Image fun with PHP – part 2

November 13th, 2007. Tagged: images, php

This post is a demo of what the imagefilter() PHP function can do for you.

The Original

Nathalie

imagefilter() called with different filter constants

img_filter_brightness_5.png
Filter: IMG_FILTER_BRIGHTNESS
Code to reproduce:
<?php
$image
imagecreatefrompng('nathalie.png');
imagefilter($imageIMG_FILTER_BRIGHTNESS5);
imagepng($image'img_filter_brightness_5.png');
imagedestroy($image);
?>

img_filter_brightness_50.png
Filter: IMG_FILTER_BRIGHTNESS
Code to reproduce:
<?php
$image
imagecreatefrompng('nathalie.png');
imagefilter($imageIMG_FILTER_BRIGHTNESS50);
imagepng($image'img_filter_brightness_50.png');
imagedestroy($image);
?>

img_filter_brightness_100.png
Filter: IMG_FILTER_BRIGHTNESS
Code to reproduce:
<?php
$image
imagecreatefrompng('nathalie.png');
imagefilter($imageIMG_FILTER_BRIGHTNESS100);
imagepng($image'img_filter_brightness_100.png');
imagedestroy($image);
?>

img_filter_grayscale.png
Filter: IMG_FILTER_GRAYSCALE
Code to reproduce:
<?php
$image
imagecreatefrompng('nathalie.png');
imagefilter($imageIMG_FILTER_GRAYSCALE);
imagepng($image'img_filter_grayscale.png');
imagedestroy($image);
?>

img_filter_contrast_5.png
Filter: IMG_FILTER_CONTRAST
Code to reproduce:
<?php
$image
imagecreatefrompng('nathalie.png');
imagefilter($imageIMG_FILTER_CONTRAST5);
imagepng($image'img_filter_contrast_5.png');
imagedestroy($image);
?>

img_filter_contrast_-40.png
Filter: IMG_FILTER_CONTRAST
Code to reproduce:
<?php
$image
imagecreatefrompng('nathalie.png');
imagefilter($imageIMG_FILTER_CONTRAST, -40);
imagepng($image'img_filter_contrast_-40.png');
imagedestroy($image);
?>

img_filter_contrast_50.png
Filter: IMG_FILTER_CONTRAST
Code to reproduce:
<?php
$image
imagecreatefrompng('nathalie.png');
imagefilter($imageIMG_FILTER_CONTRAST50);
imagepng($image'img_filter_contrast_50.png');
imagedestroy($image);
?>

img_filter_colorize_100_0_0.png
Filter: IMG_FILTER_COLORIZE
Code to reproduce:
<?php
$image
imagecreatefrompng('nathalie.png');
imagefilter($imageIMG_FILTER_COLORIZE10000);
imagepng($image'img_filter_colorize_100_0_0.png');
imagedestroy($image);
?>

img_filter_colorize_0_100_0.png
Filter: IMG_FILTER_COLORIZE
Code to reproduce:
<?php
$image
imagecreatefrompng('nathalie.png');
imagefilter($imageIMG_FILTER_COLORIZE01000);
imagepng($image'img_filter_colorize_0_100_0.png');
imagedestroy($image);
?>

img_filter_colorize_0_0_100.png
Filter: IMG_FILTER_COLORIZE
Code to reproduce:
<?php
$image
imagecreatefrompng('nathalie.png');
imagefilter($imageIMG_FILTER_COLORIZE00100);
imagepng($image'img_filter_colorize_0_0_100.png');
imagedestroy($image);
?>

img_filter_colorize_100_100_-100.png
Filter: IMG_FILTER_COLORIZE
Code to reproduce:
<?php
$image
imagecreatefrompng('nathalie.png');
imagefilter($imageIMG_FILTER_COLORIZE100100, -100);
imagepng($image'img_filter_colorize_100_100_-100.png');
imagedestroy($image);
?>

img_filter_colorize_50_-50_50.png
Filter: IMG_FILTER_COLORIZE
Code to reproduce:
<?php
$image
imagecreatefrompng('nathalie.png');
imagefilter($imageIMG_FILTER_COLORIZE50, -5050);
imagepng($image'img_filter_colorize_50_-50_50.png');
imagedestroy($image);
?>

img_filter_edgedetect.png
Filter: IMG_FILTER_EDGEDETECT
Code to reproduce:
<?php
$image
imagecreatefrompng('nathalie.png');
imagefilter($imageIMG_FILTER_EDGEDETECT);
imagepng($image'img_filter_edgedetect.png');
imagedestroy($image);
?>

img_filter_emboss.png
Filter: IMG_FILTER_EMBOSS
Code to reproduce:
<?php
$image
imagecreatefrompng('nathalie.png');
imagefilter($imageIMG_FILTER_EMBOSS);
imagepng($image'img_filter_emboss.png');
imagedestroy($image);
?>

img_filter_gaussian_blur.png
Filter: IMG_FILTER_GAUSSIAN_BLUR
Code to reproduce:
<?php
$image
imagecreatefrompng('nathalie.png');
imagefilter($imageIMG_FILTER_GAUSSIAN_BLUR);
imagepng($image'img_filter_gaussian_blur.png');
imagedestroy($image);
?>

img_filter_selective_blur.png
Filter: IMG_FILTER_SELECTIVE_BLUR
Code to reproduce:
<?php
$image
imagecreatefrompng('nathalie.png');
imagefilter($imageIMG_FILTER_SELECTIVE_BLUR);
imagepng($image'img_filter_selective_blur.png');
imagedestroy($image);
?>

img_filter_mean_removal.png
Filter: IMG_FILTER_MEAN_REMOVAL
Code to reproduce:
<?php
$image
imagecreatefrompng('nathalie.png');
imagefilter($imageIMG_FILTER_MEAN_REMOVAL);
imagepng($image'img_filter_mean_removal.png');
imagedestroy($image);
?>

img_filter_smooth_5.png
Filter: IMG_FILTER_SMOOTH
Code to reproduce:
<?php
$image
imagecreatefrompng('nathalie.png');
imagefilter($imageIMG_FILTER_SMOOTH5);
imagepng($image'img_filter_smooth_5.png');
imagedestroy($image);
?>

img_filter_smooth_50.png
Filter: IMG_FILTER_SMOOTH
Code to reproduce:
<?php
$image
imagecreatefrompng('nathalie.png');
imagefilter($imageIMG_FILTER_SMOOTH50);
imagepng($image'img_filter_smooth_50.png');
imagedestroy($image);
?>

img_filter_negate.png
Filter: IMG_FILTER_NEGATE
Code to reproduce:
<?php
$image
imagecreatefrompng('nathalie.png');
imagefilter($imageIMG_FILTER_NEGATE);
imagepng($image'img_filter_negate.png');
imagedestroy($image);
?>

A lazy way to do sepia

In order to do sepia, first you do grayscale, then colorize. Here are some experiments:

sepia_100_50_0.png

<?php
$image
imagecreatefrompng('nathalie.png');
imagefilter($imageIMG_FILTER_GRAYSCALE);
imagefilter($imageIMG_FILTER_COLORIZE100500);
imagepng($image'sepia_100_50_0.png');
imagedestroy($image);
?>

sepia_100_70_50.png

<?php
$image
imagecreatefrompng('nathalie.png');
imagefilter($imageIMG_FILTER_GRAYSCALE);
imagefilter($imageIMG_FILTER_COLORIZE1007050);
imagepng($image'sepia_100_70_50.png');
imagedestroy($image);
?>

sepia_90_60_30.png

<?php
$image
imagecreatefrompng('nathalie.png');
imagefilter($imageIMG_FILTER_GRAYSCALE);
imagefilter($imageIMG_FILTER_COLORIZE906030);
imagepng($image'sepia_90_60_30.png');
imagedestroy($image);
?>

sepia_60_60_0.png

<?php
$image
imagecreatefrompng('nathalie.png');
imagefilter($imageIMG_FILTER_GRAYSCALE);
imagefilter($imageIMG_FILTER_COLORIZE60600);
imagepng($image'sepia_60_60_0.png');
imagedestroy($image);
?>

