1 files changed, 32 insertions, 23 deletions

diff --git a/src/DisplayWidth.zig b/src/DisplayWidth.zig
index d15dbae..dee7ebd 100644
--- a/src/DisplayWidth.zig
+++ b/src/DisplayWidth.zig
@@ -100,6 +100,34 @@ test "codePointWidth" {
     try testing.expectEqual(@as(i4, 2), dw.codePointWidth('统'));
 }
 
+/// graphemeClusterWidth returns the total display width of `gc` as the number
+/// of cells required in a fixed-pitch font (i.e. a terminal screen).
+/// `gc` is a slice corresponding to one grapheme cluster.
+pub fn graphemeClusterWidth(dw: DisplayWidth, gc: []const u8) isize {
+    var cp_iter = CodePointIterator{ .bytes = gc };
+    var gc_total: isize = 0;
+
+    while (cp_iter.next()) |cp| {
+        var w = dw.codePointWidth(cp.code);
+
+        if (w != 0) {
+            // Handle text emoji sequence.
+            if (cp_iter.next()) |ncp| {
+                // emoji text sequence.
+                if (ncp.code == 0xFE0E) w = 1;
+                if (ncp.code == 0xFE0F) w = 2;
+                // Skin tones
+                if (0x1F3FB <= ncp.code and ncp.code <= 0x1F3FF) w = 2;
+            }
+
+            // Only adding width of first non-zero-width code point.
+            gc_total = w;
+            break;
+        }
+    }
+    return gc_total;
+}
+
 /// strWidth returns the total display width of `str` as the number of cells
 /// required in a fixed-pitch font (i.e. a terminal screen).
 pub fn strWidth(dw: DisplayWidth, str: []const u8) usize {
@@ -114,29 +142,7 @@ pub fn strWidth(dw: DisplayWidth, str: []const u8) usize {
     var giter = dw.graphemes.iterator(str);
 
     while (giter.next()) |gc| {
-        var cp_iter = CodePointIterator{ .bytes = gc.bytes(str) };
-        var gc_total: isize = 0;
-
-        while (cp_iter.next()) |cp| {
-            var w = dw.codePointWidth(cp.code);
-
-            if (w != 0) {
-                // Handle text emoji sequence.
-                if (cp_iter.next()) |ncp| {
-                    // emoji text sequence.
-                    if (ncp.code == 0xFE0E) w = 1;
-                    if (ncp.code == 0xFE0F) w = 2;
-                }
-
-                // Only adding width of first non-zero-width code point.
-                if (gc_total == 0) {
-                    gc_total = w;
-                    break;
-                }
-            }
-        }
-
-        total += gc_total;
+        total += dw.graphemeClusterWidth(gc.bytes(str));
     }
 
     return @intCast(@max(0, total));
@@ -201,6 +207,9 @@ test "strWidth" {
     try testing.expectEqual(@as(usize, 9), dw.strWidth("Ẓ̌á̲l͔̝̞̄̑͌g̖̘̘̔̔͢͞͝o̪̔T̢̙̫̈̍͞e̬͈͕͌̏͑x̺̍ṭ̓̓ͅ"));
     try testing.expectEqual(@as(usize, 17), dw.strWidth("슬라바 우크라이나"));
     try testing.expectEqual(@as(usize, 1), dw.strWidth("\u{378}"));
+
+    // https://codeberg.org/atman/zg/issues/82
+    try testing.expectEqual(@as(usize, 12), dw.strWidth("✍️✍🏻✍🏼✍🏽✍🏾✍🏿"));
 }
 
 /// centers `str` in a new string of width `total_width` (in display cells) using `pad` as padding.