/// <summary>
/// Goes through the Workbook, optimising the fonts by
/// removing duplicate ones.
/// For now, only works on fonts used in HSSFCellStyle
/// and HSSFRichTextString. Any other font uses
/// (eg charts, pictures) may well end up broken!
/// This can be a slow operation, especially if you have
/// lots of cells, cell styles or rich text strings
/// </summary>
/// <param name="workbook">The workbook in which to optimise the fonts</param>
public static void OptimiseFonts(HSSFWorkbook workbook)
{
// Where each font has ended up, and if we need to
// delete the record for it. Start off with no change
short[] newPos =
new short[workbook.Workbook.NumberOfFontRecords + 1];
bool[] zapRecords = new bool[newPos.Length];
for (int i = 0; i < newPos.Length; i++)
{
newPos[i] = (short)i;
zapRecords[i] = false;
}
// Get each font record, so we can do deletes
// without Getting confused
FontRecord[] frecs = new FontRecord[newPos.Length];
for (int i = 0; i < newPos.Length; i++)
{
// There is no 4!
if (i == 4) continue;
frecs[i] = workbook.Workbook.GetFontRecordAt(i);
}
// Loop over each font, seeing if it is the same
// as an earlier one. If it is, point users of the
// later duplicate copy to the earlier one, and
// mark the later one as needing deleting
// Note - don't change built in fonts (those before 5)
for (int i = 5; i < newPos.Length; i++)
{
// Check this one for being a duplicate
// of an earlier one
int earlierDuplicate = -1;
for (int j = 0; j < i && earlierDuplicate == -1; j++)
{
if (j == 4) continue;
FontRecord frCheck = workbook.Workbook.GetFontRecordAt(j);
if (frCheck.SameProperties(frecs[i]))
{
earlierDuplicate = j;
}
}
// If we got a duplicate, mark it as such
if (earlierDuplicate != -1)
{
newPos[i] = (short)earlierDuplicate;
zapRecords[i] = true;
}
}
// Update the new positions based on
// deletes that have occurred between
// the start and them
// Only need to worry about user fonts
for (int i = 5; i < newPos.Length; i++)
{
// Find the number deleted to that
// point, and adjust
short preDeletePos = newPos[i];
short newPosition = preDeletePos;
for (int j = 0; j < preDeletePos; j++)
{
if (zapRecords[j]) newPosition--;
}
// Update the new position
newPos[i] = newPosition;
}
// Zap the un-needed user font records
for (int i = 5; i < newPos.Length; i++)
{
if (zapRecords[i])
{
workbook.Workbook.RemoveFontRecord(
frecs[i]
);
}
}
// Tell HSSFWorkbook that it needs to
// re-start its HSSFFontCache
workbook.ResetFontCache();
// Update the cell styles to point at the
// new locations of the fonts
for (int i = 0; i < workbook.Workbook.NumExFormats; i++)
{
ExtendedFormatRecord xfr = workbook.Workbook.GetExFormatAt(i);
xfr.FontIndex = (
newPos[xfr.FontIndex]
);
}
// Update the rich text strings to point at
// the new locations of the fonts
// Remember that one underlying unicode string
// may be shared by multiple RichTextStrings!
ArrayList doneUnicodeStrings = new ArrayList();
for (int sheetNum = 0; sheetNum < workbook.NumberOfSheets; sheetNum++)
{
HSSFSheet s = workbook.GetSheetAt(sheetNum);
IEnumerator rIt = s.GetRowEnumerator();
while (rIt.MoveNext())
{
HSSFRow row = (HSSFRow)rIt.Current;
IEnumerator cIt = row.GetCellEnumerator();
while (cIt.MoveNext())
{
HSSFCell cell = (HSSFCell)cIt.Current;
if (cell.CellType == HSSFCell.CELL_TYPE_STRING)
{
HSSFRichTextString rtr = cell.RichStringCellValue;
UnicodeString u = rtr.RawUnicodeString;
// Have we done this string already?
if (!doneUnicodeStrings.Contains(u))
{
// Update for each new position
for (short i = 5; i < newPos.Length; i++)
{
if (i != newPos[i])
{
u.SwapFontUse(i, newPos[i]);
}
}
// Mark as done
doneUnicodeStrings.Add(u);
}
}
}
}
}
}