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This note formerly described the known bugs with the version of Styled TextEdit
that was provided with System 4.1. Many of these bugs were fixed in System 4.2.
This updated Technical Note describes the remaining known problems.
[Mar 01 1988]
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TEStylInsert
Calling TEStylInsert while the TextEdit record is deactivated causes
unpredictable results, so make sure to only call TEStylInsert when the
TextEdit record is active.
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TESetStyle
When using the doFace mode with TESetStyle, the style that
you pass as a parameter is ORed into the style of the currently
selected text. If you pass the empty set (no styles) though,
TESetStyle is supposed to remove all styles from the selected text.
But TESetStyle checks an entire word instead of just the high-order
byte of the tsFace field. The style information is contained
completely in the high-order byte, and the low-order byte may contain
garbage.
If the low-order byte isn't zero, TESetStyle thinks that the
tsFace field isn't empty, so it goes ahead and ORs it with the
selected text's style. Since the actual style portion of the tsFace
field is zero, no change occurs with the text. If you want to have
TESetStyle remove all styles from the text, you can explicitly set the
tsFace field to zero like this:
VAR
myStyle : TextStyle;
anIntPtr : ^Integer;
BEGIN
...
anIntPtr := @myStyle.tsFace;
anIntPtr^ := 0;
TESetStyle(doFace, myStyle, TRUE, textH);
...
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TEStylNew
The line heights array does not get initialized when TEStylNew is
called. Because of this, the caret is initially drawn in a random height. This
is easily solved by calling TECalText immediately after calling
TEStylNew. Extra calls to TECalText don't hurt anything
anyway, so this will be compatible with future Systems.
An extra character run is placed at the beginning of the text which corresponds
to the font, size, and style which were in the grafPort when TEStylNew
was called. This can cause the line height for the first line to be too large.
To avoid this, call TextSize with the desired text size before calling
TEStylNew. If the text's style information cannot be determined in
advance, then call TextSize with a small value (like 9) before calling
TEStylNew.
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TEScroll
The bug documented in M.TE.TEScrollBug remains in the new TextEdit.
TEScroll called with zero for both vertical and horizontal
displacements causes the insertion point to disappear. The workaround is the
same as before; check to make sure that dV and dH are not
both zero before calling TEScroll.
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Growing TextEdit Record
TextEdit is supposed to dynamically grow and shrink the LineStarts
array in the TERec so that it has one entry per line. Instead, when
lines are added, TextEdit expands the array without first checking to see if
it's already big enough. In addition, TextEdit never reduces the size of this
array.
Because of this, the longer a particular TextEdit record is used, the larger it
will get. This can be particularly nasty in programs that use a single
TERec for many operations during the program's execution.
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Restoring Saved TextEdit Records
Applications have used a technique for saving and restoring styled text which
involves saving the contents of all of the TextEdit record handles. When
restoring, TEStylNew is called and the TextEdit record's handles are
disposed. The saved handles are then loaded and put into the TextEdit record.
This technique should not be used for the nullStyle handle in the
style record.
Instead, when TEStylNew is called, the nullStyle handle from
the style record should be copied into the saved style record. This will ensure
that the fields in the null-style record point to valid data.
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Downloadables
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Acrobat version of this Note (48K).
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