""" 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""" # no_expose = None # def draw_with_context(self, context): # """ # Draws the cairo widget with the passed cairo context. # This will be called if the widget is child of an overlayer. # """ # 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 self.__realizer = self.connect("expose-event", self.__init_realized) self.connect("size-allocate", self.__size_allocate) self.show() self.__render_handle = None 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). @param child the child to add @param x the horizontal coordinate for positionning @param y the vertical coordinate for positionning """ if hasattr(child, "no_expose"): # if the widget has the CanvasDrawable protocol, use it. child.no_expose = True gtk.Layout.put(self, child, x, y) 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, "draw_with_context"): drawn_child.draw_with_context(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): """ A CanvasDrawableWidget drawing a round textbox and a tail pointing to a specified 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 compute the tail position from @param tailpos (optional) position relative to the bubble to use as the tail position, 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 = None self.__text_dimentions = None self.__exposer = None # refer to expose event handler self.label = text self.speaker = speaker self.tailpos = tailpos self.line_width = 5 self.connect("expose-event", self.__on_expose) def draw_with_context(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.line_width height -= self.line_width # bubble border context.move_to(self.line_width, yradius) context.curve_to(self.line_width, self.line_width, self.line_width, self.line_width, xradius, self.line_width) context.curve_to(width, self.line_width, width, self.line_width, width, yradius) context.curve_to(width, height, width, height, xradius, height) context.curve_to(self.line_width, height, self.line_width, height, self.line_width, yradius) context.set_line_width(self.line_width) context.set_source_rgb(0.0, 0.0, 0.0) context.stroke() # TODO fetch speaker coordinates # draw bubble tail if self.tailpos: context.move_to(xradius-40, yradius) context.line_to(self.tailpos[0], self.tailpos[1]) context.line_to(xradius+40, yradius) context.set_line_width(self.line_width) context.set_source_rgb(0.0, 0.0, 0.0) context.stroke_preserve() context.set_source_rgb(1.0, 1.0, 0.0) context.fill() # bubble painting. Redrawing the inside after the tail will combine # both shapes. # TODO: we could probably generate the shape at initialization to # lighten computations. context.move_to(self.line_width, yradius) context.curve_to(self.line_width, self.line_width, self.line_width, self.line_width, xradius, self.line_width) context.curve_to(width, self.line_width, width, self.line_width, width, yradius) context.curve_to(width, height, width, height, xradius, height) context.curve_to(self.line_width, height, self.line_width, height, self.line_width, yradius) context.set_source_rgb(1.0, 1.0, 0.0) context.fill() # text # FIXME create layout in realize method context.set_source_rgb(0.0, 0.0, 0.0) 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): """ Setup gdk window creation. """ self.set_flags(gtk.REALIZED | gtk.NO_WINDOW) self.window = self.get_parent_window() def __on_expose(self, widget, event): """Redraw event callback.""" # TODO: handle gtk window management in case there is no overlay ctx = self.window.cairo_create() self.draw_with_context(ctx) return True def _set_label(self, value): """Sets the label and flags the widget to be redrawn.""" self.__label = value # FIXME hack to calculate size. necessary because may not have been # realized. We create a fake surface to use builtin math. 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): """Fill requisition with size occupied by the widget.""" width, height = self.__text_dimentions # FIXME bogus values follows. will need to replace them with # padding relative to font size and line border size requisition.width = int(width+30) requisition.height = int(height+40) def do_size_allocate(self, allocation): """Save zone allocated to the widget.""" 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) no_expose = property(fset=_set_will_expose, doc="Whether the widget should handle exposition events or not.") 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: