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Review by  Kevin Ouellet
Reviewed on 2010-02-20
I personally do not recommend this program to anyone because of much smaller (and faster) ASM alternatives and even some much smaller BASIC alternatives, but this program is a prime example of how much speed you can gain in BASIC by sacrifying all the memory you can.

Instead of simply doing For(C,0,94:For(D,0,62:Pxl-Change(D,C:End:End, which is CONSIDERABLY smaller, the programmer has decided to just use one single For( loop and have one Pxl-Test( command for every pixel in the column number contained in the For( loop variable. In addition to this, he inverts two columns at once every loop, one on the left side and the other on the right side, until it reaches the center of the screen. The result: a whooping 1499 bytes of code just to do one thing that could have been done in about 14 bytes of code: invert the graph screen. But here's the thing: TI-BASIC For( loops are so slow to process that if he used the conventional 14 bytes method to do what he wanted, his program would run about twice slower. Had Netham inverted more pixels per For( loops than he did, his program would even have ran slightly faster. It's as pathetic as BASIC can get, sometimes: in cases where many things have to be displayed on screen in one loop, memory has to be sacrified to keep the program or game running at a decent speed.

Maybe the speed sacrifice in this program was too rash, since people will most likely not want a screen inverter this large on their calc, but I think if this method was used in a game where several enemies has to be displayed at once on the screen, their position/health being stored inside a list, like Galaxian, Space Invaders or a Warcraft, it would improve their speed a lot

Anyway, on the scoring of this screen inverter I would give:

Size: 0/10

Speed: 10/10 (for a BASIC program)

Originality: 5/10

Overall: 5/10 only download if you want something fast, but no ASM, and don't care about speed.

Review by  Jonathan Pezzino
Reviewed on 2004-09-27
“Invert” is essentially the brute force approach to inverting the screen. A peek at the source will reveal the program's technique: manually telling EVERY pixel in each row to change, then incrementing a variable that determines the column. Unfortunately, this takes many, many lines of code (and thus a HUGE amount of space for such a simple program) and still does not go very quickly. (Though some much-needed code optimization, such as competent implementation of For( and While( Loops, might improve this). If you need a program to inverse the screen at a slightly faster rate than the traditional pixel-by-pixel program and do not mind sacrificing almost 1500 bytes of RAM, then go ahead and download this.
Overall: 5/10
Accomplishes what it sets out to do (sort of), though it is poorly coded and absolutely enormous in size.

Review by  Tim McMahon
Reviewed on 2004-09-22
“Invert” is truly amazing. The rate in which the pixels are changed is mind blowing. As soon as the first line is changed I'm on the edge of my seat for yet another to follow suit. This may not be original, but it is the first “Invert” program in BASIC that I've come across! A few improvements to this program would be to use ASM, but it was very well done in BASIC. If you are a “1337” BASIC programmer and want to spice up your games with this uber cool inverting, download it now!

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