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Getting Channels

Every color in Negarity Color consists of channels that represent the color's values in its color space. This guide shows you how to access these channel values.

Using getChannel()​

The getChannel() method allows you to access any channel by name:

use Negarity\Color\Color;

$color = Color::rgb(255, 100, 50);

echo $color->getChannel('r'); // 255
echo $color->getChannel('g'); // 100
echo $color->getChannel('b'); // 50

This works for any color space:

$hsl = Color::hsl(210, 50, 40);

echo $hsl->getChannel('h'); // 210
echo $hsl->getChannel('s'); // 50
echo $hsl->getChannel('l'); // 40

Using Getter Methods​

For convenience, you can use dedicated getter methods for each channel. These methods are dynamically available based on the color space:

RGB/RGBA Channels​

$color = Color::rgb(255, 100, 50);

echo $color->getR(); // 255
echo $color->getG(); // 100
echo $color->getB(); // 50

// For RGBA
$rgba = Color::rgba(255, 100, 50, 128);
echo $rgba->getA(); // 128

HSL/HSLA Channels​

$hsl = Color::hsl(210, 50, 40);

echo $hsl->getH(); // 210 (Hue)
echo $hsl->getS(); // 50 (Saturation)
echo $hsl->getL(); // 40 (Lightness)

HSV Channels​

$hsv = Color::hsv(210, 50, 40);

echo $hsv->getH(); // 210
echo $hsv->getS(); // 50
echo $hsv->getV(); // 40 (Value)

CMYK Channels​

$cmyk = Color::cmyk(0, 50, 100, 0);

echo $cmyk->getC(); // 0 (Cyan)
echo $cmyk->getM(); // 50 (Magenta)
echo $cmyk->getY(); // 100 (Yellow)
echo $cmyk->getK(); // 0 (Key/Black)

Lab Channels​

$lab = Color::lab(50, 20, -30);

echo $lab->getL(); // 50 (Lightness)
echo $lab->getA(); // 20
echo $lab->getB(); // -30

LCh Channels​

$lch = Color::lch(50, 30, 210);

echo $lch->getL(); // 50 (Lightness)
echo $lch->getC(); // 30 (Chroma)
echo $lch->getH(); // 210 (Hue)

XYZ Channels​

$xyz = Color::xyz(20, 30, 40);

echo $xyz->getX(); // 20
echo $xyz->getY(); // 30
echo $xyz->getZ(); // 40

YCbCr Channels​

$ycbcr = Color::ycbcr(128, 100, 150);

echo $ycbcr->getY(); // 128
echo $ycbcr->getCb(); // 100
echo $ycbcr->getCr(); // 150

Getting All Channels​

Using getChannels()​

Get all channel names for the current color space:

$color = Color::rgb(255, 100, 50);
$channels = $color->getChannels();
// Returns: ['r', 'g', 'b']

Using toArray()​

Get all channel values as an associative array:

$color = Color::rgb(255, 100, 50);
$array = $color->toArray();
// Returns: [
//     'color-space' => 'rgb',
//     'values' => ['r' => 255, 'g' => 100, 'b' => 50]
// ]

JSON Serialization​

Colors implement JsonSerializable, so you can easily serialize them:

$color = Color::rgb(255, 100, 50);
$json = json_encode($color);
// Returns: {"color-space":"rgb","values":{"r":255,"g":100,"b":50}}

Getting Color Space Information​

Color Space Name​

Get the human-readable name of the color space:

$color = Color::rgb(255, 100, 50);
echo $color->getColorSpaceName(); // "rgb"

Color Space Class​

Get the class name of the color space:

$color = Color::rgb(255, 100, 50);
echo $color->getColorSpace(); // "Negarity\Color\ColorSpace\RGB"

Practical Examples​

Iterating Over Channels​

$color = Color::rgb(255, 100, 50);

foreach ($color->getChannels() as $channel) {
    echo "$channel: " . $color->getChannel($channel) . "\n";
}
// Output:
// r: 255
// g: 100
// b: 50

Accessing Channels After Conversion​

$rgb = Color::rgb(255, 100, 50);
$hsl = $rgb->toHSL();

// Access HSL channels
echo "Hue: " . $hsl->getH() . "°\n";
echo "Saturation: " . $hsl->getS() . "%\n";
echo "Lightness: " . $hsl->getL() . "%\n";

Working with Alpha Channels​

$rgba = Color::rgba(255, 100, 50, 128);

// Check if color has transparency
if ($rgba->getA() < 255) {
    $opacity = ($rgba->getA() / 255) * 100;
    echo "Color is " . $opacity . "% opaque\n";
}

Error Handling​

If you try to access a channel that doesn't exist in the current color space, an exception will be thrown:

$rgb = Color::rgb(255, 100, 50);

try {
    echo $rgb->getChannel('h'); // Throws InvalidArgumentException
} catch (\InvalidArgumentException $e) {
    echo "Channel 'h' doesn't exist in RGB color space\n";
}

Next Steps​

Now that you can access channel values, learn about: