[Tutor] How do you make yellow?

Fri Nov 22 19:36:08 2002

At 17:40 2002-11-22 -0500, James M Lang wrote:
>While trying to figure out how to change colors from the example on the=20
>livewires package, I was wondering how a TV would create yellow,=20
>considering that it only has red, green, and blue. It's been mystifying =
me.

To make this a bit python related: The following program will
generate tables with 216 (6*6*6) colours. A text in a cell
like "R40% G00% B40%" means Red: 40%, Green 0% and Blue 40%.

The program will create a file called colorcube.html. Inspect
it with a web browser such as Mozilla or MS IE.

# colorcobe.py, Magnus Lyck=E5, 2002

page =3D """<html><head><title>Color Cube</title></head>
<body>
%s
</body></html>"""

table =3D "<table>%s</table>"

row =3D "<tr>%s</tr>"

cell =3D """<td bgcolor=3D"#%(red)02X%(green)02X%(blue)02X">
              <font color=3D"white">R%(redP)02i%% G%(greenP)02i%%
               B%(blueP)02i%%</font><br>
              <font color=3D"black">R%(redP)02i%% G%(greenP)02i%%
               B%(blueP)02i%%</font>"""

safeColors =3D range(0, 256, 51)

tables =3D []
for red in safeColors:
     redP =3D red / 2.55
     rows =3D []
     for green in safeColors:
         greenP =3D green / 2.55
         cells =3D []
         for blue in safeColors:
             blueP =3D blue / 2.55
             cells.append(cell % locals())
         rows.append(row % "\n".join(cells))
     tables.append(table % "\n".join(rows))

o =3D file('colorcube.html', 'wt')
print >> o, page % "\n".join(tables)
o.close()

--=20
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