Writer\Html output is much too large

[werbfred]

…stDataColumn() which seems to be more adequate than Worksheet::calculateWorksheetDimension which uses Worksheet::getHighestColumn(). This latest one includes all available columns not those with effective data.

This is:

- [x] a bugfix
- [ ] a new feature

Checklist:

• Changes are covered by unit tests
• Code style is respected
• Commit message explains why the change is made (see https://github.com/erlang/otp/wiki/Writing-good-commit-messages)
• CHANGELOG.md contains a short summary of the change
• Documentation is updated as necessary

Why this change is needed?

When using the save method from PhpOffice\PhpSpreadsheet\Writer\Html, we could expect that only the usefull data is being outputed. This works fine for *PhpOffice\PhpSpreadsheet\Writer\Csv

[werbfred]

This Pull Request is related to issue : Writer\Html output is much too large #1235

[MarkBaker]

There is a block of code in the HTML Writer that tries to identify images that exist in the spreadsheet below the last data row, and to ensure that they are included in the html output. I suspect that this change would break that.
In the case of a csv file, that isn't an issue, because images aren't written to csv output

[PowerKiKi]

@MarkBaker, I added tests for the case you mention and fixed the bug

[aagarwal8]

@PowerKiKi the same issue exists when there are charts or images after the last column. Can a similar fix be applied for it?

[PowerKiKi]

if there is something after the last column, then it is correct to output a "too large" spreadsheet in order to show that thing, isn't it ? or are you talking about something else ?

[aagarwal8]

Perhaps, but it is not working as expected.

Spreadsheet with 6 columns, 50 odd rows; couple of charts placed over columns G thru K.
The only way HTML writer is showing the charts is if we populate a cell after column K (doesnt matter what we put in the cell; even a space works).

[PowerKiKi]

What you describe is the "opposite" of OP. OP said "there is too many blank cells", but you're saying "there's not enough blank cell to see my chart". You should open a new PR to fix that, or at least a PR with a failing test that demonstrate the issue.