CSS Triangles in React Native

Question

I'm working on an app that uses triangles that overlay other containers/divs. Had that solved with CSS before:

.triangle:after {
  content: "";
  display: block;
  position: absolute;
  top: 15px;
  left: -15px;
  width: 0;
  border-width: 0px 0px 15px 15px;
  border-style: solid;
}

but that doesn't work in React any more. What's the best solution to go here?

Answer 1

It is still possible to draw triangles in React Native using the CSS trick. I wrote a class to encapsulate this: https://github.com/Jpoliachik/react-native-triangle

If you'd like to write it yourself, I used this tool: http://apps.eky.hk/css-triangle-generator/ to generate the triangle I wanted and modify the styles to React Native syntax.

For example, an Isosceles triangle 90x90 pointing up in CSS reads:

width: 0;
height: 0;
border-style: solid;
border-width: 0 45px 90px 45px;
border-color: transparent transparent #007bff transparent;

But in React Native the styles would be:

triangle: {
     width: 0,
     height: 0,
     backgroundColor: 'transparent',
     borderStyle: 'solid',
     borderTopWidth: 0,
     borderRightWidth: 45,
     borderBottomWidth: 90,
     borderLeftWidth: 45,
     borderTopColor: 'transparent',
     borderRightColor: 'transparent',
     borderBottomColor: 'red',
     borderLeftColor: 'transparent',
   },