Programming Web Graphics with Perl and GNU Softwar

Name

colorspace — type of colorspace

Synopsis

$image->Set(colorspace=>string)
$image->Get('colorspace')

Color reduction takes place in the RGB colorspace by default, but in certain cases you may get better results with a different colorspace. string corresponds to one of several color models. The values we are interested in are:

• RGB: red, green, blue

• Gray (not “Grey”): grayscale

• Transparent: RGB with retained transparent colors (if any)

• YIQ: a color model used by NTSC

• YUV: Luminance, Chrominance used by MPEG

• YCbCr: a variant of YUV that gives good results with skin tones

• CMYK: Cyan, Magenta, Yellow, Black

The colorspace attribute must be followed by a Quantize( ) method call for the change to take effect. The attribute may also be set directly from the Quantize( ) call, as in:

$image->Quantize(colorspace=>'Gray');