wxruby users - Sep 2005 - Swig generates bad interface to GetTextExtent

Swig''s bad interface generation strikes again.  get_text_extent called 
with 1 argument maps to WindowDC''s
_wrap_wxWindowDC_GetTextExtent__SWIG_0

Since this generates a wxFont that''s not initialized to nil it fails 
when calling into wxWindows.  Anyone have a suggestion?

Roy Sutton wrote:
> Swig''s bad interface generation strikes again.  get_text_extent
called
> with 1 argument maps to WindowDC''s
_wrap_wxWindowDC_GetTextExtent__SWIG_0
> 
> Since this generates a wxFont that''s not initialized to nil it
fails
> when calling into wxWindows.  Anyone have a suggestion?
Ugh. I need to report this to the swig list to see if they have any 
plans to fix it.

For this case, I think the solution is to do what wxPerl did, which is 
to define a get_text_extent(string, font=nil) that returns four values 
(width, height, descent, externalLeading). To do that, I think we would 
get rid of those icky typemaps in WindowDC.i, and %ignore GetTextExtent. 
Then %extend the class to implement our own get_text_extent. Much like 
we did for App#main_loop.

The actual body of our get_text_extent should be fairly straightforward: 
Validate the parameters, call GetTextExtent with some locals to hold the 
results, create a ruby array, copy the results to it, and return it.

We''ll need to do the same thing for DC.i, so it would probably be best 
to put the %extend stuff in a .i file that is %include''d from both. 
Maybe "../dcextensions.i"? I''m not sure if there will be
issues trying
to make it work for two different classes. If so, we could have 
duplicated code to start with, and later figure out how to merge them.

Kevin

Well, I fixed it.  Font isn''t an in/out parameter.  Given the
discussion
earlier on moving typemaps into the typemap.i, attached is a patch to 
the three affected files.

Given that wxWindowDC doesn''t actually seem to declare all the methods 
defined in the wxWindowDC.h file, should we clean that out?

Roy

Roy Sutton wrote:
> Swig''s bad interface generation strikes again.  get_text_extent
called
> with 1 argument maps to WindowDC''s
_wrap_wxWindowDC_GetTextExtent__SWIG_0
>
> Since this generates a wxFont that''s not initialized to nil it
fails
> when calling into wxWindows.  Anyone have a suggestion?
-------------- next part --------------
--- wxruby2_old/swig/typemap.i	2005-09-03 17:33:46.000000000 -0400
+++ wxruby2/swig/typemap.i	2005-09-11 00:17:57.043641600 -0400
@@ -334,3 +334,33 @@
 
 
 ##############################################################
+
+%typemap(in,numinputs=0) (wxCoord * w , wxCoord * h , wxCoord * descent,
wxCoord * externalLeading) (wxCoord a, wxCoord b, wxCoord c, wxCoord d) {
+	$1=&a;
+	$2=&b;
+	$3=&c;
+	$4=&d;
+}
+
+%typemap(argout) (wxCoord * w , wxCoord * h , wxCoord * descent, wxCoord *
externalLeading) {
+	$result = rb_ary_new();
+	rb_ary_push($result, INT2NUM(*$1));
+	rb_ary_push($result, INT2NUM(*$2));
+	rb_ary_push($result, INT2NUM(*$3));
+	rb_ary_push($result, INT2NUM(*$4));
+}
+
+%typemap(in,numinputs=0) (wxCoord * width , wxCoord * height , wxCoord *
heightLine) (wxCoord a, wxCoord b, wxCoord c) {
+	$1=&a;
+	$2=&b;
+	$3=&c;
+}
+
+%typemap(argout) (wxCoord * width , wxCoord * height , wxCoord * heightLine) {
+	$result = rb_ary_new();
+	rb_ary_push($result, INT2NUM(*$1));
+	rb_ary_push($result, INT2NUM(*$2));
+	rb_ary_push($result, INT2NUM(*$3));
+}
+
+##############################################################
-------------- next part --------------
--- wxruby2_old/swig/classes/DC.i	2005-09-09 23:31:22.000000000 -0400
+++ wxruby2/swig/classes/DC.i	2005-09-11 00:17:37.205115200 -0400
@@ -15,37 +15,6 @@
 %ignore wxDC::EnableCache;
 %ignore wxDC::StartPage;
 
