terminal/kitty: support cells with no diacritics

src/terminal/kitty/graphics_unicode.zig

@@ -31,14 +31,17 @@ pub const PlacementIterator = struct {
 
     pub fn next(self: *PlacementIterator) ?Placement {
         while (self.row) |*row| {
+            // This row flag is set on rows that have the virtual placeholder
+            if (!row.rowAndCell().row.kitty_virtual_placeholder) {
+                self.row = self.row_it.next();
+                continue;
+            }
+
             // Our current run. A run is always only a single row. This
             // assumption is built-in to our logic so if we want to change
             // this later we have to redo the logic; tests should cover;
             var run: ?IncompletePlacement = null;
 
-            // A row must have graphemes to possibly have virtual placements
-            // since virtual placements are done via diacritics.
-            if (row.rowAndCell().row.grapheme) {
             // Iterate over our remaining cells and find one with a placeholder.
             const cells = row.cells(.right);
             for (cells, row.x..) |*cell, x| {
@@ -56,10 +59,6 @@ pub const PlacementIterator = struct {
                     continue;
                 }
 
-                    // TODO: we need to support non-grapheme cells that just
-                    // do continuations all the way through.
-                    assert(cell.hasGrapheme());
-
                 // If we don't have a previous run, then we save this
                 // incomplete one, start a run, and move on.
                 const curr = IncompletePlacement.init(row, cell);
@@ -84,7 +83,6 @@ pub const PlacementIterator = struct {
                     run = prev;
                 }
             }
-            }
 
             // We move to the next row no matter what
             self.row = self.row_it.next();
@@ -730,6 +728,33 @@ test "unicode placement: continuation with no col" {
     try testing.expect(it.next() == null);
 }
 
+test "unicode placement: continuation with no diacritics" {
+    const alloc = testing.allocator;
+    var t = try terminal.Terminal.init(alloc, .{ .rows = 5, .cols = 10 });
+    defer t.deinit(alloc);
+    t.modes.set(.grapheme_cluster, true);
+
+    // Three cells. They'll continue even though they're explicit
+    try t.printString("\u{10EEEE}");
+    try t.printString("\u{10EEEE}");
+    try t.printString("\u{10EEEE}");
+
+    // Get our top left pin
+    const pin = t.screen.pages.getTopLeft(.viewport);
+
+    // Should have exactly one placement
+    var it = placementIterator(pin, null);
+    {
+        const p = it.next().?;
+        try testing.expectEqual(0, p.image_id);
+        try testing.expectEqual(0, p.placement_id);
+        try testing.expectEqual(0, p.row);
+        try testing.expectEqual(0, p.col);
+        try testing.expectEqual(3, p.width);
+    }
+    try testing.expect(it.next() == null);
+}
+
 test "unicode placement: run ending" {
     const alloc = testing.allocator;
     var t = try terminal.Terminal.init(alloc, .{ .rows = 5, .cols = 10 });