From 2d600887c7612aff5be84e0b50b2df02c1fe3bf3 Mon Sep 17 00:00:00 2001
From: Manuel Quiñones <manuq@laptop.org>
Date: Mon, 26 Mar 2012 07:07:45 +0000
Subject: Read and write image and metadata (stroke width for now)

Signed-off-by: Manuel Quiñones <manuq@laptop.org>
---
diff --git a/drawing.py b/drawing.py
index 3e73f6f..a77f795 100644
--- a/drawing.py
+++ b/drawing.py
@@ -20,6 +20,7 @@ from gettext import gettext as _
 import logging
 
 import gtk
+import gobject
 import cairo
 
 
@@ -28,6 +29,11 @@ STROKE_MAX_POINTS = 80
 
 
 class Drawing(gtk.DrawingArea):
+    __gsignals__ = {'width-changed': (gobject.SIGNAL_RUN_FIRST,
+                                      gobject.TYPE_NONE,
+                                      (gobject.TYPE_INT,)),
+                    }
+
     def __init__(self, parent):
         super(Drawing, self).__init__()
 
@@ -63,15 +69,16 @@ class Drawing(gtk.DrawingArea):
         self.connect("motion-notify-event", self._motion_cb)
         self.connect("button-release-event", self._release_cb)
 
-    def setup(self, width, height):
+    def setup(self, width, height, clear=True):
         """Setup a blank canvas of specified size."""
         logging.debug("drawing set up")
-        self._drawing_canvas = cairo.ImageSurface(cairo.FORMAT_ARGB32,
-                                                  width, height)
-        context = cairo.Context(self._drawing_canvas)
-        context.rectangle(0, 0, width, height)
-        context.set_source_rgb(1.0, 1.0, 1.0)
-        context.fill()
+        if clear:
+            self._drawing_canvas = cairo.ImageSurface(cairo.FORMAT_ARGB32,
+                                                      width, height)
+            context = cairo.Context(self._drawing_canvas)
+            context.rectangle(0, 0, width, height)
+            context.set_source_rgb(1.0, 1.0, 1.0)
+            context.fill()
         self.queue_draw()
 
     def set_sharing(self, share=True):
@@ -93,6 +100,7 @@ class Drawing(gtk.DrawingArea):
 
     def set_stroke_width(self, width):
         self._settings['stroke width'] = width
+        self.emit('width-changed', width)
 
     def get_stroke_width(self):
         return self._settings['stroke width']
@@ -184,3 +192,14 @@ class Drawing(gtk.DrawingArea):
         # Get context from widget and paint:
         self._set_stroke_context(context)
         self._paint_stroke(context, self._stroke_points)
+
+    def load_png(self, file_path):
+        logging.debug("reading from png")
+        self._drawing_canvas = cairo.ImageSurface.create_from_png(file_path)
+        self.setup(self._drawing_canvas.get_width(),
+                   self._drawing_canvas.get_height(),
+                   clear=False)
+
+    def save_png(self, file_path):
+        logging.debug("writing to png")
+        self._drawing_canvas.write_to_png(file_path)
diff --git a/paintwithme.py b/paintwithme.py
index 6052cba..3a3f568 100644
--- a/paintwithme.py
+++ b/paintwithme.py
@@ -18,6 +18,7 @@
 
 from gettext import gettext as _
 import logging
+import json
 
 from sugar.activity import activity
 
@@ -29,6 +30,7 @@ from sugar.presence.tubeconn import TubeConnection
 
 from toolbar import PaintToolbar
 from drawing import Drawing
+# FIXME use json from standard lib
 from utils import json_load, json_dump
 
 
@@ -66,6 +68,26 @@ class PaintWithMeActivity(activity.Activity):
         self._setup_handle = self.canvas.connect('size_allocate',
                                                  size_allocate_cb)
 
+    def read_file(self, file_path):
+        """Read from Sugar Journal."""
+        self._drawing.load_png(file_path)
+
+        state = json.loads(self.metadata['state'])
+        logging.debug("read_file")
+        logging.debug(state)
+        self._drawing.set_stroke_width(state['width'])
+
+    def write_file(self, file_path):
+        """Write to Sugar Journal."""
+        self.metadata['mime_type'] = 'image/png'
+        self._drawing.save_png(file_path)
+
+        state = {}
+        state['width'] = self._drawing.get_stroke_width()
+        self.metadata['state'] = json.dumps(state)
+        logging.debug("write_file")
+        logging.debug(state)
+
     # Collaboration-related methods below:
 
     def _setup_presence_service(self):
diff --git a/toolbar.py b/toolbar.py
index dfb3a82..8490ef5 100644
--- a/toolbar.py
+++ b/toolbar.py
@@ -80,11 +80,18 @@ class PaintToolbar(ToolbarBox):
 
     def set_drawing(self, drawing):
         self._drawing = drawing
+        self._drawing.connect('width-changed', self._width_changed_cb)
         self._update_buttons()
 
+    def _update_width_spin(self, width):
+        self._width_spin.props.value = width
+
     def _update_buttons(self):
         width = self._drawing.get_stroke_width()
-        self._width_spin.props.value = width
+        self._update_width_spin(width)
+
+    def _width_changed_cb(self, widget, width):
+        self._update_width_spin(width)
 
     def _width_spin_cb(self, width_spin):
         width = width_spin.get_value_as_int()
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