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add a note on cli chaining

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This commit is contained in:
John Cupitt 2015-04-21 16:41:03 +01:00
parent e0a5d28100
commit 7ded77cd4d
1 changed files with 25 additions and 2 deletions
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27
doc/using-command-line.xml
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@ -54,7 +54,7 @@ where:
You can list all classes with: You can list all classes with:
<programlisting> <programlisting>
$ vips list classes $ vips -l
... ...
VipsOperation (operation), operations VipsOperation (operation), operations
VipsSystem (system), run an external command VipsSystem (system), run an external command
@ -142,7 +142,7 @@ $ vips bandjoin "k2.jpg k4.jpg" x.tif
list of all the supported file formats with something like: list of all the supported file formats with something like:
<programlisting> <programlisting>
$ vips list classes | grep -i foreign $ vips -l foreign
</programlisting> </programlisting>
Then get a list of the options a format supports with, for example: Then get a list of the options a format supports with, for example:
@ -165,6 +165,29 @@ vips affine k2.jpg x.jpg[Q=90,strip] "2 0 0 1"
</para> </para>
</refsect3> </refsect3>
<refsect3 id="using-command-line-chaining">
<title>Chaining operations</title>
<para>
Because each operation runs in a separate process, you can't use
libvips's chaining system to join operations together, you have to use
intermediate files. The command-line interface is therefore quite a bit
slower than Python or C.
</para>
<para>
The best alternative is to use vips files for intermediates.
Something like:
<programlisting>
vips invert input.jpg t1.v
vips affine t1.v output.jpg "2 0 0 1"
rm t1.v
</programlisting>
</para>
</refsect3>
<refsect3 id="using-command-line-other"> <refsect3 id="using-command-line-other">
<title>Other features</title> <title>Other features</title>