Scale2x

This is a Gimp plugin that uses Python to re-implement Scalex algorythm. This plugins come with an extra, Scale2Ex that combine scale2x and gimp dilate plugin.

Scale2x is real-time graphics effect able to increase the size of small bitmaps guessing the missing pixels without interpolating pixels and blurring the images.

It was originally developed for the AdvanceMAME project in the year 2001 to improve the quality of old games with a low video resolution.

The Scale2x effect was developed by Andrea Mazzoleni in the year 2001 for the project AdvanceMAME.

The effect works repeating a computation pattern for every pixel of the original image. The pattern starts from a square of 9 pixels and expands the central pixel computing 4 new pixels.

Starting from this pattern :
A B C
D E F
G H I

The central pixel E is expanded in 4 new pixels:
E0 E1
E2 E3

with these rules (in C language) :

E0 = D == B && B != F && D != H ? D : E;
E1 = B == F && B != D && F != H ? F : E;
E2 = D == H && D != B && H != F ? D : E;
E3 = H == F && D != H && B != F ? F : E;

You are allowed to use the Scale2x implementations in your program if it’s released with the GPL license, or alternatively under all the following conditions:

* the program is not used in commercial activities.
* the whole source code of the program is released with the binary.
* derivative works of the program are allowed.

Instead, you are free to use the algorithm, but please call the effect “Scale2x”.

Source: http://scale2x.sourceforge.net/

You can see images in : http://trialforce.nostaljia.eng.br/?page_id=502