You need to pass this function a colour:
<?php
$img->blackThresholdImage( "#FFFFFF" );
?>
E.g. this blackens any pixel which isn't pure white.
(PECL imagick 2.0.0)
Imagick::blackThresholdImage — Forces all pixels below the threshold into black
Is like Imagick::thresholdImage() but forces all pixels below the threshold into black while leaving all pixels above the threshold unchanged.
thresholdThe threshold below which everything turns black
Returns TRUE on success.
| Version | Description |
|---|---|
| 2.1.0 | Now allows a string representing the color as a parameter. Previous versions allow only an ImagickPixel object. |
Example #1 Imagick::blackThresholdImage()
<?php
function blackThresholdImage($imagePath, $thresholdColor) {
$imagick = new \Imagick(realpath($imagePath));
$imagick->blackthresholdimage($thresholdColor);
header("Content-Type: image/jpg");
echo $imagick->getImageBlob();
}
?>
You need to pass this function a colour:
<?php
$img->blackThresholdImage( "#FFFFFF" );
?>
E.g. this blackens any pixel which isn't pure white.
Here's a example of this function:
<?php
$img = new Imagick();
$img->readImage($image_file_name);
$img->blackThresholdImage('grey');
$img->writeImage($thumb_file_name);
$img->clear();
$img->destroy();
?>