Vertical Flip function for Sprites/Tilemap (DLL)

[FenriX`]

i've seen some methods and functions for the various classes that are used to show the tilemap and the events on map... nothing let me think that there's an easy way to vertically flip the images whitout create a lot of lag...
the easy way is this:
@sprite.angle = 180
@sprite.mirror = true
like this i can, rotate a sprite by 180° and then flip it orizontally, creating a vertical flip, as i want to do...
but i can't use this way, i want to do it with the map, 'cause of the big lag!!
the method "mirror" is lag free, completely, i can use it any time i want and there's not a single issue, but this is not the case of the "angle" method...
i don't think there's a solution with the RGSS, there's no other method that rotate a picture, and there's no method that flip the graphic vertically...
i was thinking about the DLL, looking at the libpng.dll i've found nothing usefull, also the png.dll is apparently useless.
Do someone know a good DLL to make a vertical flip?
or maybe it does exist a method that make a vertical flip without the "angle" method...
i hope that someone has an answer to this question!! thanks!!

 

[Glitchfinder]

I've worked with the RMXP and RMVX image data via dll before, and it's a bit more complex than simply using an existing dll file. RM stores them with extra data that these libraries can't handle, meaning any dll you use has to be custom tooled to the program. I've posted source on a dll that modifies images for RM* in the past, but your real problem will be the tilemap. RM* doesn't just display a bunch of images and move them all at once. You would have to custom tool a tilemap rewrite to manage to use the dll file to do what you need, and I'm not sure exactly how well that would work, having never worked with the tilemap.

One thing to note is that, if you do decide to custom make a dll, or find someone else willing to do so, RPG Maker stores colors as BGRA rather than RGBA. (In other words, each pixel amounts to an array of four values from 0-255, in the order of blue, green, red, alpha)