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CSS drawing fan pattern

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Release： 2018-03-20 17:26:11

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This time I will bring you Css to draw a fan-shaped pattern. What are the precautions for drawing a fan-shaped pattern with Css? The following is a practical case, let's take a look.

Reading this article requires basic mathematical knowledge: central angle, radian system, trigonometric

function.

We have worked hard to achieve the following effects:

Of course you can embrace Svg... Here I will share how to create a circle with pure Css

Progress Bar, just three steps!

This item is 2 + 1 sandwich biscuits, the blue-green part is jam. It is obvious that the biscuit is made of two round p's. Let's focus on demonstrating how to make jam:

As shown in the picture, the large fan shape is composed of 6 small fans. , each small fan shape accounts for 1/15 of the entire round cake, and the large fan shape accounts for 6/15 of the entire round cake. We only need to construct a sector unit, copy it into 6 copies, rotate them at corresponding angles and connect them together.

How to construct a sector? Use triangles to disguise...

#How to calculate the width and height of a triangle? Assume the circle radius $radius is 100px and the fraction $count is 15. Then the central angle of the small sector is 360deg / 15, the height of the triangle is 100px, and the width is 2 * 100px * tan(360deg / 15 / 2). Among them, 360deg / 15 / 2 is converted into radians as PI / 15 (PI == 360deg / 2).

span {
    width: 0;
    height: 0;
    border: $radius solid transparent;
    $borderWidth: tan(pi() / $count) * $radius;
    border-left-width: $borderWidth;
    border-right-width: $borderWidth;
}

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Students who are not good at mathematics, please educate yourself...

Special handling is required when $count is 1 or 2, because tan(PI) and tan(PI / 2) are Infinite value. If you don’t understand, please study the tangent function image:

Related code (where $diameter = 2 * $radius is the diameter of the circle):

span {
    @if $count == 1 {
        width: $diameter;
        height: $diameter;
    } @else if $count == 2 {
        width: $diameter;
        height: $radius;
    } @else {
        width: 0;
        height: 0;
        border: $radius solid transparent;
        $borderWidth: tan(pi() / $count) * $radius;
        border-left-width: $borderWidth;
        border-right-width: $borderWidth;
    }
}

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Finally, copy and rotate the sector units one by one:

@for $index from 0 to $count {
    span:nth-child(#{$index + 1}) {
        $transform: translate(-50%, 0) rotate(360deg / $count / 2 + 360deg * $index / $count);
        $origin: if($count == 2, bottom, center);
        -webkit-transform: $transform;
                transform: $transform;
        -webkit-transform-origin: $origin;
                transform-origin: $origin;
    }
}

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I believe you have mastered the method after reading the case in this article. For more exciting information, please pay attention to other related articles on the php Chinese website!