diff options
Diffstat (limited to 'doc/expert/pre_colo')
| -rw-r--r-- | doc/expert/pre_colo | 10 |
1 files changed, 4 insertions, 6 deletions
diff --git a/doc/expert/pre_colo b/doc/expert/pre_colo index 21ae85b..752fe57 100644 --- a/doc/expert/pre_colo +++ b/doc/expert/pre_colo @@ -24,21 +24,19 @@ produces the red result } } Of course, a colour output device is needed to see the effect; on -a monochrome device the result will be some shade of grey. The -@@SetColour command will not accept an empty left parameter -(it refuses to believe that this could cause a change of colour), -but otherwise it trusts the user to supply something sensible. +a monochrome device the result will be some shade of grey. @PP The @@SetColour command accepts the special value {@Code "nochange"} for the left parameter. This value causes the right parameter to have -the colour it would have had without the @@SetColour command. +the colour it would have had without the @@SetColour command. An +empty left parameter also has this effect. @PP There is no default colour, so the user must ensure that the root galley or each of its components is enclosed in a @@SetColour symbol whose left parameter is not {@Code "nochange"}. @PP Lout makes no attempt to understand colour, it simply prints -the PostScript commands when appropriate. This has the advantage +the PostScript or PDF commands when appropriate. This has the advantage of permitting access to any of PostScript's colour models (some require initialization which can be supplied using @@PrependGraphic), but the disadvantage of offering no way to make relative changes |