Horizontal Scrolling, Clipping, and Text Views

One of the Newton 2.x OS Q&As
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This document was exported on 7/23/97.

Horizontal Scrolling, Clipping, and Text Views (2/7/96)

Q: I want to draw 80 columns in a clParagraphView that's inside a smaller view and be able to scroll back and forth. When I try this, it always wraps at the bounds of the parent. How can I create a horizontal scrolling text view?

A: Normal paragraph views are written so that their right edge will never go beyond their parent. This is done to avoid the circumstance where a user could select and delete some text from the left part of a paragraph in a clEditView, leaving the rest of it off screen and unselectable.

What happens is the viewBounds of the clParagraphView are modified during creation of the view so that the view's right edge is aligned with the parent's right edge. After that, wrapping is automatic.

The so-called "lightweight" text views do not work this way. You can force a paragraph to be lightweight by: 1) Making sure the viewFlag vReadOnly is set, 2) making sure vCalculateBounds and vGesturesAllowed, are off, and 3) not using tabs or styles. Lightweight text views are not editable, but you can use SetValue to change their text slots dynamically.

If you must use an editable clParagraphView or if tabs or styles are required, there is another workaround. The code to check for clipping only looks one or two levels up the parent chain, so you could nest the paragraph in a couple of otherwise useless views which were large enough to prevent clipping, and let the clipping happen several layers up the parent chain.