LabVIEW Idea Exchange

I'd really like the ability to write some metadata information in the PNG Write (and read from Read) VIs. JPG, BMP would be nice for completeness.

Lately I'm using PNGs a lot. The W3.org spec and most PNG readers allow the use of the "tEXt" chuck tag to allow labels for simple text, keywords include: Title, Author, Description, Copyright,... -- simple stuff.

I'd modify the built-in "Write PNG File.vi" but it is password protected 😞

My workaround is to write the PNG normally, then tweak the binary file, inserting the tEXt chuck myself, just before the IEND tag, with size and CRC-32 considered.

I would really like to see it built in. Perhaps a cluster input with some of the reserved keywords. It seems functionally like a simple concatenation on the file IO stream prior to IEND and file close.

Here's the W3 spec for PNG

W3 PNG Specification

Thanks!

I don't think it makes sense that you should have to switch to the front panel to drop a waveform chart or graph on the block diagram. I believe you should have the ability to create them as you would an indicator using the right click BD functionality.

I think it would be cool to be able to define custom units in the build unit string function.  For example (%, dB, or Dan's).  The ability to include custom units would remove the burden to include every unit in this dialog.  Adding custom units would also help people who have large complex calculations.

I'd like to see a function that provides default data for any given data type. I think there could be multiple uses for this; I've detailed mine below.

In this example, I have a test results array that is indexed by test number. If I run tests out of order, I want be able to fill in the results of the array at the desired index. To do this, I have to add empty rows to the results array up to the current test's index. To do get the default data I used a diagram disable structrue with an empty "Enabled" case, with the output set to "Use Default if unwired. This is obviously a kludge.

I'd like to see a function that takes in any data type and returns the default data for that type:

The ability to specify a Format String for each index in the Array to Spreadsheet String would let individually saved data columns have different numbers of digits of precision or significant digits.

I use the Array to Spreadsheet String to save 2D column data consisting of Time (X) and one or more Data (Y) columns.  Sometimes the columns have different inherent resolutions yet the Format String needs to be set to allow the largest number of digits for all columns.  This can result in :

0.0000000 -0.0000003
0.2500000 -0.0000035
0.5000000 -0.0000030
0.7500000 -0.0000020
1.0000000 -0.0000013

If a different Format String could be used for each index, then the result would be :

0.00 -0.0000003
0.25 -0.0000035
0.50 -0.0000030
0.75 -0.0000020
1.00 -0.0000013

If nothing else, it saves on file size.  The Array to Spreadsheet String function could check whether an array of Format Strings was wired into it or not to decide what to do (make it polymorphic).  Thus existing code could still be used.