Control quiver arrow head width vs height.

27 次查看（过去 30 天）
Patrick
Patrick 2024-9-12
编辑： Sreeram 2024-9-16
Hi, I have a quiver plot where the arrow heads are incredibly wide by default, so I used "MaxHeadSize" to shrink them to a reasonable size. Also, the scaling behavior is set to 0 because I want them to connect the way they do currently. The downside is that now, instead of looking like arrowheads, they almost look like horizontal bars. I'm wondering if there is a way to control the head length independently of the head width.
  3 个评论
显示 1更早的评论
Patrick
Patrick 2024-9-12
编辑：Patrick 2024-9-12
The original code depends on data external to MATLAB (Matlab calls a C function which calls other stuff to generate the data).
What I can give is a simple way to reproduce the scaling issue:
` ` `
X = 10000*rand(1, 50);
Y = [50:-1:1];
%{----------------------------------------------------------%}
%{ Generate list of steps from each "X" to the next "1" %}
%{----------------------------------------------------------%}
C = {};
D = {};
count0 = 0;
for (n = 1:length( X ))
if (X(n) >=50)
C{n-count0} = n;
else
count0 = count0 + 1;
end
end
alpha = 1;
for (n = 1:length( Y ))
D{n} = C{alpha} - n;
if (n == C{alpha})
D{n} = 0;
end
end
Y = cell2mat(D);
Z = Y;
%{---------------------------%}
%{ Create U and V arrays %}
%{---------------------------%}
E = {};
F = {};
for ( n = 2:length(X) )
if (X(n) == 1)
E{n} = 0;
else
E{n} = X(n)-X(n-1);
end
end
U = cell2mat(E);
U(end+1) = 0;
for ( n = 1:length(X) )
if (Y(n) == 0)
F{n} = 0;
else
F{n} = -1;
end
end
V = cell2mat(F);
W = V;
%% Create plots
f = figure();
f.WindowState = "maximized";
%{-----------------------------------------%}
%{ Quiver plot 1 with labels and stuff %}
%{-----------------------------------------%}
Q2A = subplot(1, 2, 1);
q2a = quiver(Y, X, U, V, 0);
q2a.MaxHeadSize = 0.1;
q2a.Marker = "*";
%{-----------------------------------------%}
%{ Quiver plot 2 with labels and stuff %}
%{-----------------------------------------%}
Q2B = subplot(1, 2, 2);
q2b = quiver(Y, X, V, U, 0);
q2b.MaxHeadSize = 0.01;
q2b.Marker = "*";
` ` `

请先登录，再进行评论。

请先登录，再回答此问题。

回答（1 个）

Sreeram
Sreeram 2024-9-16
编辑：Sreeram 2024-9-16
Hi Patrick,
This is happening because the range of X- and Y-coordinates differ significantly. The arrow heads are scaled in relation to the range of axes.
Although I could not find any way to adjust arrow’s head length independent of head width, you can follow the workaround by the MathWorks Support Team here:
https://www.mathworks.com/matlabcentral/answers/95537
Here’s how I implemented it:
scale_factor = range(Y)/range(X);
q2b = quiver(Y, X*scale_factor, V, U*scale_factor, 0);
q2b.Marker = "*";
ytlbls=Q2B.YTickLabel;
ytlbls=cellfun(@(c)str2double(c)/scale_factor,ytlbls);
set(Q2B,'YTickLabel',ytlbls)
Here’s a comparison of before and after for the second subplot (which had arrows appearing as horizontal line):
Before
Before
After
I hope it helps!

类别

在 Help Center 和 File Exchange 中查找有关 Vector Fields 的更多信息

标签

产品


版本

R2024a

Community Treasure Hunt

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

Start Hunting!

Translated by