rodarima left a comment (fltk/fltk#1138)

Sorry for the long delay. I have read the issue again, and I would like to focus on this problem:

dillo uses fl_scroll() which is not pixel accurate for non-integral scaling values

Dillo uses fl_scroll() because it implements its own scrolling widget, rather than using Fl_Scroll. I'm not sure on the reasons for this choice (I didn't wrote this code), and it seems to come from the port to FLTK 2 which used scrollrect().

However, the current solution in FL_Scroll to handle non integral scales (for example 1.05) seems to consist in redrawing the whole canvas, which is a costly operation:

https://github.com/fltk/fltk/blob/5830c72b58c3cf8e7683d1765145537fef828ee9/src/Fl_Scroll.cxx#L353-L360

I would like to explore another solution which is to provide our own implementation of fl_scroll that can handle non-integral scales. To that end, I would need to know how many pixels (not FLTK units) do I need to move the canvas, so I only need to redraw the relevant part. I will open another issue to track this problem.

—
Reply to this email directly, view it on GitHub, or unsubscribe.
You are receiving this because you are subscribed to this thread.Message ID: <fltk/fltk/issues/1138/3240416241@github.com>