prototype for hypertidy#9

dcooley · May 3, 2020 · 58a13ad · 58a13ad
1 parent 7f86d61
commit 58a13ad
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Showing 4 changed files with 73 additions and 1 deletion.
diff --git a/DESCRIPTION b/DESCRIPTION
@@ -18,7 +18,8 @@ Encoding: UTF-8
 LazyData: true
 ByteCompile: true
 LinkingTo: 
-    Rcpp
+    Rcpp,
+    sfheaders
 Depends: R (>= 3.0.0)
 Imports: 
     Rcpp

diff --git a/R/RcppExports.R b/R/RcppExports.R
@@ -9,3 +9,7 @@ earcut_sfg <- function(sfg) {
     .Call(`_decido_earcut_sfg`, sfg)
 }
 
+earcut_sfc <- function(sfc) {
+    .Call(`_decido_earcut_sfc`, sfc)
+}
+
diff --git a/src/RcppExports.cpp b/src/RcppExports.cpp
@@ -30,10 +30,22 @@ BEGIN_RCPP
     return rcpp_result_gen;
 END_RCPP
 }
+// earcut_sfc
+SEXP earcut_sfc(Rcpp::List& sfc);
+RcppExport SEXP _decido_earcut_sfc(SEXP sfcSEXP) {
+BEGIN_RCPP
+    Rcpp::RObject rcpp_result_gen;
+    Rcpp::RNGScope rcpp_rngScope_gen;
+    Rcpp::traits::input_parameter< Rcpp::List& >::type sfc(sfcSEXP);
+    rcpp_result_gen = Rcpp::wrap(earcut_sfc(sfc));
+    return rcpp_result_gen;
+END_RCPP
+}
 
 static const R_CallMethodDef CallEntries[] = {
     {"_decido_earcut_cpp", (DL_FUNC) &_decido_earcut_cpp, 4},
     {"_decido_earcut_sfg", (DL_FUNC) &_decido_earcut_sfg, 1},
+    {"_decido_earcut_sfc", (DL_FUNC) &_decido_earcut_sfc, 1},
     {NULL, NULL, 0}
 };
 

diff --git a/src/decido.cpp b/src/decido.cpp
@@ -5,6 +5,11 @@ using namespace Rcpp;
 
 #include "decido/decido.hpp"
 
+
+#include "sfheaders/df/sfg.hpp"
+#include "sfheaders/sfg/multipolygon/sfg_multipolygon.hpp"
+#include "sfheaders/sfc/sfc.hpp"
+
 // [[Rcpp::export]]
 Rcpp::IntegerVector earcut_cpp(
     NumericVector x,
@@ -21,3 +26,53 @@ Rcpp::IntegerVector earcut_sfg( SEXP& sfg ) {
   return decido::api::earcut( sfg );
 }
 
+// [[Rcpp::export]]
+SEXP earcut_sfc( Rcpp::List& sfc ) {
+  // expecting an sfc objet
+
+  Rcpp::List attributes = sfheaders::sfc::get_sfc_attributes( sfc );
+
+  // TODO
+  // - cast to POLYGON
+  // - for each sfg
+  // - tringulate
+  // - convert to sfg_POLYGON
+  R_xlen_t i;
+  R_xlen_t n = sfc.length();
+  Rcpp::List res( n );
+  for( i = 0; i < n; ++i ) {
+    SEXP poly = sfc[ i ];
+    Rcpp::DataFrame df = sfheaders::df::sfg_to_df( poly );
+    Rcpp::IntegerVector indices = decido::api::earcut( poly );
+    R_xlen_t n_triangles = indices.length() / 3;
+
+    Rcpp::NumericVector x = df["x"];
+    Rcpp::NumericVector y = df["y"];
+    Rcpp::NumericVector xx = x[ indices ];
+    Rcpp::NumericVector yy = y[ indices ];
+
+    Rcpp::IntegerVector triangle_idx = Rcpp::seq(1, n_triangles );
+    Rcpp::IntegerVector triangle_ids = Rcpp::rep_each( triangle_idx, 3 );
+
+    Rcpp::DataFrame df_tri = Rcpp::DataFrame::create(
+      Rcpp::_["triangle_id"] = triangle_ids,
+      Rcpp::_["x"] = xx,
+      Rcpp::_["y"] = yy
+    );
+
+    Rcpp::StringVector geometry_cols {"x","y"};
+    Rcpp::String polygon_id = "triangle_id";
+    Rcpp::String line_id = polygon_id;
+
+    std::string xyzm = "XY";
+    bool close = false;
+
+    res[ i ] = sfheaders::sfg::sfg_multipolygon( df_tri, geometry_cols, polygon_id, line_id, xyzm, close );
+
+  }
+
+  sfheaders::sfc::attach_sfc_attributes( res, attributes );
+
+  return res;
+
+}