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# imagefilter

(PHP 5)

imagefilter — Applies a filter to an image

### Description

bool imagefilter ( resource `$image` , int `$filtertype` [, int `$arg1` [, int `$arg2` [, int `$arg3` [, int `$arg4` ]]]] )

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`

  `filtertype` can be one of the following:

  - `IMG_FILTER_NEGATE`: Reverses all colors of the image.
  - `IMG_FILTER_GRAYSCALE`: Converts the image into grayscale.
  - `IMG_FILTER_BRIGHTNESS`: Changes the brightness of the image. Use `arg1` to set the level of brightness.
  - `IMG_FILTER_CONTRAST`: Changes the contrast of the image. Use `arg1` to set the level of contrast.
  - `IMG_FILTER_COLORIZE`: Like `IMG_FILTER_GRAYSCALE`, except you can specify the color. Use `arg1` , `arg2` and `arg3` in the form of `red` , `blue` , `green` and `arg4` for the `alpha` channel. 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. Use `arg1` to set the level of smoothness.
`arg1`

`arg2`

`arg3`

### Return Values

Returns `TRUE` on success or `FALSE` on failure.

### ChangeLog

Version | Description
--- | ---
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');
} else {
echo 'Image brightness change failed.';
}
imagedestroy($im);
?>`

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');
} else {
echo 'Green shading failed.';
}
imagedestroy($im);
?>`

### Notes

> Note: This function is only available if PHP is compiled with the bundled version of the GD library.

### See Also

- imageconvolution()

imagefilltoborder
imagefontheight
GD Functions
PHP Manual