Re: [fltk.coredev] Vote about using antialiased lines and curves on the Windows platform - Forums

On Monday, May 17, 2021 at 10:26:47 PM UTC+2 imacarthur wrote:

I’m greatly in favour of anti-aliased rendering, and I do not want to be negative about the great work Manolo has done in getting it to run inside fltk, but I’m not at all convinced by GDI+.
As Manolo said, I have hit issues with it being *slow*.
Now, others tried testing when I reported slowness, and didn’t see the effect I was seeing, and Manolo reports it is “slightly slower” than GDI for him. (And others report no noticeable slowness under Vbox, for example...)
But for me *on some machines* it can be very slow - whereas the same code on another machine seems fine.
I assume it is some display-driver related issue though I have no clue what.
For me, one of the “slow” machines is my good HP laptop, which is pretty decent spec., Nvidia GPU etc. and generally swift (by laptop standards) but chokes sometimes on the GDI+ tests I did.

@Ian: I would like to be sure you measure the current proposal is meant to account for the findings you have reported.

With it, GDI+ would be used only to draw circles, arcs and oblique lines, so that the vast majority of FLTK drawings

are unchanged. I also stress the test/doublebuffer program is very artificial in that each line gets drawn 10 times.

If all windows were GL windows, could we just render “everything” via GL and get h/w accelerated rendering pretty much on all hosts that way?

That would be achievable completing the implementaton of the Fl_OpenGL_Graphics_Driver class which is now only sketched.