Imagick::contrastImage
(PECL imagick 2.0.0)
Imagick::contrastImage — Change the contrast of the image
说明
$sharpen
)Enhances the intensity differences between the lighter and darker elements of the image. Set sharpen to a value other than 0 to increase the image contrast otherwise the contrast is reduced.
参数
-
sharpen -
The sharpen value
返回值
成功时返回 TRUE 。
错误／异常
错误时抛出 ImagickException。
范例
Example #1 Imagick::contrastImage()
<?php
function contrastImage ( $imagePath , $contrastType ) {
$imagick = new \ Imagick ( realpath ( $imagePath ));
if ( $contrastType != 2 ) {
$imagick -> contrastImage ( $contrastType );
}
header ( "Content-Type: image/jpg" );
echo $imagick -> getImageBlob ();
}
?> 用户评论:
[#1] removespam dot roland at tannerritchie dot com [2015-02-12 19:14:07]
Both xyking and quickshiftin include errors in their comments. xyking's error is in looping through negative numbers. quickshifting is incorrect in stating that 0 *increases* contrast (it does not - it decreases it).
Here is a (tested, working) method to increment or decrement contrast:
<?php
class Images {
public function contrastImage($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);
}
}
}
}
?>
[#2] quickshiftin at gmail dot com [2014-11-07 21:24:44]
xyking's comment is wrong so be careful if you read it. You pass a value of 0 to *increase* the contrast.
[#3] xyking [2010-04-16 08:14:25]
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);
}
}
}
?>