Tables pose a special challenge for screen readers because they present textual or numerical data to be easily referenced visually. Content within table cells can be complex and might contain lists, paragraphs, form fields, or another table.
The Touch Up Reading Order Table Editor displays the selected table into cells and allows the user to apply additional table markup. The table must be tagged as a table before using TURO’s Table Editor command.
For best results when tagging tables, use the application that created the document to add tags when the PDF is created. If a PDF is not tagged and the source document is not available, add tags by using the Add Tags To Document command in the Accessibility pane. Most tables are properly recognized using this command; however, the command may not recognize a table that lacks clear borders, headings, columns, and rows. Use the Touch Up Reading Order tool to determine if the table has been properly recognized and to correct recognition problems such as missing cells. The Tags panel can also be used to manually tag data table elements.
Use the Table Editor to check and correct table tags. By viewing table tags, determine whether columns, rows, and cells have been correctly identified. Tables that lack well-defined borders and rules are often tagged incorrectly or contain adjacent page elements. It is possible to correct poorly tagged tables by selecting and redefining them; it is possible to split combined cells by creating a tag for each cell.
- Select the Touch Up Reading Order tool.
- Select the Show Tables And Figures button.
- If the table is not clearly labeled in the document pane, drag to select the entire table, and then click Table in the dialog box.
- Click Show Table Cells to make sure that all cells in the table are defined as individual elements.
If cells do not appear as separate elements:
- Use the Touch Up Reading Order tool to select a single cell from within a merged cell.
- Select the Cell button in the dialog box. Repeat for each split merged cell.
Note: If cells are not highlighted, the table might not use standard table formatting. Re-create the table in the authoring application.
Add a Table Summary
With the cursor over the table, right click to add a Table Summary. The Edit Table Summary option is available in the menu that appears when a right-click is performed on a highlighted table. This allows the user to add or edit a text description about the table properties that may be read by a screen reader or other assistive technology.
Editing Table Tags
Place the Table in Editing Mode
There are two ways to place Tables in Table Editing Mode with the Touch Up Reading Order tool:
- With the cursor over the table, right click to select Table Editor from the context menu to place the table in Table Editing mode.
- Use the Order panel.
- Activate the Show Order Panel button in the Touch Up Reading Order dialog.
- Highlight a cell from the table in the Order panel.
- The Table Editor button in the Touch Up Reading Order tool becomes active.
- Select the Table Editor button on the Touch Up Reading Order dialog to place the table in Table Editing Mode (See “Figure 30. Using the Order Panel to Activate the Table Editor”).
Table Editor Options
In Table Editing mode, the borders of the table cells are highlighted. It is possible to change the color of the border.
Table Editing Mode
Right click on the table and choose “Table Editor Options” to display the options dialog. The Table Editor Options dialog allows users to control how table cells and table headers are displayed by Acrobat when using the Touch Up Reading Order Table Editor.
Selecting Table Cells
Select individual cells by clicking within the borders with the mouse. Select multiple table cells by holding down Shift and clicking. (This is an efficient method for selecting the first row of data cells in a table which need to be changed to header cells.) Some properties for multiple cells can be set at once thus saving time tagging large and complex tables.
Edit Cell Properties
Once in Table Editing mode, right click to display the Table Cell Properties dialog.
The Table Cell Properties dialog can be used to:
- Specify the type of a table cell (Header cell or Data cell)
- Set cell attributes that span more than one row or column
- Assign a scope of row, column, both, or none to header cells
- Assign a unique header ID for Table Headers
- Associate Data cells with Header IDs that have been created for the table
To correct complex tagging issues in data tables, it may be necessary to use the Tags panel and the Table Editor in combination. For simple tables with only one row or column of header cells, the easiest approach is to set each cell in the header row or column to type “header cell”. Then set the scope on each cell to the appropriate item “row” for row headers on the left side of the table or “column” for column headers that appear across the top of a table. Data tables should always have headers tagged this way, or with IDs and headers.
For complex tables, those with more than one row or column of header cells IDs and headers must be used. IDs and headers refers to the method to associate data and header cells in data tables. This process is very similar to that of HTML data tables. When IDs and headers are used, the type of cells (header or data) should still be set but the scope option should not. Assign an ID property to each header cell. Then add mappings to the ID or IDs that label the cell in the Headers list. Headers are announced by screen readers in reverse order in the headers list.
Verifying Table Structure with the Tags Panel
- In the Tags panel, expand the tags root to view a table tag.
- Select the table tag <Table> and verify that it contains one of the following elements:
- Table Rows <TR>, each of which contains Table Header <TH> or Table Data <TD> cells
- <THead>, <TBody>, or <TFoot> section, each of which contains Table Rows (The Table Rows contain <TH> cells, <TD> cells, or both).
Do one or more of the following:
- If the tag for the table doesn’t contain these elements, but rows, columns, and cells appear in the table in the document pane, use the Touch Up Reading Order tool to select and define the table or individual cells.
- If the table contains cells that span two or more columns or rows, set ColSpan or RowSpan attributes as appropriate for these cells in the Table Editor of the Touch Up Reading Order tool.
- Re-create the table in the authoring application, and then convert it to a tagged PDF.