| <html><head> |
| <style> |
| td { |
| font-size: 12px; |
| font-family: monospace; |
| text-align: center; |
| padding-left: 3px; |
| padding-right: 3px |
| } |
| td.bright { color: #eee; } |
| td.dark { color: #222; } |
| </style> |
| </head> |
| <body> |
| <table> |
| <? |
| # we create a 9x9 table selecting a different background for each cell |
| |
| for {set i 0} { $i < 9 } {incr i} { |
| puts "<tr>" |
| for {set j 0} {$j < 9} {incr j} { |
| |
| set r [expr int(255 * ($i + $j) / 16)] |
| set g [expr int(255 * (8 + $j - $i) / 16)] |
| set b [expr int(255 * (abs (4 - $i) + abs(4 - $j)) / 8)] |
| |
| # determining the background luminosity (YIQ space of NTSC) and choosing |
| # the foreground color accordingly in order maintain maximum contrast |
| |
| if { [expr ($r*0.29894)+($g*0.58704)+($b*0.11402)] > 148.0} { |
| set cssclass "dark" |
| } else { |
| set cssclass "bright" |
| } |
| |
| set cell [format "%3d %3d %3d" $r $g $b] |
| |
| puts [format \ |
| "<td bgcolor=\"%02x%02x%02x\" class=\"%s\">%s</td>" \ |
| $r $g $b $cssclass $cell] |
| } |
| puts "</tr>" |
| } |
| ?> |
| </table> |
| </body></html> |