sepia_90_90_0.png

<?php
$image
imagecreatefrompng('nathalie.png');
imagefilter($imageIMG_FILTER_GRAYSCALE);
imagefilter($imageIMG_FILTER_COLORIZE90900);
imagepng($image'sepia_90_90_0.png');
imagedestroy($image);
?>

sepia_45_45_0.png

<?php
$image
imagecreatefrompng('nathalie.png');
imagefilter($imageIMG_FILTER_GRAYSCALE);
imagefilter($imageIMG_FILTER_COLORIZE45450);
imagepng($image'sepia_45_45_0.png');
imagedestroy($image);
?>

You can read about the right way to do sepia in Wikipedia, but I'd say that the fakes above look pretty good too.
You can try with different values for R, G and B, but hear this - the thing about sepia is that it's brownish-yellow.
Brown is something that has more red, little blue and the green exactly in between the red and the blue. So brown examples would be (200, 100, 0) or (150, 100, 50).
Yellow on the other hand is equal red and green and no blue, like (255, 255, 0). So if you want more brownish sepia, use the first pattern when calling the colorize filter.

About part one

Part one of the image fun is here, it contains code that more or less does the same things, but pixel by pixel, which is very slow, but also works in PHP4.
At the time of writing part one, imagefilter() funtion was probaly only in cvs, not part of the official PHP. imagefilter() is PHP5-only.

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26 Responses

  1. Lol! Looks like you’ve been having endless fun with the GD library. So many gorgeous filters, it’s just a shame that it’s so impractical for PHP really because of the CPU cycles – otherwise I’d certainly implement them in the next imaging system I did. Then again, I may do just that and then sell the website based on its “gorgeous” factor.

  2. Stoyan Stefanov’s Blog: Image fun with PHP – part 2…

    SToyan Stefanov has posted some examples of what sort of output ……

  3. [...] SToyan Stefanov has posted some examples of what sort of output can be made with the imagefilter function in PHP. [...]

  4. [...] You can read the full story here [...]

  5. Nice tutorial :)

    As a good complement, one can use imageconvolution. This function applies a convolution matrix to an image. It helps to apply more custom filters. Future versions will increase the matrix size.

    On the news side, the colorize filter supports the alpha channel now. An easy way to add transparency to an image.

    Keep the good work :)

  6. [...] phpied.com » Blog Archive » Image fun with PHP – part 2 A demo of what the imagefilter() PHP function can do for you (tags: PHP image gd) [...]

  7. Thanks Pierre, I’ll look into posting about imageconvolution() and help spreading the good news :)

  8. Wooh! its nice one

  9. [...]  Image fun part 2 (0 visite) [...]

  10. Good article maybe i would use your ideas on mine image upload script v2

  11. Me again! And yes, you should! Although be careful because your host may be none too happy with all the CPU cycles. Image manipulation is very server intensive stuff.

  12. [...] Image fun with PHP – part 2 [...]

  13. That’s a great demo, thanks very much.
    I’m just starting a simple tool to add filters on images through PHP, and you’ve saved me to do experiments myself, I’ll go straight from your results.
    Thanks again!

  14. [...] The phpied blog has some cool demos of the imagefilter() function in particular. Bookmark It Hide Sites [...]

  15. This is no doubt great tutorial. Good Work!

  16. Yes, this looks great, but you can do much much more if you will use imagemagick.

  17. Is there a way to make theses filters to work with a png image with a transparent background?
    Thanks a lot!!!

  18. Great Article, I looking for such article.

    Thanks

  19. [...] http://www.phpied.com/image-fun-with-php-part-2/ [...]

  20. [...] photo filters?)How does Instagram develop their filters? (second answer has a javascript library)http://www.phpied.com/image-fun-…http://www.pythonware.com/librar…This answer .Please specify the necessary improvements. Edit [...]

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    [...]Image fun with PHP – part 2 / Stoyan’s phpied.com[...]…

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  23. Very nice, thank you !

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