私が見つけたのは、これに対する解決策は、コードを使用して個々の文字の背景を設定できることです(テキストをリッチエディットに追加する前に)...
var
Format: CHARFORMAT2;
begin
...
myrichedit.SelStart:=myrichedit.GetTextLen;
FillChar(Format, SizeOf(Format), 0);
with Format do begin
cbSize := SizeOf(Format);
dwMask := CFM_BACKCOLOR;
crBackColor := charbackgroundcolor;
myrichedit.Perform(EM_SETCHARFORMAT, SCF_SELECTION, Longint(@Format));
end;
myrichedit.SetText:='Hello';
...しかし、テキストブロック全体の背景色を取得するには、これを実行してテキストを描画します...
var
size : Tsize;
Range: TFormatRange;
Rect: TRect;
LogX, LogY : Integer;
bm : tbitmap;
aCanvas : TCanvas;
ExStyle: DWord;
begin
aCanvas:=Printer.Canvas;
Range.hdc := aCanvas.Handle;
Range.hdcTarget := aCanvas.Handle;
LogX := GetDeviceCaps(Range.hdc, LOGPIXELSX);
LogY := GetDeviceCaps(Range.hdc, LOGPIXELSY);
Range.rc.Left := x * 1440 div LogX;
Range.rc.Right := (x+myrichedit.ClientWidth) * 1440 div LogX; // (1440=twips/inch)
Range.rc.Top := y * 1440 div LogY;
Range.rc.Bottom := 5000 * 1440 div LogY; // Some bigish number
Range.rcPage := Range.rc;
Range.chrg.cpMin := 0;
Range.chrg.cpMax := -1;
myrichedit.Perform(EM_FORMATRANGE, 0, Longint(@Range)); // Measure the formatted text
rect:=Range.rc;
rect.Left:=Range.rc.Left * LogX div 1440;
rect.Top:=Range.rc.Top * LogY div 1440;
rect.Right:=Range.rc.Right * LogX div 1440;
rect.Bottom:=Range.rc.Bottom * LogY div 1440;
acanvas.Brush.Color:=myblockcolor;
acanvas.FillRect(rect); // Fill the background rectangle
ExStyle := GetWindowLong(re.Handle, GWL_EXSTYLE); // Draw richedit transparently over coloured area
ExStyle := ExStyle or WS_EX_TRANSPARENT;
SetWindowLong(re.Handle, GWL_EXSTYLE, ExStyle);
myrichedit.Perform(EM_FORMATRANGE, 1, Longint(@Range));
end;