[dia] dxf: changing scales during import to the reciprocal

[Hans Breuer <hans src gnome org>]

commit 15deb6b1cfa5b190e3f3637d5b8013ba46a9e8ca
Author: Hans Breuer <hans breuer org>
Date:   Sun Jun 19 19:33:25 2011 +0200

    dxf: changing scales during import to the reciprocal
    
    AFAICT this is all not documented by the DXF specification,
    but with the original values some files I've tested are coming
    out much too huge.

 plug-ins/dxf/dxf-import.c |   37 +++++++++++++++++++++++++++++++++++--
 1 files changed, 35 insertions(+), 2 deletions(-)
---
diff --git a/plug-ins/dxf/dxf-import.c b/plug-ins/dxf/dxf-import.c
index 0b10d26..f8ab2b1 100644
--- a/plug-ins/dxf/dxf-import.c
+++ b/plug-ins/dxf/dxf-import.c
@@ -56,7 +56,7 @@ Point extent_min, extent_max;
 Point limit_min, limit_max;
 
 /* maximum line length */
-#define DXF_LINE_LENGTH 256
+#define DXF_LINE_LENGTH 257
 
 typedef struct _DxfLayerData 
 {
@@ -985,6 +985,8 @@ read_entity_scale_dxf(FILE *filedxf, DxfData *data, DiagramData *dia)
      {
       case 40: 
 	coord_scale = g_ascii_strtod(data->value, NULL);
+	if (coord_scale > 0.0)
+	  coord_scale = 1.0 / coord_scale;
 	g_message("Scale: %f", coord_scale );
 	break;
       
@@ -994,6 +996,30 @@ read_entity_scale_dxf(FILE *filedxf, DxfData *data, DiagramData *dia)
    
 }
 
+static void
+read_entitiy_lengthunit_dxf(FILE *filedxf, DxfData *data, DiagramData *dia)
+{
+   real e; /* undocumented ... */
+
+   if(read_dxf_codes(filedxf, data) == FALSE)
+      return;
+
+   switch(data->code)
+     {
+      case 70: 
+	/* 1 = Scientific; 2 = Decimal; 3 = Engineering;
+         * 4 = Architectural; 5 = Fractional; 6 = Windows desktop 
+	 */
+	e = atoi(data->value);
+	g_message("LengthUnit: %f", coord_scale );
+	break;
+      
+      default:
+	break;
+     }	
+   
+}
+
 /* reads a scale entity from the dxf file */
 static void 
 read_entity_measurement_dxf(FILE *filedxf, DxfData *data, DiagramData *dia)
@@ -1029,6 +1055,8 @@ read_entity_textsize_dxf(FILE *filedxf, DxfData *data, DiagramData *dia)
      {
       case 40:
 	text_scale = g_ascii_strtod(data->value, NULL);
+	if (text_scale > 0.0)
+	  text_scale = 1.0 / text_scale;
 	/*printf( "Text Size: %f\n", text_scale );*/
 	break;		
       default:
@@ -1047,6 +1075,9 @@ read_section_header_dxf(FILE *filedxf, DxfData *data, DiagramData *dia)
     do {
        if((data->code == 9) && (strcmp(data->value, "$DIMSCALE") == 0)) {
 	  read_entity_scale_dxf(filedxf, data, dia);
+	} else if((data->code == 9) && (strcmp(data->value, "DIMLUNIT") == 0)) {
+	  /* nothing documented */
+	  read_entitiy_lengthunit_dxf(filedxf, data, dia);
         } else if((data->code == 9) && (strcmp(data->value, "$TEXTSIZE") == 0)) {
 	  read_entity_textsize_dxf(filedxf, data, dia);
         } else if((data->code == 9) && (strcmp(data->value, "$MEASUREMENT") == 0)) {
@@ -1297,7 +1328,9 @@ import_dxf(const gchar *filename, DiagramData *dia, void* user_data)
 }
 
 /* reads a code/value pair from the DXF file */
-gboolean read_dxf_codes(FILE *filedxf, DxfData *data){
+static gboolean 
+read_dxf_codes(FILE *filedxf, DxfData *data)
+{
     int i;
     char *c;