# How to get different colours for different regions for this problem

8 views (last 30 days)
Atom on 17 Jun 2019
Edited: Image Analyst on 30 Jun 2019
How to get different colours for different regions for this problem? Here are 10 regions and I want to colour the regions? How to modify the code to get the desired result?
x=0:.00001:1;
y=x.*x;
plot(x,y,'r')
hold on
z=sqrt(x);
plot(x,z);
hold on
y=x;
plot(x,y,'g')
y=1-x;
hold on
plot(x,y,'k')
x=0:.00001:.334;
y=1-2*x;
hold on
plot(x,y,'r')
axis([0 1 0 1])
##### 2 CommentsShow NoneHide None
KSSV on 17 Jun 2019
Take the vertices of required closed area and use patch or fill.
Atom on 17 Jun 2019
How to do that? Please show me by one example using the code above

Robert U on 17 Jun 2019
Edited: Robert U on 18 Jun 2019
Hi pallav pal,
one example patch as requested. All others can be drawn accordingly.
x1=0:.00001:1;
x2=0:.00001:.334;
y1=x1.*x1;
z1=sqrt(x1);
y2=x1;
y3=1-x1;
y4=1-2*x2;
plot(x1,y1,'r')
hold on
plot(x1,z1);
plot(x1,y2,'g')
plot(x1,y3,'k')
plot(x2,y4,'r')
axis([0 1 0 1])
area1 = min(y1,y3);
patch('XData',[x1,0],'YData',[area1,0],'FaceAlpha',0.7,'FaceColor','red')
Kind regards,
Robert
Robert U on 26 Jun 2019
Edited: Image Analyst on 30 Jun 2019
x1=0:.00001:1;
x2=0:.00001:.334;
y1=x1.*x1;
z1=sqrt(x1);
y2=x1;
y3=1-x1;
y4=1-2*x2;
plot(x1,y1,'r')
hold on
plot(x1,z1);
plot(x1,y2,'g')
plot(x1,y3,'k')
plot(x2,y4,'r')
axis([0 1 0 1])
area1 = min(y1,y3);
% resample y4, out of range set to Zero
y4res = interp1(x2,y4,x1,'linear',0);
% define boolean selections
boolSel1 = z1>=y4res & z1<=y3;
boolSel2 = y3 >= y2 & z1 >= y3;
boolSel3 = y2 >= y4res;
boolSel4 = y4res >= y2 & y4res <= z1;
%create patch y coordinates of "smallest area"
area2 = [z1( boolSel1 ) y3(boolSel2) flip(y2(boolSel3)) flip(y4res(boolSel4))];
patch('XData',[x1,0],'YData',[area1,0],'FaceAlpha',0.7,'FaceColor','red')
patch('XData',[x1(boolSel1|boolSel2),flip(x1(boolSel3|boolSel4))],'YData',[area2],...
'FaceAlpha',0.7,'FaceColor','green')
Kind regards,
Robert
Atom on 30 Jun 2019
thanks a lot

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