Thanks, DDRM for reiterating the BB4W case, I had forgotten where that was detailed. And I was aware that BBCSDL graphics were different although exactly how I hadn't determined
Presumably the SDL drawing routines make different decisions: both outlines and fills include all four "edges".
That was my presumption also which I really wanted to check from Linux users of BBCSDL. BBCSDL on WIndows maps the same rectangles and I think that will hold true for all BBCSDL versions but I was after verification.
Why I am pursuing this is because SDLIDE has very minor interface issues that I wanted to correct because I like the program and can see it being useful to customize. I made a suggested change to Richard which worked for me but it turned out didn't work on BBCSDL and so was not acceptable, obviously.
Upon digging deeper I think that this RECTANGLE FILL difference is the heart of the issue and so it is important that I verify how any change might work on other BBCSDL platforms. So before offering any further fixes I want to do my homework, as it were.
Even so there appear to be more things that need to be changed to make SDLIDE totally compatible for BB4W users or are perhaps very minor flaws for everybody, I don't know at present, but I suspect most of the things aren't there on BBCSDL.
I think that since SDLIDE uses dlglib that is where most of the changes need to be made but as Richard pointed out to me that using SLDIDE under BB4W was not really the intended use, but he would consider changes if they worked for all platforms.
So anyone running BBCSDL under Linux that would be willing run that routine to give confirmation of your result that would be useful. I am expecting you will see all zeros.
Thanks in advance, if I have any SDLIDE suggestions I may be asking for testers later.