First, conisder the change of w=z2 .Consider a source figure of a mouse ( on the right ). Consider how this figure will be changed by the function w=z2.
It is necessary to picture a house first, because there is a " picture definition " in Decimal BASIC. Let's try to define this picture with the name, "House".
PICTURE House SET AREA COLOR 15 PLOT AREA: 0,1; 0,0; 2,0; 2,1 ! The wall SET AREA COLOR 2 PLOT AREA: -0.6,1; 2.6,1; 2,2; 0,2 ! The roof SET AREA COLOR 10 PLOT AREA: 0.1,0; 0.1,0.8; 0.5,0.8; 0.5,0 ! The door SET AREA COLOR 5 PLOT AREA: 1.4,0.4; 1.9,0.4; 1.9,0.8; 1.4,0.8 ! The window SET AREA COLOR 12 PLOT AREA: 1.7,2; 1.7,2.3; 1.5,2.3; 1.5,2 ! The chimney END PICTURE
As previous, let's trace this house with mouse pen. The result is shown below.
Next, consider a car and an elephant are changed. In some places, they become crushed out of shape.
Now, having placed the starting point in the lower left edge of the figure, let's try to shift the position of the figure. In Decimal BASIC, use introduction
. DRAW PICTURE WIDTH SHIFT(a,b)
to shift figure
