A graphical user interface for direct control of data displayed in a window-based computing environment. A slider element is displayed which is variable in size according to user input. The slider defines a selected area of an image, which is then displayed. The scope of the selected area corresponds to the size of the slider. The resizable slider is then resized by a user's direct manipulation, e.g. by a click-and-drag technique, to redefine the selected area, which is then displayed. The scope of the redefined selected area corresponds to the size of the resized slider. Accordingly, a user directly controls (by resizing the slider) the scope of data displayed in a window, and directly controls the presentation of data by translating the slider to define various selected areas. More than one independently resizable slider may intersect to define the selected area and provide independent control of scope in various directions.