Add the FixedDimensionPanel

This renders a single child (you'd likely want that child to be a Vertical or Horizontal Stack Panel) with constrained dimensions.

For example to achieve a fixed two column 50/50 display you could have a layout of;
Root
 - Horizontal Stack
   - Fixed Dimension (50% display width)
     - Vertical Stack
       - Text, Display, etc...
   - Fixed Dimension (50% display width)
     - Vertical Stack
       - More elements...

esphome/components/graphical_layout/__init__.py

@@ -6,6 +6,7 @@ from . import horizontal_stack
 from . import vertical_stack
 from . import text_panel
 from . import display_rendering_panel
+from . import fixed_dimension_panel
 
 graphical_layout_ns = cg.esphome_ns.namespace("graphical_layout")
 RootLayoutComponent = graphical_layout_ns.class_("RootLayoutComponent", cg.Component)
@@ -51,6 +52,9 @@ ITEM_TYPE_SCHEMA = cv.typed_schema(
         display_rendering_panel.CONF_DISPLAY_RENDERING_PANEL: display_rendering_panel.get_config_schema(
             BASE_ITEM_SCHEMA, item_type_schema
         ),
+        fixed_dimension_panel.CONF_FIXED_DIMENSION_PANEL: fixed_dimension_panel.get_config_schema(
+            BASE_ITEM_SCHEMA, item_type_schema
+        ),
     }
 )
 
@@ -59,6 +63,7 @@ CODE_GENERATORS = {
     horizontal_stack.CONF_HORIZONTAL_STACK: horizontal_stack.config_to_layout_item,
     vertical_stack.CONF_VERTICAL_STACK: vertical_stack.config_to_layout_item,
     display_rendering_panel.CONF_DISPLAY_RENDERING_PANEL: display_rendering_panel.config_to_layout_item,
+    fixed_dimension_panel.CONF_FIXED_DIMENSION_PANEL: fixed_dimension_panel.config_to_layout_item,
 }
 
 CONFIG_SCHEMA = cv.Schema(
@@ -100,6 +105,7 @@ async def to_code(config):
         )
         cg.add(var.set_layout_root(layout_var))
     else:
-        raise f"Do not know how to build type {layout_type}"
+        err = f"Do not know how to build type {layout_type}"
+        raise RuntimeError(f"Do not know how to build type {layout_type}")
 
     cg.add_define("USE_GRAPHICAL_LAYOUT")

esphome/components/graphical_layout/fixed_dimension_panel.cpp

@@ -0,0 +1,34 @@
+#include "fixed_dimension_panel.h"
+
+#include "esphome/components/display/display.h"
+#include "esphome/components/display/rect.h"
+#include "esphome/core/log.h"
+
+namespace esphome {
+namespace graphical_layout {
+
+static const char *const TAG = "fixeddimensionpanel";
+
+void FixedDimensionPanel::dump_config(int indent_depth, int additional_level_depth) {
+  ESP_LOGCONFIG(TAG, "%*sWidth: %i (Will use display width: %s)", indent_depth, "", this->width_.value(), YESNO(this->width_.value() < 1));
+  ESP_LOGCONFIG(TAG, "%*sHeight: %i (Will use display height: %s)", indent_depth, "", this->height_.value(), YESNO(this->height_.value() < 1));
+  this->child_->dump_config(indent_depth + additional_level_depth, additional_level_depth);
+}
+
+display::Rect FixedDimensionPanel::measure_item_internal(display::Display *display) {
+  display::Rect rect(0, 0, this->width_.value(), this->height_.value());
+  if (rect.w < 1) {
+    rect.w = display->get_width();
+  }
+  if (rect.h < 1) {
+    rect.h = display->get_height();
+  }
+  return rect;
+}
+
+void FixedDimensionPanel::render_internal(display::Display *display, display::Rect bounds) {
+  this->child_->render_internal(display, bounds);
+}
+
+}  // namespace graphical_layout
+}  // namespace esphome

esphome/components/graphical_layout/fixed_dimension_panel.h

@@ -0,0 +1,28 @@
+#pragma once
+
+#include "esphome/components/graphical_layout/graphical_layout.h"
+#include "esphome/core/automation.h"
+
+namespace esphome {
+namespace graphical_layout {
+
+/** The FixedDimensionPanel is a UI element which will render a single child with constrained dimensions
+ */
+class FixedDimensionPanel : public LayoutItem {
+ public:
+  display::Rect measure_item_internal(display::Display *display) override;
+  void render_internal(display::Display *display, display::Rect bounds) override;
+  void dump_config(int indent_depth, int additional_level_depth) override;
+
+  void set_child(LayoutItem *child) { this->child_ = child; };
+  template<typename V> void set_width(V width) { this->width_ = width; };
+  template<typename V> void set_height(V height) { this->height_ = height; }
+
+ protected:
+  LayoutItem *child_{nullptr};
+  TemplatableValue<int> width_{0};
+  TemplatableValue<int> height_{0};
+};
+
+}  // namespace graphical_layout
+}  // namespace esphome

esphome/components/graphical_layout/fixed_dimension_panel.py

@@ -0,0 +1,46 @@
+import esphome.codegen as cg
+import esphome.config_validation as cv
+from esphome.const import CONF_TYPE, CONF_WIDTH, CONF_HEIGHT
+
+graphical_layout_ns = cg.esphome_ns.namespace("graphical_layout")
+FixedDimensionPanel = graphical_layout_ns.class_("FixedDimensionPanel")
+
+CONF_ITEM_PADDING = "item_padding"
+CONF_FIXED_DIMENSION_PANEL = "fixed_dimension_panel"
+CONF_CHILD = "child"
+
+
+def get_config_schema(base_item_schema, item_type_schema):
+    return base_item_schema.extend(
+        {
+            cv.GenerateID(): cv.declare_id(FixedDimensionPanel),
+            cv.Optional(CONF_ITEM_PADDING, default=0): cv.int_,
+            cv.Required(CONF_CHILD): item_type_schema,
+            cv.Optional(CONF_WIDTH, default=-1): cv.templatable(cv.int_range(min=-1)),
+            cv.Optional(CONF_HEIGHT, default=-1): cv.templatable(cv.int_range(min=-1)),
+        }
+    )
+
+
+async def config_to_layout_item(pvariable_builder, item_config, child_item_builder):
+    var = await pvariable_builder(item_config)
+
+    width = await cg.templatable(item_config[CONF_WIDTH], args=[], output_type=cg.int_)
+    cg.add(var.set_width(width))
+
+    height = await cg.templatable(
+        item_config[CONF_HEIGHT], args=[], output_type=cg.int_
+    )
+    cg.add(var.set_height(height))
+
+    child_item_config = item_config[CONF_CHILD]
+    child_item_type = child_item_config[CONF_TYPE]
+    if child_item_type in child_item_builder:
+        child_item_var = await child_item_builder[child_item_type](
+            pvariable_builder, child_item_config, child_item_builder
+        )
+        cg.add(var.set_child(child_item_var))
+    else:
+        raise f"Do not know how to build type {child_item_type}"
+
+    return var