r7024 - bigboard/trunk/bigboard

[commits mugshot org]

Author: hp
Date: 2007-12-11 15:46:09 -0600 (Tue, 11 Dec 2007)
New Revision: 7024

Added:
   bigboard/trunk/bigboard/scroll_ribbon.py
Log:
initial attempt at scroll ribbon canvas item in python

Added: bigboard/trunk/bigboard/scroll_ribbon.py
===================================================================
--- bigboard/trunk/bigboard/scroll_ribbon.py	2007-12-11 21:16:54 UTC (rev 7023)
+++ bigboard/trunk/bigboard/scroll_ribbon.py	2007-12-11 21:46:09 UTC (rev 7024)
@@ -0,0 +1,209 @@
+import copy
+import logging
+
+import gobject
+import hippo
+import layout_utils
+
+_logger = logging.getLogger("bigboard.ScrollRibbon")
+
+class ScrollRibbonLayout(gobject.GObject,hippo.CanvasLayout):
+    """A Canvas Layout manager that creates a scrollable area with buttons
+
+    """
+
+    def __init__(self):
+        gobject.GObject.__init__(self)
+        self.__box = None
+
+        self.__content_height = 0
+        self.__offset = 0
+
+        self.viewport = gtk.gdk.Rectangle(0, 0, 0, 0)
+
+    def scroll_by(self, increment):
+        self.__offset = self.__offset + increment
+        self.__box.emit_request_changed()
+
+    def __on_up_clicked(self, button):
+        self.scroll_by(-5)
+
+    def __on_down_clicked(self, button):
+        self.scroll_by(5)
+
+    def add(self, child):
+        if self.__box == None:
+            raise Exception("Layout must be set on a box before adding children")
+        
+        self.__box.append(child)
+        box_child = self.__box.find_box_child(child)
+        box_child.is_contents = True
+        box_child.x = 0
+        box_child.y = 0
+
+    def do_set_box(self, box):
+        self.__box = box
+
+        self.__up_button = hippo.CanvasButton(text="Up")
+        self.__down_button = hippo.CanvasButton(text="Down")
+
+        self.__box.append(self.__up_button)
+        self.__box.append(self.__down_button, flags=hippo.PACK_END)
+
+        box_child = self.__box.find_box_child(self.__up_button)
+        box_child.is_contents = False
+        box_child.x = 0
+        box_child.y = 0
+
+        box_child = self.__box.find_box_child(self.__down_button)
+        box_child.is_contents = False
+        box_child.x = 0
+        box_child.y = 0
+
+        self.__up_button.connect('activated', self.__on_up_clicked)
+        self.__down_button.connect('activated', self.__on_down_clicked)
+
+    def do_get_width_request(self):
+
+        content_min = 0
+        content_natural = 0
+
+        for box_child in self.__box.get_layout_children():
+
+            #_logger.debug("Width requesting child " + str(box_child))
+
+            (child_min, child_natural) = box_child.get_width_request()
+            
+            content_min = max(content_min, child_min)
+            content_natural = max(content_natural, child_natural)
+
+        return (content_min, content_natural)
+        
+    def __get_height_request(self, item, for_width):
+        box_child = self.__box.find_box_child(item)
+        return box_child.get_height_request(for_width)
+
+    def do_get_height_request(self, for_width):
+
+        (up_min, up_natural) = self.__get_height_request(self.__up_button, for_width)
+        (down_min, down_natural) = self.__get_height_request(self.__down_button, for_width)
+
+        MIN_CONTENT_HEIGHT = 5
+
+        self.__content_height = 0
+        for box_child in self.__box.get_layout_children():
+
+            #_logger.debug("Height requesting child " + str(box_child))
+
+            if not box_child.is_contents:
+                continue
+
+            (child_min, child_natural) = box_child.get_height_request(for_width)
+            self.__content_height = self.__content_height + child_natural
+
+        return (up_min + down_min + MIN_CONTENT_HEIGHT, up_natural + down_natural + MIN_CONTENT_HEIGHT)
+
+    def do_allocate(self, x, y, width, height, requested_width, requested_height, origin_changed):
+        (up_min, up_natural) = self.__get_height_request(self.__up_button, width)
+        (down_min, down_natural) = self.__get_height_request(self.__down_button, width)
+
+        box_child = self.__box.find_box_child(self.__up_button)
+        box_child.x = 0
+        box_child.y = 0
+        box_child.allocate(box_child.x, box_child.y, width, up_natural, origin_changed)
+
+        box_child = self.__box.find_box_child(self.__down_button)
+        box_child.x = 0
+        box_child.y = height - down_natural
+        box_child.allocate(box_child.x, box_child.y, width, down_natural, origin_changed)
+
+        self.viewport.x = 0
+        self.viewport.y = up_natural
+        self.viewport.width = width
+        self.viewport.height = height - down_natural - up_natural
+
+        ## this only works with a single child right now, despite the loop.
+        ## add a box, put stuff in the box, if you want two children.
+        for box_child in self.__box.get_layout_children():
+
+            #_logger.debug("Allocating child " + str(box_child))
+            
+            if box_child.is_contents:
+                (child_min, child_natural) = box_child.get_height_request(width)
+                
+                # min offset has bottom of child aligned with bottom of viewport, 
+                # but if there's too much space for child, child is always top-aligned
+                min_offset = self.viewport.height - child_natural
+                if min_offset > 0:
+                    min_offset = 0
+
+                # max offset has top of child aligned with top of viewport
+                max_offset = 0
+
+                offset = max(self.__offset, min_offset)
+                offset = min(offset, max_offset)
+
+                ## save this new offset
+                self.__offset = offset
+
+                # we always allocate the child its full height; then we 
+                # don't draw the parts outside the viewport
+                box_child.x = 0
+                box_child.y = self.viewport.y + self.__offset
+                box_child.allocate(box_child.x, box_child.y, width,
+                                   child_natural, origin_changed)
+
+
+gobject.type_register(ScrollRibbonLayout)
+
+
+class VerticalScrollArea(hippo.CanvasBox):
+    """A box with scroll arrows on top and bottom."""
+
+    def __init__(self, **kwargs):
+        hippo.CanvasBox.__init__(self, **kwargs)
+
+        self.__offset = 0
+
+        self.__layout = ScrollRibbonLayout()
+        self.set_layout(self.__layout)
+
+    def add(self, child):
+        self.__layout.add(child)
+
+    def do_paint_children(self, cr, damaged_box):
+        for box_child in self.get_layout_children():
+            if not box_child.visible:
+                continue
+            
+            if box_child.is_contents:
+                cr.save()
+                cr.rectangle(self.__layout.viewport.x,
+                             self.__layout.viewport.y,
+                             self.__layout.viewport.width, 
+                             self.__layout.viewport.height)
+                cr.clip()
+
+            box_child.item.process_paint(cr, damaged_box, box_child.x, box_child.y)
+
+            if box_child.is_contents:
+                cr.restore()
+
+gobject.type_register(VerticalScrollArea)
+
+if __name__ == "__main__":
+
+    import gtk
+    import bigboard.libbig.logutil
+
+    bigboard.libbig.logutil.init("DEBUG", ['bigboard.ScrollRibbon'], '')
+
+    window = hippo.CanvasWindow()
+    area = VerticalScrollArea()
+
+    area.add(hippo.CanvasText(text='A\nB\nC\nD\nE\nF\nG'))
+
+    window.set_root(area)
+    window.show()
+    
+    gtk.main()