LibWeb: Add array to keep track of grid boxes left to place

This structure will be useful to subtract from after placing different
boxes into the grid.

1 files changed, 43 insertions, 0 deletions

diff --git a/Userland/Libraries/LibWeb/Layout/GridFormattingContext.cpp b/Userland/Libraries/LibWeb/Layout/GridFormattingContext.cpp
index 33bb129fdc..4de50b0b84 100644
--- a/Userland/Libraries/LibWeb/Layout/GridFormattingContext.cpp
+++ b/Userland/Libraries/LibWeb/Layout/GridFormattingContext.cpp
@@ -35,10 +35,53 @@ void GridFormattingContext::run(Box const& box, LayoutMode)
         return false;
     };
 
+    // https://drafts.csswg.org/css-grid/#overview-placement
+    // 2.2. Placing Items
+    // The contents of the grid container are organized into individual grid items (analogous to
+    // flex items), which are then assigned to predefined areas in the grid. They can be explicitly
+    // placed using coordinates through the grid-placement properties or implicitly placed into
+    // empty areas using auto-placement.
+
     Vector<Vector<bool>> occupation_grid;
     Vector<bool> occupation_grid_row;
     for (int column_index = 0; column_index < max((int)box.computed_values().grid_template_columns().size(), 1); column_index++)
         occupation_grid_row.append(false);
     for (int row_index = 0; row_index < max((int)box.computed_values().grid_template_rows().size(), 1); row_index++)
         occupation_grid.append(occupation_grid_row);
+
+    Vector<Box const&> boxes_to_place;
+    box.for_each_child_of_type<Box>([&](Box& child_box) {
+        if (should_skip_is_anonymous_text_run(child_box))
+            return IterationDecision::Continue;
+        boxes_to_place.append(child_box);
+        return IterationDecision::Continue;
+    });
+
+    // https://drafts.csswg.org/css-grid/#auto-placement-algo
+    // 8.5. Grid Item Placement Algorithm
+
+    // 0. Generate anonymous grid items
+
+    // 1. Position anything that's not auto-positioned.
+
+    // 2. Process the items locked to a given row.
+
+    // 3. Determine the columns in the implicit grid.
+
+    // 3.1. Start with the columns from the explicit grid.
+
+    // 3.2. Among all the items with a definite column position (explicitly positioned items, items
+    // positioned in the previous step, and items not yet positioned but with a definite column) add
+    // columns to the beginning and end of the implicit grid as necessary to accommodate those items.
+    // NOTE: "Explicitly positioned items" and "items positioned in the previous step" done in step 1
+    // and 2, respectively. Adding columns for "items not yet positioned but with a definite column"
+    // will be done in step 4.
+
+    // 3.3. If the largest column span among all the items without a definite column position is larger
+    // than the width of the implicit grid, add columns to the end of the implicit grid to accommodate
+    // that column span.
+
+    // 4. Position the remaining grid items.
+    // For each grid item that hasn't been positioned by the previous steps, in order-modified document
+    // order:
 }