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imagefilter

Applies a filter to an image (PHP 5)
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

VersionDescription
5.2.5 Alpha support for IMG_FILTER_COLORIZE was added.

Examples

Example 1011. imagefilter() grayscale example

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<?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 1012. imagefilter() brightness example

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<?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 1013. imagefilter() colorize example

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<?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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