HTMLTableCellElement* HTMLTableCellElement::cellAbove() const
{
RenderObject* cellRenderer = renderer();
if (!cellRenderer)
return 0;
if (!cellRenderer->isTableCell())
return 0;
RenderTableCell* tableCellRenderer = toRenderTableCell(cellRenderer);
RenderTableCell* cellAboveRenderer = tableCellRenderer->table()->cellAbove(tableCellRenderer);
if (!cellAboveRenderer)
return 0;
return static_cast<HTMLTableCellElement*>(cellAboveRenderer->node());
}
AccessibilityObject* AccessibilityTableColumn::headerObjectForSection(RenderTableSection* section, bool thTagRequired)
{
if (!section)
return 0;
int numCols = section->numColumns();
if (m_columnIndex >= numCols)
return 0;
if (!section->numRows())
return 0;
RenderTableCell* cell = 0;
// also account for cells that have a span
for (int testCol = m_columnIndex; testCol >= 0; --testCol) {
RenderTableCell* testCell = section->primaryCellAt(0, testCol);
if (!testCell)
continue;
// we've reached a cell that doesn't even overlap our column
// it can't be our header
if ((testCell->col() + (testCell->colSpan()-1)) < m_columnIndex)
break;
Node* node = testCell->node();
if (!node)
continue;
if (thTagRequired && !node->hasTagName(thTag))
continue;
cell = testCell;
}
if (!cell)
return 0;
return m_parentTable->axObjectCache()->getOrCreate(cell);
}
AccessibilityObject* AccessibilityTableCell::titleUIElement() const
{
// Try to find if the first cell in this row is a <th>. If it is,
// then it can act as the title ui element. (This is only in the
// case when the table is not appearing as an AXTable.)
if (isTableCell() || !m_renderer || !m_renderer->isTableCell())
return 0;
// Table cells that are th cannot have title ui elements, since by definition
// they are title ui elements
Node* node = m_renderer->node();
if (node && node->hasTagName(thTag))
return 0;
RenderTableCell* renderCell = toRenderTableCell(m_renderer);
// If this cell is in the first column, there is no need to continue.
int col = renderCell->col();
if (!col)
return 0;
int row = renderCell->rowIndex();
RenderTableSection* section = renderCell->section();
if (!section)
return 0;
RenderTableCell* headerCell = section->primaryCellAt(row, 0);
if (!headerCell || headerCell == renderCell)
return 0;
Node* cellElement = headerCell->node();
if (!cellElement || !cellElement->hasTagName(thTag))
return 0;
return axObjectCache()->getOrCreate(headerCell);
}
bool AXTable::isDataTable() const
{
if (!m_renderer)
return false;
// Do not consider it a data table is it has an ARIA role.
if (hasARIARole())
return false;
// When a section of the document is contentEditable, all tables should be
// treated as data tables, otherwise users may not be able to work with rich
// text editors that allow creating and editing tables.
if (node() && node()->rendererIsEditable())
return true;
// This employs a heuristic to determine if this table should appear.
// Only "data" tables should be exposed as tables.
// Unfortunately, there is no good way to determine the difference
// between a "layout" table and a "data" table.
RenderTable* table = toRenderTable(m_renderer);
Node* tableNode = table->node();
if (!tableNode || !isHTMLTableElement(tableNode))
return false;
// if there is a caption element, summary, THEAD, or TFOOT section, it's most certainly a data table
HTMLTableElement* tableElement = toHTMLTableElement(tableNode);
if (!tableElement->summary().isEmpty() || tableElement->tHead() || tableElement->tFoot() || tableElement->caption())
return true;
// if someone used "rules" attribute than the table should appear
if (!tableElement->rules().isEmpty())
return true;
// if there's a colgroup or col element, it's probably a data table.
for (Node* child = tableElement->firstChild(); child; child = child->nextSibling()) {
if (child->hasTagName(colTag) || child->hasTagName(colgroupTag))
return true;
}
// go through the cell's and check for tell-tale signs of "data" table status
// cells have borders, or use attributes like headers, abbr, scope or axis
table->recalcSectionsIfNeeded();
RenderTableSection* firstBody = table->firstBody();
if (!firstBody)
return false;
int numCols = firstBody->numColumns();
int numRows = firstBody->numRows();
// If there's only one cell, it's not a good AXTable candidate.
if (numRows == 1 && numCols == 1)
return false;
// If there are at least 20 rows, we'll call it a data table.
if (numRows >= 20)
return true;
// Store the background color of the table to check against cell's background colors.
