[gdal-dev] Usage of styles in C API

[Even Rouault]

Le dimanche 03 août 2014 12:41:56, Nik Sands a écrit :
> Sorry, my mistake... I had my logging in the wrong place.  styleChars is
> actually of the form (including the leading space):
> 
> 	' PEN(c:#A08080,w:2pt); LABEL(c:#000000,s:18pt,t:{title})'

The issue must be the leading space before PEN, and potentially LABEL too.

> 
> On 3 Aug 2014, at 8:35 pm, Nik Sands <nixanz at nixanz.com> wrote:
> > On one of the iterations through this code, styleChars is:
> > 	'vegetation_low: BRUSH(fc:#A0F0A0); LABEL(c:#004000,s:18pt,t:{title})'
> > 
> > So perhaps the inclusion of the style name is the problem?
> > 
> > This was read into a style table from a text file using
> > 'OGR_STBL_LoadStyleTable()'.  I had assumed that a similar format to
> > .ofs was suitable.  If this is not the case, how should I read a style
> > table from a text file in such a way that I can distinguish the various
> > styles by name?
> > 
> > In guess my more general question is:  What is the correct way to read
> > styles from an arbitrary text file into a style table, and then use a
> > style manager to get the various parts/tools?
> > 
> > On 3 Aug 2014, at 8:26 pm, Even Rouault <even.rouault at mines-paris.org> 
wrote:
> >> Le dimanche 03 août 2014 12:11:42, Nik Sands a écrit :
> >>> I'm just starting out using the styles features of OGR (using the C
> >>> API) but at struggling with a few elements of it.
> >>> 
> >>> My code (copied below) fails to get any OGRStyleToolH.  Ie, the "if (
> >>> tool )" block never gets run, because 'tool' is always NULL at the
> >>> point indicated by the comment.  But the execution does reach that
> >>> point in the code which indicates that the OGRStyleMrgH does in fact
> >>> include at least one part (tool).
> >>> 
> >>> I'd be grateful if somebody could point out what I'm doing wrong.
> >> 
> >> Nothing strikes me as wrong. A potential explanation is that styleChars
> >> doesn't contain a valid OGR Feature Style string.
> >> GetPartCount() counts the number of ";" separating style parts, but it
> >> doens't check that each style part actually begins by a recognized tool
> >> name (PEN, BRUSH, SYMBOL, LABEL). OGR_SM_GetPart() does this check
> >> however and if it cannot recognize it it returns a NULL tool.
> >> 
> >>> Thanks,
> >>> Nik.
> >>> 
> >>> 
> >>> -------------------------------------------
> >>> 
> >>> 	const char *styleChars = OGR_STBL_GetNextStyle(table) ) )
> >>> 	NSString *styleName = [NSString
> >>> 
> >>> stringWithUTF8String:OGR_STBL_GetLastStyleName(table)]; OGRStyleMgrH
> >>> styleMgr = OGR_SM_Create(NULL);
> >>> 
> >>> 	OGR_SM_InitStyleString(styleMgr, styleChars);
> >>> 	
> >>> 	
> >>> 	for ( int i = 0; i < OGR_SM_GetPartCount(styleMgr, NULL); i++ )
> >>> 	{
> >>> 	
> >>> 		OGRStyleToolH tool = OGR_SM_GetPart(styleMgr, i, NULL);
> >>> 		
> >>> 		if ( tool )  //  'tool' always NULL here
> >>> 		{
> >>> 		
> >>> 			switch ( OGR_ST_GetType(tool) )
> >>> 			{
> >>> 			
> >>> 				case OGRSTCPen:
> >>> 					self.pen = tool;
> >>> 					break;
> >>> 				
> >>> 				case OGRSTCBrush:
> >>> 					self.brush = tool;
> >>> 					break;
> >>> 				
> >>> 				case OGRSTCSymbol:
> >>> 					self.symbol = tool;
> >>> 					break;
> >>> 				
> >>> 				case OGRSTCLabel:
> >>> 					self.label = tool;
> >>> 					break;
> >>> 				
> >>> 				default:
> >>> 					NSLog(@"Unknown style tool type!");
> >>> 					break;
> >>> 			
> >>> 			}
> >>> 		
> >>> 		}
> >>> 	
> >>> 	}
> >>> 
> >>> -------------------------------------------
> >>> 
> >>> 
> >>> _______________________________________________
> >>> gdal-dev mailing list
> >>> gdal-dev at lists.osgeo.org
> >>> http://lists.osgeo.org/mailman/listinfo/gdal-dev
> > 
> > _______________________________________________
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> > http://lists.osgeo.org/mailman/listinfo/gdal-dev

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