Class: Mathematical::Process

Inherits:
Object
  • Object
show all
Defined in:
ext/mathematical/mathematical.c

Instance Method Summary collapse

Constructor Details

#initialize(rb_Options) ⇒ Object 



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# File 'ext/mathematical/mathematical.c', line 63

static VALUE MATHEMATICAL_init(VALUE self, VALUE rb_Options) {
  Check_Type (rb_Options, T_HASH);
  VALUE rb_ppi, rb_zoom, rb_maxsize;

  rb_ppi = rb_hash_aref(rb_Options, CSTR2SYM("ppi"));
  rb_zoom = rb_hash_aref(rb_Options, CSTR2SYM("zoom"));
  rb_maxsize = rb_hash_aref(rb_Options, CSTR2SYM("maxsize"));

  Check_Type(rb_ppi, T_FLOAT);
  Check_Type(rb_zoom, T_FLOAT);
  Check_Type(rb_maxsize, T_FIXNUM);

  rb_iv_set(self, "@ppi", rb_ppi);
  rb_iv_set(self, "@zoom", rb_zoom);
  rb_iv_set(self, "@maxsize", rb_maxsize);
  rb_iv_set(self, "@svg", Qnil);

  return self;
}

Instance Method Details

#process(rb_LatexCode) ⇒ Object 



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# File 'ext/mathematical/mathematical.c', line 83

static VALUE MATHEMATICAL_process(VALUE self, VALUE rb_LatexCode) {
  Check_Type (rb_LatexCode, T_STRING);

  unsigned long maxsize = (unsigned long) FIX2INT(rb_iv_get(self, "@maxsize"));

  const char *latex_code = StringValueCStr(rb_LatexCode);
  unsigned long latex_size = (unsigned long) strlen(latex_code);

  // make sure that the passed latex string is not larger than the maximum value of a signed long (or the maxsize option)
  if (maxsize == 0)
    maxsize = LONG_MAX;

  if (latex_size > maxsize)
    rb_raise(rb_eMaxsizeError, "Size of latex string (%lu) is greater than the maxsize (%lu)!", latex_size, maxsize);

#if !GLIB_CHECK_VERSION(2,36,0)
  g_type_init ();
#endif

  // convert the TeX math to MathML
  char * mathml = lsm_itex_to_mathml(latex_code, latex_size);
  if (mathml == NULL) rb_raise(rb_eParseError, "Failed to parse itex");

  int mathml_size = strlen(mathml);

  LsmDomDocument *document;
  document = lsm_dom_document_new_from_memory(mathml, mathml_size, NULL);

  lsm_itex_free_mathml_buffer (mathml);

  if (document == NULL) rb_raise(rb_eDocumentCreationError, "Failed to create document");

  LsmDomView *view;

  double ppi = NUM2DBL(rb_iv_get(self, "@ppi"));
  double zoom = NUM2DBL(rb_iv_get(self, "@zoom"));

  view = lsm_dom_document_create_view (document);
  lsm_dom_view_set_resolution (view, ppi);

  double width_pt = 2.0, height_pt = 2.0;
  unsigned int height, width;

  lsm_dom_view_get_size (view, &width_pt, &height_pt, NULL);
  lsm_dom_view_get_size_pixels (view, &width, &height, NULL);

  width_pt *= zoom;
  height_pt *= zoom;

  cairo_t *cairo;
  cairo_surface_t *surface;

  surface = cairo_svg_surface_create_for_stream (cairoSvgSurfaceCallback, self, width_pt, height_pt);
  cairo = cairo_create (surface);
  cairo_surface_destroy (surface);
  cairo_scale (cairo, zoom, zoom);
  lsm_dom_view_render (view, cairo, 0, 0);

  cairo_destroy (cairo);
  g_object_unref (view);
  g_object_unref (document);

  if (rb_iv_get(self, "@svg") == Qnil) rb_raise(rb_eDocumentReadError, "Failed to read SVG contents");

  VALUE result_hash = rb_hash_new();

  rb_hash_aset (result_hash, rb_tainted_str_new2 ("width"),  INT2FIX(width_pt));
  rb_hash_aset (result_hash, rb_tainted_str_new2 ("height"), INT2FIX(height_pt));
  rb_hash_aset (result_hash, rb_tainted_str_new2 ("svg"),    rb_iv_get(self, "@svg"));

  // we need to clear out this key when attempting multiple calls. See http://git.io/i1hblQ
  rb_iv_set(self, "@svg", Qnil);

  return result_hash;
}