Add test_string_info()

r-lib · Jun 7, 2018 · 2906666 · 2906666
1 parent 34f9e53
commit 2906666
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Showing 3 changed files with 50 additions and 0 deletions.
diff --git a/R/RcppExports.R b/R/RcppExports.R
@@ -25,3 +25,7 @@ test_string_width <- function(string, font_size, font_file) {
     .Call(`_vdiffr_test_string_width`, string, font_size, font_file)
 }
 
+test_string_info <- function(string, font_size, font_file) {
+    .Call(`_vdiffr_test_string_info`, string, font_size, font_file)
+}
+
diff --git a/src/RcppExports.cpp b/src/RcppExports.cpp
@@ -85,6 +85,19 @@ BEGIN_RCPP
     return rcpp_result_gen;
 END_RCPP
 }
+// test_string_info
+SEXP test_string_info(SEXP string, SEXP font_size, SEXP font_file);
+RcppExport SEXP _vdiffr_test_string_info(SEXP stringSEXP, SEXP font_sizeSEXP, SEXP font_fileSEXP) {
+BEGIN_RCPP
+    Rcpp::RObject rcpp_result_gen;
+    Rcpp::RNGScope rcpp_rngScope_gen;
+    Rcpp::traits::input_parameter< SEXP >::type string(stringSEXP);
+    Rcpp::traits::input_parameter< SEXP >::type font_size(font_sizeSEXP);
+    Rcpp::traits::input_parameter< SEXP >::type font_file(font_fileSEXP);
+    rcpp_result_gen = Rcpp::wrap(test_string_info(string, font_size, font_file));
+    return rcpp_result_gen;
+END_RCPP
+}
 
 static const R_CallMethodDef CallEntries[] = {
     {"_vdiffr_compare_files", (DL_FUNC) &_vdiffr_compare_files, 2},
@@ -93,6 +106,7 @@ static const R_CallMethodDef CallEntries[] = {
     {"_vdiffr_get_svg_content", (DL_FUNC) &_vdiffr_get_svg_content, 1},
     {"_vdiffr_library_load", (DL_FUNC) &_vdiffr_library_load, 0},
     {"_vdiffr_test_string_width", (DL_FUNC) &_vdiffr_test_string_width, 3},
+    {"_vdiffr_test_string_info", (DL_FUNC) &_vdiffr_test_string_info, 3},
     {NULL, NULL, 0}
 };
 

diff --git a/src/utils.cpp b/src/utils.cpp
@@ -49,3 +49,35 @@ SEXP test_string_width(SEXP string, SEXP font_size, SEXP font_file) {
   UNPROTECT(n_protect);
   return info;
 }
+
+
+const char* string_info_names[] = {
+  "width", "height", "ascent", "descent", ""
+};
+
+// [[Rcpp::export]]
+SEXP test_string_info(SEXP string, SEXP font_size, SEXP font_file) {
+  int n_protect = validate_string_info_inputs(&string, &font_size, &font_file);
+
+  const char* text = Rf_translateCharUTF8(STRING_ELT(string, 0));
+  const char* font_path = CHAR(STRING_ELT(font_file, 0));
+  double size = REAL(font_size)[0];
+
+  struct fthb_string_info metrics;
+  int error = fthb_calc_string_info(text, font_path, size, &metrics);
+  if (error) {
+    Rf_errorcall(R_NilValue, "Couldn't compute textbox metrics: %d", error);
+  }
+
+  SEXP info = PROTECT(Rf_mkNamed(REALSXP, string_info_names));
+  ++n_protect;
+  double* info_ptr = REAL(info);
+
+  *info_ptr = metrics.width;
+  *(++info_ptr) = metrics.height;
+  *(++info_ptr) = metrics.ascent;
+  *(++info_ptr) = metrics.descent;
+
+  UNPROTECT(n_protect);
+  return info;
+}