renderer refactor

examples/test_layout.py

@@ -0,0 +1,20 @@
+from rich import print
+from rich.console import Console
+
+from textual.geometry import Offset, Region
+from textual.widgets import Placeholder
+
+
+from textual.views import WindowView
+
+p = Placeholder(height=10)
+view = WindowView(p)
+
+console = Console()
+view.layout.reflow(console, 30, 25, Offset(0, 3))
+
+print(view.layout._layout_map.widgets)
+
+console.print(view.layout.render(console))
+
+# console.print(view.layout.render(console, Region(100, 2, 10, 10)))