Bug exporting invisible column to PDF

[ghost]

I found a bug where a column with property "bVisible":false is not properly exported to PDF. I have written a sample HTML page, see https://gist.github.com/4599023. Unfortunately you have to run the HTML page from a local webserver because of Flash security restrictions. (It seams the .swf must be served from the same webserver as the HTML file, opening the file with the browser wan't work. I also wrote a jsFiddle with the same problem, perhaps because of the iframe).

The example contains a table with 4 columns, the 3rd column is hidden with "bVisible":false. I would like export all 4 columns, TableTools has been configured with:

"aButtons": [
    {
        "sExtends": "pdf",
        "mColumns": [0, 1, 2, 3],
        "sPdfOrientation": "landscape"
     }
]

The exported PDF has the 4th column merged into the 3rd.

[rgavrilov]

I'm getting the same behavior. Apparently bug is caused by fnCalcColRatios function, which calculates invisible column width as 0:

iWidth = aoCols[i].nTh.offsetWidth;

Not sure what the good fix would be though, to get proper width we need to render the column, i.e. make it visible.

[DataTables]

Hmmm - tricky one. Note sure what the correct thing to do is either. Possibly calculate the widths based on the content of the headers (strlen)... What I really would like is for the PDF generator to figure it out, but it doesn't seem to work that way.

[afshinm]

Any update on this?

[DataTables]

Sorry no. I've not had time to work on it yet.

[EverpathDano]

A hack, super easy, super fast, "at least it looks better than terrible" workaround until someone figures out something better:

iWidth = aoCols[i].nTh.offsetWidth;
if (!iWidth && typeof iDTTTDefaultHiddenColumnWidth !== 'undefined') {
    iWidth = iDTTTDefaultHiddenColumnWidth;
}

then we set the variable in the global scope to have a reasonable default (we have one table per page, we tune to that specific table). Even simpler could be iWidth = aoCols[i].nTh.offsetWidth || 200;.

I know, I know, it's hideous and horrible, I'm not suggesting this as a change to the mainline. It has the advantage of getting us up and running again without rolling our own PDF generator, I figured I'd pass it along to other desperate coders. :-)