[reland] cleanup column width and font size setting

[JanMarvin]

I have updated to font size settings to default to column width of 8.43 and a font size of 11 and to use the windows size setting. On Mac the column width will be slightly off, but otherwise we'd have to skip a couple of tests.

This adjusts a few functions to use default column width of 10 and default font size 12. This is what MS365 uses on Mac. It is changed, because otherwise column widths were slightly off. 9. something instead of 10. Adjusted to this new values, all calculations are correct for Calibri. Yet, I would not bet that our calculations are valid for all versions. Previously we were using 8.43 and font size 11 as default. Which might be correct for the MS365 webbrowser edition or certain Windows low dpi versions.

Maybe you can check the following on Windows @jmbarbone ? On Mac the column width is exactly 8.5 ... 17.5.

  wb <- wb_workbook()$
    add_worksheet()$
    set_col_widths(cols = 1:10, width = (8:17) + .5)$
    add_data(x = rbind(8:17), colNames = FALSE)$
    open()

Orignal PR was #341 which was accidentally merged and reverted

[jmbarbone]

@JanMarvin, I'm seeing an extra 0.25 on Windows. Column widths are appearing as 8.75, 9.75, etc.

[JanMarvin]

Thanks @jmbarbone , I have modified their formula here:

widths <- trunc((as.numeric(col_width) * mdw + 5 + 2) / mdw * 256) / 256

The +2 is my fix for Mac. Could you see if it works without the +2? I'm not sure if the width relies on the OS or DPI of the screen somehow. I will check with the web browser version of MS365.

[jmbarbone]

@JanMarvin , removing the +2 seems to do the trick. All the columns are at the appropriate x.5 widths.

[JanMarvin]

So their formula actually works on Windows. Maybe we should stick with that.
My initial hope was that the value in the XML file would match the value Excel shows. Though that is not the case and the value we are currently setting was off when applied on Mac. This PR is an improvement, though the default width seems to be varying across Excel and OS versions. MS365 on Mac has a default width of 10. My work Excel 2013 has 10.71 and MS365 in the browser was 8.43. Do you have any preference? (The calculated value is depending on the default width as well.)
We could go with the 10 and this PR and formula for Windows. This way if someone sets a column width the result would match on one OS.

[JanMarvin]

@jmbarbone If you find the time, could you please give this another feature test and run the check again? Just want to make sure that we set the column width correctly for Windows Excel. Unfortunately the width values are different on Mac and I haven't found a way to please both Excels. Might be a general issue: link to ms forum

This changes the column width setting to calculate the values, whereas previously we simply set a value which was not identical to whatever Excel was using. This aligns a few functions to return width 8.43 and Calibri 11 font. I'd like to include this with 0.3.1 due to the more expected column widths. Prior to this PR you would set the width to 10 and would end up with something different, now you end up with column width 10 on Windows and 9.8 or so on Mac.

[jmbarbone]

@JanMarvin , with the current build the column widths seem fine when set to integers or integer-like values. Decimals seem to have some random offset:

devtool::load_all()
wb <- wb_workbook()
wb$add_worksheet()
wb$add_data(x = rbind(8:17), colNames = FALSE)
wb$set_col_widths(cols = 1:10, width = (8:17) + seq(0.1, 1, .1))
wb$open()

width	offset	actual	difference
8	0.1	8.14	0.04
9	0.2	9.14	-0.06
10	0.3	10.29	-0.01
11	0.4	11.43	0.03
12	0.5	12.43	-0.07
13	0.6	13.57	-0.03
14	0.7	14.71	0.01
15	0.8	15.86	0.06
16	0.9	16.86	-0.04
17	1.0	18.00	0.00

[JanMarvin]

Thanks. Might be related to the use of round. With .2 it is -0.06 and with .8 it's 0,06. Do you feel like this is reason enough to hold the pull request back? I'd say we can merge it the way it is and improve from there on (if we ever have to). After all it is already much better than the previous implementation.

[jmbarbone]

@JanMarvin , if this is an improvement from the current version, then it's probably good to include it

Might just need a disclaimer:

column width setting has been improved but may not be exact on Windows