PHP: imagefilter

Description

bool imagefilter ( resource src_im, int filtertype [, int arg1 [, int arg2 [, int arg3]]] )

imagefilter() applies the filter filtertype to the image, using arg1, arg2 and arg3 where necessary.

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.

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

Returns TRUE on success or FALSE on failure.

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); ?>

User Contributed Notes
imagefilter

vdepizzol at hotmail dot com
04-Sep-2004 03:36


Examples using imagefilter():



<?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);

?>



/////////////////////////////



<?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);

?>



/////////////////////////////



<?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);

?>

kees at tweakers dot net
20-Jul-2004 08:26


From what i have been able to find from this function, it accepts the following arguments:

        IMG_FILTER_NEGATE

        IMG_FILTER_GRAYSCALE

        IMG_FILTER_EDGEDETECT

        IMG_FILTER_GAUSSIAN_BLUR

        IMG_FILTER_SELECTIVE_BLUR

        IMG_FILTER_EMBOSS

        IMG_FILTER_MEAN_REMOVAL



The following arguments need one or more arguments.

        IMG_FILTER_SMOOTH, -1924.124

        IMG_FILTER_COLORIZE, -127.12, -127.98, 127

        IMG_FILTER_CONTRAST, -90

        IMG_FILTER_BRIGHTNESS, 98

        

I haven't tested them all, the names speak for themselves.