# Color areas between two curves and the x and y-axis (not polynomial)

9 vues (au cours des 30 derniers jours)
Yvespaul Auffray le 28 Fév 2024
Commenté : Yvespaul Auffray le 28 Fév 2024
I have two functions of one variable (p). I am trying to color the areas on the right of each curve. I succeed in doing this on a separate figure for each curve. I want to put those two curves on the same graph. When I try to do this, somehow it is the area on the left of the red curve that is shaded instead of the area of the right side of the red curve.
p = 0:0.001:1;
curve1 = ((3.*p)-2)./p
curve5 = 1./(2.*p);
ax1 = axes;
figure(1)
hold(ax1, 'on')
hold on
plot(p, curve1, 'LineWidth', 1.5,'linestyle','-','color',[0 0.4470 0.7410]);
hold on;
xlim([0 1]);
ylim([0 1]);
grid on;
lowerboundary = min(ylim(ax1));
area(curve1,lowerboundary,'FaceColor','b','FaceAlpha',0.2);
hold on
area(p,curve1,'FaceColor','b','FaceAlpha',0.2);
ax=gca;
figure(2)
hold(ax1, 'on')
hold on
plot(p, curve5, 'LineWidth', 1.5,'linestyle','-','color',[0.6350 0.0780 0.1840]);
hold on;
xlim([0 1]);
ylim([0 1]);
grid on;
upperboundary = max(ylim(ax1));
area(p,curve5,'FaceColor','r','FaceAlpha',0.2);
hold on
area(curve5,upperboundary,'FaceColor','r','FaceAlpha',0.2);
ax=gca;
figure(3)
hold(ax1, 'on')
hold on
plot(p, curve5, 'LineWidth', 1.5,'linestyle','-','color',[0.6350 0.0780 0.1840]);
hold on
plot(p, curve1, 'LineWidth', 1.5,'linestyle','-','color',[0 0.4470 0.7410]);
xlim([0 1]);
ylim([0 1]);
grid on
upperboundary = max(ylim(ax1));
lowerboundary = min(ylim(ax1));
area(curve5,upperboundary,'FaceColor','r','FaceAlpha',0.2);
hold on
area(p,curve5,'FaceColor','r','FaceAlpha',0.2);
hold on
area(curve1,lowerboundary,'FaceColor','b','FaceAlpha',0.2);
hold on
area(p,curve1,'FaceColor','b','FaceAlpha',0.2);
ax=gca;
Here are the outputs for the respectively figure 1, 2 and 3. My goal is to have on figure 3 the red color area on the right side of the red line, as if figures 1 and 2 were superposed/merged.
Any help would be appreciated!
##### 0 commentairesAfficher -2 commentaires plus anciensMasquer -2 commentaires plus anciens

Connectez-vous pour commenter.

### Réponse acceptée

Chunru le 28 Fév 2024
It seems that area function cannot individually change the basevalue (I have done some separate tests).
One work around is to use two axes of same position in the same figure so that each axes has its one basevalue.
p = 0:0.001:1;
curve1 = ((3.*p)-2)./p;
curve5 = 1./(2.*p);
figure(1)
ax1 = axes;
hold(ax1, 'on')
plot(p, curve1, 'LineWidth', 1.5,'linestyle','-','color',[0 0.4470 0.7410]);
xlim([0 1]);
ylim([0 1]);
grid on;
lowerboundary = min(ylim(ax1));
area(p, curve1, lowerboundary,'FaceColor','b','FaceAlpha',0.2);
figure(2)
ax1 = axes;
hold(ax1, 'on')
plot(p, curve5, 'LineWidth', 1.5,'linestyle','-','color',[0.6350 0.0780 0.1840]);
xlim([0 1]);
ylim([0 1]);
grid on;
upperboundary = max(ylim(ax1));
area(p,curve5,upperboundary,'FaceColor','r','FaceAlpha',0.2);
% Workaround with 2 axes
f = figure(3);
ax1 = axes(f);
hold(ax1, 'on')
plot(ax1, p, curve5, 'LineWidth', 1.5,'linestyle','-','color',[0.6350 0.0780 0.1840]);
xlim(ax1,[0 1]);
ylim(ax1,[0 1]);
grid on
upperboundary = max(ylim(ax1));
area(ax1, p, curve5, upperboundary,'FaceColor','r','FaceAlpha',0.2);
ax2= axes(f, "Position", ax1.Position, "Color", "none");
hold(ax2, 'on')
plot(ax2, p, curve1, 'LineWidth', 1.5,'linestyle','-','color',[0 0.4470 0.7410]);
xlim(ax2,[0 1]);
ylim(ax2,[0 1]);
grid on
lowerboundary = min(ylim(ax2));
area(ax2,p, curve1,lowerboundary,'FaceColor','b','FaceAlpha',0.2);
##### 1 commentaireAfficher -1 commentaires plus anciensMasquer -1 commentaires plus anciens
Yvespaul Auffray le 28 Fév 2024
Many thanks, the workaround does the trick very well!

Connectez-vous pour commenter.

### Catégories

En savoir plus sur Surface and Mesh Plots dans Help Center et File Exchange

R2023b

### Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!

Translated by