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CHAPTER 3

Views

3-12 About Views

View Size Relative to Parent Size 3

A view is normally entirely enclosed by its parent view. You shouldn’t create a

view whose bounds extend outside its parent’s bounds. If you do create such a view,

for example containing a picture that you want to show just part of, you need to set

the

vClipping ﬂag in the viewFlags slot of the parent view.

If you do not set the

vClipping ﬂag for the parent view, the behavior is

unpredictable. The portions of the view outside the parent’s bounds may or may

not draw properly. All pen input is clipped to the parent’s bounds.

Note that the base views of all applications (all root view children, in fact) are

automatically clipped, whether or not the

vClipping ﬂag is set.

If your application base view is very small and you need to create a larger ﬂoating

child view, for example, a slip, you should use the

BuildContext function. This

function creates a special view that is a child of the root view. To open the view,

you send the

Open message to it.

Using Screen-Relative Bounds 3

Newton is a family of products with varying screen sizes. If you want your

application to be compatible with a variety of individual Newton products, you

should design your application so that it sizes itself dynamically (that is, at run

time), accounting for the size of the screen on which it is running, which could be

smaller or larger than the original Newton MessagePad screen.

You may want to dynamically size the base view of your application so that it

changes for different screen sizes, or you may want it to remain a ﬁxed size on all

platforms. In the latter case, you should still check the actual screen size at run

time to make sure there is enough room for your application.

You can use the global function

GetAppParams to check the size of the screen at

run time. This function returns a frame containing the coordinates of the drawable

area of the screen, as well as other information (see “Utility Functions Reference”

(page 23-1) in the Newton Programmer’s Reference for a description). The frame

returned looks like this:

{appAreaLeft: 0,

appAreaTop: 0,

appAreaWidth: 240,

appAreaHeight: 320,

...}

The following example shows how to use the ViewSetupFormScript method in

your application base view to make the application a ﬁxed size, but no larger than

the size of the screen:

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