RenderStyle* tableStyle = table->style();
if (!tableStyle)
return false;
Color tableBGColor = tableStyle->visitedDependentColor(CSSPropertyBackgroundColor);
// check enough of the cells to find if the table matches our criteria
// Criteria:
// 1) must have at least one valid cell (and)
// 2) at least half of cells have borders (or)
// 3) at least half of cells have different bg colors than the table, and there is cell spacing
unsigned validCellCount = 0;
unsigned borderedCellCount = 0;
unsigned backgroundDifferenceCellCount = 0;
unsigned cellsWithTopBorder = 0;
unsigned cellsWithBottomBorder = 0;
unsigned cellsWithLeftBorder = 0;
unsigned cellsWithRightBorder = 0;
Color alternatingRowColors[5];
int alternatingRowColorCount = 0;
int headersInFirstColumnCount = 0;
for (int row = 0; row < numRows; ++row) {
int headersInFirstRowCount = 0;
for (int col = 0; col < numCols; ++col) {
RenderTableCell* cell = firstBody->primaryCellAt(row, col);
if (!cell)
continue;
Node* cellNode = cell->node();
if (!cellNode)
continue;
if (cell->width() < 1 || cell->height() < 1)
continue;
validCellCount++;
bool isTHCell = cellNode->hasTagName(thTag);
// If the first row is comprised of all <th> tags, assume it is a data table.
if (!row && isTHCell)
headersInFirstRowCount++;
// If the first column is comprised of all <th> tags, assume it is a data table.
if (!col && isTHCell)
headersInFirstColumnCount++;
// in this case, the developer explicitly assigned a "data" table attribute
if (cellNode->hasTagName(tdTag) || cellNode->hasTagName(thTag)) {
HTMLTableCellElement* cellElement = toHTMLTableCellElement(cellNode);
if (!cellElement->headers().isEmpty() || !cellElement->abbr().isEmpty()
|| !cellElement->axis().isEmpty() || !cellElement->scope().isEmpty())
return true;
}
RenderStyle* renderStyle = cell->style();
if (!renderStyle)
continue;
// If the empty-cells style is set, we'll call it a data table.
if (renderStyle->emptyCells() == HIDE)
return true;
// If a cell has matching bordered sides, call it a (fully) bordered cell.
if ((cell->borderTop() > 0 && cell->borderBottom() > 0)
|| (cell->borderLeft() > 0 && cell->borderRight() > 0))
borderedCellCount++;
// Also keep track of each individual border, so we can catch tables where most
// cells have a bottom border, for example.
if (cell->borderTop() > 0)
cellsWithTopBorder++;
if (cell->borderBottom() > 0)
cellsWithBottomBorder++;
if (cell->borderLeft() > 0)
cellsWithLeftBorder++;
if (cell->borderRight() > 0)
cellsWithRightBorder++;
// If the cell has a different color from the table and there is cell spacing,
// then it is probably a data table cell (spacing and colors take the place of borders).
Color cellColor = renderStyle->visitedDependentColor(CSSPropertyBackgroundColor);
if (table->hBorderSpacing() > 0 && table->vBorderSpacing() > 0
&& tableBGColor != cellColor && cellColor.alpha() != 1)
backgroundDifferenceCellCount++;
// If we've found 10 "good" cells, we don't need to keep searching.
if (borderedCellCount >= 10 || backgroundDifferenceCellCount >= 10)
return true;
// For the first 5 rows, cache the background color so we can check if this table has zebra-striped rows.
if (row < 5 && row == alternatingRowColorCount) {
RenderObject* renderRow = cell->parent();
if (!renderRow || !renderRow->isBoxModelObject() || !toRenderBoxModelObject(renderRow)->isTableRow())
continue;
RenderStyle* rowRenderStyle = renderRow->style();
if (!rowRenderStyle)
continue;
Color rowColor = rowRenderStyle->visitedDependentColor(CSSPropertyBackgroundColor);
alternatingRowColors[alternatingRowColorCount] = rowColor;
alternatingRowColorCount++;
}
}
if (!row && headersInFirstRowCount == numCols && numCols > 1)
return true;
}
if (headersInFirstColumnCount == numRows && numRows > 1)
return true;
// if there is less than two valid cells, it's not a data table
if (validCellCount <= 1)
return false;
// half of the cells had borders, it's a data table
unsigned neededCellCount = validCellCount / 2;
if (borderedCellCount >= neededCellCount
|| cellsWithTopBorder >= neededCellCount
|| cellsWithBottomBorder >= neededCellCount
|| cellsWithLeftBorder >= neededCellCount
|| cellsWithRightBorder >= neededCellCount)
return true;
// half had different background colors, it's a data table
if (backgroundDifferenceCellCount >= neededCellCount)
return true;
// Check if there is an alternating row background color indicating a zebra striped style pattern.
if (alternatingRowColorCount > 2) {
Color firstColor = alternatingRowColors[0];
for (int k = 1; k < alternatingRowColorCount; k++) {
// If an odd row was the same color as the first row, its not alternating.
if (k % 2 == 1 && alternatingRowColors[k] == firstColor)
return false;
// If an even row is not the same as the first row, its not alternating.
if (!(k % 2) && alternatingRowColors[k] != firstColor)
return false;
}
return true;
}
return false;
}