Front-end daily combat: # 8 video demonstrates how a charge loader special effects creation with pure CSS

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https://codepen.io/zhang-ou/pen/deNqdV

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https://scrimba.com/c/cvrwJAK

Source code download

Please download from github.

https://github.com/comehope/front-end-daily-challenges/tree/master/008-charging-loader-animation

Code Reading

Define dom, only one container element:

<div class="battery"></div>

Centered:

html, body {
    height: 100%;
    display: flex;
    align-items: center;
    justify-content: center;
    background: linear-gradient(to bottom, teal, aqua);
}

Draw the outline of the main battery:

.battery {
    width: 6em;
    height: 3em;
    color: midnightblue;
    border: 0.5em solid currentColor;
    border-radius: 0.2em;
    font-size: 2em;
}

Battery projection shown:

.battery {
    position: relative;
}

.battery::after {
    content: '';
    position: absolute;
    width: 0.5em;
    height: 2em;
    background-color: currentColor;
    top: 0.5em;
    right: -1em;
    border-radius: 0 0.2em 0.2em 0;
}

Draw charge capacity:

.battery {
    background-image: linear-gradient(to right, whitesmoke, whitesmoke);
    background-repeat: no-repeat;
    background-size: 30% 80%;
    background-position: 0.3em 50%;
}

Definition and application of animation:

@keyframes charge {
    from {
        background-size: 10% 80%;
    }

    to {
        background-size: 95% 80%;
    }
}

.battery {
    animation: charge 5s linear infinite;
}

Finally, the animation by a linear function of time to change the step size:

.battery {
    animation: charge 5s steps(8) infinite;
}

We're done!

Knowledge Point

linear-gradient() https://developer.mozilla.org/en-US/docs/Web/CSS/linear-gradient

background-size https://developer.mozilla.org/en-US/docs/Web/CSS/background-size

background-position https://developer.mozilla.org/en-US/docs/Web/CSS/background-position

steps() https://developer.mozilla.org/en-US/docs/Web/CSS/single-transition-timing-function#Timing_functions

currentColor https://developer.mozilla.org/en-US/docs/Web/CSS/color_value#Values

border-radius https://developer.mozilla.org/en-US/docs/Web/CSS/border-radius