TopEdge));
+                if (tableCellBorderStyle(currentNodeIdx, QCss::RightEdge) != QTextFrameFormat::BorderStyle_None)
+                    fmt.setRightBorderStyle(tableCellBorderStyle(currentNodeIdx, QCss::RightEdge));
+                if (tableCellBorderStyle(currentNodeIdx, QCss::BottomEdge) != QTextFrameFormat::BorderStyle_None)
+                    fmt.setBottomBorderStyle(tableCellBorderStyle(currentNodeIdx, QCss::BottomEdge));
+                if (tableCellBorderStyle(currentNodeIdx, QCss::LeftEdge) != QTextFrameFormat::BorderStyle_None)
+                    fmt.setLeftBorderStyle(tableCellBorderStyle(currentNodeIdx, QCss::LeftEdge));
+                if (tableCellBorderBrush(currentNodeIdx, QCss::TopEdge) != Qt::NoBrush)
+                    fmt.setTopBorderBrush(tableCellBorderBrush(currentNodeIdx, QCss::TopEdge));
+                if (tableCellBorderBrush(currentNodeIdx, QCss::RightEdge) != Qt::NoBrush)
+                    fmt.setRightBorderBrush(tableCellBorderBrush(currentNodeIdx, QCss::RightEdge));
+                if (tableCellBorderBrush(currentNodeIdx, QCss::BottomEdge) != Qt::NoBrush)
+                    fmt.setBottomBorderBrush(tableCellBorderBrush(currentNodeIdx, QCss::BottomEdge));
+                if (tableCellBorderBrush(currentNodeIdx, QCss::LeftEdge) != Qt::NoBrush)
+                    fmt.setLeftBorderBrush(tableCellBorderBrush(currentNodeIdx, QCss::LeftEdge));
+
                 cell.setFormat(fmt);
 
                 cursor.setPosition(cell.firstPosition());