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no help

Export/output to png/pdf/eps from LayoutEditor

by anonymous - 15 May 2009, 8:40 CEST

I would like to ask you for help with export (output) to various formats: png (gif), pdf, (e)ps. However, I see many problems here.

My GDS drawings is a complete mask for a 100 mm wafer. There can be cca 3000 lines, boxes and text objects in the drawing. The unit is 1 mm, i.e. 1 um = 0.001, therefore the userunit is set to 0.001 m. I would like to export the image (black+white or colour):

1. into bitmap format: png/gif with 1 pixel = 1 micrometer
2. into vectorial formats: eps and pdf

The following problems are encountered:

Pixel output by means of "Save As":
- using Setup/Fileformat/pixel: "user userunits" is smearing the output resolution
- the output image does not have a tight bounding box (a lot of artificial white space is added below the figure)
- using "1000000 pixel per meter" crashes LayoutEditor
- in some cases, an empty file is created

Vectorial output by means of "Print":
- Printing to "pdf" produces 3 files: print.png, print.pdf, print.ps.
- Neither file has tight bounding box.
- The pdf and ps files are not vectorial!
They are pixel with uncontrolled resolution!
- According to program pdfimage, the pdf file contains just one jpeg image ... i.e. a looseless pixel format instead of the vectorial pdf.
- Postscript sources contain an ASCII85Decode operator thus a pixel image instead of the vectorial output.

I use the May edition of LayoutEditor on OpenSUSE 11.1.

Can you please help me how to export correctly the drawing?
Thanks.

by Juergen Thies - 15 May 2009, 9:53 CEST

'Save as' to a pixel format:
If you have a 100mm wafer and export it with a resolution of 1µm, you will get an image of 100000*100000 pixel. With 32 bits per pixel (all images will be exported as true color) the resulting image has a size of 37Gb. Most image formats have a size limit of 2Gb. So in that case the LayoutEditor will split the image in pices of 2Gb each. To generate a 2Gb image you will need 2Gb free memory in your system plus some memory for your design. On a 32 bit system you can reach the application limit of about 3Gb of RAM. A resolution of 10µm(=100000pixel per meter) will result in a useable sized image of about 370 Mb.
The exported image is extended by 5 pixel to each side. If you have more free space on one side, there is additional element in your design (may be on a hidden layer). The pixel export only exports layers which are visible on the screen.
To avoid a craching with not enough memory, i will add a memory detection in the pixel export with the next release.

'Print':
The print function prints/saves the current screen with the printer resolution. It is scaled to the available paper space of the printer. The output is always performed via pixels. To achieve a vector export save it as SVG.

by anonymous - 15 May 2009, 18:07 CEST

As a new testcase, I've taken the distribution file example/test-layouts/test-gds.gds. Well... no printing works:
- GIF file is always zero
- all other bitmaps are very small (typical file size 200 B); trying the "Setup" options do not bring any changes in the output resolution, even after cleaning $HOME/.config/... files ... funny, it worked in the morning :-(
- printing to PDF brings the large surroundings as indicated in my first description
- saving as SVG: how to draw this file? Konqueror, Inkscape and Firefox 3 draw nothing.

Please tell me how to export and print realiably. Thanks!

by Juergen Thies - 15 May 2009, 18:55 CEST

The example/test-layouts/test-gds.gds file has a total size of 5x7µm. With the standard resolution of 1µm/pixel you will get a image you hardly can see anything. To export that file to a pixel format use a resolution of 10nm/pixel.

With a SVG export it is similar. If you view the exported SVG file with Inkscape you will get a little small gray dot in the upper left corner. Click on that dot and scale it to a useable value and you will see the total test file.

If have have a surrounding after useing the printing function, please zoom in before printing. In the print function it is always zoomed, so that the whole screen is printed. If the screen format differs from the paper size, some additional area is printed in one direction.

by anonymous - 22 May 2009, 16:30 CEST

The problem is that for "print to postscript/pdf file", it does not ask for resolution.

Thanks for the hint with SVG. Useful hotkeys for Inkscape are "3" and "4".

I wonder how you would print a zoom from a postscript file. I can code this in postscript or in LaTeX, however I have never seen such a function in any visual postscript viewer.

All these problems motivated me to write a converter to postscript. I'll start a new thread.

by Juergen Thies - 22 May 2009, 18:19 CEST

If the operating system has information on the printer resolution, this resolution is used. In all other cases like postscript printers a resolution of 1200 DPI is used.

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