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两点之间的有向箭头

比如我们需要画一条从A点到B点的有向箭头。

涉及知识点：

• 矩阵的旋转 平移 缩放

1、main.m

% 根据两点坐标画箭头

clear;

close all;

start_point = [0, 0];

end_point = [3, 4];

draw_arrow(start_point, end_point);

2、draw_arrow.m

function draw_arrow(start_point, end_point)

% 从start_point到end_point画一箭头

K = 0.05; %箭头比例系数

theta = pi / 8; %箭头角度

A1 = [cos(theta), -sin(theta);

sin(theta), cos(theta)]; %旋转矩阵

theta = -theta;

A2 = [cos(theta), -sin(theta);

sin(theta), cos(theta)]; %旋转矩阵

arrow = start_point' - end_point';

arrow_1 = A1 * arrow; %旋转

arrow_2 = A2 * arrow;

arrow_1 = K * arrow_1 + end_point'; %缩放加平移

arrow_2 = K * arrow_2 + end_point';

hold on;

grid on;

axis equal;

plot([start_point(1), end_point(1)], [start_point(2), end_point(2)], 'k');

plot([arrow_1(1), end_point(1)], [arrow_1(2), end_point(2)], 'k');

plot([arrow_2(1), end_point(1)], [arrow_2(2), end_point(2)], 'k');

hold off;

3、运行结果

改变起点和终点的坐标，结果如下图所示。