如果y方向设置为“反向”，如何在Matlab中修复矢量注释头的错误对齐

Question

代码

figure
scatter([1,2,3],[1,2,3]);
ax = gca;
ax.YDir = 'reverse'
ah = annotation('arrow','position',[ 2.5 2.5 -1 -1]);
set(ah,'parent',ax);

给出了错误的向量头对齐方式：

有什么办法解决吗？

Answer 1

一种解决问题的方法是用两个分开的注释创建箭头和直线：

import requests
from bs4 import BeautifulSoup
import pandas as pd


url = 'http://www.intermediary.natwest.com/intermediary-solutions/lending-criteria.html'
headers = {'User-Agent': 'Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/73.0.3683.103 Safari/537.36'}

response = requests.get(url)
soup = BeautifulSoup(response.text, 'html.parser')

sections = soup.find_all('div',{'class':'accordion-section-content'})

results = {}
for section in sections:
    splits = section.prettify().split('<strong>')
    for each in splits:
        try:
            headline, content = each.split('</strong>')[0].strip(), each.split('</strong>')[1]
            headline = BeautifulSoup(headline, 'html.parser').text.strip()
            content = BeautifulSoup(content, 'html.parser').text.strip()

            content_split = content.split('\n')
            content = ' '.join([ text.strip() for text in content_split if text != ''])

            results[headline] = content
        except:
            continue

df = pd.DataFrame(results.items(), columns = ['Headings','Content'])
df.to_csv('C:/test.csv', index=False)

现在箭头坐标为figure scatter([1,2,3],[1,2,3]); ax = gca; ax.YDir = 'reverse' %Define the variable xac = 2.5; %x arrow coordinate yac = 2.5; %y arrow coordinate xas = -1; %x arrow shift yas = -1; %y arrow shift if get(ax,'Ydir') == 'reverse': %Create the arrow ah1 = annotation('arrow','position',[ xac yac+2*yas xas -yas],'linestyle','none'); set(ah1,'parent',ax); %Create the line ah2 = annotation('arrow','position',[ xac yac xas yas],'headstyle','none'); set(ah2,'parent',ax); else: ah = annotation('arrow','position',[ xac yac xas yas]); set(ah,'parent',ax); end ，

结果：

Answer 2

您可以在Matlab文件交换中使用Annotate：

fig = figure;
scatter([1,2,3],[1,2,3]);
ax = gca;
ax.YDir = 'reverse';
Annotate(ax, 'arrow',[2.5 1.5],[2.5 1.5])

这样，您就不必依赖Mathworks来修复该错误了，但是您需要下载其他文件...

Answer 3

根据Matlab colormap line plot，annotation对象应位于“图形，uipanel或uitab对象”内部。请勿将其放在轴对象中。

相反，请计算箭头的位置。图本身。您可以按照以下步骤进行操作：

figure;
scatter([1,2,3],[1,2,3]);
ax = gca;
ax.YDir = 'reverse';

% Original arrow definition
origin = [2.5,2.5];
direction = [-1,-1];

% Convert coordinates from axes to figure
origin = origin - [ax.XLim(1),ax.YLim(1)];
origin = origin ./ [diff(ax.XLim),-diff(ax.YLim)]; % minus for inverse Y axis
origin(2) = origin(2) + 1; % for inverse Y axis
origin = origin .* ax.Position(3:4) + ax.Position(1:2);

direction = direction ./ [diff(ax.XLim),-diff(ax.YLim)]; % minus for inverse Y axis
direction = direction .* ax.Position(3:4);

% Draw arrow in figure
ah = annotation('arrow','position',[origin,direction]);

您可以创建一个简单的函数来执行此计算。反转y轴所需的位可以以ax.YDir == 'reverse'为条件。