""" This guy manages drawing of overlayed widgets. The class responsible for drawing management (Overlayer) and overlayable widgets are defined here. """ # Copyright (C) 2009, Tutorius.org # # This program is free software; you can redistribute it and/or modify # it under the terms of the GNU General Public License as published by # the Free Software Foundation; either version 2 of the License, or # (at your option) any later version. # # This program is distributed in the hope that it will be useful, # but WITHOUT ANY WARRANTY; without even the implied warranty of # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the # GNU General Public License for more details. # # You should have received a copy of the GNU General Public License # along with this program; if not, write to the Free Software # Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA import gobject import gtk import cairo import pangocairo class CanvasDrawable(object): """Defines the CanvasDrawable protocol""" should_expose = None def drawWithContext(self, context): pass class Overlayer(gtk.Layout): """ This guy manages drawing of overlayed widgets. Those can be standard GTK widgets or special "cairoDrawable" widgets which support the defined interface (see the put method). """ def __init__(self): gtk.Layout.__init__(self) # no overlayed child yet self.__overlayed = None ## win.connect("expose-event", self.__transparent_overlay) self.__realizer = self.connect("expose-event", self.__init_realized) self.connect("size-allocate", self.__size_allocate) self.show() ## win.show_all() ## win.connect_after("expose-event", self.__expose_overlay) def reparent(self, parent): """Reparent this widget as child of parent instead.""" self.__realizer = self.connect("expose-event", self.__init_realized) gtk.Layout.reparent(self, parent) def inject(self, child): """ Insert this widget at "child" level so that it can overlay "child". """ assert not self.__overlayed, "trying to reinject while already injected" parent = child.parent self.__overlayed = child child.reparent(self) parent.add(self) self.__realizer = parent.connect("expose-event", self.__init_realized) def put(self, child, x, y): """ Adds a child widget to be overlayed. This can be, overlay widgets or normal GTK widgets (though normal widgets will alwas appear under cairo widgets due to the rendering chain). """ if hasattr(child, "should_expose"): # if the widget has the CanvasDrawable protocol, use it. # protocol is defined as # should_expose property with setter to flag as not drawn using # expose-events # drawWithContext(context) method to pass a context to draw with. child.should_expose = True gtk.Layout.put(self, child, x, y) def eject(self): """ Remove this widget from the widget hierarchy without affecting its children. """ parent = self.parent parent.disconnect(self.__render_handle) assert hasattr(parent, "remove"), "parent should be a container" self.parent.remove(self) self.__overlayed.reparent(parent) self.__overlayed = None def __init_realized(self, widget, event): """ Initializer to set once widget is realized. Since an expose event is signaled only to realized widgets, we set this callback for the first expose run. It should also be called after beign reparented to ensure the window used for drawing is set up. """ assert hasattr(self.window, "set_composited"), \ "compositing not supported or widget not realized." self.disconnect(self.__realizer) del self.__realizer # use RGBA on overlayer so that when we paint we don't cover what's # under screen = self.get_screen() rgba_map = screen.get_rgba_colormap() self.set_colormap(rgba_map) # will fail if already realized # app paintable will ensure that what we draw isn't erased by gtk self.parent.set_app_paintable(True) # the parent is composited, so we can access gtk's rendered buffer # and overlay over. If we don't composite, we won't be able to read # pixels and background will be black. self.window.set_composited(True) self.__render_handle = self.parent.connect_after("expose-event", \ self.__expose_overlay) def __expose_overlay(self, widget, event): """expose event handler to draw the thing.""" #get our child (in this case, the event box) child = widget.get_child() #create a cairo context to draw to the window ctx = widget.window.cairo_create() #the source data is the (composited) event box ctx.set_source_pixmap(child.window, child.allocation.x, child.allocation.y) #draw no more than our expose event intersects our child ## region = gtk.gdk.region_rectangle(child.allocation) ## rect = gtk.gdk.region_rectangle(event.area) ## region.intersect(rect) ## ctx.region (region) ## ctx.clip() ctx.set_operator(cairo.OPERATOR_OVER) # has to be blended and a 1.0 alpha would not make it blend ctx.paint_with_alpha(0.99) #draw overlay for drawn_child in self.get_children(): if hasattr(drawn_child, "drawWithContext"): drawn_child.drawWithContext(ctx) def __size_allocate(self, widget, allocation): """set size allocation (actual gtk widget size) and propagate it to overlayed child""" self.allocation = allocation # One may wonder why using size_request instead of size_allocate; # Since widget is laid out in a Layout box, the Layout will honor the # requested size. Using size_allocate could make a nasty nested loop in # some cases. self.__overlayed.set_size_request(allocation.width, allocation.height) class TextBubble(gtk.Widget): def __init__(self, text, speaker=None, tailpos=None): """ Creates a new cairo rendered text bubble. @param text the text to render in the bubble @param speaker the widget to associate with the bubble tail @param tailpos an optional position for the tail if no speaker """ gtk.Widget.__init__(self) ##self.set_app_paintable(True) # else may be blank # FIXME ensure previous call does not interfere with widget stacking self.label = text self.speaker = speaker self.tailpos = tailpos self.lineWidth = 5 self.connect("expose-event", self.__on_expose) def drawWithContext(self, context): """ Draw using the passed cairo context instead of creating a new cairo context. This eases blending between multiple cairo-rendered widgets. """ context.translate(self.allocation.x, self.allocation.y) width = self.allocation.width height = self.allocation.height xradius = width/2 yradius = height/2 width -= self.lineWidth height -= self.lineWidth # TODO fetch speaker coordinates # draw bubble tail if self.tailpos: ## speaker_alloc = self.speaker.get_allocation() context.move_to(xradius-40, yradius) context.line_to(self.tailpos[0], self.tailpos[1]) ## context.line_to(speaker_alloc.x-self.allocation.x, ## speaker_alloc.y - self.allocation.y) context.line_to(xradius+40, yradius) context.set_source_rgb(1.0, 1.0, 0.0) context.fill_preserve() context.set_line_width(self.lineWidth) context.set_source_rgb(0.0, 0.0, 0.0) context.stroke() # bubble context.move_to(self.lineWidth, yradius) context.curve_to(self.lineWidth, self.lineWidth, self.lineWidth, self.lineWidth, xradius, self.lineWidth) context.curve_to(width, self.lineWidth, width, self.lineWidth, width, yradius) context.curve_to(width, height, width, height, xradius, height) context.curve_to(self.lineWidth, height, self.lineWidth, height, self.lineWidth, yradius) context.set_source_rgb(1.0, 1.0, 0.0) context.fill_preserve() context.set_line_width(self.lineWidth) context.set_source_rgb(0.0, 0.0, 0.0) context.stroke() # text # FIXME create layout in realize method pangoctx = pangocairo.CairoContext(context) text_layout = pangoctx.create_layout() text_layout.set_text(self.__label) pangoctx.move_to(int((self.allocation.width-self.__text_dimentions[0])/2), int((self.allocation.height-self.__text_dimentions[1])/2)) pangoctx.show_layout(text_layout) # work done. Be kind to next cairo widgets and reset matrix. context.identity_matrix() def do_realize(self): self.set_flags(gtk.REALIZED | gtk.NO_WINDOW) self.window = self.get_parent_window() def __on_expose(self, widget, event): """Redraw event callback.""" # TODO ctx = self.window.cairo_create() # set drawing region. Useless since this widget has its own window. ## region = gtk.gdk.region_rectangle(self.allocation) ## region.intersect(gtk.gdk.region_rectangle(event.area)) ## ctx.region(region) ## ctx.rectangle(event.area.x, event.area.y, event.area.width, event.area.height) ## ctx.clip() ##import pdb; pdb.set_trace() ##ctx.set_operator(cairo.OPERATOR_CLEAR) ##ctx.paint() ##ctx.set_operator(cairo.OPERATOR_OVER) self.drawWithContext(ctx) return True def _set_label(self, value): """Sets the label and flags the widget to be redrawn.""" # yes we use the setter self.__label = value # FIXME hack to calculate size. necessary because may not have been # realized surf = cairo.SVGSurface("/dev/null", 0, 0) ctx = cairo.Context(surf) pangoctx = pangocairo.CairoContext(ctx) text_layout = pangoctx.create_layout() text_layout.set_text(value) self.__text_dimentions = text_layout.get_pixel_size() del text_layout, pangoctx, ctx, surf def do_size_request(self, requisition): width, height = self.__text_dimentions # FIXME bogus values follows requisition.width = int(width+30) requisition.height = int(height+40) def do_size_allocate(self, allocation): self.allocation = allocation def _get_label(self): """Getter method for the label property""" return self.__label def _set_will_expose(self, value): """setter for will_expose property""" if self.__exposer and not value: self.disconnect(self.__exposer) elif not (self.__exposer or value): self.__exposer = self.connect(self.__on_expose) should_expose = property(fset=_set_will_expose) label = property(fget=_get_label, fset=_set_label,\ doc="Text label which is to be painted on the top of the widget") gobject.type_register(TextBubble) # vim:set ts=4 sts=4 sw=4 et: