xfpolys

Arguments

xpols,ypols

matrices of the same size (p,n) (points of the polygons).

fill

vector of size n or of size (p,n)

Description

xfpolys fills a set of polygons of the same size defined by the two matrices xpols and ypols. The coordinates of each polygon are stored in a column of xpols and ypols.

The polygons may be filled with a given color (flat) or painted with interpolated (shaded) colors.

flat color painting

In this case fill should be a vector of size n. The pattern for filling polygon number i is given by fill(i):

• if fill(i)<0, the polygon is filled with pattern id -fill(i).

• if fill(i)=0, the polygon is drawn with the current dash style (or current color) and not filled.

• if fill(i)>0, the polygon is filled with pattern id fill(i). Then its contour is drawn with the current dash (or color) and closed if necessary.

interpolated color painting

In this case fill should be a matrix with same sizes as xpols and ypols. Note that p must be equal to 3 or 4.

fill(k,i) gives the color at the kth edge of polygon i.

Examples

a=gca();
a.data_bounds=[0,-10;210,40];
a.foreground=color('red');
x1=[0,10,20,30,20,10,0]';
y1=[15,30,30,15,0,0,15]';
xpols=[x1 x1 x1 x1];
xpols=xpols+[0,60,120,180].*.ones(x1);
ypols=[y1 y1 y1 y1];
xfpolys(xpols,ypols,[-1,0,1,2])

// interpolated colors
clf()
f=gcf();
a=gca();
a.data_bounds=[0,-10;40,30];
isoview();
x1=[0,10,20,10]';
y1=[10,0,10,20]';
c=linspace(2,100,4)';
xpols=[x1 x1+20 x1+10 x1+10];
ypols=[y1 y1    y1+10 y1-10];
cols= [c c($:-1:1) c([3 4 1 2]) c]
f.color_map=jet(max(cols));
xfpolys(xpols,ypols,cols)

// interpolated colors
clf()
f=gcf();
x11=[0;20;20;0];
y11=[10;10;30;30];
c11=[10;10;30;30];
x12=x11;
y12=y11+20;
c12=[20;20;1;1];
c12=[30;30;10;10];
x21=[0;30;30;0]+22;
y21=[20;20;30;30];
c21=[20;20;30;30];
x22=x21;
y22=y21+10;
c22=[30;30;20;20];
x31=[0;40;40;0]+55;
y31=[0;0;30;30];
c31=[0;0;30;30];
x32=x31;
y32=y31+30;
c32=[30;30;0;0];
X=[x11 x12 x21 x22 x31 x32];
Y=[y11 y12 y21 y22 y31 y32];
C=([c11 c12 c21 c22 c31 c32]+1)*5;
a=gca();
isoview();
a.data_bounds=[min(X),min(Y);max(X),max(Y)];
f=gcf();
f.color_map=gray(max(C));
xfpolys(X,Y,C)

See also

• xfpoly — fill a polygon
• xpoly — draw a polyline or a polygon
• xpolys — draw a set of polylines or polygons