The application Blitzin2 was sending WM_VSCROLL messages to the
richedit control directly, when normally this message is supposed to
be a notification sent after the scrollinfo is set. Native richedit
controls always use the 16-bit value passed to this message to set the
scroll position for SB_THUMBPOSITION, rather than trying to find a
32-bit value through GetScrollInfo like I had previously done.
The missing return was to prevent automatic vertically scrolling when
style for it is not set, but is set for the horizontal scrollbar. I
initially missed this by testing with no autoscrolling on either
scrollbar.
When the richedit control is created without the ES_AUTOHSCROLL or the
ES_AUTOVSCROLL, then scrolling isn't done automatically when moving the
cursor with the arrow keys, drag selecting with the mouse, or even from
using the EM_SCROLLCARET (based on testing using a modified version of
wordpad).
The scrollbar visibility can be changed from SetScrollRange or
SetScrollInfo, but the visiblity that is a result of these calls are
not consistent with the calculation made by richedit controls to
decide whether to show or hide the scrollbars.
This prevents some needless searching for the start of the paragraph
from a run stored in a cursor. Usually a pointer to the paragraph is
already available when the cursor is set anyway.
These functions were probably previously needed because of some wierd
special handling of backspace characters, but currently there is no
reason why the nLen field can't be accessed directly.
Having to functions that just access the string length field just causes
slightly more effort for someone to look at the code, because they need
to enter the function to find out what it actually is doing.
When finding an adjacent paragraph, the next_para and prev_para pointers
should be used because they are direct pointers, a constant time
operation. Instead I found some places in the code that searched through
the general linked list to get to an adjacent paragraph, which is a linear
time operation, depending on the number of rows and runs in between
paragraphs.
These calls to ME_WrapMarkedParagraphs never do anything, and don't make
sense to be called in these places. These places are for ME_MoveCaret,
and ME_ArrowHome, which both don't involve any text being modified, and
all (direct and indirect) calls to these functions are done after the
text has already been wrapped.
If the scrollbar style isn't initially used, then the scrollbar should
be shown. Otherwise this can be a problem when the horizontal scrollbar
is shown for a single line richedit control, since it will cover all the
text (See bug 12088).
Previously a count of the carraige returns and line feeds were stored
for end of paragraph runs, and a paragraph sign was stored as the actual
string. This was causing many special cases where the length of the
run needed to be determined differently if the run was or wasn't an
end of paragraph run.
There wasn't any use for storing the paragraph sign unless some drawing
code gets commented out to allow the end paragraphs to be shown,
therefore I changed the code to store the actual string that gets
retrieved by WM_GETTEXT.
Certain operations will simply not be done for windowless richedit
controls, such as WM_PAINT which isn't done for windowless richedit
controls since ITextServices provides a TxDraw method.
The methods in ITextHost are mostly thin wrappers around functions that
take a handle to a window as their first parameter. This patch just
uses the wrapper functions provided by ITextHost instead of using the
functions that require a handle to a window that the editor might now
have (for windowless richedit controls).
A common case for richedit controls are that a large amount of text is
set initially with word wrap enabled. This causes the initially
wrapping of the text, which also calculates the text length. After
this the vertical scrollbar will be shown, which causes the text to be
rewrapped again. After this there are two redundant rewraps that are
done which this patch eliminates.
When the text is wrapped, the positions for all the runs, paragraphs,
and cells are already calculated and stored. The only thing left to do
for painting is to offset them by the formatting rectangle and the
scroll position.
During wrapping there were three different heights that were being
stored, with only one of them being done correctly. The other ones
failed to incorporate the height of the paragraph or row, so ended up
being incorrect.
The formatting rectangle is set with EM_SETRECT, and retrieved with
EM_GETRECT, so it corresponds to rcFormat in the code. This defines the
area that the richedit control should draw the text so that it is
offset by the top-left corner of the formatting rectangle, and clipped
so that it doesn't draw past the bottom or right hand side. Thus this
is important for implementing windowless richedit controls to not
interfere with the rest of the window.
In version 1.0 of the richedit controls highlighting is done by
inverting the colours. Version 2.0 and up highlight instead draw
the text using system colours for the background and the text.
Dylan Smith