Both xyking and quickshiftin include errors in their comments. xyking's error is in looping through negative numbers. quickshifting is incorrect in stating that 0 *increases* contrast (it does not - it decreases it).
Here is a (tested, working) method to increment or decrement contrast:
<?php
class Images {
public function contrastImage($contrast, $imagePath){
$this->image = new Imagick();
$this->image->readImage($imagePath);
if ($contrast > 0){
for ($i = 1; $i < $contrast; $i++){
$this->image->contrastImage(1);
}
}else if ($contrast <= 0) {
for ($i = 0; $i > $contrast; $i--) {
$this->image->contrastImage(0);
}
}
}
}
?>
Imagick::contrastImage
(PECL imagick 2, PECL imagick 3)
Imagick::contrastImage — Change le contraste de l'image
Description
Améliore l'intensité des différences entre les éléments clairs et sombres de l'image. Donnez une valeur différente de zéro si vous voulez améliorer le contraste, et sinon, il sera réduit.
Liste de paramètres
-
sharpen -
La valeur de contraste.
Valeurs de retour
Retourne true en cas de succès.
Erreurs / Exceptions
Lance une exception ImagickException si une erreur survient.
Exemples
Exemple #1 Exemple avec Imagick::contrastImage()
<?php
function contrastImage($imagePath, $contrastType) {
$imagick = new \Imagick(realpath($imagePath));
if ($contrastType != 2) {
$imagick->contrastImage($contrastType);
}
header("Content-Type: image/jpg");
echo $imagick->getImageBlob();
}
?>
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User Contributed Notes 3 notes
removespam dot roland at tannerritchie dot com ¶
9 years ago
xyking ¶
14 years ago
Tip:
<?php
$image->contrastImage(1); //Increase contrast once
$image->contrastImage(1); //Increase contrast more
$image->contrastImage(1); //Increase contrast even more
$image->contrastImage(0); //Decrease contrast once
$image->contrastImage(0); //Decrease contrast more
$image->contrastImage(0); //Decrease contrast even more
//This could be made into a function like this:
public function contrast($level) {
$level = (int)$level;
if ($level < -10) {
$level = -10;
} else if ($level > 10) {
$level = 10;
}
if ($level > 0) {
for ($i = 0; $i < $level; $i++) {
$this->image->contrastImage(1);
}
} else if ($level < 0) {
for ($i = $level; $i > 0; $i--) {
$this->image->contrastImage(0);
}
}
}
?>
quickshiftin at gmail dot com ¶
9 years ago
xyking's comment is wrong so be careful if you read it. You pass a value of 0 to *increase* the contrast.
