JS/TXY._

//:LONG_HANDED:LLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLL://
var F = ( Math.floor );
s_x = F( ((d_x-dx0) /   (dx1-dx0+1)) * (sx1-sx0+1)   ) + sx0 ;
s_y = F( ((d_y-dy0) /   (dy1-dy0+1)) * (sy1-sy0+1)   ) + sy0 ;

t_x = F(  (d_x-dx0) / ( (dx1-dx0+1)  / (sx1-sx0+1) ) ) + sx0 ;
t_y = F(  (d_y-dy0) / ( (dy1-dy0+1)  / (sy1-sy0+1) ) ) + sy0 ;
//:LLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLL:LONG_HANDED://
//:SHORT_HANDED:SSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSS://
var   F = ( Math.floor );
s_x = F(((ldx)/  (vp0_wid))*(vp1_wid) ) + sx0 ;
s_y = F(((ldy)/  (vp0_hig))*(vp1_hig) ) + sy0 ;

t_x = F( (ldx)/( (vp0_wid) /(vp1_wid))) + sx0 ;
t_y = F( (ldy)/( (vp0_hig) /(vp1_hig))) + sy0 ;
//:SSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSS:SHORT_HANDED://