Pixel Scaling by Row or Column Removal

The pixel scaling is controlled via a command line option. The options -dpx:N and -dpy:M can be used in addition to existing command line options. Both options can be used simultaneously if desired.

Command Line Examples

The images below were created using the Gerber file hface.gbr and the gbr2tiff.exe with the following command line options:

No pixel scaling
gbr2tiff.exe hface.gbr -274x -mm -aw -dpi:4000         -pack:normal.tif 

Scaling Along X
gbr2tiff.exe hface.gbr -274x -mm -aw -dpi:4000 -dpx:2  -pack:dpx2.tif
gbr2tiff.exe hface.gbr -274x -mm -aw -dpi:4000 -dpx:3  -pack:dpx3.tif
gbr2tiff.exe hface.gbr -274x -mm -aw -dpi:4000 -dpx:4  -pack:dpx4.tif
gbr2tiff.exe hface.gbr -274x -mm -aw -dpi:4000 -dpx:5  -pack:dpx5.tif

Scaling Along Y
gbr2tiff.exe hface.gbr -274x -mm -aw -dpi:4000 -dpy:2  -pack:dpy2.tif
gbr2tiff.exe hface.gbr -274x -mm -aw -dpi:4000 -dpy:3  -pack:dpy3.tif
gbr2tiff.exe hface.gbr -274x -mm -aw -dpi:4000 -dpy:4  -pack:dpy4.tif
gbr2tiff.exe hface.gbr -274x -mm -aw -dpi:4000 -dpy:5  -pack:dpy5.tif


where

gbr2tiff.exe    the gbr_rip executable
hface.gbr       the input gerber file
-274x           indicates input is RS274X
-mm             indicates input is in mm
-aw             auto calculation of data extents
-dpi:4000       the nominal dots per inch
-dpx:N          scale down along X by factor of N (column removal)
-dpy:M          scale down along Y by factor of M (row removal)
-pack:file      output using packbits compression to this file name.

Mixing Vector and Pixel Scaling

Because pixel scaling is done on the intermediate rasterized data it is possible to combine gbr_rip's vector scaling and pixel scaling together. For example, suppose your application requires a DPI of 5080 along X but only 1000 along Y. If you set the resolution using -dpi:5080 and pixel scaling using dpy:5 then you have an effective DPI along Y of 5080/5 = 1016.

To get your exact scaling, first figure the additional 1000/1016 ratio (0.98425) and then use the -scale option with values: -scale:1,0.98425 which will result in the desired ration of 5080/1000.

Reference [No scaling]
gbr2tiff.exe onebyone.gbr -274x -inch -aw -dpi:5080 -scale:1,1 -pack:onebyone.tif

Mixed Scaling (vector/pixel)
gbr2tiff.exe onebyone.gbr -274x -inch -aw -dpi:5080 -scale:1,0.98425 -dpy:5 -pack:mixed.tif

You can see the results using the input file onebyone.gbr which is exactly 1 x 1 inch showing the unscaled raster image (onebyone.tif) on the left with the scaled raster image (mixed.tif) on the right.