前言
这个是我之前搞数学建模需要用到的一个绘图函数，忘记出处哪里了，如果有冒犯之处，麻烦和我联系下。
箭头绘图
实现代码
- 使用教程在上头注释。
function H = arrowPlot(X, Y, varargin)
%ARROWPLOT Plot with arrow on the curve.
% ARROWPLOT(X, Y) plots X, Y vectors with 2 arrows directing the trend of data.
%
% You can use some options to edit the properties of arrow or curve.
% The options that you can change are as follow:
% number: The number of arrows, default number is 2;
% color: The color of arrows and curve, default color is [0, 0.447, 0.741];
% LineWidth: The line width of curve, default LineWidth is 0.5;
% scale: To scale the size of arrows, default scale is 1;
% limit: The range to plot, default limit is determined by X, Y data;
% ratio: The ratio of X-axis and Y-axis, default ratio is determined by X, Y data;
% You can use 'equal' for 'ratio', that means 'ratio' value is [1, 1, 1].
%
% Example 1:
% ---------
% t = [0:0.01:20];
% x = t.*cos(t);
% y = t.*sin(t);
% arrowPlot(x, y, 'number', 3)
%
% Example 2:
% ---------
% t = [0:0.01:20];
% x = t.*cos(t);
% y = t.*sin(t);
% arrowPlot(x, y, 'number', 5, 'color', 'r', 'LineWidth', 1, 'scale', 0.8, 'ratio', 'equal')
% Copyright 2017 TimeCoder.
h = plot(X, Y);
hold on;
if nargout == 1
H = h;
end
ratio = get(gca, 'DataAspectRatio');
limit = axis;
d = max(limit(2)-limit(1), limit(4)-limit(3));
default_options.number = 2;
default_options.color = [0 0.447 0.741];
default_options.LineWidth = 0.5;
default_options.size = d;
default_options.scale = 1;
default_options.limit = axis;
default_options.ratio = ratio;
Options = creat_options(varargin, default_options);
useroptions = creat_useroptions(varargin);
if ~isfield(useroptions, 'size')
Options.size = max(Options.limit(2)-Options.limit(1), Options.limit(4)-Options.limit(3));
end
if ~isfield(useroptions, 'ratio')
axis(Options.limit);
Options.ratio = get(gca, 'DataAspectRatio');
end
set(h, 'color', Options.color);
set(h, 'LineWidth', Options.LineWidth);
if isa(Options.ratio, 'char') && strcmp(Options.ratio, 'equal')
r = 1;
else
r = Options.ratio(2) / Options.ratio(1);
end
n_X = length(X);
journey = 0;
for i = 1 : n_X-1
journey = journey + sqrt( (X(i+1)-X(i))^2 + (Y(i+1)-Y(i))^2 );
end
journey_part = journey / Options.number;
if 10*journey<Options.size
Options.size = 10*journey;
end
[X_arrow, Y_arrow] = arrow_shape(50, 25);
[X_arrow1, Y_arrow1] = Scale(X_arrow, Y_arrow, 0.015*Options.scale*Options.size);
k=0.5;
journey_now = 0;
for i = 1 : n_X-1
journey_step = sqrt( (X(i+1)-X(i))^2 + (Y(i+1)-Y(i))^2 );
journey_next = journey_now + journey_step;
if journey_now<=k*journey_part && journey_next>k*journey_part
s = (k*journey_part - journey_now) / journey_step;
x0 = X(i) + s * (X(i+1)-X(i));
y0 = Y(i) + s * (Y(i+1)-Y(i));
[X_arrow2, Y_arrow2] = Rotate(X_arrow1, Y_arrow1, arg(X(i+1)-X(i), (Y(i+1)-Y(i))/r) );
[X_arrow3, Y_arrow3] = Translation(X_arrow2, r*Y_arrow2, [x0, y0]);
g = fill(X_arrow3, Y_arrow3, Options.color);
set(g, 'EdgeColor', Options.color);
k=k+1;
end
journey_now = journey_next;
end
axis(Options.limit);
if isequal(Options.ratio, 'equal')
axis equal;
end
hold off;
end
function Options = creat_options(user_choice, default_choice_struct)
n = length(user_choice);
if ~ispair(n)
error('varargin is not an options''s struct.');
end
Options = default_choice_struct;
i = 1;
while i <= n
if isfield(default_choice_struct, user_choice{i})
Options = setfield(Options, user_choice{i}, user_choice{i+1});
end
i = i + 2;
end
end
function Options = creat_useroptions(VARARGIN)
if ~isa(VARARGIN, 'cell')
error('VARARGIN is not of class cell!');
end
n = length(VARARGIN);
if ~ispair(n)
error('length of VARARGIN is not pair!');
end
i = 1;
Options = struct();
while i < n
Options = setfield(Options, VARARGIN{i}, VARARGIN{i+1});
i = i+2;
end
end
function check = ispair(x)
check = ( isint(x) && isint( 1.0*x / 2.0 ) );
end
function check = isint(x)
check = ( floor(x) == x );
end
function theta = arg(x, y)
if nargin == 2
[m, n] = size(x);
theta = zeros(m, n);
for i = 1 : m
for j = 1 : n
if x(i, j) > 0 || y(i, j) ~= 0
theta(i, j) = 2 * atan( y(i, j) ./ ( x(i, j) + sqrt(x(i, j).^2+y(i, j).^2) ) );
elseif x(i, j) < 0 && y(i, j) == 0
theta(i, j) = pi;
elseif x(i, j) == 0 && y(i, j) == 0
theta(i, j) = 0;
end
end
end
elseif nargin==1
theta = arg(real(x), imag(x));
end
end
function [X, Y] = arrow_shape(theta1, theta2)
theta1 = theta1/180*pi;
theta2 = theta2/180*pi;
x0 = tan(theta2) / ( tan(theta2) - tan(theta1) );
y0 = tan(theta1) * tan(theta2) / ( tan(theta2) - tan(theta1) );
X = [0, x0, 1, x0, 0];
Y = [0, y0, 0, -y0, 0];
end
function [X_new, Y_new] = Rotate( X, Y, varargin )
if length(varargin)==1
center = [0, 0];
theta = varargin{1};
elseif length(varargin)==2
center = varargin{1};
theta = varargin{2};
end
[m1, n1] = size(X);
[m2, n2] = size(Y);
if min(m1, n1) ~= 1
error('The size of X is wrong!');
end
if min(m2, n2) ~= 1
error('The size of Y is wrong!');
end
if n1 == 1
X = X';
end
if n2 == 1
Y = Y';
end
if length(X) ~= length(Y)
error('length(X) and length(Y) must be equal!');
end
XY_new = [cos(theta), -sin(theta); sin(theta), cos(theta)] * [X-center(1); Y-center(2)];
X_new = XY_new(1, :)+center(1);
Y_new = XY_new(2, :)+center(2);
end
function [X_new, Y_new] = Scale( X, Y, varargin )
if length(varargin)==1
center = [0, 0];
s = varargin{1};
elseif length(varargin)==2
center = varargin{1};
s = varargin{2};
end
X_new = s * ( X - center(1) ) + center(1);
Y_new = s * ( Y - center(2) ) + center(2);
end
function [X_new, Y_new] = Translation( X, Y, increasement )
X_new = X + increasement(1);
Y_new = Y + increasement(2);
end
附录
- 出处我也忘记了……╮(╯▽╰)╭
