private void CheckColumnWidth(int expectedWidth, int column, bool useMergedCells)
{
int bestFitWidth = tracker.GetBestFitColumnWidth(column, useMergedCells);
if (bestFitWidth < 0 && expectedWidth < 0)
{
return;
}
double abs_error = Math.Abs(bestFitWidth - expectedWidth);
double rel_error = abs_error / expectedWidth;
if (rel_error > 0.25)
{
Assert.Fail("check column width: " +
rel_error + ", " + abs_error + ", " +
expectedWidth + ", " + bestFitWidth);
}
}
/**
* Adjusts the column width to fit the contents.
* <p>
* This process can be relatively slow on large sheets, so this should
* normally only be called once per column, at the end of your
* processing.
* </p>
* You can specify whether the content of merged cells should be considered or ignored.
* Default is to ignore merged cells.
*
* <p>
* Special note about SXSSF implementation: You must register the columns you wish to track with
* the SXSSFSheet using {@link #trackColumnForAutoSizing(int)} or {@link #trackAllColumnsForAutoSizing()}.
* This is needed because the rows needed to compute the column width may have fallen outside the
* random access window and been flushed to disk.
* Tracking columns is required even if all rows are in the random access window.
* </p>
* <p><i>New in POI 3.14 beta 1: auto-sizes columns using cells from current and flushed rows.</i></p>
*
* @param column the column index to auto-size
* @param useMergedCells whether to use the contents of merged cells when calculating the width of the column
*/
public void AutoSizeColumn(int column, bool useMergedCells)
{
// Multiple calls to autoSizeColumn need to look up the best-fit width
// of rows already flushed to disk plus re-calculate the best-fit width
// of rows in the current window. It isn't safe to update the column
// widths before flushing to disk because columns in the random access
// window rows may change in best-fit width. The best-fit width of a cell
// is only fixed when it becomes inaccessible for modification.
// Changes to the shared strings table, styles table, or formulas might
// be able to invalidate the auto-size width without the opportunity
// to recalculate the best-fit width for the flushed rows. This is an
// inherent limitation of SXSSF. If having correct auto-sizing is
// critical, the flushed rows would need to be re-read by the read-only
// XSSF eventmodel (SAX) or the memory-heavy XSSF usermodel (DOM).
int flushedWidth;
try
{
// get the best fit width of rows already flushed to disk
flushedWidth = _autoSizeColumnTracker.GetBestFitColumnWidth(column, useMergedCells);
}
catch (Exception e)
{
throw new InvalidOperationException("Could not auto-size column. Make sure the column was tracked prior to auto-sizing the column.", e);
}
// get the best-fit width of rows currently in the random access window
int activeWidth = (int)(256 * SheetUtil.GetColumnWidth(this, column, useMergedCells));
// the best-fit width for both flushed rows and random access window rows
// flushedWidth or activeWidth may be negative if column contains only blank cells
int bestFitWidth = Math.Max(flushedWidth, activeWidth);
if (bestFitWidth > 0)
{
int maxColumnWidth = 255 * 256; // The maximum column width for an individual cell is 255 characters
int width = Math.Min(bestFitWidth, maxColumnWidth);
SetColumnWidth(column, width);
}
}