How to draw a trapezium/trapezoid with css3?

问题:

When you go to the page http://m.google.com using Mobile Safari, you will see the beautiful bar on the top of the page.

I wanna draw some trapeziums (US: trapezoids) like that, but I don't know how. Should I use css3 3d transform? If you have a good method to achieve it please tell me.

回答1:

You can use some CSS like this:

#trapezoid {
    border-bottom: 100px solid red;
    border-left: 50px solid transparent;
    border-right: 50px solid transparent;
    height: 0;
    width: 100px;
}

<div id="trapezoid"></div>

It is really cool to make all this shapes, Take a look to more nice shapes at:

http://css-tricks.com/examples/ShapesOfCSS/

EDIT: This css is applied to a DIV element

回答2:

As this is quite old now, I feel it could use with some new updated answers with some new technologies.

CSS Transform Perspective

.trapezoid {
  width: 200px;
  height: 200px;
  background: red;
  transform: perspective(10px) rotateX(1deg);
  margin: 50px;
}

<div class="trapezoid"></div>

SVG

<svg viewBox="0 0 20 20" width="20%">
  <path d="M3,0 L17,0 L20,20 L0,20z" fill="red" />
</svg>

Canvas

var c = document.getElementById("myCanvas");
var ctx = c.getContext("2d");
ctx.moveTo(30, 0);
ctx.lineTo(170, 0);
ctx.lineTo(200, 200);
ctx.lineTo(0, 200);
ctx.fillStyle = "#FF0000";
ctx.fill();

<canvas id="myCanvas" width="200" height="200"></canvas>

回答3:

You have a few options available to you. You can just plain use an image, draw something with svg or distort a regular div with css transforms. An image would be easiest, and would work across all browsers. Drawing in svg is a bit more complex and is not guaranteed to work across the board.

Using css transforms on the other hand would mean you'd have to have your shape divs in the background, then layer the actual text over them in another element to that the text isn't skewed as well. Again, browser support isn't guaranteed.