Window to Viewport Transformation in Computer Graphics
In General, the mapping of a part of a world coordinate scene to a device coordinate is referred to as Viewing Transformation (V). mathematically expressed as:
Sometimes the two dimensional view transformation is simply called Window to Viewport Transformation.
By defining a closed boundary or window the enclosed portion of a world coordinate scene is clipped against the window boundary and the data of the clipped portion is extracted for mapping to a separately defined region known as Viewport.
While the window selects a part of the scene, the viewport displays the selected part at the desired location in the display area. If we change the viewport only, we see the same part of the scene drawn at a different scale or a different place on the display. By successively increasing or decreasing the size of the window around a part of the scene with the viewport remaining fixed, we can get the effect of the zoom out or zoom in respectively on the displayed part.