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, 8 insertions, 0 deletions

diff --git a/src/gui/text/qtexthtmlparser_p.h b/src/gui/text/qtexthtmlparser_p.h
index ff5f5b4c35..31f558709f 100644
--- a/src/gui/text/qtexthtmlparser_p.h
+++ b/src/gui/text/qtexthtmlparser_p.h
@@ -195,8 +195,12 @@ struct QTextHtmlParserNode {
     int tableCellColSpan;
     qreal tableCellSpacing;
     qreal tableCellPadding;
+    qreal tableCellBorder[4];
+    QBrush tableCellBorderBrush[4];
+    QTextFrameFormat::BorderStyle tableCellBorderStyle[4];
     QBrush borderBrush;
     QTextFrameFormat::BorderStyle borderStyle;
+    bool borderCollapse;
     int userState;
 
     int cssListIndent;
@@ -290,6 +294,10 @@ public:
     inline int leftPadding(int i) const { return at(i).padding[MarginLeft]; }
     inline int rightPadding(int i) const { return at(i).padding[MarginRight]; }
 
+    inline qreal tableCellBorder(int i, int edge) const { return at(i).tableCellBorder[edge]; }
+    inline QTextFrameFormat::BorderStyle tableCellBorderStyle(int i, int edge) const { return at(i).tableCellBorderStyle[edge]; }
+    inline QBrush tableCellBorderBrush(int i, int edge) const { return at(i).tableCellBorderBrush[edge]; }
+
     void dumpHtml();
 
     void parse(const QString &text, const QTextDocument *resourceProvider);