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I would like to create a magnifying glass to enlarge the region around where the keyboard cursor is positioned and also the focus on a form. I wonder if anyone has any suggestions on the subject.
I found a source but it’s about the mouse position.
procedure TForm1.Timer1Timer(Sender: TObject);
var
Srect,Drect,PosForme:TRect;
iWidth,iHeight,DmX,DmY:Integer;
iTmpX,iTmpY:Real;
C:TCanvas;
hDesktop: Hwnd;
Kursor:TPoint;
begin
If not IsIconic(Application.Handle) then begin
hDesktop:= GetDesktopWindow;
GetCursorPos(Kursor);
PosForme:=Rect(Form1.Left,Form1.Top,Form1.Left+Form1.Width,Form1.Top+Form1.Height);
If not PtInRect(PosForme,Kursor) then begin
If Panel1.Visible=True then Panel1.Visible:=False;
If Image1.Visible=False then Image1.Visible:=True;
iWidth:=Image1.Width;
iHeight:=Image1.Height;
Drect:=Rect(0,0,iWidth,iHeight);
iTmpX:=iWidth / (Slider.Position * 4);
iTmpY:=iHeight / (Slider.Position * 4);
Srect:=Rect(Kursor.x,Kursor.y,Kursor.x,Kursor.y);
InflateRect(Srect,Round(iTmpX),Round(iTmpY));
// move Srect if outside visible area of the screen
If Srect.Left<0 then OffsetRect(Srect,-Srect.Left,0);
If Srect.Top<0 then OffsetRect(Srect,0,-Srect.Top);
If Srect.Right>Screen.Width then OffsetRect(Srect,-(Srect.Right-Screen.Width),0);
If Srect.Bottom>Screen.Height then OffsetRect(Srect,0,-(Srect.Bottom-Screen.Height));
C:=TCanvas.Create;
try
C.Handle:=GetDC(GetDesktopWindow);
Image1.Canvas.CopyRect(Drect,C,Srect);
finally
ReleaseDC(hDesktop, C.Handle);
C.Free;
end;
If cbSrediste.Checked=True then begin // show crosshair
with Image1.Canvas do begin
DmX:=Slider.Position * 2 * (Kursor.X-Srect.Left);
DmY:=Slider.Position * 2 * (Kursor.Y-Srect.Top);
MoveTo(DmX - (iWidth div 4),DmY); // -
LineTo(DmX + (iWidth div 4),DmY); // -
MoveTo(DmX,DmY - (iHeight div 4)); // |
LineTo(DmX,DmY + (iHeight div 4)); // |
end; // with image1.Canvas
end; // show crosshair
Application.ProcessMessages;
end // Cursor not inside form
else begin // cursor inside form
If Panel1.Visible=False then Panel1.Visible:=True;
If Image1.Visible=True then Image1.Visible:=False;
end;
end; // IsIconic
end;
end.