Initial import

code/ProbeCamera.pas

@@ -0,0 +1,33 @@
+unit ProbeCamera;
+{$mode delphi}{$H+}
+{$ASSERTIONS ON}{$R+}{$Q+}{$B-}
+interface
+uses Math;
+type
+ TProbeCamera = record
+  OffsetX, OffsetY, PixelsPerCell: Double;
+  procedure Reset;
+  procedure Pan(DX,DY: Double);
+  procedure ZoomAt(Factor,SX,SY: Double);
+  function CellAt(SX,SY: Double;Cols,Rows:Integer;out X,Y:Integer):Boolean;
+ end;
+implementation
+procedure TProbeCamera.Reset;
+begin OffsetX:=20;OffsetY:=20;PixelsPerCell:=10;end;
+procedure TProbeCamera.Pan(DX,DY:Double);
+begin OffsetX:=OffsetX+DX;OffsetY:=OffsetY+DY;end;
+procedure TProbeCamera.ZoomAt(Factor,SX,SY:Double);
+var WX,WY,NewScale:Double;
+begin
+ if (Factor<=0) or IsNan(Factor) or IsInfinite(Factor) then Exit;
+ WX:=(SX-OffsetX)/PixelsPerCell;WY:=(SY-OffsetY)/PixelsPerCell;
+ NewScale:=EnsureRange(PixelsPerCell*Factor,2.0,128.0);
+ PixelsPerCell:=NewScale;OffsetX:=SX-WX*NewScale;OffsetY:=SY-WY*NewScale;
+end;
+function TProbeCamera.CellAt(SX,SY:Double;Cols,Rows:Integer;out X,Y:Integer):Boolean;
+begin
+ X:=Floor((SX-OffsetX)/PixelsPerCell)+1;
+ Y:=Rows-Floor((SY-OffsetY)/PixelsPerCell);
+ Result:=(X>=1) and (X<=Cols) and (Y>=1) and (Y<=Rows);
+end;
+end.