The internal style flags are used to determine whether to show or hide
the scrollbar when ME_UpdateScrollBar is called. EM_SHOWSCROLLBAR seems
to update this state in native richedit controls.
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.
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.
EM_GETTEXTRANGE allows the start character offset and end characters
offset to be used to specify the range of text to retrieve. If the
start offset is in the middle of an end of paragraph run (i.e. \r\n),
then it should only retrieve the characters after the specified
character offset.
I found that ME_FindItemAtOffset and ME_CursorFromCharOfs are used
almost identically, except for how they handle a character offset that
is between a carriage return and line feed. In this case
ME_CursorFromCharOfs sets the cursor's run offset to 0, but
ME_FindItemAtOffset instead returns the next run which is what was
causing ME_LINELENGTH to incorrectly return the length of the next
line.
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.
I noticed a while ago that on Windows XP richedit controls ignored
characters typed while the mouse is captured (e.g. from holding the left
or middle button down). Arrow keys, delete, and backspace, copying,
cutting, pasting, and everything else handled on WM_CHAR and WM_KEYDOWN
messages are also ignored.
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).
EM_GETPARAFORMAT previously would overwrite the cbSize field with the
size of PARAFORMAT2, would read past the end of the struct, and might
indicate that PARAFORMAT2 fields are valid using the mask regardless
of the value of cbSize.
If a EM_SETPARAFORMAT message is sent to the richedit control with bits
in the dwMask field that correspond to PARAFORMAT2 fields, then these
fields should be ignored. Instead data was copied from outside of the
structure.
Using the WS_VSCROLL style causes the ES_AUTOVSCROLL option to be set,
and using the WS_HSCROLL style causes the ES_AUTOHSCROLL flag to be
set (except with richedit v1.0).
The contents of the text can be zoomed in with EM_SETZOOM, or with the
mouse wheel. EM_SETZOOM is implemented, but these tests show bugs in
the implementation, and zooming using the mouse wheel isn't
implemented at all yet.
Windowless richedit control will not be able to call GetCapture without
a handle to the host window (and there is no ITextHost_TxGetCapture
method), but there is a ITextHost_TxSetCapture method available for
setting and releasing the capture on the mouse. This means that the
richedit control will need to keep track of whether it has captured the
mouse or not to implement windowless richedit controls.
Previously the WM_NCCREATE was handled by the as if it was always for
later versions, then the window proc for version 1.0 would make
appropriate changes afterwards. Instead both versions should call the
same function (e.g. ME_MakeEditor) and provide the value for
bEmulateVersion10 to make the code clearer.
This fixes inconsistencies shown in the tests I added for the
WM_GETDLGCODE. The tests covered different cases handled by the
current implementation in order to show that the native implementation
is simpler for all these cases.
Marcus Meissner