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LCL, grids, fix windows problem when drawing italic text, issue #23313

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git-svn-id: trunk@46561 -
This commit is contained in:
jesus 2014-10-14 23:45:47 +00:00
parent 53baa605e0
commit c8ff5d66b9
1 changed files with 37 additions and 0 deletions
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37
lcl/interfaces/win32/win32winapi.inc
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@ -1131,6 +1131,10 @@ function TWin32WidgetSet.DrawText(DC: HDC; Str: PChar; Count: Integer; var Rect:
var
s: AnsiString;
w: WideString;
res: WINBOOL;
lf: LOGFONT;
aABC: ABC;
paABC: LPABC;
{$endif}
begin
{$ifdef WindowsUnicodeSupport}
@ -1153,6 +1157,39 @@ begin
S := Utf8ToAnsi(S);
Result := Windows.DrawText(DC, PChar(S), Length(S), @Rect, Flags);
end;
// Theoretically, we need to augment the returned rect by the text overhang
// The overhang is returned in the abcC field as documented in the
// following article: http://support.microsoft.com/kb/94646/en-us
// for italic text, usually this value is negative, so the adjusted
// value could be calculated by Rect.Right:=Rect.Right-aABC.abcC, oddly enough
// sometimes this it's positive, yielding an incorrect Rect.Right value.
// As the objective is to return a more correct value so the text overhang
// is not clipped out, I found the next solution works better most times.
//
// NOTE. this doesn't solve (most of the times) the problem of right
// aligned bold italic text. The DrawText windows function is documented to
// clip out text in some special cases, specially when drawing italic text,
// but I found it's even worse with drawing bold italic text.
if (Count>0) and (flags and DT_CALCRECT = DT_CALCRECT) then
begin
GetObject(GetCurrentObject(DC, OBJ_FONT), SizeOf(LOGFONT), @lf);
if lf.lfItalic<>0 then
begin
paABC := @aABC;
if UnicodeEnabledOS then
res := GetCharABCWidthsW(DC, Uint(W[Count-1]), Uint(W[Count-1]), paABC)
else
res := GetCharABCWidthsA(DC, ord(s[Count-1]), ord(s[Count-1]), paABC);
if res then
Rect.Right := Rect.Right + Abs(aABC.abcC);
end;
end;
{$else}
Result := Windows.DrawText(DC, Str, Count, @Rect, Flags);
{$endif}