Fix#434, which went stale in 2018 and is now reopened. User reported a fatal error in Writer/Html. Regrettably, there is no example code/spreadsheet to illustrate the error. However, the area of code where the error happened is identified. Studying that, it was clear that the error could be avoided through the use of the nullsafe operator `?->` without any performance hit, while making the resulting code a little clearer.
Fix#413, which went stale in 2018 and is now reopened. A DataTable can be used on a chart in place of a Legend (or in addition to one, but it doesn't really make sense to have both). The fix was substantially developed by @topaDev before the issue went stale. This PR provides basic support for reading and writing DataTables on charts. The new sample on this PR shows them in action. They have obscure features which are not implemented (e.g. `glow`); those will have to wait for another day.
Fix#411, which went stale in 2018 and is now reopened. You can get a style for a set of cells which uses multiple ranges, e.g. `A1:B2,C5:H10`, but we throw an exception if you try to change the style. I don't know how useful that is, but it's been requested and it's pretty easy to implement with recursion.
The comma in the ranges represents the `union` operator. `getStyle` is very permissive - it will allow almost anything to be specified. However, attempts to use a space as the `intersection` operator, or, indeed, many other nonsense strings, will still be permitted for `getStyle` but will continue to throw an Exception if an attempt is made to alter the style.
Fix#863, which went stale in 2019 and is now reopened. Add methods to `Cell` which operate in a cursor-like manner, allowing you to change to cells on the right, left, down, or up.
Fix#661 (marked stale in 2018, but now reopened). That issue was already mostly resolved by many changes to Xlsx Chart Writer logic some time ago. However, a new problem popped up. PR #2950 added `brightness` logic to Xlsx Reader and Writer. That was done primarily for the benefit of scatter charts. Xlsx Writer writes two brightness properties `lumMod` and `lumOff`. These values are complete complementary (if you know one, you know the other), so I am not sure why both are needed, but my scatter chart testing indicated that they were. It turns out that Radar charts can also set brightness, but, if the writer specifies both `lumMod` and `lumOff`, the resulting chart is slightly off. There may be more to this, but that's all I can deal with for now - I suppress writing `lumOff` if we're writing a radar chart. If there are other problems in this area, I will wait for them to be reported. None of the existing radar chart samples used the brightness properties; however, the example attached to 661 did. It is added as a new Sample, and tests are added.
It requires an index to an array which needs to be supplied as a string, even though the array is indexed exclusively by int. It is called only once in the code base, by some inefficient code which becomes much simpler when restructured and eliminates the call altogether. It is not independently tested. The use case for its existence is not clear. It should probably just be deprecated. However, for now, I'm just allowing the parameter to be int|string, rather than just string, and adding tests.
A large volume of changes due to "sealed" arrays. Some are sensible; some are very confusing and are handled with `ignore` annotations.
Modules in src with changed code (as opposed to doc-blocks or annotations) are:
- DateTimeExcelDays
- Reader/Xlsx
- Reader/Xlsx/AutoFilter
- Reader/Xlsx/Chart
- Reader/Xlsx/ConditionalStyles
- Reader/Xlsx/TableReader