Setting graphic context values

User can change graphic context to modify the action of graphic drawing primitives. Sequence of instruction below produce the picture :

• Setting a clipping zone

  // draw segments
  x=0:0.2:2*%pi;
  x1=[sin(x);10*sin(x)];y1=[cos(x);10*cos(x)];
  xsegs(10*x1+200*ones(x1),10*y1+200*ones(y1));
  //draw segments with clipping zone
  xrect(150,460,100,150);xclip(150,460,100,150);
  x=0:0.2:2*%pi;
  x1=[sin(x);10*sin(x)];y1=transl([cos(x);10*cos(x)],20);
  xsegs(10*x1+200*ones(x1),10*y1+200*ones(y1));
  xset('clipgrf');
  

• Setting a dash style

  xset('dashes',1,2,2);
  xrect(140,470,120,170);
  

• Setting font style and size

  xset('font',2,0);xstring(0,130,'Scilab');
  xset('font',2,1);xstring(0,150,'Scilab');
  xset('font',2,2);xstring(0,170,'Scilab');
  xset('font',2,3);xstring(0,200,'Scilab');
  xset('font',2,4);xstring(0,230,'Scilab');
  xset('font',2,5);xstring(0,270,'Scilab');
  xset('font',3,5);xstring(0,310,'Scilab');
  xset('font',4,5);xstring(0,350,'Scilab');
  

• Changing current mark

  x1=[350,400,450];y1=300*ones(x1);
  xset('mark',6,2);xpoly(x1,y1,'marks',0);
  x1=[350,400,450];y1=300*ones(x1);
  xset('mark',7,2);xpoly(x1,y1+50*ones(x1),'marks',0);
  xset('mark',8,3);xpoly(x1,y1+100*ones(x1),'marks',0);
  

• Changing lines thickness

  xset('thickness',5);xrect(400,200,50,100);
  

• Clear a rectangle

  xfrect(400,50,50,100);xclea(410,50,10,100);