Hi:

As of LabVIEW 8.0, LabVIEW will print graphs with the plot area empty! All grid lines, controls, etc will show up OK, but the all important graph will be empty! In some cases LabVIEW prints empty pages altogether. NI application engineers acknowledge that this is a known bug but it is yet to be fixed as of LabVIEW 8.5.

The work-around I am doing now is to capture a *.png image of the original front panel and import that into a picture control and print the FP panel of the VI with that picture control. However, the print quality degrades due to this image handover process.

Can NI please elevate the priority for this problem for fixing in the next release?

Anthony L.

Anthony: How are you getting this behavior? Both the Print Window... command (under the File menu) and the VI method Print.Panel to Printer work for me in LabVIEW 8.2 and 8.5.

It would be interesting to see an example of this behaviour.

Maybe it's an effect similar to what I saw in one project, where I printed a front panel as a report:
First call: panel with default values was printed,
Second call: panel with values from first call was printed,
and so on...

It seems that LabVIEW simply generated the image to print before updating the data in the controls.
Fortunately, all the elements were in one cluster, so the solution was easy: I wired the cluster control directly into a local variable of itself and used a sequence structure to make shure the image was generated after this.

Could this be the same thing you are experiencing?

I can't support the original complain either, printing front panels quite often both to real printers as also to redirected PDF file printer drivers. But yes making sure that the front panel is drawn before you invoke the print operation is very important ;-). There are actually many ways to cause this, such as using an explicit Print Panel To Printer.vi I got from the NI site as well as print on completion of a VI, but I think I haven't used the later in quite some time. Also making sure the front panel is visible during printing might make a difference too, depending on the display driver. In that case decreasing the display speed optimization often can make it work even with hidden front panel.

And if these things won't help (quite unlikely and probably the reason why this hasn't been adressed yet as the OP thinks, as addressing bugs that are hard to reproduce or are really more an operator error is something most developers react with a "Not a bug" label), changing the printing method could make a difference too. bitmap, Postscript, greyscale as well as changing printer drivers could actually give more information as to what could be wrong. Not all printer drivers work well in all print modes and that is quite often more a bug in the printer driver than in LabVIEW.

Rolf Kalbermatter

I just ran across the same problem.
I have a VI with 4 waveform graphs and I can't get it to print out. i only get white graphs with no data (plots) in it.
The strange thing about it is this:
I have tried LV8.0 (Windows), LV8.2 (Linux) and LB8.2 (Windows), on three different boxes with exactly the same result.
Now if copy all front panel elements and copy them to a new VI (with all the data in the graphs) I can print them without problems.
I have never seen this behaviour before and I have absolutely no idea how I can make it work!
Confused to death-
macbeth

Why not show your VIs?

Rolf Kalbermatter