//panel that will hold the bmap
PANEL* testPan {};

//the function that does your task
void shot()
{
   //Create a bmap at runtime
   BMAP* testB=bmap_createblack(screen_size.x,screen_size.y,32);

   //Get the screenshot and 
   bmap_for_screen(testB,0,1);

   //use the just created bmap as the 'bmap' source
   testPan.bmap=testB;
   
   //Make the panel visible
   set(testPan,SHOW);

   //while the scale size is greater than 0.25 (25%)
   while(testPan.size_x > 0.25){wait(1);//always wait 1 frame each cycle

      //change to a higher number 0.5 for a faster scale time
      testPan.size_x -= 0.05 * time_step;

      // Keep the panel aligned while scaling
      testPan.pos_x = (screen_size.x - testPan.size_x)/4;
      testPan.pos_y = (screen_size.y - testPan.size_y)/4;
   }
}

//In the function main
function main(){
   //infinitely
   while(1){wait(1);
      if(key_x) shot();//update the corner image with the x key
   }
}