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List:       php-general
Subject:    [PHP] Re: Changing black to blue (2)
From:       195.252.185.134
Date:       2002-03-31 19:52:44
[Download RAW message or body]

thanx!

"Hugh Bothwell" <hugh_bothwell@hotmail.com> schrieb im Newsbeitrag
news:20020331160429.53145.qmail@pb1.pair.com...
> > I have a map of the world with all countries. I have
> > 250 maps of the same size as png where only one
> > country is black, rest is transp.
> > Now I neeed to set this country color to blue or red
> > to indicate a special spot.
> > I just don't want to save the same map double or tripple.
>
> Good!  Makes much more sense.
>
> Call this like
> <img src='country.php?cty=germany&col=255,0,0'>
> (functions in bold you will have to write yourself)
> ====== country.php ===========
> <?php
>     Header("Content-type: image/png");
>     $mapURL = '\images\countrymask\'.MAKESAFE($cty);
>
>     // load image
>     $img = ImageCreateFromPNG($mapURL.$mapname)
>         or MAKEDEFAULTIMAGE();
>
>     // parse new desired color
>     $newcolor = split(',', $col);
>
>     // find black
>     $oldcolor = ImageColorResolve($img, 0, 0, 0);
>
>     // change to new color
>     ImageColorSet($img, $oldcolor, $newcolor[0], $newcolor[1],
> $newcolor[2]);
>
>     // ... and return result
>     ImagePNG($img);
> ?>
>
> Note that depending on how much this gets used,
> it may indeed be better (faster, less computationally
> intensive) in the long run to use multiple image
> copies, ie country_red.png, country_blu.png etc.
>
>



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