How to enlarge an image with anti-aliasing in php?

Question

PHP

How to enlarge an image with anti-aliasing in php to get the result in the figure on the right.
With the use of imagecopyresampled it turns out as on the left. And I need muddy.

Answer 1

Searching the documentation helped me find the imagesetinterpolation function . Try setting IMG_BICUBIC, IMG_GAUSSIAN etc.
The default is bilinear (IMG_BILINEAR_FIXED), which gives the result on the left.

Answer 2

Further process with imagefilter with any blur filter.