They should be switched. And, if I can suggest, one line step is too small. This looks better:
- Code: Select all
procedure TPrintPreview.WMMouseWheel(var Message: TMessage);
var I: Integer;
[...]
if IsNeg then
begin
WheelAccumulator := -WheelAccumulator;
case LoWord(Message.WParam) of
MK_CONTROL: Zoom := Zoom - ZoomStep;
MK_SHIFT, MK_MBUTTON: CurrentPage := CurrentPage + 1;
// 0: Perform(WM_VSCROLL, SB_LINEUP, 0);
0: for I:= 0 to 4 do Perform(WM_VSCROLL, SB_LINEDOWN, 0); // klin
[...]