actually, use both

Cargo.toml

@@ -17,4 +17,5 @@ keywords = ["ascii", "table"]
 colorful = "0.2"
 
 [dependencies]
+unicode-segmentation = "1.7.1"
 unicode-width = "0.1.8"

src/lib.rs

@@ -58,6 +58,7 @@ mod test;
 use std::collections::BTreeMap;
 use std::fmt::Display;
 
+use unicode_segmentation::UnicodeSegmentation;
 use unicode_width::UnicodeWidthStr;
 
 const SE: &str = "┌";
@@ -398,7 +399,8 @@ impl SmartString {
     fn char_len(&self) -> usize {
         self.fragments.iter()
             .filter(|(visible, _)| *visible)
-            .map(|(_, string)| UnicodeWidthStr::width(string.as_str()))
+            .map(|(_, string)| UnicodeSegmentation::graphemes(string.as_str(), true)
+                .map(|x| if UnicodeWidthStr::width(x) > 1 { 2 } else { 1 }).sum::<usize>())
             .sum()
     }
 

src/test.rs

@@ -335,12 +335,12 @@ fn show_one_character_for_header2() {
 #[test]
 fn cube_with_partial_content() {
     let config = cube_config();
-    let input: Vec<&[&str]> = vec![&["1", "2", "😞"], &["4", "5"], &["7"]];
+    let input: Vec<&[&str]> = vec![&["1", "2", "😞"], &["4", "5", "👩‍🔬"], &["7"]];
     let expected = "┌───┬───┬────┐\n\
                     │ a │ b │ c  │\n\
                     ├───┼───┼────┤\n\
                     │ 1 │ 2 │ 😞 │\n\
-                    │ 4 │ 5 │    │\n\
+                    │ 4 │ 5 │ 👩‍🔬 │\n\
                     │ 7 │   │    │\n\
                     └───┴───┴────┘\n";