buttons.py 文件源码

def _cache_bg_for_state(self, state):
        a = self.get_allocation()
        # tmp surface on which we render the button bg as per the gtk
        # theme engine
        _surf = cairo.ImageSurface(cairo.FORMAT_ARGB32,
                                   a.width, a.height)
        cr = cairo.Context(_surf)

        context = self.get_style_context()
        context.save()
        context.set_state(state)

        Gtk.render_background(context, cr,
                          -5, -5, a.width + 10, a.height + 10)
        Gtk.render_frame(context, cr,
                          -5, -5, a.width + 10, a.height + 10)
        del cr

        # new surface which will be cached which
        surf = cairo.ImageSurface(cairo.FORMAT_ARGB32,
                                  a.width, a.height)
        cr = cairo.Context(surf)

        # gradient for masking
        lin = cairo.LinearGradient(0, 0, 0, a.height)
        lin.add_color_stop_rgba(0.0, 1, 1, 1, 0.1)
        lin.add_color_stop_rgba(0.25, 1, 1, 1, 0.7)
        lin.add_color_stop_rgba(0.5, 1, 1, 1, 1.0)
        lin.add_color_stop_rgba(0.75, 1, 1, 1, 0.7)
        lin.add_color_stop_rgba(1.0, 1, 1, 1, 0.1)

        cr.set_source_surface(_surf, 0, 0)
        cr.mask(lin)
        del cr

        # cache the resulting surf...
        self._bg_cache[state] = surf