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 -
filtertypecan 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. Usearg1to set the level of brightness. -
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.
-
-
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.
-
-
arg2 -
-
IMG_FILTER_COLORIZE: Value of green component. -
IMG_FILTER_PIXELATE: Whether to use advanced pixelation effect or not (defaults toFALSE).
-
-
arg3 -
-
IMG_FILTER_COLORIZE: Value of blue component.
-
-
arg4 -
-
IMG_FILTER_COLORIZE: Alpha channel, A value between 0 and 127. 0 indicates completely opaque while 127 indicates completely transparent.
-
Return Values
Returns TRUE on success or FALSE on failure.
Changelog
| Version | Description |
|---|---|
| 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:
