在matlab 画箭头

[转载]在matlab 画箭头

原文地址：在matlab 画箭头作者：纯情小郎君

完整见链接http://www.mathworks.com/matlabcentral/fx_files/14056/1/content/arrow3_examples.html

ARROW3   EXAMPLES   (R13)

• Two-dimensional Quiver Plots
  • Example 1.
  • Example 2.
  • Example 3.
• Three-Dimensional Quiver Plots
  • Example 4.
  • Example 5.
• Cone Plots
  • Example 6.
  • Example 7.
• Feather Plots
  • Example 8.
  • Example 9.
• Compass Plots
  • Example 10.
  • Example 11.
• Reference Frames
  • Example 12.
  • Example 13.
  • Example 14.
• Named Colors
  • Example 15.
• Update (Modify and Restore)
  • Example 16.

Two-Dimensional Quiver Plots

Example 1. (cf. Joukowski Airfoil Transformation)

t=10*pi/180; u=0.1; v=0.1; r=1.1; tol=8e-2;
s=u+i*v; k=2*r*sin(t); w=exp(i*t);
[x,y]=meshgrid(-2.5:0.1:3.5,-3:0.1:3);
z=x+i*y; z(abs(z-s)<r-tol)=NaN;
f=w*z+exp(-i*t)*r^2./(z-s)+i*k*log(z);
a=0:0.1:2*pi; zc=r*(cos(a)+i*sin(a))+s;
c1=-1.5; c2=2.5; c3=c2-c1;
c=contour(x,y,imag(f),c1:c3/16:c2);
set(gca,'color',0.5*[1 1 1])
hold on, daspect([1 1 1])
fill(real(zc),imag(zc),'y'), colorbar
map=get(gcf,'colormap');
domain=0:1/(size(map,1)-1):1; m=1;
while m<length(c), n=m+c(2,m);
if c(2,m)>9, p=c(:,m+1:n)';
    if p(end,1)>p(1,1), p=flipud(p); end
    ndx=10:10:length(p);
    p2=p(ndx,:); p1=p(ndx-3,:);
    cc=interp1(domain,map,(c(1,m)-c1)/c3);
    set(gca,'ColorOrder',cc)
    arrow3(p1,p2,'0o',0.8)
end, m=n+1;
end, hold off


Example 2. (cf. Quiver)

[x,y]=meshgrid(-1:1/21:1);
z=x.*exp(-x.^2-y.^2);
[c,h]=contour(x,y,z);
set(h,'EdgeColor',0.45*[1 1 1])
ndx=1:3:length(x);
x=x(ndx,ndx); y=y(ndx,ndx); z=z(ndx,ndx);
[u,v]=gradient(z,1/7);
p1=[x(:),y(:)]; u=u(:); v=v(:);
m=abs(u+i*v); % gradient magnitude
daspect([1 1 1]), set(gca,'color',0.3*[1 1 1])
hold on, colormap hot, scale=0.4;
arrow3(p1,p1+scale*[u,v],'|',min(1.25*m,0.85))
hold off, h=colorbar;
set(h,'YTickLabel',num2str(str2num(get(h,...
'YTickLabel'))/scale))


Example 3. (cf. Two-Dimensional Quiver Plots)

[x,y,z]=peaks(-2:0.05:2);
contour(x,y,z,10); h=gca;
ndx=1:4:length(x);
x=x(ndx,ndx); y=y(ndx,ndx); z=z(ndx,ndx);
[u,v]=gradient(z,0.2);
p1=[x(:),y(:)]; u=u(:); v=v(:);
m=abs(u+i*v); % gradient magnitude
hold on, daspect([1 1 1]), scale=0.025;
arrow3(p1,p1+scale*[u,v],'|',0.9*m/max(m))
hold off, title('Dual Colormap')
h1=colorbar; h2=copyobj(h1,gcf);
set(h,'color',0.4*[1 1 1],...
'position',get(h,'position')+[0.05 0 0 0])
% ----------------------------------------------------- Right Colorbar
p=get(h1,'position');
set(h1,'position',[0.87,p(2),0.05,p(4)],...
'YTickLabel',num2str(str2num(get(h1,...
'YTickLabel'))/scale))                               % freeze labels
map=colormap; cdata=reshape(map,size(map,1),1,3);
set(get(h1,'children'),'cdata',cdata)              % freeze colors
set(get(h1,'title'),'string','Gradient')
% ------------------------------------------------------ Left Colorbar
caxis auto, colorbar, colormap autumn
set(h2,'YAxisLocation','left',...
'position',[0.08,p(2),0.05,p(4)])
set(get(h2,'title'),'string','Contour')


Three-Dimensional Quiver Plots

Example 4. (cf. Quiver3)

[x,y]=meshgrid(-2:0.25:2,-1:0.25:1);
z=x.*exp(-x.^2-y.^2);
surf(x,y,z,'EdgeColor','none')
axis([-2.5 2.5 -1.5 1.5 -1 1]), daspect([1 1 1])
set(gca,'CameraViewAngle',7)
[u,v,w]=surfnorm(x,y,z);
p1=[x(:),y(:),z(:)]; N=[u(:),v(:),w(:)];
hold on
arrow3(p1,p1+0.5*N,'1.5_b')
hold off, colormap spring
light('position',[-1 -1 -1],'style','local')
light('position',[0 1 1]), lighting gouraud


Example 5. (cf. Three-Dimensional Quiver Plots)

vx=2; vy=3; vz=10; a=-32; t=(0:.1:1)';
x=vx*t; y=vy*t; z=vz*t+1/2*a*t.^2;
r=[x,y,z]; v=gradient(r')';
axis([0 3 0 4 -10 2]), pbaspect([2 1 1])
hold on, grid on, view([70 18])
arrow3(r,r+v,'b',0.9)
hold off


Cone Plots

Example 6. (cf. Coneplot)

load wind, wind_speed=sqrt(u.^2+v.^2+w.^2);
xmin=min(x(:)); xmax=max(x(:));
ymin=min(y(:)); ymax=max(y(:));
zmin=min(z(:));
hsurfaces=slice(x,y,z,wind_speed,[xmin,xmax],ymax,zmin);
set(hsurfaces,'FaceColor','interp','EdgeColor','none',...
              'AmbientStrength',0.6)
hold on, daspect([2,2,1]), view(30,40), axis tight
xrange=linspace(xmin,xmax,8);
yrange=linspace(ymin,ymax,8);
[cx cy cz]=meshgrid(xrange,yrange,3:4:15);
ui=interp3(x,y,z,u,cx,cy,cz);
vi=interp3(x,y,z,v,cx,cy,cz);
wi=interp3(x,y,z,w,cx,cy,cz);
m=sqrt(ui.^2+vi.^2+wi.^2); m=m(:)/30;
p1=[cx(:),cy(:),cz(:)]; p2=[ui(:),vi(:),wi(:)];
hcones=arrow3(p1,p2,'r',m,3*m,'cone');
set(hcones,'DiffuseStrength',0.8)
hold off, axis off
camproj perspective, camzoom(1.2)
camlight right, lighting phong


Example 7. (cf. Vector Field Displayed with Cone Plots)

load wind, wind_speed=sqrt(u.^2+v.^2+w.^2);
hiso=patch(isosurface(x,y,z,wind_speed,40),...
          'FaceColor','red','EdgeColor','none');
isonormals(x,y,z,wind_speed,hiso)
hcap=patch(isocaps(x,y,z,wind_speed,40),...
          'FaceColor','interp','EdgeColor','none',...
          'AmbientStrength',0.6);
hold on, colormap hsv, daspect([1,1,1]), view(65,45)
[f verts]=reducepatch(isosurface(x,y,z,wind_speed,30),0.07);
cx=verts(:,1); cy=verts(:,2); cz=verts(:,3);
ui=interp3(x,y,z,u,cx,cy,cz);
vi=interp3(x,y,z,v,cx,cy,cz);
wi=interp3(x,y,z,w,cx,cy,cz);
m=sqrt(ui.^2+vi.^2+wi.^2); m=m(:)/40;
p1=[cx(:),cy(:),cz(:)]; p2=[ui(:),vi(:),wi(:)];
h1=arrow3(p1,p2,'b',m,3*m,'cone');
xrange=linspace(min(x(:)),max(x(:)),10);
yrange=linspace(min(y(:)),max(y(:)),10);
[cx,cy,cz]=meshgrid(xrange,yrange,3:4:15);
ui=interp3(x,y,z,u,cx,cy,cz);
vi=interp3(x,y,z,v,cx,cy,cz);
wi=interp3(x,y,z,w,cx,cy,cz);
m=sqrt(ui.^2 + vi.^2 + wi.^2); m=m(:)/50;
p1=[cx(:),cy(:),cz(:)]; p2=[ui(:),vi(:),wi(:)];
h2=arrow3(p1,p2,'g',m,3*m,'cone');
hold off, axis tight, box on
set(gca,'xtick',[],'ytick',[],'ztick',[])
camproj perspective, camzoom(1.2)
camlight(-45,45), lighting phong


Feather Plots

Example 8. (cf. Feather)

theta=(-90:10:90)'*pi/180;
n=length(theta); p1=[1:n;zeros(1,n)]';
r=2*ones(n,1); [u,v]=pol2cart(theta,r);
plot([1 n],[0 0],'r')
axis([0 20 -2 2]), daspect([8 2 1])
hold on, grid on
arrow3(p1,p1+[u,v],'r',0.9)
hold off


Example 9. (cf. Plotting Complex Numbers)

t=(0:0.5:10)'; s=0.05+i; Z=exp(-s*t);
n=length(Z); p1=[1:n;zeros(1,n)]';
plot([1 n],[0 0],'b')
axis([0 22 -1 1]), daspect([8 1 1])
hold on, grid on
arrow3(p1,p1+[real(Z),imag(Z)],'b',0.8)
hold off


Compass Plots

Example 10. (cf. Compass Plots)

wdir =[45 90 90 45 360 335 360 270 335 270 335 335];
knots=[ 6 6 8 6   5   9   8   8   9 10 14 12];
[x,y]=pol2cart(wdir*pi/180,knots);
polar(0,15), axis(15.9*[-1 1 -1 1])
hold on
arrow3(zeros(length(x),2),[x',y'],'r',1.25)
hold off


Example 11. (cf. Compass)

Z=eig(randn(20)); m=abs(Z);
R=ceil(max(m)); r=R+0.3;
polar(0,R), axis(r*[-1 1 -1 1])
hold on
arrow3(zeros(length(Z),2),[real(Z),imag(Z)],'b',1.75*m/R)
hold off


Reference Frames

Example 12. Coordinate Axes

p=[4 2 1]; axis([-6 6 0 5 -1 1])
pbaspect([2 1.5 1]), view(55,15)
hold on
arrow3(repmat([p(1:2),0],4,1),...
[0 p(2) 0;p(1) 0 0;p;0 0 0],'--o',0,0,0.5)
arrow3(zeros(3),diag([7,5,1]),'o')
arrow3([0 0 0],p,'2.5s',1.5,[],0)
hold off, axis off, camlight left
set(gca,'CameraViewAngle',4)
text(7.1,0,0,'X'), text(0,5.05,0,'Y')
text(0,0,1,'Z','VerticalAlignment','bottom',...
'HorizontalAlignment','center')


Example 13. Eigenvectors

n=500; % generate test data
newz=[ 1 1 1]/sqrt(3);
newy=[ 0 -1 1]/sqrt(2);
newx=cross(newy,newz);
R=[newx;newy;newz]; % rotation matrix
U=randn(n,3)*diag([1,2,3])*R;
u=U(:,1)+10; v=U(:,2)+20; w=U(:,3)+30;
% plot eigenvectors with mean origin
plot3(u,v,w,'r.')
axis([0 20 10 29 20 40]), daspect([1 1 1])
view([-70,15]), set(gca,'CameraViewAngle',8)
hold on, grid on
mu=repmat(mean([u,v,w]),3,1);
[V,D]=eig(cov([u,v,w]));
p=9*V'+mu;
arrow3(mu,p,[],1.25,[],0)
p=p+ones(3);
text(p(1,1),p(1,2),p(1,3),'bfU')
text(p(2,1),p(2,2),p(2,3),'bfV')
text(p(3,1),p(3,2),p(3,3),'bfW')
hold off


Example 14. (cf. Frenet)

z=(0:2/99:2)'; t=2*pi*z; r=2+z;
x=r.*cos(t); y=r.*sin(t);
R=[x,y,z]; dR=gradient(R')';
m=repmat(sqrt(sum(dR.*dR,2)),1,3);
T=dR./m; dT=gradient(T')';
m=repmat(sqrt(sum(dT.*dT,2)),1,3);
N=dT./m; B=cross(T,N);
plot3(x,y,z,'color',0.5*[1 1 1])
axis([-4 4 -4 4 0 2.5])
hold on, grid on, pbaspect([1 1 1])
set(gca,'CameraViewAngle',7)
plot3(0,0,0,'r'), plot3(0,0,0,'color',[0 0.5 0])
plot3(0,0,0,'b')
legend('Curve','Tangent','Normal','Binormal',2)
ndx=1:4:length(x); R=R(ndx,:);
arrow3(R,R+1.4*T(ndx,:),'r',0.9)
arrow3(R,R+1.4*N(ndx,:),'e',0.9)
arrow3(R,R+0.4*B(ndx,:),'b',0.9)
hold off, view(-50,5)
set(gcf,'renderer','zbuffer')


Named Colors

Example 15. Named Color Table

arrow3('colors',0.4) % 24 named colors with 44 adjustable shades


Color Equivalencies

ColorOrder

Arrow3

Simulink

Arrow3

Color1

Blue

LightBlue

aZure

Color2

Evergreen

DarkGreen

Asparagus

Color3

Red

Orange

kumQuat

Color4

Sky blue

Gray

Light gray

Color5

Violet

Color6

Pear

Color7

Dark gray