imagefilter
(PHP 5, PHP 7)
imagefilter — Applies a filter to an image
Description
$image
, int $filtertype
[, int $arg1
[, int $arg2
[, int $arg3
[, int $arg4
]]]] ) : bool
imagefilter() applies the given filter
filtertype on the image.
Parameters
-
image -
An image resource, returned by one of the image creation functions, such as imagecreatetruecolor().
-
filtertype -
filtertypecan be one of the following:-
IMG_FILTER_NEGATE: Reverses all colors of the image. -
IMG_FILTER_GRAYSCALE: Converts the image into grayscale by changing the red, green and blue components to their weighted sum using the same coefficients as the REC.601 luma (Y') calculation. The alpha components are retained. For palette images the result may differ due to palette limitations. -
IMG_FILTER_BRIGHTNESS: Changes the brightness of the image. Usearg1to set the level of brightness. The range for the brightness is -255 to 255. -
IMG_FILTER_CONTRAST: Changes the contrast of the image. Usearg1to set the level of contrast. -
IMG_FILTER_COLORIZE: LikeIMG_FILTER_GRAYSCALE, except you can specify the color. Usearg1,arg2andarg3in the form ofred,green,blueandarg4for thealphachannel. The range for each color is 0 to 255. -
IMG_FILTER_EDGEDETECT: Uses edge detection to highlight the edges in the image. -
IMG_FILTER_EMBOSS: Embosses the image. -
IMG_FILTER_GAUSSIAN_BLUR: Blurs the image using the Gaussian method. -
IMG_FILTER_SELECTIVE_BLUR: Blurs the image. -
IMG_FILTER_MEAN_REMOVAL: Uses mean removal to achieve a "sketchy" effect. -
IMG_FILTER_SMOOTH: Makes the image smoother. Usearg1to set the level of smoothness. -
IMG_FILTER_PIXELATE: Applies pixelation effect to the image, usearg1to set the block size andarg2to set the pixelation effect mode. -
IMG_FILTER_SCATTER: Applies scatter effect to the image, usearg1andarg2to define the effect strength and additionallyarg3to only apply the on select pixel colors.
-
-
arg1 -
-
IMG_FILTER_BRIGHTNESS: Brightness level. -
IMG_FILTER_CONTRAST: Contrast level. -
IMG_FILTER_COLORIZE: Value of red component. -
IMG_FILTER_SMOOTH: Smoothness level. -
IMG_FILTER_PIXELATE: Block size in pixels. -
IMG_FILTER_SCATTER: Effect substraction level. This must not be higher or equal to the addition level set witharg2.
-
-
arg2 -
-
IMG_FILTER_COLORIZE: Value of green component. -
IMG_FILTER_PIXELATE: Whether to use advanced pixelation effect or not (defaults toFALSE). -
IMG_FILTER_SCATTER: Effect addition level.
-
-
arg3 -
-
IMG_FILTER_COLORIZE: Value of blue component. -
IMG_FILTER_SCATTER: Optional array indexed color values to apply effect at.
-
-
arg4 -
-
IMG_FILTER_COLORIZE: Alpha channel, A value between 0 and 127. 0 indicates completely opaque while 127 indicates completely transparent.
-
Changelog
| Version | Description |
|---|---|
| 7.4.0 |
Scatter support (IMG_FILTER_SCATTER) was added.
|
| 5.3.0 |
Pixelation support (IMG_FILTER_PIXELATE) was added.
|
| 5.2.5 |
Alpha support for IMG_FILTER_COLORIZE was added.
