Changes between Initial Version and Version 1 of rfc18_ogr_styles_c_api

Timestamp:

Dec 3, 2007, 1:31:03 PM (16 years ago)

Author:

Daniel Morissette

Comment:

--

rfc18_ogr_styles_c_api

@@ +1 @@
+= RFC 18: OGR Style Support in C API = 
+
+Author: Daniel Morissette[[BR]]
+Contact: dmorissette@mapgears.com[[BR]]
+Status: Development
+
+== Summary ==
+
+OGR has a number of C++ classes that deal with the encoding of style information and attaching that to features. More information is available in the http://www.gdal.org/ogr/ogr_feature_style.html document.
+
+With GDAL/OGR version 1.4.x and older, it was not possible to deal with style information using the C API. This RFC proposes the addition of functions to the C API to manipulate style information in GDAL/OGR 1.5.
+
+== Implementation Details ==
+
+ * The following enums will be moved from ogr_featurestyle.h to ogr_core.h:
+
+{{{
+    OGRSTClassId;
+    OGRSTUnitId;
+    OGRSTPenParam;
+    OGRSTBrushParam;
+    OGRSTSymbolParam;
+    OGRSTLabelParam;
+    OGRSTVectorParam;
+    OGRSType;
+}}}
+
+ * The OGRStyleMgrH (corresponding to the OGRStyleMgr C++ class) will be added to the C API:
+
+{{{
+    OGRStyleMgrH  OGR_SM_Create()
+    void          OGR_SM_Destroy(OGRStyleMgrH hSM)
+
+    const char   *OGR_SM_InitFromFeature(OGRStyleMgrH hSM)
+    int           OGR_SM_InitFromStyleString(const char *pszStyleString)
+    int           OGR_SM_GetPartCount(OGRStyleMgrH hSM)
+    OGRStyleToolH OGR_SM_GetPart(OGRStyleMgrH hSM)
+    int           OGR_SM_AddPart(OGRStyleMgrH hSM, OGRStyleTool *sPart)
+
+    OGRStyleToolH OGR_SM_CreateStyleToolFromStyleString(OGRStyleMgrH hSM, const char *pszStyleString)
+}}}
+
+ * The OGRStyleToolH (corresponding to the OGRStyleTool C++ class) will be added to the C API:
+
+{{{
+     OGRStyleToolH OGR_ST_Create(OGRSTClassId eClassId)
+     void          OGR_ST_Destroy(OGRStyleToolH hST)
+     OGRSTClassId  OGR_ST_GetType(OGRStyleToolH hST)
+
+     OGRSTUnitId   OGR_ST_GetUnit(OGRStyleToolH hST)
+     void          OGR_ST_SetUnit(OGRStyleToolH hST, OGRSTUnitId eUnit, double dfGroundPaperScale)
+
+     int           OGR_ST_GetParamIsNull(OGRStyleToolH hST, OGRSTParam eParam)
+     const char   *OGR_ST_GetParamStr(OGRStyleToolH hST, OGRSTParam eParam)
+     int           OGR_ST_GetParamNum(OGRStyleToolH hST, OGRSTParam eParam)
+     double        OGR_ST_GetParamDbl(OGRStyleToolH hST, OGRSTParam eParam)
+     void          OGR_ST_SetParamStr(OGRStyleToolH hST, OGRSTParam eParam, const char *pszParamString)
+     void          OGR_ST_SetParamNum(OGRStyleToolH hST, OGRSTParam eParam, int nParam)
+     void          OGR_ST_SetParamDbl(OGRStyleToolH hST, OGRSTParam eParam, double dfParam)
+     const char   *OGR_ST_GetStyleString(OGRStyleToolH hST)
+
+     int           OGR_ST_GetRGBFromString(OGRStyleToolH hST, const char *pszColor, 
+                                          int *nRed, int *nGreen, int *nBlue, int *nAlpha);
+}}}
+
+ * Note that *NO* wrappers will be needed for the following C++ classes which are handled internally by the OGR_ST_* wrappers above:
+
+{{{
+    class OGRStylePen : public OGRStyleTool
+    class OGRStyleBrush : public OGRStyleTool
+    class OGRStyleSymbol : public OGRStyleTool
+    class OGRStyleLabel : public OGRStyleTool
+    class OGRStyleVector : public OGRStyleTool
+}}}
+
+== Python and other language bindings ==
+
+The initial implementation will be for the C API only and will not be ported/tested with the Python and other scripting language bindings. This will have to wait for a later release.
+
+== Implementation ==
+
+Daniel Morissette will implement the changes to the C API described in this RFC for the GDAL/OGR 1.5.0 release.
+
+The first test of the new C API functions will be the conversion of MapServer's mapogr.cpp to use them.
+
+== Voting History ==
+
+None yet.