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C H A P T E R 3
Views
3-42
Using Views
In the latter kind of scrolling, the child views are moved within the parent view by
changing their view bounds. Newly visible views will be opened for the first time,
and views which have scrolled completely out-of-view will be closed. The
viewOriginX and viewOriginY slots are not used.
For information about techniques you can use to optimize scrolling so that it
happens as fast as possible, see "Scrolling" (page 3-46), and "Optimizing View
Performance" (page 3-44).
Redirecting Scrolling Messages
3
You can redirect scrolling messages from the base view to another view. Scrolling
and overview messages are sent to the frontmost view; this is the same view that is
returned if you call
GetView('viewFrontMost)
.
The
viewFrontMost
view is found by looking recursively at views that have
both the
vVisible
and
vApplication
bits set in their
viewFlags
. This
means that you can set the
vApplication
bit in a descendant of your base view,
and as long as
vApplication
is set in all of the views in the parent chain for that
view, the scrolling messages will go directly to that view. The
vApplication
bit
is not just for base views, despite what the name might suggest.
If your situation is more complex, where the view that needs to be scrolled cannot
have
vApplication
set or is not a descendant of your base view, you can have the
base view's scrolling scripts call the appropriate scripts in the view you wish scrolled.
Working With View Highlighting
3
A highlighted view is identified visually by being inverted. That is, black and white
are reversed.
To highlight or unhighlight a view, send the view the
Hilite
message.
To highlight or unhighlight a single view from a group, send the view the
HiliteUnique
message. (The group is defined as all of the child views of one
parent view.)
To highlight a view when the current pen position is within it, send the view the
TrackHilite
message. The view is unhighlighted when the pen moves outside
the view bounds. If the view is a button, you can send the view the
TrackButton
message to accomplish the same task.
To get the view containing highlighted data, you can call the global function
HiliteOwner
; to get the highlighted text use
GetHiliteOffsets
.
To highlight some or all of the text in a paragraph, you can use the
SetHilite
method.
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