[Gerbv-devel] Possible libgerbv image size bug

[Erik W. <er...@ba...>]

Hi All,

 Not sure who would know would know about this so I'll just ask 
generally. This may be a bug, or it may be that I am not using libgerbv 
correctly.

 I have a little program that attempts to determine the extents of a 
gerber image - it uses the following code:

<code>

        gerbv_project_t *m_project = gerbv_create_project();

        /* parse the Gerber file and store it in the gerbv_project_t 
struct */
        gerbv_open_layer_from_filename (m_project, infile);

        /* make sure we parsed the file - these functions do not return 
anything
        so we just have to check if the file is null ..*/
        if (m_project->file[0] == NULL)
            printf("Error: Unable to open file %s", infile);
        else
        {
            if(verbose) printf("\tFile: %s\n",m_project->file[0]->name);
            printf("X Max: %f\nY Max: %f\nX Min: %f\nY Min: %f\n",
                        m_project->file[0]->image->info->max_x,
                        m_project->file[0]->image->info->max_y,
                        m_project->file[0]->image->info->min_x,
                        m_project->file[0]->image->info->min_y
                        );
       }

</code>

  I am occasionally getting both spurious and incorrect coordinates from 
this. It will sometimes return a coordinate that is not found in the 
gerber at all (Y axis seems particularly troublesome ..). I can provide 
example gerbers if in fact I am not simply misusing something. The error 
is not frequent - on batchpcb.com I started using this about one month 
ago and have only gotten a few reports, but I would like to figure it out.

 BTW, even though this is a trivial implementation I am happy to add it 
(and gbr2png for creating images) to the code base at any time - 
assuming I can make it work correctly. Also, you can see gbr2png at work 
on the site now if you upload a design :).

Thanks very much,
Erik Winn
er...@ba...