Using the ITextHost interface allows this notification to be received
for windowless richedit controls. Windowed richedit conrols have an
ITextHost implementation that will fill in hwndFrom and idFrom, but
these should probably be initialized to 0 for windowless richedit
controls.
For some reason the code previously mixed up a selection cursor with the
result cursor. The problem seemed to have corrected itself before as a
result of conversion between offsets and cursors, but my recent changes
made this bug more severe.
Previously the function was only used to move a single character in
either direction, so I made the function more general so that it could
be used in more places.
Plenty of places in the code find following or preceding runs, then
afterwards find the paragraph from the run. This is inefficient because
the same linked list is used for both runs and paragraphs, so changes in
paragraphs can be detected while returning the next or previous run.
Previously the only convenient way to get the start and end of the
selection was through offsets, which eventually need to get converted
back into items in the linked list storing the text. The new function
will help with eliminating these inefficiencies.
This function will make it easier to work with ME_Cursor objects, which
should be used in a lot of places instead of character offsets (which
often require seeking through the linked lists to perform operations
with).
Style objects are referenced counted in richedit controls, so I tried to
make sure styles were released properly. This can be checked using with
the all_refs global reference count to see if everything is cleaned up.
Previously inserting the object didn't result in the text being wrapped,
which would cause an assertion error when this is checked for during
repainting the text. It is also important to invalidate the affected
areas of text, update the scrollbar, and end the creation of undo
transactions for this insertion.
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 just being used for addition, so it was simpler to
remove the functions and modify the places it was used.
The ME_StrRelPos2 and ME_PosToVPos were just simple wrappers around
ME_StrRelPos, and ME_PosToVPos wasn't being used.
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.
ME_GetCursorCoordinates had two conditions that were always taken. The
first condition was if(pCursor->pRun->type == diRun) was following an
assertion making the exact same check. The next one, if(row), should
always be taken, otherwise the richedit controls are in a corrupt state,
therefore an assertion is more appropriate.
Previously it found the start or end by traversing the linked lists of
run, rows, paragraphs, and cells from the current position of the
cursors. Clearly it is better to get the start or end directly to make
it a constant time operation.
The fixme comment is suggesting wrapping a paragraph within a function
that is for moving the selection cursor up or down a line when the up
or down keys are pressed. The contents fo paragraph aren't being
changed, so there is no need to wrap the paragraph.
Rather than get the paragraph from the run, the function allows the
caller to provide the paragraph, since it is already available. This
reduces unnecessary traversals of lists that take longer as more runs
and rows are in the paragraph.
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.
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.
The two functions ME_FindItemAtOffset and ME_RunOfsFromCharOfs were almost
identically used, since ME_FindItemAtOffset was always used to find a run.
The only difference was how they returned the offset within the run for an
end of paragraph run.
For ME_FindItemAtOffset it would return the next run if it was in between \r
and \n. ME_RunOfsFromCharOfs would instead return an nOffset of 0 for end
paragraph runs. This subtle difference introduced bugs, so I decided to
avoid having special case in this function when creating this patch, and
instead let the caller handle this case.
riched32.dll does preserve the carriage returns and line feeds unlike
later versions of the richedit control, however the tests previously
missed the fact that a sequence of carriage returns followed by a line
feed (e.g. \r\r\r\n) can actually cause multiple paragraph breaks.
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).
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.
The code for the ME_EnsureVisible function does exactly what
EM_SCROLLCARET does, yet this code is duplicated in order to handle
this message. It is simpler to just use the existing function to
implement the message, and avoid internally sending the EM_SCROLLCARET
when this function is available.
Huw Davies