Delphi: manually draw list view when horizontal bar is present

Question

I draw list view items with OwnerDraw, but I have bugs: please resize a column -> you will have a horizontal bar, scroll it -> items are drawn on a visible area :(

Please help me to edit a code below. Thanks for your attention and help!!!

Added:

I checked, Rect.Right and Rect.Left increase/decrease while scrolling. E.g. we scroll 50 px right, Rect.Right will be Rect.Right+50, Rect.Left will be -50 (0-50)

A normal view:

Bugs:

procedure TDownloadFrame.DownloadListDrawItem(Sender: TCustomListView;
  Item: TListItem; Rect: TRect; State: TOwnerDrawState);
var
  i: integer;
  x1, x2: integer;
  R: TRect;
  s: string;
const
  DT_ALIGN: array [TAlignment] of integer = (DT_LEFT, DT_RIGHT, DT_CENTER);
begin
  if odSelected in State then
  begin
    Sender.Canvas.Font.Color := clWhite;
    Sender.Canvas.Brush.Color := $00FF8000;
  end
  else
  begin
    Sender.Canvas.Font.Color := clBlack;
    Sender.Canvas.Brush.Color := clWhite;
  end;
  Sender.Canvas.Brush.Style := bsSolid;
  Sender.Canvas.FillRect(Rect);

  x1 := 0;
  x2 := 0;
  R := Rect;
  Sender.Canvas.Brush.Style := bsClear;
  MainForm.Icons_16x16.Draw(DownloadList.Canvas, 3, R.Top + (R.Bottom - R.Top - 16) div 2, 1, true);
  for i := 0 to DownloadList.Columns.Count - 1 do
  begin
    Inc(x2, ListView_GetColumnWidth(DownloadList.Handle,
      DownloadList.Columns[i].Index));
    R.Left := x1;
    R.Right := x2;
    if i = 0 then
    begin
      s := Item.Caption;
      R.Left := 16 + 6;
    end
    else
      s := Item.SubItems[i - 1];
    if i <> 3 then
    DrawText(Sender.Canvas.Handle, s, length(s), R, DT_SINGLELINE or
      DT_ALIGN[DownloadList.Columns[i].Alignment] or DT_VCENTER or
      DT_END_ELLIPSIS);
    x1 := x2;
  end;
end;

Answer 1

Change:

1)

  x1 := 0;
  x2 := 0;

to

  x1 := Rect.Left;
  x2 := Rect.Left;

2)

MainForm.Icons_16x16.Draw(DownloadList.Canvas, 3, R.Top + (R.Bottom - R.Top - 16) div 2, 1, true);

to

MainForm.Icons_16x16.Draw(DownloadList.Canvas, R.Left+3, R.Top + (R.Bottom - R.Top - 16) div 2, ImgIndex, true);

3)

if i = 0 then
begin
  s := Item.Caption;
  R.Left := 16 + 6;
end

to

 if i = 0 then
    begin
      s := Item.Caption;
      R.Left := R.Left + 16 + 6;
    end

Answer 2

i came across a bug in the VCL recently where if i draw on a ListItem with an imagelist, then the listview's canvas would no longer honor any font color, font size, or font face changes of Sender.Canvas.Font:

Sender.Canvas.Font.Color := clHighlightText;
Sender.Canvas.Font.Size := 14;
Sender.Canvas.Font.Name := 'Consolas';

...none would work. This would only stop working if i first drew on the canvas using:

imageList.Draw(Sender.Canvas, ....);

If i removed the imageList.Draw everything was fine.

i was forced to set the font and colors using GDI directly:

savedDC := SaveDC(Sender.Canvas.Handle);
try
   SetTextColor(Sender.Canvas.Handle, clHighlightText); //don't use clWhite, use the correct color

   newfont := TFont.Create;
   try
      newFont.Assign(Sender.Canvas.Font);
      newFont.Name := 'Consolas';
      newfont.Size := 14;
      SelectObject(Sender.Canvas.Handle, newFont.Handle);  


      szText = 'Hello, world!';

      TextOut(Sender.Canvas.Handle, 0, 0, PChar(szText), Length(szText));
   finally
      newFont.Free;
   end;
finally
   RestoreDC(Sender.Canvas.Handle, savedDC);
end;

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