imagecolorclosestalpha(3) [php man page]
IMAGECOLORCLOSESTALPHA(3) 1 IMAGECOLORCLOSESTALPHA(3) imagecolorclosestalpha - Get the index of the closest color to the specified color + alpha SYNOPSIS
int imagecolorclosestalpha (resource $image, int $red, int $green, int $blue, int $alpha) DESCRIPTION
Returns the index of the color in the palette of the image which is "closest" to the specified RGB value and $alpha level. PARAMETERS
o $ image -An image resource, returned by one of the image creation functions, such as imagecreatetruecolor(3). o $red -Value of red component. o $green -Value of green component. o $blue -Value of blue component. o $alpha - A value between 0 and 127. 0 indicates completely opaque while 127 indicates completely transparent. The colors parameters are integers between 0 and 255 or hexadecimals between 0x00 and 0xFF. RETURN VALUES
Returns the index of the closest color in the palette. EXAMPLES
Example #1 Search for a set of colors in an image <?php // Start with an image and convert it to a palette-based image $im = imagecreatefrompng('figures/imagecolorclosest.png'); imagetruecolortopalette($im, false, 255); // Search colors (RGB) $colors = array( array(254, 145, 154, 50), array(153, 145, 188, 127), array(153, 90, 145, 0), array(255, 137, 92, 84) ); // Loop through each search and find the closest color in the palette. // Return the search number, the search RGB and the converted RGB match foreach($colors as $id => $rgb) { $result = imagecolorclosestalpha($im, $rgb[0], $rgb[1], $rgb[2], $rgb[3]); $result = imagecolorsforindex($im, $result); $result = "({$result['red']}, {$result['green']}, {$result['blue']}, {$result['alpha']})"; echo "#$id: Search ($rgb[0], $rgb[1], $rgb[2], $rgb[3]); Closest match: $result. "; } imagedestroy($im); ?> The above example will output something similar to: #0: Search (254, 145, 154, 50); Closest match: (252, 150, 148, 0). #1: Search (153, 145, 188, 127); Closest match: (148, 150, 196, 0). #2: Search (153, 90, 145, 0); Closest match: (148, 90, 156, 0). #3: Search (255, 137, 92, 84); Closest match: (252, 150, 92, 0). NOTES
Note This function requires GD 2.0.1 or later (2.0.28 or later is recommended). SEE ALSO
imagecolorexactalpha(3), imagecolorclosest(3), imagecolorclosesthwb(3). PHP Documentation Group IMAGECOLORCLOSESTALPHA(3)
Check Out this Related Man Page
IMAGEFILTER(3) 1 IMAGEFILTER(3) imagefilter - Applies a filter to an image SYNOPSIS
bool imagefilter (resource $image, int $filtertype, [int $arg1], [int $arg2], [int $arg3], [int $arg4]) DESCRIPTION
imagefilter(3) applies the given filter $filtertype on the $image. PARAMETERS
o $ image -An image resource, returned by one of the image creation functions, such as imagecreatetruecolor(3). o $filtertype -$filtertype can be one of the following: o IMG_FILTER_NEGATE: Reverses all colors of the image. o IMG_FILTER_GRAYSCALE: Converts the image into grayscale. o 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. o IMG_FILTER_CONTRAST: Changes the contrast of the image. Use $arg1 to set the level of contrast. o 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. o IMG_FILTER_EDGEDETECT: Uses edge detection to highlight the edges in the image. o IMG_FILTER_EMBOSS: Embosses the image. o IMG_FILTER_GAUSSIAN_BLUR: Blurs the image using the Gaussian method. o IMG_FILTER_SELECTIVE_BLUR: Blurs the image. o IMG_FILTER_MEAN_REMOVAL: Uses mean removal to achieve a "sketchy" effect. o IMG_FILTER_SMOOTH: Makes the image smoother. Use $arg1 to set the level of smoothness. o IMG_FILTER_PIXELATE: Applies pixelation effect to the image, use $arg1 to set the block size and $arg2 to set the pixela- tion effect mode. o $arg1 - o IMG_FILTER_BRIGHTNESS: Brightness level. o IMG_FILTER_CONTRAST: Contrast level. o IMG_FILTER_COLORIZE: Value of red component. o IMG_FILTER_SMOOTH: Smoothness level. o IMG_FILTER_PIXELATE: Block size in pixels. o $arg2 - o IMG_FILTER_COLORIZE: Value of green component. o IMG_FILTER_PIXELATE: Whether to use advanced pixelation effect or not (defaults to FALSE). o $arg3 - o IMG_FILTER_COLORIZE: Value of blue component. o $arg4 - o 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(3) 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(3) 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(3) 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($im); } else { echo 'Green shading failed.'; } ?> Example #4 imagefilter(3) negate example <?php // Define our negate function so its portable for // php versions without imagefilter() function negate($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(3) 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:[NOT DISPLAYABLE MEDIA]Output of example : imagefilter() pixelate NOTES
SEE ALSO
imageconvolution(3). PHP Documentation Group IMAGEFILTER(3)