[Libdlo] SVG renderer

[Phil Endecott]

All,

Here is a simple SVG renderer using librsvg.  On Friday it was crashing 
if I asked for
more than 189 lines of output and I assumed this was because I didn't 
understand how to
use gobjects properly.  I now know more than I ever wanted to know 
about gobject reference
counting and resorted to valgrind, which pointed me to the same bit of 
libdlo that Q has
just sent a patch for.  Thanks Q!  So this now works, with Q's buffer 
overflow bug, and
my earlier patch to add claim_default_device().

BTW valgrind also reports lots of use of undefined data warnings which 
I think are
probably because it doesn't know about the usb ioctls; does anyone know 
anything about
this?

This works fine with my mimo; with my dongle I'm not sure what it's 
supposed to do with
screen modes.  I have a 1600x1200 DVI monitor and I don't think the 
dongle supports that
(does it?).  I would hope that the default initialisation would choose 
the highest res
mode that it does support.  Instead I seem to get a 0x0 mode.  I can 
then set 1024x768,
which works, but 1280x1024 (which should be supported, right?) fails 
with "unsupported
mode parameters".

Here's the code; compile with something like:

gcc -o dlorsvg -I/usr/include/gtk-2.0 -I/usr/include/glib-2.0 -I/usr/lib/glib-2.0/include
-W -Wall -O dlorsvg.c -ldlo -lrsvg-2 -lgdk_pixbuf-2.0


#include <libdlo.h>
#include <librsvg-2/librsvg/rsvg.h>
#include <stdio.h>


static void check(dlo_retcode_t err)
{
   if (err!=dlo_ok) {
     fprintf(stderr,"DLO error: %s\n",dlo_strerror(err));
   }
}


static void usage()
{
   fprintf(stderr,"dlorsvg [--dlo:display <serial>] <image.svg>\n");
}


int main(int argc, char* argv[])
{
   dlo_init_t dlo_init_flags;
   check(dlo_init(dlo_init_flags));

   dlo_claim_t dlo_claim_flags;
   dlo_dev_t d = dlo_claim_default_device(&argc, argv, dlo_claim_flags, 0);
   if (!d) {
     fprintf(stderr,"no device found\n");
     exit(1);
   }

   dlo_mode_t* mode = dlo_get_mode(d);

   if (argc!=2) {
     usage();
     exit(1);
   }

   const char* fn = argv[1];

   check(dlo_fill_rect(d,0,0,0));

   rsvg_init();
   GError* error = NULL;
   GdkPixbuf* pixbuf = rsvg_pixbuf_from_file_at_size(fn,
                                                     mode->view.width,mode->view.height,
                                                     &error);
   if (error) {
     fprintf(stderr,"GError\n");
     exit(1);
   }

   dlo_bmpflags_t bmpflags = { false };
   dlo_fbuf_t fbuf = { gdk_pixbuf_get_width(pixbuf), gdk_pixbuf_get_height(pixbuf),
                       dlo_pixfmt_abgr8888, gdk_pixbuf_get_pixels(pixbuf),
                       gdk_pixbuf_get_rowstride(pixbuf)/4 };
   dlo_dot_t origin = {0,0};
   dlo_copy_host_bmp(d,bmpflags,&fbuf,NULL,&origin);

   return 0;
}