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962 bytes added ,  13:15, 11 November 2011
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== Tips to Activity Developers ==
 
== Tips to Activity Developers ==
   −
'''this is just a stub'''
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===Going from Drawable to Cairo===
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GTK-3 does not support gtk Drawable objects, so the first step is to get your activity running under Cairo.
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# From activity.Activity, you inherit a canvas. Get its window.
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win = self.canvas.get_window()
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# Create a Cairo context from the window.
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cr = win.cairo_create()
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# Create a Cairo surface from the context
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surface = cr.get_target()
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# Create an XLib surface to be used for drawing
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xlib_surface = surface.create_similar(cairo.CONTENT_COLOR,
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                                      gtk.gdk.screen_width(),
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                                      gtk.gdk.screen_height())
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# You'll need a Cairo context from which you'll build a GTK Cairo context
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cr = cairo.Context(xlib_surface)
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cr = gtk.gdk.CairoContext(cr)
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# Use this context as you would a Drawable, substituting Cairo commands for gtk commands, e.g.,
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cr.move_to(0, 0)
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cr.set_source_rgb(r, g, b)  # Cairo uses floats from 0 to 1 for RGB values
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cr.rectangle(x, y, w, h)
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cr.fill()
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# To invalidate a region to forse a refresh, use:
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self.canvas.queue_draw_area(x, y, w, h)
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   −
* GTK-3 does not support Drawable, so the first step is to get your activity running under Cairo.
   
:* Example: abacus-cairo
 
:* Example: abacus-cairo
 
:* Example: abacus-gtk3
 
:* Example: abacus-gtk3