-%typemap(in,numinputs=0) (wxCoord * w , wxCoord * h , wxCoord * descent,
wxCoord * externalLeading, wxFont *font) (wxCoord a, wxCoord b, wxCoord c,
wxCoord d, wxFont f) {
-	$1=&a;
-	$2=&b;
-	$3=&c;
-	$4=&d;
-	$5=&f;
-}
-
-%typemap(argout) (wxCoord * w , wxCoord * h , wxCoord * descent, wxCoord *
externalLeading, wxFont *font) {
-	$result = rb_ary_new();
-	rb_ary_push($result, INT2NUM(*$1));
-	rb_ary_push($result, INT2NUM(*$2));
-	rb_ary_push($result, INT2NUM(*$3));
-	rb_ary_push($result, INT2NUM(*$4));
-	rb_ary_push($result, SWIG_NewPointerObj((void *) $5, SWIGTYPE_p_wxFont,0));
-}
-
-%typemap(in,numinputs=0) (wxCoord * width , wxCoord * height , wxCoord *
heightLine, wxFont *font) (wxCoord a, wxCoord b, wxCoord c, wxFont f) {
-	$1=&a;
-	$2=&b;
-	$3=&c;
-	$4=&f;
-}
-
-%typemap(argout) (wxCoord * width , wxCoord * height , wxCoord * heightLine,
wxFont *font) {
-	$result = rb_ary_new();
-	rb_ary_push($result, INT2NUM(*$1));
-	rb_ary_push($result, INT2NUM(*$2));
-	rb_ary_push($result, INT2NUM(*$3));
-	rb_ary_push($result, SWIG_NewPointerObj((void *) $4, SWIGTYPE_p_wxFont,0));
-}
 %import "include/wxObject.h"
 
 %include "include/wxDC.h"
-------------- next part --------------
--- wxruby2_old/swig/classes/WindowDC.i	2005-09-03 17:33:46.000000000 -0400
+++ wxruby2/swig/classes/WindowDC.i	2005-09-11 00:19:09.868358400 -0400
@@ -5,38 +5,6 @@
 
 %module(directors="1") wxWindowDC
 
-%typemap(in,numinputs=0) (wxCoord * w , wxCoord * h , wxCoord * descent,
wxCoord * externalLeading, wxFont *font) (wxCoord a, wxCoord b, wxCoord c,
wxCoord d, wxFont f) {
-	$1=&a;
-	$2=&b;
-	$3=&c;
-	$4=&d;
-	$5=&f;
-}
-
-%typemap(argout) (wxCoord * w , wxCoord * h , wxCoord * descent, wxCoord *
externalLeading, wxFont *font) {
-	$result = rb_ary_new();
-	rb_ary_push($result, INT2NUM(*$1));
-	rb_ary_push($result, INT2NUM(*$2));
-	rb_ary_push($result, INT2NUM(*$3));
-	rb_ary_push($result, INT2NUM(*$4));
-	rb_ary_push($result, SWIG_NewPointerObj((void *) $5, SWIGTYPE_p_wxFont,0));
-}
-
-%typemap(in,numinputs=0) (wxCoord * width , wxCoord * height , wxCoord *
heightLine, wxFont *font) (wxCoord a, wxCoord b, wxCoord c, wxFont f) {
-	$1=&a;
-	$2=&b;
-	$3=&c;
-	$4=&f;
-}
-
-%typemap(argout) (wxCoord * width , wxCoord * height , wxCoord * heightLine,
wxFont *font) {
-	$result = rb_ary_new();
-	rb_ary_push($result, INT2NUM(*$1));
-	rb_ary_push($result, INT2NUM(*$2));
-	rb_ary_push($result, INT2NUM(*$3));
-	rb_ary_push($result, SWIG_NewPointerObj((void *) $4, SWIGTYPE_p_wxFont,0));
-}
-
 %import "include/wxObject.h"
 %import "include/wxDC.h"