[XaraXtreme-dev] GDraw bitmap width limit

[Alex Bligh <alex@xxxxxxxxxxx>]

Gavin,

There seems to be a limit on GDraw re plotting to bitmaps more
than 4096 pixels wide (in GDraw_SetupBitmap). I will not pretend
I am lucky enough to have a 4096 pixel wide monitor, but this seems
to cause serious difficulty if you want to print via bitmap to a
landscape A4 page. As far as I can see, you are limited to about 340
dpi. You can't get 600dpi even on A4 portrait.

Is this a hard limit? And if so, are we going to have to work
around it through horizontal (as well as vertical) banding
(yuck)? If we could get up to a 32,768 pixel limit, we'd
be able to do an A4 page at 2,400 dpi without code redesign
(though I am assuming that GDraw's pixel referencing stuff
may not be sign-safe at least on 32bit, so we'd be limited
to 16,384 pixel high stripes, giving 2Gb patches - quite
doable on a modern machine). At 2,400dpi a whole page is
just over 2Gb, and whilst clearly you wouldn't want everything
at 2,400dpi as it's screened, if you are printing as a bitmap
you haven't got much choice if you want screen text, and
2Gb is perfectly feasible these days with a DVD. Equally
it would allow us to do A0 at 600dpi, which is pretty reasonable
for posters etc.

Alex