On 10/08/2013 11:22 AM, Stephen Chang wrote:
Short question:
Is there a way to separate the gui-requiring parts of plot from the
non-gui-requiring parts?
Long question:
Many people have expressed pleasant surprise with the plot-evaluating
ability of the racket pastebin Sam and I are working on.
Most of the effort is due to scribble's nice sandbox evaluation
capabilities but to get it fully working, I had to hack the plot
library in my racket install.
The problem is that plot uses racket/gui/base too eagerly but the
server has no display, resulting in a gtk initialization error. I
ultimately got around it by just commenting out all the gui parts of
plot, knowing that it would never get invoked, but obviously this is
an ugly solution.
I should say that I don't think plot is at fault. The plot library
does lazy-require racket/gui/base but that's not good enough because
the laziness has to propagate to other requires that also require
racket/gui/base (ie plot/snip) which isnt the case. But this cannot
work anyways because lazy-require only works with functions and some
of the things imported by plot/snip are classes.
I spent awhile trying to separate the gui-requiring parts of plot but
was unsuccessful. Maybe the change has to be in racket/gui/base itself
(related to PR 12465) I don't really know. I guess I'm just looking
for additional insight. Naively, slideshow/pict and 2htdp/draw do not
have this problem so it seemed like it should be possible.
Right, racket/gui/base is necessary for snips. In all the documentation
that uses plots (plot, math, images) I've used the following hack when
setting up the evaluators:
(eval '(require (rename-in (except-in plot plot plot3d)
[plot-pict plot]
[plot3d-pict plot3d])))
You could also rename `plot-bitmap' and `plot3d-bitmap'. (The docs use
picts because they look better rendered in a PDF.) It wouldn't be hard
to make a module that does that and provides everything. (Except
possibly `plot-snip', `plot-frame', etc.)
I'm reluctant to single out one way of rendering when the GUI isn't
available. Picts look nicer when scaled, but bitmaps look nicer when
unscaled (plots are subpixel-rendered in this case). Picts take much
more time to redraw, but for bitmaps it's just a blit.
Neil ⊥
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