Bug 5686

Can you should us an snippet of how this will be used?

/* widget initialisation code, realize() or somesuch */

/* set up cairo */
...
self->savepoint = cairo_save_named (self->cr);


/* drawing code, e.g. expose () */

for (r = 0; r < rows; r++) {
  for (c = 0; c < cols; c++) {
    x = c * self->tile_width;
    y = r * self->tile_height;
    /* no longer needed cairo_save (self->cr); */
    cairo_translate (self->cr, x, y);
    rsvg_cairo_render (self->cr, self->svgh);
    cairo_restore_named (self->cr, self->savepoint);
  }
}

I think what you need is a cairo_copy that clones cairo_t objects.

cairo_save: malloc + copy
cairo_restore: free

cairo_restore_named: copy

cairo_copy: copy

it seems that cairo_copy() is deprecated in HEAD

Basically I take that as a sign that your proposal will be rejected either. 
cairo_copy is a cleaner API than savepoints afterall...

Actually, cairo_copy had some huge problems and that's why we removed it.

I've always known we needed a real solution for the use case and I had often
imagined adding:

cairo_gstate_t *
cairo_get_gstate (cairo_t *cr);

void
cairo_set_gstate (cairo_t *cr, cairo_gstate_t *gstate);

but I've never been satisfied enough with that interface to actually implement.

But, now, Robert, you've made a fantastic suggestion. I really like the insight
that the desired action here is a variant of save/restore. Here's the API I
think I would like:

cairo_state_t *
cairo_save_state (cairo_t *cr);

void
cairo_restore_state (cairo_t *cr, cairo_state_t *state);

We should talk about this on the cairo@cairographics.org mailing list.

I like this enough that I'll draft a message there if nobody beats me to it.

-Carl

Moved to todo.