Replacing the shutdown screen: Difference between revisions
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(Link to bootanim page.) |
(Update the ppmto565 script, document the '-z' option.) |
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For example, you might wish to try: [http://dev.laptop.org/~cscott/modified-shutdown.565 modified-shutdown.565]. |
For example, you might wish to try: [http://dev.laptop.org/~cscott/modified-shutdown.565 modified-shutdown.565]. |
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On a linux system, you can convert 1200x900 PNG images to 565-format images as follows: |
On a linux system, you can convert 1200x900 PNG images to 565-format images as follows: |
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$ yum -y install netpbm-progs |
$ yum -y install netpbm-progs |
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$ pngtopnm myfile.png | ./ppmto565.py |
$ pngtopnm myfile.png | ./ppmto565.py -z -o myfile.565 |
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using the following python script named 'ppmto565.py': |
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<pre><nowiki> |
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#!/usr/bin/python2.5 |
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"""Convert PPM-format images to 565-format.""" |
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from __future__ import division, with_statement |
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import sys |
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def eat_comment(inf): # just read #, read until next EOL |
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while True: |
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c = inf.read(1) |
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if c == '\n' or c == '\r': break # read to EOL |
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return c |
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def read_token(inf): |
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# eat up leading whitespace |
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while True: |
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c = inf.read(1) |
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if c == '#': eat_comment(inf) |
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elif not c.isspace(): break |
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# now read in non-whitespace. |
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s = c |
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while True: |
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c = inf.read(1) |
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if c == '#': c = eat_comment(inf) |
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if c.isspace(): break |
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s += c |
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# done! |
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return s |
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Using the <code>ppmto565.py</code> script found at http://dev.laptop.org/~cscott/ppmto565.py |
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def main(inf, outf): |
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import struct |
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# read ppm from input |
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magic = inf.read(2) |
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assert magic == 'P6' |
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width = int(read_token(inf)) |
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height = int(read_token(inf)) |
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maxval = int(read_token(inf)) |
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unpackstr = '!3B' if maxval < 256 else '!3H' |
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unpacklen = struct.calcsize(unpackstr) |
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# write header |
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outf.write(struct.pack('@IIP', width, height, 0)) |
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# read pixel data, convert, and write it to output |
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def scale(x, y): return int((y*x/maxval)+0.5) |
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for y in xrange(0, height): |
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for x in xrange(0, width): |
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red, green, blue = struct.unpack(unpackstr, inf.read(unpacklen)) |
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encoded = (scale(red, 0x1f) << 11) + \ |
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(scale(green, 0x3f) << 5) + \ |
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(scale(blue, 0x1f)) |
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outf.write(struct.pack('@H', encoded)) |
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if __name__ == '__main__': |
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import sys |
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main(sys.stdin, sys.stdout) |
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</nowiki></pre> |
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Revision as of 18:33, 29 June 2008
See also: Tweaking the boot animation.
The UL warning image displayed during shutdown can be modified by replacing the file
/usr/share/boot-anim/ul_warning.565
with an appropriate alternative, in 1200x900 "565" format.
For example, you might wish to try: modified-shutdown.565.
On a linux system, you can convert 1200x900 PNG images to 565-format images as follows:
$ yum -y install netpbm-progs $ pngtopnm myfile.png | ./ppmto565.py -z -o myfile.565
Using the ppmto565.py script found at http://dev.laptop.org/~cscott/ppmto565.py
On core OS versions prior to 8.2, you must omit the -z option. The resulting raw 565-format files seem large, but we use a compressing filesystem on the XO which slims them down nicely.