Where are ghostscript options / switches documented?
From the Overview of Ghostscript page, I found the Ps2pdf.htm page explains dPDFSETTINGS
:
-dPDFSETTINGS=
configuration
Presets the "distiller parameters" to one of four predefined settings:
/screen
selects low-resolution output similar to the Acrobat Distiller "Screen Optimized" setting./ebook
selects medium-resolution output similar to the Acrobat Distiller "eBook" setting./printer
selects output similar to the Acrobat Distiller "Print Optimized" setting./prepress
selects output similar to Acrobat Distiller "Prepress Optimized" setting./default
selects output intended to be useful across a wide variety of uses, possibly at the expense of a larger output file.
On the same page, MaxSubsetPct
only appears in a table of recognized "Acrobat Distiller 5 parameters defined in the DistillerParameters document included in the Acrobat SDK", and links to that SDK.
Instead of downloading the large SDK, I searched for "Distiller Parameters" on Adobe's site and found Adobe PDF Creation Settings which explains MaxSubsetPct on page 88:
MaxSubsetPct
Supported by: all applications
Type: integer
UI name: Subset embedded fonts when percent of characters used is less than: value %
Default value: 100The maximum percentage of glyphs in a font that can be used before the entire font is embedded instead of a subset. The allowable range is 1 through 100.
Distiller only uses this value if SubsetFonts is
true
. For example, a value of 30 means that a font will be embedded in full (not subset) if more than 30% of glyphs are used; a value of 100 means all fonts will be subset no matter how many glyphs are used (because you cannot use more than 100% of glyphs).
To get a list of all these options supported by -dPDFSETTINGS=...
, you can do this:
gs \
-dNODISPLAY \
-c ".distillersettings {exch ==only ( ) print ==} forall quit"
You should see this Result:
/default -dict-
/prepress -dict-
/PSL2Printer -dict-
/ebook -dict-
/screen -dict-
/printer -dict-
You can execute the following Ghostscript command to query for the detailed settings of the -dPDFSETTINGS=/screen
parameter:
gs \
-q \
-dNODISPLAY \
-c ".distillersettings /screen get {exch ==only ( ) print ===} forall quit" \
| sort
This one queries Ghostscript's internal .distillersettings
dictionary, which holds a key named /screen
, whose value again is another dictionary... The output should be something like this (may vary slightly depending on your exact Ghostscript version):
/AutoRotatePages /PageByPage
/CannotEmbedFontPolicy /Warning
/ColorACSImageDict << /ColorTransform 1 /QFactor 0.76 /Blend 1 /HSamples [2 1 1 2] /VSamples [2 1 1 2] >>
/ColorConversionStrategy /sRGB
/ColorImageDownsampleType /Average
/ColorImageResolution 72
/CompatibilityLevel 1.3
/CreateJobTicket false
/DoThumbnails false
/EmbedAllFonts true
/GrayACSImageDict << /ColorTransform 1 /QFactor 0.76 /Blend 1 /HSamples [2 1 1 2] /VSamples [2 1 1 2] >>
/GrayImageDownsampleType /Average
/GrayImageResolution 72
/MonoImageDownsampleType /Average
/MonoImageResolution 300
/NeverEmbed [/Courier /Courier-Bold /Courier-Oblique /Courier-BoldOblique /Helvetica /Helvetica-Bold /Helvetica-Oblique /Helvetica-BoldOblique /Times-Roman /Times-Bold /Times-Italic /Times-BoldItalic /Symbol /ZapfDingbats]
/PreserveEPSInfo false
/PreserveOPIComments false
/PreserveOverprintSettings false
/UCRandBGInfo /Remove
The same you can do for all the (other) parameters -dPDFSETTINGS=...
can take:
/prepress
/printer
/default
/screen
/ebook
/PSL2Printer
It's quite interesting to compare the detailed settings of all these (and also look up in parallel the Documentation for Ps2pdf.htm...).
This is a good document for new users:
http://www.ghostscript.com/doc/9.05/Use.htm