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LAYOUT DYNAMICS

Due to the space-filling tiled nature of the layout, window size changes affect size of other windows as well. In elastic windows the proximity of effect is limited only to windows under the same group and their subwindows.

Effect of the changes in the window size under the same group is split proportionally according to the window sizes. Depending on the border dragged and the direction of drag, it results in either a push or pull as shown in Figure 3.a and b. In both of these cases, window sizes are updated proportional to the sizes, but the set of windows affected changes.

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Figure 3: Effect of resize operations on other windows: a) Pull effect b) Push effect c) Recovering proportions on resize with minimum size windows.

Referring to Figure 3.a, Window C pulls windows A and B, since the left border of Window C is dragged to the right. In Figure 3.b, Window B pushes windows C, D, and E, since the right border of Window B is dragged to the right. Windows not affected are grayed in the figure. New window sizes are calculated as follows:

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Changes in the upper levels are propagated down to their subwindows recursively. For example, subwindows of Window A, B, and C in 3.a adjust their width accordingly.

Each elastic window has a default minimum window size, but users can set a different value for each window. This way users can protect a window from unwanted size updates.

When windows are being resized some of the windows may reach their minimum window size. For example, in Figure 3.b, when pushing windows C, D, and E, window D may reach its minimum size, while others don't. In that case the resize operation is allowed until all of the affected windows are fully compacted i.e. all reach their minimum sizes. Since window D is kept at its minimum size, proportions do change. However, in elastic windows the old proportions are kept, so that the resize operation is reversible. Figure 3.c shows an example.

Even when the window is so small that its contents are not fully visible, it still gives users some information about its content because of the spatial placement and reminds users of unfinished tasks; and it can be enlarged rapidly and easily if needed.

The effect of changes in window size on the content depends on the application. For example, upon down-sizing a window used for viewing a document, it might be preferable to see the same content but with smaller font sizes; but when designing a system in a CAD system, keeping the same zooming factor and clipping might be preferable. When clipping is used, facilities like scrollbars are needed to move the viewing area. Similar arguments can be made for other content types like images and icons. The choice is made by the application program, based on users' preference initiated by the window manager upon a window size update.


next up previous
Next: ELASTIC WINDOW OPERATIONS Up: Elastic Windows: Improved Spatial Previous: THE ELASTIC WINDOW DECORATION

Eser Kandogan
Wed Feb 5 13:52:21 EST 1997

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