DJ Mike's Tutorials: PHP

Imagick Functions

randomThresholdImage

Description:

bool Imagick::randomThresholdImage ( float $low , float $high [, int $channel ] )

Changes the value of individual pixels based on the intensity of each pixel compared to threshold. The result is a high-contrast, two color image.

Parameters:

low

high

channel

Channel constants:

imagick::CHANNEL_UNDEFINED
imagick::CHANNEL_RED
imagick::CHANNEL_GRAY
imagick::CHANNEL_CYAN
imagick::CHANNEL_GREEN
imagick::CHANNEL_MAGENTA
imagick::CHANNEL_BLUE
imagick::CHANNEL_YELLOW
imagick::CHANNEL_ALPHA
imagick::CHANNEL_OPACITY
imagick::CHANNEL_MATTE
imagick::CHANNEL_BLACK
imagick::CHANNEL_INDEX
imagick::CHANNEL_ALL

Return Values

Returns TRUE on success.

Example

<?php
header("Content-type: image/jpeg");
$image = new Imagick("opossum.jpg"); 
# find max
$max = $image->getQuantumRange(); 
$max = $max[quantumRangeLong];
$image->randomthresholdImage( .6*$max, .4*$max );
echo $image;
?> 

<?php
header("Content-type: image/jpeg");
$image = new Imagick("opossum.jpg"); 
# find max
$max = $image->getQuantumRange(); 
$max = $max[quantumRangeLong];
$image->randomthresholdImage( .4*$max, .6*$max );
echo $image;
?> 

<?php
$image = new Imagick("opossum.jpg"); 
# find max
$max = $image->getQuantumRange(); 
$max = $max[quantumRangeLong];
$image->randomthresholdImage( .4*$max, .6*$max, imagick::CHANNEL_RED );
header("Content-type: image/jpeg");
echo $image;
?> 

^

Created by DJ Mike from Santa Barbara