| This tutorial covers PHP GD image filters. The top image is the original, followed by changes made by the different filters. | |
 Original | |
 IMG_FILTER_NEGATE: Reverses all colors of the image. | |
 IMG_FILTER_GRAYSCALE: Converts the image into grayscale. | |
 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 (applied 3 times). | |
 IMG_FILTER_SELECTIVE_BLUR: Blurs the image. | |
 IMG_FILTER_MEAN_REMOVAL: Uses mean removal to achieve a "sketchy" effect. | |
 IMG_FILTER_BRIGHTNESS,-255 Arg -255 = min brightness, 0 = no change, +255 = max brightness (anything above 100 begins to fade) | |
 IMG_FILTER_BRIGHTNESS,100 | |
 IMG_FILTER_CONTRAST,-100 Arg -100 = max contrast, 0 = no change, +100 = min contrast (over 50 fades to solid gray) | |
 IMG_FILTER_CONTRAST,50 | |
 IMG_FILTER_COLORIZE,0,-150,-150 IMG_FILTER_COLORIZE Adds (subtracts) specified RGB values to each pixel. The valid range for each color is -255 to +255, The correct order is red, green, blue. -255 = min, 0 = no change, +255 = max | |
 IMG_FILTER_COLORIZE,0,150,150 | |
 IMG_FILTER_SMOOTH,-8 IMG_FILTER_SMOOTH Applies a 9-cell convolution matrix where center pixel has the weight arg1 and others weight of 1.0. The result is normalized by dividing the sum with arg1 + 8.0 (sum of the matrix), any float is accepted, large value (in practice: 2048 or more) = no change | |
 IMG_FILTER_SMOOTH,8 | |
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PHP version 5.3.0 Pixelation support (IMG_FILTER_PIXELATE) was added. PHP version 5.2.5 Alpha support for IMG_FILTER_COLORIZE was added. I am on a server running PHP 5.1.0 and do not have access to these filters. You can check what version of php you are running by putting this code into a file. <?php phpinfo(); ?> | |
| There are other ways to get image effects with PHP. I will cover some of those in the next lesson. The basic code for these filters are on the right. | Right click, select all, ctrl+c to copy. |