Re: goffice and cairo

[Jean Bréfort <jean brefort normalesup org>]

Le mardi 23 mai 2006 à 14:08 +0200, Emmanuel Pacaud a écrit :
> Le mardi 23 mai 2006 à 11:21 +0200, Jean Bréfort a écrit :
> > Le mardi 23 mai 2006 à 11:04 +0200, Emmanuel Pacaud a écrit :
> > > Hi,
> > >
> > > Here's some words on what I'm working on currently.
> > >
> > > Last weeks, I've tried to finalize the cairo SVG backend for its
> > > inclusion as supported backend. So I hope next stable cairo will have
> > > good PDF, PS and SVG backends.
> > >
> > > It will then be possible to ditch our current rendering engine and
> > > replace it by a simplified one, based on cairo.
> > >
> > > So my plan is to implement this simplified engine, and validate it by
> > > using it in two plot plugins, via a new GogView::cairo_render.
> > >
> > > Here's the current in-progress API:
> > >
> > > typedef struct _GOPathPoint         GOPathPoint;
> > >
> > > GOPath *go_path_new             (void);
> > > GOPath *go_path_new_with_size (int size);
> > > void    go_path_free          (GOPath *path);
> > >
> > > void go_path_set_sharp  (GOPath *path, gboolean sharp);
> > >
> > > void go_path_move_to      (GOPath *path, double x, double y);
> > > void go_path_line_to      (GOPath *path, double x, double y);
> > > void go_path_curve_to     (GOPath *path, double x0, double y0, 
> > >                                  double x1, double y1, 
> > >                                  double x2, double y2);
> > > void go_path_rectangle  (GOPath *path, double x, double y, 
> > >                                  double width, double height);
> > > void go_path_ring_wedge (GOPath *path, double cx, double xy,
> > >                                  double rx_out, double ry_out, 
> > >                                  double rx_in, double ry_in, 
> > >                                  double th0, double th1);
> > > void go_path_arc  (GOPath *path, double cx, double cy, 
> > >                                  double rx, double ry, 
> > >                                  double th0, double th1);
> > > void go_path_pie_wedge  (GOPath *path, double cx, double cy, 
> > >                                  double rx, double ry, 
> > >                                  double th0, double th1);
> > > void go_path_marker       (GOPath *path);
> > > void go_path_close        (GOPath *path);
> > >
> > > typedef struct _GOCairo GOCairo;
> > >
> > > GOCairo *go_cairo_new             (void);
> > > void go_cairo_free                (GOCairo *gcairo);
> > >
> > > void go_cairo_push_style  (GOCairo *gcairo, GogStyle const *style);
> > > void go_cairo_pop_style           (GOCairo *gcairo);
> > >
> > > void go_cairo_push_clip   (GOCairo *gcairo, GOPath const *path);
> > > void go_cairo_pop_clip    (GOCairo *gcairo);
> > >
> > > void go_cairo_stroke              (GOCairo *gcairo, GOPath const *path);
> > > void go_cairo_fill                (GOCairo *gcairo, GOPath const *path);
> > > void go_cairo_draw_shape  (GOCairo *gcairo, GOPath const *path);
> > > void go_cairo_draw_markers        (GOCairo *gcairo, GOPath const *path);
> > > void go_cairo_draw_text           (GOCairo *gcairo, double x, double y, char
> > > const *text, GtkAnchorType anchor);
> > >
> > > void go_cairo_get_text_OBR        (GOCairo *gcairo, char const *text,
> > > GOGeometryOBR *obr);
> > > void go_cairo_get_text_AABR       (GOCairo *gcairo, char const *text,
> > > GOGeometryAABR *aabr);
> > >
> > > double go_cairo_line_size (GOCairo const *gcairo, double width);
> > > double go_cairo_pt_2r_x           (GOCairo const *gcairo, double d);
> > > double go_cairo_pt_2r_y           (GOCairo const *gcairo, double d);
> > > double go_cairo_pt_2r             (GOCairo const *gcairo, double d);
> > >
> > > void go_cairo_render (GOCairo *gcairo, cairo_surface_t *surface);
> >
> > All that might be included in the GOImage code I'm currently working on,
> > IMHO. I hope I can have something operational as soon as tomorrow ;-)
>
> All what ? All of what's above ?

Why not?

> > > The final step would be to port all existing plot plugins. I think I'll
> > > move pixbuf caching to gog_control_foo_canvas, and image_export and
> > > get_pixbuf to GogGraphView.
> > >
> > > Regarding printing, since there's no gnome-print backend for cairo, I
> > > guess we can just render graphs as raster image.
> >
> > Please, don't do that! It would be a serious regression (unless you use
> > high resolution. Let's use the gnome-print renderer as long as we use
> > gnome-print (hopefully not too long).
>
> We could use a high resolution. My concern is if we keep a part of
> GogRenderer, for its gnome-print support, we'll have either a lot of
> duplicated code in plot plugins, or a mess of #ifdefs...

May be it is just too early to make that change.