Adding high resolution graphics or text to a schematic


#1

I’m trying to add a table of population options to a large schematic. The sheet size is C (17 x 22"). I have a table created in Excel with about 15 columns that I would like to add to the schematic page.
From Excel, I saved it as a png, then when I placed it in the schematic it is small and the resolution is poor. I scaled it up a bit but it became unreadable because of the poor resolution.
Does anyone have any tricks for placing either a text table or a graphic on the schematic with high resolution?
THanks -
Dan


#2

I have kluged together something that resembles a table using multi-line text strings, spaces, underscore ( “_” ) and pipe ( " | " ) characters . . . . but it’s a lot of work for a poor substitute. (At least back in the days of DOS and mechanical printers, you could count on the uniform spacing of fixed-pitch fonts.)

Drawing “Notes”, “Revision History”, “List of Values” (for boards with more than one variant), are all examples where it would be very useful to have a true “Table” capability. I don’t recall seeing such a feature mentioned in any planning documents.

Dale


#3

Feel free to add any suggestions to this wishlist item.

https://bugs.launchpad.net/kicad/+bug/1769193


#4

What is the raw resolution of the png?

Looks like the import is being done at 300 pixels per inch (or ~12 pixels per mm or 118 pixels per cm), no matter what your picture is set to.
Also note, that any further scaling INSIDE EEschema will cause quality loss.
-> you have to do any scaling before you import it, to get maximum quality.

So, if you know that you have an area of like 5 cm wide and 10 cm high for an image, the raw resolution of that image should be 590 px wide and 1181 px high for maximum resolution within EEschema and no further scaling/tampering.

That is the yellow rectanlge I imported:

Which got these dimensions when created:


#5

Check to see what the resolution of the png as generated from Excel is. You may need to bump up the resolution of the Excel png export (if possible), and keep trying.

Note, however, the bitmap import into EESchema isn’t the best. I’ve added bitmaps to schematics and seen the schematic filesize get very large. Remember, the file format for KiCad is all text based, so the binary bitmap file will have to be encoded as text (ASCII). So your schematic file size will inflate by more than the imported graphics file size.

I haven’t looked into how EESchema does this. Maybe someone else can elaborate on how graphics are incorporated into schematic pages so we can come up with some best practices for reducing the extra filesize bloat.


#6

EESchema stores a PNG file in the schematic, encoded in hex. So the bitmap will take up twice as much space in the schematic as it did as a separate PNG file.


#7

Is it the same for other graphic file formats (.jpg, .tif, .bmp, etc) where the original file is simply stored as-is encoded in hex? Or does KiCAD convert to .png and store that? (I’m expecting the former…)

Just curious.


#8

I am not 100% certain, but the file format documentation seems to suggest it is always stored as a PNG, so I guess KiCad would convert other formats to PNG?

This is page 7 of file_formats.pdf:

Oh, and looking at this documentation again, I can see it puts a space between each byte, so it will actually triple the size of the file, not double it as I said before.


#9

Some time ago to get a part of pdf I print it to PdfCreator selecting output page A2,…A1 and output format png (don’t remember, but may be the resolution for png you also can set). Then I cut interesting part of output big png.
I suppose it could also work while printing from Excel.


#10

Also remember that the original post was specifically about making TABLES in KiCAD. Under the most favorable circumstances, an image of a table - whether *.png, *.jpg, or any other graphics format - is a poor substitute for a real table.

Dale


#11

I wholeheartedly agree with you there. But, unfortunately this isn’t possible in the current state of the art (and bleeding edge). The only options at the moment is to try to manually build a table using either ASCII graphics or text blocks with graphic lines; or import a graphic image of the table.

My advise at the moment to the OP with the tools currently available is to try to get a higher resolution png graphic that uses the smallest color palette available with the highest compression that KiCad can support. The PNG should be exported at a resolution that would give acceptable readability at the intended size in the schematic. This will probably take some trial and error on the OP’s part.


#12

Some time ago I experimented with a table in EEschem, by inserting tabs in text, but by lack of fixed with alignment that was a mess. Did not work.

However:
In a text window you can add multiple lines of text.
So you can relatively easily make a table by putting some text blocks next to each other.
Something like this:


#13

I’m way our of my comfort zone here but looking at comments in the raw sch file shows a relatively simple structure. Perhaps it is possible to create a script to insert a table in the comments format.


#14

Create a table in the Page Layout Editor, similar to the title block. Not a perfect solution but doable.


#15

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