GoLang imagefilter
GoLang replacement for PHP's imagefilter
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PHP imagefilter
PHP original manual for imagefilter
[
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php.net
]
imagefilter
(PHP 5, PHP 7) imagefilter — Applies a filter to an image
Description
bool imagefilter
( resource $image
, int $filtertype
[, int $arg1
[, int $arg2
[, int $arg3
[, int $arg4
]]]] )
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 by changing the red, green and blue components to their
weighted sum using the same coefficients as the REC.601 luma (Y')
calculation. The alpha components are retained. For palette images the
result may differ due to palette limitations.
-
IMG_FILTER_BRIGHTNESS: Changes the brightness
of the image. Use arg1 to set the level of
brightness. The range for the brightness is -255 to 255.
-
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, green,
blue 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.
-
IMG_FILTER_PIXELATE: Applies pixelation effect
to the image, use arg1 to set the block size
and arg2 to 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 to FALSE).
-
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.
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:
Notes
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