.TH BTRACE 8
.SH NAME
btrace \- trace bitblt protocol
.SH SYNOPSIS
.B btrace
[
.B -d
[
.B d
]] [
.BI -o " ofile"
]
[
.BI -b " bfile"
]
.SH DESCRIPTION
.PP
.I Btrace
eavesdrops on messages to and from
.BR /dev/bitblt ,
interprets them as messages in the bit device protocol (see
.IR bit (3)),
and prints a readable version of the messages
on a trace file,
.B btrace.out
by default.
After
.I btrace
is started, it runs in the background, tracing all subsequent
graphics programs run in that window.
Options for
.I btrace
are:
.TP "\w'\fL-b\fP \fIbfile\fLXX'u"
.BI -o " ofile"
Print trace output in
.I ofile
instead of
.BR btrace.out .
.TP
.BI -b " bfile"
Dump each bitmap read or written to
.IR bfile ,
using the format of
.IR bitmap (6).
Each succeeding bitmap overwrites the previous contents of
.IR file .
.IR Tweak (1)
or
.IR showimage (7)
can be used to examine the file.
.TP
.B -d
Increase the level of trace detail.  The maximum level is
.BR -dd .
.SH FILES
.B /dev/bitblt
.SH SOURCE
.B /sys/src/cmd/btrace.c
.SH SEE ALSO
.IR bit (3),
.IR bitmap (6),
.IR graphics (2),
.IR tweak (1),
.IR showimage (7)
