Magento resize with gd2 bad image

Question

i have problems to obtain good thumb from some images, when the original images are striped or checked shirt.

With the magento's gd2 library resize() in Varien_Image_Adapter_Gd2 class (magento 1.5 version) i obtain an image with a strange effect that modify the aspect of real image.

I can't find the name of this effect, so i can't search this issue on google! :(

You can see my issue in these 2 images:

As you can see, on the thumb image there are some rolling strange lines in particular in top-left position.

The issue is more evident on checked shirt, so i have to find a solution to correct this.

If anyone have some tips on this issue, please said me! :)

thx Luca

Answer 1

'Moire' is the pattern you describe and it is particularly visible due to use of 'gd2' library which may or may not use bicubic scaling.

I am not sure that @Guerra has understood the problem here, but, to me, it is a straightforward lack of bicubic (or better) scaling.

See the answer on this question and follow the link:

https://stackoverflow.com/a/255666/1617149

So you may want to scale your images for the frontend using imagemagick instead of the standard gd2 library that comes with Magento and use a filter.

You can run imagemagick through php (the proper way), or, if you have complicated image processing on the go, you can go commandline 'exec' and prototype your image processing that way. I don't have any ready-to-roll code for that, however, that is what you need: better thumbnail rendering than you get with gd2.

Answer 2

Try use cloudzoom, he autosize your images to fit on your needs. http://ecommerce-team.com/cloud-zoom.html