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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]]] )

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`. 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.

## 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()

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