When converting from CMYK to RGB using this function, the image can become inverted. To fix this, use a workaround (don't forget to download the .icc files online):
<?php
// don't use this (it inverts the image)
// $img->setImageColorspace (imagick::COLORSPACE_RGB);
if ($img->getImageColorspace() == Imagick::COLORSPACE_CMYK) {
$profiles = $img->getImageProfiles('*', false);
// we're only interested if ICC profile(s) exist
$has_icc_profile = (array_search('icc', $profiles) !== false);
// if it doesnt have a CMYK ICC profile, we add one
if ($has_icc_profile === false) {
$icc_cmyk = file_get_contents(dirname(__FILE__).'/USWebUncoated.icc');
$img->profileImage('icc', $icc_cmyk);
unset($icc_cmyk);
}
// then we add an RGB profile
$icc_rgb = file_get_contents(dirname(__FILE__).'/sRGB_v4_ICC_preference.icc');
$img->profileImage('icc', $icc_rgb);
unset($icc_rgb);
}
$img->stripImage (); // this will drop down the size of the image dramatically (removes all profiles)
?>
PHP - Manual: Imagick::setImageColorspace
2024-11-15
Imagick::setImageColorspace
(PECL imagick 2, PECL imagick 3)
Imagick::setImageColorspace — Sets the image colorspace
说明
public Imagick::setImageColorspace(int
$colorspace): boolSets the image colorspace. This method should be used when creating new images. To change the colorspace of an existing image, you should use Imagick::transformImageColorspace().
返回值
成功时返回 true。
错误／异常
错误时抛出 ImagickException。
add a note
User Contributed Notes 8 notes
eth at ethaniel dot com ¶
10 years ago
pilot114 at bk dot ru ¶
7 years ago
Simlest way converting from CMYK to RGB:
<?php
if ($jpeg->getImageColorspace() == \Imagick::COLORSPACE_CMYK) {
$jpeg->transformimagecolorspace(\Imagick::COLORSPACE_SRGB);
}
?>
It is pretty work in current stable Image Magick (6.9.0-4).
jdstraughan dot com at gmail dot com ¶
13 years ago
FYI, here is the breakdown for (int $colorspace):
Constants:
0 - UndefinedColorspace
1 - RGBColorspace
2 - GRAYColorspace
3 - TransparentColorspace
4 - OHTAColorspace
5 - LABColorspace
6 - XYZColorspace
7 - YCbCrColorspace
8 - YCCColorspace
9 - YIQColorspace
10 - YPbPrColorspace
11 - YUVColorspace
12 - CMYKColorspace
13 - sRGBColorspace
14 - HSBColorspace
15 - HSLColorspace
16 - HWBColorspace
Cesare Bordi ¶
4 years ago
These are the basic steps to convert an image from RGB to CMYK:
$image = new Imagick();
$image->readImage(rgb.jpg);
$image->setImageColorSpace(Imagick::COLORSPACE_CMYK);
$image->profileImage('icc', file_get_contents(/path/CoatedFOGRA27.icc'));
$image->negateImage(FALSE, imagick::COLOR_CYAN);
$image->negateImage(FALSE, imagick::COLOR_MAGENTA);
$image->negateImage(FALSE, imagick::COLOR_YELLOW);
$image->negateImage(FALSE, imagick::COLOR_BLACK);
$image->writeImage(cmyk.rgb);
kevin.a.florida ¶
9 years ago
I have a better solution for solving inverted colors on php 5.3.x than posted. All the other solutions I found darkens the image or messes with the colors.
See below (note: my imagick object is $jpeg)
$range = $jpeg->getQuantumRange();
$php_vs_arr = preg_split("/\./", phpversion());
$php_vs = $php_vs_arr[0] . '.' . $php_vs_arr[1];
if ($jpeg->getImageColorspace() == Imagick::COLORSPACE_CMYK) {
//make sure cmyk color-space is set correctly
$jpeg->setImageColorspace(12);
// then we add an RGB profile
$icc_rgb = file_get_contents(FRAMEWORK_PATH . DS . 'color' . DS . 'AdobeRGB1998.icc');
$jpeg->profileImage('icc', $icc_rgb);
unset($icc_rgb);
//set color space to rgb
$jpeg->setImageColorspace(13);
//fix gamma, hue, saturation, brightness
if($php_vs < 5.3) {
//ADJUST GAMMA BY 20% for 5.2.x
$jpeg->levelImage(0, 2.0, $range['quantumRangeString']);
} else {
//php 5.3 hack FOR INVERTED COLORS
$jpeg->negateImage(false, Imagick::CHANNEL_ALL);
}
}
$jpeg->stripImage();
//end convert to RGB=========================|
mettedraq at gmail dot com ¶
11 years ago
This is how to Monochrome a jpg [on Windows].. since I couldn't find it anywhere else.
<?php
header("Content-type: image/jpeg");
$IMagick = new IMagick('c:\\testing\\fruit.jpg');
$IMagick->setImageColorSpace(Imagick::COLORSPACE_GRAY);
echo $IMagick;
?>
charlie at midsouthhost dot com ¶
12 years ago
If your getting strange/bad color rendering from a PDF, after trying the colorspace constants noted by jdstraughan, try other values outside that range.
In one case for me only $image->setImageColorSpace(22) provided useful color. I have found posts elsewhere using values up to 255.
cesarebordi ¶
4 years ago
These are the basic steps to convert an image from RGB to CMYK:
$image = new Imagick();
$image->readImage(rgb.jpg);
$image->setImageColorSpace(Imagick::COLORSPACE_CMYK);
$image->profileImage('icc', file_get_contents(/path/CoatedFOGRA27.icc'));
$image->negateImage(FALSE, imagick::COLOR_CYAN);
$image->negateImage(FALSE, imagick::COLOR_MAGENTA);
$image->negateImage(FALSE, imagick::COLOR_YELLOW);
$image->negateImage(FALSE, imagick::COLOR_BLACK);
$image->writeImage(cmyk.rgb);
For more information:
http://www.cesarebordi.it/imagemagick-php-convertire-rgb-to-cmyk-web-developer/
官方地址：https://www.php.net/manual/en/imagick.setimagecolorspace.php
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