From 916a11446e79744f8f095f5ef2e4d542d0853cba Mon Sep 17 00:00:00 2001
From: Arjan Molenaar <gaphor@gmail.com>
Date: Fri, 22 May 2020 22:42:43 +0200
Subject: [PATCH] Let BoundingBoxPainter compose with ItemPainter

Instead of inheriting from it.
---
 README.md         |  2 +-
 examples/demo.py  |  2 +-
 gaphas/painter.py | 28 ++++++++++++++++++----------
 gaphas/view.py    |  4 ++--
 4 files changed, 22 insertions(+), 14 deletions(-)

diff --git a/README.md b/README.md
index a60aa8f..643377f 100644
--- a/README.md
+++ b/README.md
@@ -428,7 +428,7 @@ cairo = CairoBoundingBoxContext(cairo)
 A type of ItemPainter which is used to calculate the bounding boxes (in canvas coordinates) for the items.
 
 ```python
-view.bounding_box_painter = BoundingBoxPainter()
+view.bounding_box_painter = BoundingBoxPainter(ItemPainter())
 ```
 
 #### Class: `gaphas.painter.HandlePainter`
diff --git a/examples/demo.py b/examples/demo.py
index 365323d..0a61940 100755
--- a/examples/demo.py
+++ b/examples/demo.py
@@ -120,7 +120,7 @@ def create_window(canvas, title, zoom=1.0):
         .append(FocusedItemPainter())
         .append(ToolPainter())
     )
-    view.bounding_box_painter = FreeHandPainter(BoundingBoxPainter())
+    view.bounding_box_painter = FreeHandPainter(BoundingBoxPainter(ItemPainter()))
     w = Gtk.Window()
     w.set_title(title)
     w.set_default_size(400, 120)
diff --git a/gaphas/painter.py b/gaphas/painter.py
index b020820..9c75c89 100644
--- a/gaphas/painter.py
+++ b/gaphas/painter.py
@@ -86,7 +86,7 @@ class DrawContext(Context):
 
 
 class ItemPainter(Painter):
-    def _draw_item(self, item, cairo, area=None):
+    def draw_item(self, item, cairo, area=None):
         view = self.view
         cairo.save()
         try:
@@ -109,12 +109,12 @@ class ItemPainter(Painter):
         finally:
             cairo.restore()
 
-    def _draw_items(self, items, cairo, area=None):
+    def draw_items(self, items, cairo, area=None):
         """
         Draw the items.
         """
         for item in items:
-            self._draw_item(item, cairo, area=area)
+            self.draw_item(item, cairo, area=area)
             if DEBUG_DRAW_BOUNDING_BOX:
                 self._draw_bounds(item, cairo)
 
@@ -137,7 +137,7 @@ class ItemPainter(Painter):
         cairo = context.cairo
         cairo.set_tolerance(TOLERANCE)
         cairo.set_line_join(LINE_JOIN_ROUND)
-        self._draw_items(context.items, cairo, context.area)
+        self.draw_items(context.items, cairo, context.area)
 
 
 class CairoBoundingBoxContext:
@@ -236,15 +236,23 @@ class CairoBoundingBoxContext:
         cr.show_text(utf8)
 
 
-class BoundingBoxPainter(ItemPainter):
+class BoundingBoxPainter(Painter):
     """
     This specific case of an ItemPainter is used to calculate the
     bounding boxes (in canvas coordinates) for the items.
     """
 
-    def _draw_item(self, item, cairo, area=None):
+    def __init__(self, item_painter, view=None):
+        super().__init__(view)
+        self.item_painter = item_painter
+
+    def set_view(self, view):
+        super().set_view(view)
+        self.item_painter.set_view(view)
+
+    def draw_item(self, item, cairo, area=None):
         cairo = CairoBoundingBoxContext(cairo)
-        super()._draw_item(item, cairo)
+        self.item_painter.draw_item(item, cairo)
         bounds = cairo.get_bounds()
 
         # Update bounding box with handles.
@@ -257,15 +265,15 @@ class BoundingBoxPainter(ItemPainter):
         bounds.expand(1)
         view.set_item_bounding_box(item, bounds)
 
-    def _draw_items(self, items, cairo, area=None):
+    def draw_items(self, items, cairo, area=None):
         """
         Draw the items.
         """
         for item in items:
-            self._draw_item(item, cairo)
+            self.draw_item(item, cairo)
 
     def paint(self, context):
-        self._draw_items(context.items, context.cairo)
+        self.draw_items(context.items, context.cairo)
 
 
 class HandlePainter(Painter):
diff --git a/gaphas/view.py b/gaphas/view.py
index 87b7b9c..0b2367a 100644
--- a/gaphas/view.py
+++ b/gaphas/view.py
@@ -7,7 +7,7 @@ from gi.repository import Gdk, GLib, GObject, Gtk
 from gaphas.canvas import Context, instant_cairo_context
 from gaphas.decorators import AsyncIO, nonrecursive
 from gaphas.geometry import Rectangle, distance_point_point_fast
-from gaphas.painter import BoundingBoxPainter, DefaultPainter
+from gaphas.painter import BoundingBoxPainter, DefaultPainter, ItemPainter
 from gaphas.quadtree import Quadtree
 from gaphas.tool import DefaultTool
 
@@ -27,7 +27,7 @@ class View:
     def __init__(self, canvas=None):
         self._matrix = cairo.Matrix()
         self._painter = DefaultPainter(self)
-        self._bounding_box_painter = BoundingBoxPainter(self)
+        self._bounding_box_painter = BoundingBoxPainter(ItemPainter(self), self)
 
         # Handling selections.
         # TODO: Move this to a context?