terminal: resize page on unique style per cell

src/terminal/Screen.zig

@@ -646,9 +646,15 @@ pub fn clearCells(
             // Slow path: we need to lookup this style so we can decrement
             // the ref count. Since we've already loaded everything, we also
             // just go ahead and GC it if it reaches zero, too.
-            if (page.styles.lookupId(page.memory, cell.style_id)) |prev_style| {
+            if (page.styles.lookupId(
+                page.memory,
+                cell.style_id,
+            )) |prev_style| {
                 // Below upsert can't fail because it should already be present
-                const md = page.styles.upsert(page.memory, prev_style.*) catch unreachable;
+                const md = page.styles.upsert(
+                    page.memory,
+                    prev_style.*,
+                ) catch unreachable;
                 assert(md.ref > 0);
                 md.ref -= 1;
                 if (md.ref == 0) page.styles.remove(page.memory, cell.style_id);
@@ -962,7 +968,30 @@ pub fn manualStyleUpdate(self: *Screen) !void {
     // if that makes a meaningful difference. Our priority is to keep print
     // fast because setting a ton of styles that do nothing is uncommon
     // and weird.
-    const md = try page.styles.upsert(page.memory, self.cursor.style);
+    const md = page.styles.upsert(
+        page.memory,
+        self.cursor.style,
+    ) catch |err| switch (err) {
+        // Our style map is full. Let's allocate a new page by doubling
+        // the size and then try again.
+        error.OutOfMemory => md: {
+            const node = try self.pages.adjustCapacity(
+                self.cursor.page_pin.page,
+                .{ .styles = page.capacity.styles * 2 },
+            );
+
+            // Since this modifies our cursor page, we need to reload
+            self.cursorReload();
+
+            page = &node.data;
+            break :md try page.styles.upsert(
+                page.memory,
+                self.cursor.style,
+            );
+        },
+
+        error.Overflow => return err, // TODO
+    };
     self.cursor.style_id = md.id;
     self.cursor.style_ref = &md.ref;
 }

src/terminal/Terminal.zig

@@ -2264,6 +2264,24 @@ test "Terminal: input that forces scroll" {
     }
 }
 
+test "Terminal: input unique style per cell" {
+    const alloc = testing.allocator;
+    var t = try init(alloc, 30, 30);
+    defer t.deinit(alloc);
+
+    for (0..t.rows) |y| {
+        for (0..t.cols) |x| {
+            t.setCursorPos(y, x);
+            try t.setAttribute(.{ .direct_color_bg = .{
+                .r = @intCast(x),
+                .g = @intCast(y),
+                .b = 0,
+            } });
+            try t.print('x');
+        }
+    }
+}
+
 test "Terminal: zero-width character at start" {
     var t = try init(testing.allocator, 80, 80);
     defer t.deinit(testing.allocator);