9.8.4 Week scale

Week scales, if enabled, by default shows the week number in range 1 to 53 (as defined by ISO-8601, see the reference section).

It might be worth pointing out here that the week number calculation is carried out within JpGraph and does not rely on the underlying OS date libraries. This makes the behavior consistent over several OS:s (at least M$ Windows does not comply to ISO-8601 or supply any way of doing this through the normal libraries, e.g. strftime())

You may modify the week behavior in three ways. You can specify (with SetStyle()) a different date format using the constants

•  WEEKSTYLE_WNBR

  Show week number To further modify the formatting of the actual week number you can optionally supply a format string with a call to

   SetLabelFormatString()

  The format of the string should be a standard sprintf() syntax expecting an integer (the week number). By default a 'W' is prefixed to the number.

•  WEEKSTYLE_FIRSTDAY

  Show date of first day in week.

•  WEEKSTYLE_FIRSTDAY2

  Show date of first day in week and short month

•  WEEKSTYLE_FIRSTDAYWNBR

  Show weeknumber of first day in week.

•  WEEKSTYLE_FIRSTDAY2WNBR

  Show weeknumber of first day in week and month