Function TestingCanvas

vispy/testing/_testing.py:307–350

Avoid importing scene until necessary.

(bgcolor='black', size=(100, 100), dpi=None, decorate=None,
                  **kwargs)

@nottest
def TestingCanvas(bgcolor='black', size=(100, 100), dpi=None, decorate=None,
                  **kwargs):
    """Avoid importing scene until necessary."""
    # On Windows decorations can force windows to be an incorrect size
    # (e.g., instead of 100x100 they will be 100x248), having no
    # decorations works around this
    from ..scene import SceneCanvas

    class TestingCanvas(SceneCanvas):
        def __init__(self, bgcolor, size, dpi, decorate, **kwargs):
            self._entered = False
            self._wanted_vp = None
            if decorate is None:
                # deal with GLFW's problems
                from vispy.app import use_app
                app = use_app()
                if _bad_glfw_decorate(app):
                    decorate = True
                else:
                    decorate = False
            SceneCanvas.__init__(self, bgcolor=bgcolor, size=size,
                                 dpi=dpi, decorate=decorate,
                                 **kwargs)

        def __enter__(self):
            SceneCanvas.__enter__(self)
            # sometimes our window can be larger than our requsted draw
            # area (e.g. on Windows), and this messes up our tests that
            # typically use very small windows. Here we "fix" it.
            scale = np.array(self.physical_size) / np.array(self.size, float)
            scale = int(np.round(np.mean(scale)))
            self._wanted_vp = 0, 0, size[0] * scale, size[1] * scale
            self.context.set_state(clear_color=self._bgcolor)
            self.context.set_viewport(*self._wanted_vp)
            self._entered = True
            return self

        def draw_visual(self, visual, event=None):
            if not self._entered:
                return
            SceneCanvas.draw_visual(self, visual, event)
            self.context.finish()

    return TestingCanvas(bgcolor, size, dpi, decorate, **kwargs)


@nottest