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# Zoom

Function: Zoom( | size, start, end, time, after_child=None, time_warp=None, bilinear=True, opaque=True, **properties)

This causes a zoom to take place, using image scaling. When used as an `at` clause, this creates a displayable. The render of this displayable is always of the supplied size. The child displayable is rendered, and a rectangle is cropped out of it. This rectangle is interpolated between the start and end rectangles. The rectangle is then scaled to the supplied size. The zoom will take time seconds, after which it will show the end rectangle, unless an after_child is given.

The start and end rectangles must fit completely inside the size of the child, otherwise an error will occur.

size - The size that the rectangle is scaled to, a (width, height) tuple.

start - The start rectangle, an (xoffset, yoffset, width, height) tuple.

end - The end rectangle, an (xoffset, yoffset, width, height) tuple.

time - The amount of time it will take to interpolate from the start to the end rectange.

after_child - If present, a second child widget. This displayable will be rendered after the zoom completes. Use this to snap to a sharp displayable after the zoom is done.

time_warp - If not None, a function that takes a fractional period (between 0.0 and 0.1), and returns a fractional period. Use this to implement non-linear zooms. This function may be pickled, so it cannot be a lambda or other non-top-level function.

bilinear - If True, the default, this will use bilinear filtering. If false, this will use ugly yet fast nearest neighbor filtering.

opaque - If True and bilinear is True, this will use a very efficient method that does not support transparency. If False, this supports transparency, but is less efficient.

## Example

    scene bg whitehouse at Zoom((800, 600), (0, 0, 800, 600), (225, 150, 400, 300), 1.0)

    "We can zoom into images..."

    scene bg whitehouse at Zoom((800, 600), (225, 150, 400, 300), (0, 0, 800, 600), 1.0)

    "... and zoom back out of them again."

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