BITMAP (Allegro 4) to ALLEGRO_BITMAP (Allegro 5) conversion

[MarekRatajczak2024]

Hi everyone,
Does optimised procedure exist converting BITMAP (Allegro 4 style) to ALLEGRO_BITMAP (Allegro 5 style) assuming that both bitmaps are the same dimensions, the same colour depth, so they are "visually" identical, but doing that conversion somehow smart by simply memmove of entire lines (horizontal lines) rather then doing it pixel by pixel, with pixel colour conversion which I realized is platform dependant, and what I have done so far in my program, what is not really optimal, and that I have to do 30 times per second, using Allegro-Legacy library due to nearly entire code I have done in Allegro 4, so all based on BITMAPs. Thanks for your attention and awaiting for any answer.
Marek.

[miquelfire]

First question, are you linking both A4 and A5 to your program? Or are you using some backwards compatibility library that allows you to use A4 style code?

[MarekRatajczak2024]

Hi miquelfire,
Yes, my entire program AlfaCAD (https://alfacad.net) is based on Allegro 4 (for Linux, and for Windows with my own 64bit implementation of Allegro for Windows, because didn't exist), but to do that for MacOS I was enforced to use Allegro 5, due to decommissioned QuickDraw, so eventually I'm using Allegro-Legacy, with some changes - mostly for MacOS platform, however on development stage I do the same on Linux (it's just test version, production version is on Allegro 4 with my extensions), my main programming platform, to replicate all on MacOS x64 then MacOS aa64.
So basically all is nearly done using Allegro-Legacy (https://github.com/NewCreature/Allegro-Legacy), which is the replica of Allegro 4.4 or 4.3.1 it doesn't really matters, but all is drawn on virtual screen as Allegro 4 style BITMAP, than, in separate thread, that screen is converted to ALLEGRO_BITMAP (in fact there is first blit of the "screen" (so BITMAP) to it's copy in the same format, and can be done by blit, or can be done by memmove of entire image on n-lines x m-rows at once, and from my experience both methods are fast, to avoid some flickering in real time, then that copy is copied to ALLEGRO_BITMAP) . But that what takes most time is copying BITMAP to ALLEGRO_BITMAP, and so far I have to do that - as Allegro-Legacy is doing at the very last stage, pixel by pixel. I can provide details how it's done, but maybe this is not important now. So I was asking if maybe somebody invented the procedure avoiding copying pixel-by-pixel, rather doing it line by line or so, what could increase the speed dramatically. There is no problem with M4 processor, it's only important for older platform, x64 especially when we deal with retina screen, because there are many pixels to copy, and this is some 30 FPS or more. As I wrote, I'm happy with M4, I do not see any lagging, all works smooth, because M4 is bloody fast. Not necessary it's like that with i7. As a matter of fact, I do not know ell the structure of ALLEGRO_BITMAP, while I do know very well structure of BITMAP, which I also use to produce printing image, also PDF images etc. I'm not able to say if copying by lines is even possible due to the format of each pixel, what is platform dependant.