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4649b3c422
Option -usebgcolor may be used to display ANIM background color (or white if no ANIM chunk), blended on top of checkerboard. By default this is disabled (old behavior) to easily see transparent areas. Spec says that "background color MAY be used", so it's an option. Key b may be pressed to toggle ANIM background color display. There are visual artifacts (leftovers) when toggling during an animation. This is already the case for rescaling, toggling info etc. (fixing it implies storing viewport render or rendering whole animation from start till current frame). BUG=webp:394 Change-Id: If9ab898b2eac77226f30f062d522f9861789ef8f
102 lines
2.5 KiB
Groff
102 lines
2.5 KiB
Groff
.\" Hey, EMACS: -*- nroff -*-
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.TH VWEBP 1 "July 20, 2018"
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.SH NAME
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vwebp \- decompress a WebP file and display it in a window
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.SH SYNOPSIS
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.B vwebp
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.RI [ options ] " input_file.webp
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.br
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.SH DESCRIPTION
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This manual page documents the
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.B vwebp
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command.
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.PP
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\fBvwebp\fP decompresses a WebP file and displays it in a window using OpenGL.
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.SH OPTIONS
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.TP
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.B \-h
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Print usage summary.
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.TP
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.B \-version
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Print version number and exit.
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.TP
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.B \-noicc
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Don't use the ICC profile if present.
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.TP
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.B \-nofancy
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Don't use the fancy YUV420 upscaler.
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.TP
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.B \-nofilter
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Disable in-loop filtering.
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.TP
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.BI \-dither " strength
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Specify a dithering \fBstrength\fP between 0 and 100. Dithering is a
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post-processing effect applied to chroma components in lossy compression.
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It helps by smoothing gradients and avoiding banding artifacts. Default: 50.
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.TP
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.BI \-noalphadither
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By default, quantized transparency planes are dithered during decompression,
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to smooth the gradients. This flag will prevent this dithering.
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.TP
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.B \-usebgcolor
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Fill transparent areas with the bitstream's own background color instead of
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checkerboard only. Default is white for non-animated images.
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.TP
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.B \-mt
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Use multi-threading for decoding, if possible.
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.TP
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.B \-info
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Display image information on top of the decoded image.
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.TP
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.BI \-\- " string
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Explicitly specify the input file. This option is useful if the input
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file starts with an '\-' for instance. This option must appear \fBlast\fP.
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Any other options afterward will be ignored. If the input file is "\-",
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the data will be read from \fIstdin\fP instead of a file.
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.TP
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.SH KEYBOARD SHORTCUTS
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.TP
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.B 'c'
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Toggle use of color profile.
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.TP
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.B 'b'
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Toggle display of background color.
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.TP
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.B 'i'
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Overlay file information.
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.TP
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.B 'd'
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Disable blending and disposal process, for debugging purposes.
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.TP
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.B 'q' / 'Q' / ESC
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Quit.
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.SH BUGS
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Please report all bugs to the issue tracker:
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https://bugs.chromium.org/p/webp
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.br
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Patches welcome! See this page to get started:
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http://www.webmproject.org/code/contribute/submitting-patches/
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.SH EXAMPLES
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vwebp picture.webp
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.br
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vwebp picture.webp -mt -dither 0
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.br
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vwebp \-\- \-\-\-picture.webp
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.SH AUTHORS
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\fBvwebp\fP is a part of libwebp and was written by the WebP team.
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.br
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The latest source tree is available at
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https://chromium.googlesource.com/webm/libwebp
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.PP
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This manual page was written for the Debian project (and may be used by others).
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.SH SEE ALSO
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.BR dwebp (1)
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.br
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Please refer to http://developers.google.com/speed/webp/ for additional
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information.
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