PHP Dokumentation: Function imagecolorclosestalpha
12. Januar 2010 von werner
imagecolorclosestalpha
(PHP 4 >= 4.0.6, PHP 5)
imagecolorclosestalpha — Get the index of the closest color to the specified color + alpha
Beschreibung
Returns the index of the color in the palette of the image which is "closest" to the specified RGB value and alpha level.
Parameter-Liste
- image
Eine von den verschiedenen Erzeugungsfunktionen wieimagecreatetruecolor() gelieferteGrafikressource.
- red
Value of red component.
- green
Value of green component.
- blue
Value of blue component.
- alpha
A value between 0 and 127. 0 indicates completely opaque while 127 indicates completely transparent.
The colors parameters are integers between 0 and 255 or hexadecimals between 0×00 and 0xFF.
Rückgabewerte
Returns the index of the closest color in the palette.
Beispiele
Beispiel #1 Search for a set of colors in an image
<?php
// Start with an image and convert it to a palette-based image
$im = imagecreatefrompng('figures/imagecolorclosest.png');
imagetruecolortopalette($im, false, 255);// Search colors (RGB)
$colors = array(
array(254, 145, 154, 50),
array(153, 145, 188, 127),
array(153, 90, 145, 0),
array(255, 137, 92, 84)
);// Loop through each search and find the closest color in the palette.
// Return the search number, the search RGB and the converted RGB match
foreach($colors as $id => $rgb)
{
$result = imagecolorclosestalpha($im, $rgb[0], $rgb[1], $rgb[2], $rgb[3]);
$result = imagecolorsforindex($im, $result);
$result = "({$result['red']}, {$result['green']}, {$result['blue']}, {$result['alpha']})"; echo
"#$id: Search ($rgb[0], $rgb[1], $rgb[2], $rgb[3]); Closest match: $result.\n";
}imagedestroy($im);
?>Das oben gezeigte Beispiel erzeugteine ähnliche Ausgabe wie:
#0: Search (254, 145, 154, 50); Closest match: (252, 150, 148, 0).#1: Search (153, 145, 188, 127); Closest match: (148, 150, 196, 0).#2: Search (153, 90, 145, 0); Closest match: (148, 90, 156, 0).#3: Search (255, 137, 92, 84); Closest match: (252, 150, 92, 0).
Anmerkungen
Hinweis: Diese Funktion setzt die GD-Bibliothek inder Version 2.0.1 oder höher (empfohlen wird mindestens 2.0.28) voraus.
Siehe auch
- imagecolorexactalpha() – Get the index of the specified color + alpha
- imagecolorclosest() – Ermittelt den Farbwert-Index, der den angegebenen Farben am nächsten liegt
- imagecolorclosesthwb() – Get the index of the color which has the hue, white and blackness
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