|
Examples
Example #1 imagefilter() grayscale example
<?php
$im = imagecreatefrompng('dave.png');
if($im && imagefilter($im, IMG_FILTER_GRAYSCALE))
{
echo 'Image converted to grayscale.';
imagepng($im, 'dave.png');
}
else
{
echo 'Conversion to grayscale failed.';
}
imagedestroy($im);
?>
Example #2 imagefilter() brightness example
<?php
$im = imagecreatefrompng('sean.png');
if($im && imagefilter($im, IMG_FILTER_BRIGHTNESS, 20))
{
echo 'Image brightness changed.';
imagepng($im, 'sean.png');
imagedestroy($im);
}
else
{
echo 'Image brightness change failed.';
}
?>
Example #3 imagefilter() colorize example
<?php
$im = imagecreatefrompng('philip.png');
/* R, G, B, so 0, 255, 0 is green */
if($im && imagefilter($im, IMG_FILTER_COLORIZE, 0, 255, 0))
{
echo 'Image successfully shaded green.';
imagepng($im, 'philip.png');
imagedestroy($im);
}
else
{
echo 'Green shading failed.';
}
?>
Example #4 imagefilter() negate example
<?php
// Define our negate function so its portable for
// php versions without imagefilter()
function negate($im)
{
if(function_exists('imagefilter'))
{
return imagefilter($im, IMG_FILTER_NEGATE);
}
for($x = 0; $x < imagesx($im); ++$x)
{
for($y = 0; $y < imagesy($im); ++$y)
{
$index = imagecolorat($im, $x, $y);
$rgb = imagecolorsforindex($index);
$color = imagecolorallocate($im, 255 - $rgb['red'], 255 - $rgb['green'], 255 - $rgb['blue']);
imagesetpixel($im, $x, $y, $color);
}
}
return(true);
}
$im = imagecreatefromjpeg('kalle.jpg');
if($im && negate($im))
{
echo 'Image successfully converted to negative colors.';
imagejpeg($im, 'kalle.jpg', 100);
imagedestroy($im);
}
else
{
echo 'Converting to negative colors failed.';
}
?>
Example #5 imagefilter() pixelate example
<?php
// Load the PHP logo, we need to create two instances
// to show the differences
$logo1 = imagecreatefrompng('./php.png');
$logo2 = imagecreatefrompng('./php.png');
// Create the image instance we want to show the
// differences on
$output = imagecreatetruecolor(imagesx($logo1) * 2, imagesy($logo1));
// Apply pixelation to each instance, with a block
// size of 3
imagefilter($logo1, IMG_FILTER_PIXELATE, 3);
imagefilter($logo2, IMG_FILTER_PIXELATE, 3, true);
// Merge the differences onto the output image
imagecopy($output, $logo1, 0, 0, 0, 0, imagesx($logo1) - 1, imagesy($logo1) - 1);
imagecopy($output, $logo2, imagesx($logo2), 0, 0, 0, imagesx($logo2) - 1, imagesy($logo2) - 1);
imagedestroy($logo1);
imagedestroy($logo2);
// Output the differences
header('Content-Type: image/png');
imagepng($output);
imagedestroy($output);
?>
The above example will output something similar to:
Example #6 imagefilter() scatter example
<?php
// Load the image
$logo = imagecreatefrompng('./php.png');
// Apply a very soft scatter effect to the image
imagefilter($logo, IMG_FILTER_SCATTER, 3, 5);
// Output the image with the scatter effect
header('Content-Type: image/png');
imagepng($logo);
imagedestroy($logo);
?>
The above example will output something similar to:
English translation
You have asked to visit this site in English. For now, only the interface is translated, but not all the content yet.If you want to help me in translations, your contribution is welcome. All you need to do is register on the site, and send me a message asking me to add you to the group of translators, which will give you the opportunity to translate the pages you want. A link at the bottom of each translated page indicates that you are the translator, and has a link to your profile.
Thank you in advance.
Document created the 30/01/2003, last modified the 26/10/2018
Source of the printed document:https://www.gaudry.be/en/php-rf-imagefilter.html
The infobrol is a personal site whose content is my sole responsibility. The text is available under CreativeCommons license (BY-NC-SA). More info on the terms of use and the author.
References
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