'\" t
.\"     Title: cjxl
.\"    Author: [FIXME: author] [see http://www.docbook.org/tdg5/en/html/author]
.\" Generator: DocBook XSL Stylesheets vsnapshot <http://docbook.sf.net/>
.\"      Date: 06/27/2023
.\"    Manual: \ \&
.\"    Source: \ \&
.\"  Language: English
.\"
.TH "CJXL" "1" "06/27/2023" "\ \&" "\ \&"
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.SH "NAME"
cjxl \- compress images to JPEG XL
.SH "SYNOPSIS"
.sp
\fBcjxl\fR [\fIoptions\fR\&...] \fIinput\fR [\fIoutput\&.jxl\fR]
.SH "DESCRIPTION"
.sp
cjxl compresses an image or animation to the JPEG XL format\&. It is intended to spare users the trouble of determining a set of optimal parameters for each individual image\&. Instead, for a given target quality, it should provide consistent visual results across various kinds of images\&. The defaults have been chosen to be sensible, so that the following commands should give satisfactory results in most cases:
.sp
.if n \{\
.RS 4
.\}
.nf
cjxl input\&.png output\&.jxl
cjxl input\&.jpg output\&.jxl
cjxl input\&.gif output\&.jxl
.fi
.if n \{\
.RE
.\}
.SH "OPTIONS"
.PP
\-h, \-\-help
.RS 4
Displays the options that
cjxl
supports\&. On its own, it will only show basic options\&. It can be combined with
\-v
or
\-v \-v
to show increasingly advanced options as well\&.
.RE
.PP
\-v, \-\-verbose
.RS 4
Increases verbosity\&. Can be repeated to increase it further, and also applies to
\-\-help\&.
.RE
.PP
\-d \fIdistance\fR, \-\-distance=\fIdistance\fR
.RS 4
The preferred way to specify quality\&. It is specified in multiples of a just\-noticeable difference\&. That is,
\-d 0
is mathematically lossless,
\-d 1
should be visually lossless, and higher distances yield denser and denser files with lower and lower fidelity\&. Lossy sources such as JPEG and GIF files are compressed losslessly by default, and in the case of JPEG files specifically, the original JPEG can then be reconstructed bit\-for\-bit\&. For lossless sources,
\-d 1
is the default\&.
.RE
.PP
\-q \fIquality\fR, \-\-quality=\fIquality\fR
.RS 4
Alternative way to indicate the desired quality\&. 100 is lossless and lower values yield smaller files\&. There is no lower bound to this quality parameter, but positive values should approximately match the quality setting of libjpeg\&.
.RE
.PP
\-e \fIeffort\fR, \-\-effort=\fIeffort\fR
.RS 4
Controls the amount of effort that goes into producing an \(lqoptimal\(rq file in terms of quality/size\&. That is to say, all other parameters being equal, a higher effort should yield a file that is at least as dense and possibly denser, and with at least as high and possibly higher quality\&.
.sp
Recognized effort settings, from fastest to slowest, are:
.sp
.RS 4
.ie n \{\
\h'-04'\(bu\h'+03'\c
.\}
.el \{\
.sp -1
.IP \(bu 2.3
.\}
1 or \(lqlightning\(rq
.RE
.sp
.RS 4
.ie n \{\
\h'-04'\(bu\h'+03'\c
.\}
.el \{\
.sp -1
.IP \(bu 2.3
.\}
2 or \(lqthunder\(rq
.RE
.sp
.RS 4
.ie n \{\
\h'-04'\(bu\h'+03'\c
.\}
.el \{\
.sp -1
.IP \(bu 2.3
.\}
3 or \(lqfalcon\(rq
.RE
.sp
.RS 4
.ie n \{\
\h'-04'\(bu\h'+03'\c
.\}
.el \{\
.sp -1
.IP \(bu 2.3
.\}
4 or \(lqcheetah\(rq
.RE
.sp
.RS 4
.ie n \{\
\h'-04'\(bu\h'+03'\c
.\}
.el \{\
.sp -1
.IP \(bu 2.3
.\}
5 or \(lqhare\(rq
.RE
.sp
.RS 4
.ie n \{\
\h'-04'\(bu\h'+03'\c
.\}
.el \{\
.sp -1
.IP \(bu 2.3
.\}
6 or \(lqwombat\(rq
.RE
.sp
.RS 4
.ie n \{\
\h'-04'\(bu\h'+03'\c
.\}
.el \{\
.sp -1
.IP \(bu 2.3
.\}
7 or \(lqsquirrel\(rq (default)
.RE
.sp
.RS 4
.ie n \{\
\h'-04'\(bu\h'+03'\c
.\}
.el \{\
.sp -1
.IP \(bu 2.3
.\}
8 or \(lqkitten\(rq
.RE
.sp
.RS 4
.ie n \{\
\h'-04'\(bu\h'+03'\c
.\}
.el \{\
.sp -1
.IP \(bu 2.3
.\}
9 or \(lqtortoise\(rq
.RE
.RE
.SH "EXAMPLES"
.sp
.if n \{\
.RS 4
.\}
.nf
# Compress a PNG file to a high\-quality JPEG XL version\&.
$ cjxl input\&.png output\&.jxl

# Compress it at a slightly lower quality, appropriate for web use\&.
$ cjxl \-d 2 input\&.png output\&.jxl

# Compress it losslessly\&. These are equivalent\&.
$ cjxl \-d 0   input\&.png lossless\&.jxl
$ cjxl \-q 100 input\&.png lossless\&.jxl

# Compress a JPEG file losslessly\&.
$ cjxl input\&.jpeg lossless\-jpeg\&.jxl
.fi
.if n \{\
.RE
.\}
.SH "SEE ALSO"
.sp
\fBdjxl\fR(1)