Moving Backgrounds With Mouse Position

Let’s say you wanted to move the background-position on an element as you mouse over it to give the design a little pizzazz. You have an element like this:

<div class="module" id="module"></div>

And you toss a background on it:

.module { background-image: url(big-image.jpg);
}

You can adjust the background-position in JavaScript like this:

const el = document.querySelector("#module"); el.addEventListener("mousemove", (e) => { el.style.backgroundPositionX = -e.offsetX + "px"; el.style.backgroundPositionY = -e.offsetY + "px";
});

See the Pen Move a background with mouse by Chris Coyier (@chriscoyier) on CodePen.

Or, you could update CSS custom properties in the JavaScript instead:

const el = document.querySelector("#module"); el.addEventListener("mousemove", (e) => { el.style.setProperty('--x', -e.offsetX + "px"); el.style.setProperty('--y', -e.offsetY + "px");
});
.module { --x: 0px; --y: 0px; background-image: url(large-image.jpg); background-position: var(--x) var(--y);
}

See the Pen Move a background with mouse by Chris Coyier (@chriscoyier) on CodePen.

Here’s an example that moves the background directly in JavaScript, but with a transition applied so it slides to the new position rather than jerking around the first time you enter:

See the Pen Movable Background Ad by Chris Coyier (@chriscoyier) on CodePen.

Or, you could move an actual element instead (rather than the background-position). You’d do this if there is some kind of content or interactivity on the sliding element. Here’s an example of that, which sets CSS custom properties again, but then actually moves the element via a CSS translate() and a calc() to temper the speed.

See the Pen Hotjar Moving Heatmap Ad by Chris Coyier (@chriscoyier) on CodePen.

I’m sure there are loads of other ways to do this — a moving SVG viewBox, scripts controlling a canvas, webGL… who knows! If you have some fancier ways to handle this, link ’em up in the comments.

The post Moving Backgrounds With Mouse Position appeared first on CSS-Tricks.

CSS Basics: Using Multiple Backgrounds

With CSS, you can control the background of elements. You can set a background-color to fill it with a solid color, a background-image to fill it with (you guessed it) an image, or even both:

body { background-color: red; background-image: url(pattern.png);
}

Here’s an example where I’m using an SVG image file as the background, embedded right in the CSS as a data URL.

See the Pen background color and image together by Chris Coyier (@chriscoyier) on CodePen.

That’s just a single image there, repeated, but we can actually set multiple background images if we want. We do that by separating the values with commas.

body { background-image: url(image-one.jpg), url(image-two.jpg);
}

If we leave it like that, image-one.jpg will repeat and entirely cover image-two.jpg. But we can control them individually as well, with other background properties.

body { background-image: url(image-one.jpg), url(image-two.jpg); background-position: top right, /* this positions the first image */ bottom left; /* this positions the second image */ background-repeat: no-repeat; /* this applies to both images */
}

See how background-position also has comma-separated values? Those will apply individually to each image respectively. And then how background-repeat has only one value? We could have done two values in the same way, but by using just one value, it applies to both.

Here’s an example using four separate images, one in each corner, offset by a smidge:

See the Pen Example of multiple backgrounds by Chris Coyier (@chriscoyier) on CodePen.

It’s too bad you can’t rotate or flip background images or else we could have used just one. We can rotate and flip entire elements (or psuedo elements) though, so in cases like that, we can get away with using a single image!

See the Pen Flipping Image So You Can Use Just One by Chris Coyier (@chriscoyier) on CodePen.

Just a few other things to be aware of here:

  1. The stacking order of multiple background is “first is on top.”
  2. Gradients are applied through background-image, so they can be used as part of all this. For example, you could set a transparent gradient over a raster image.

See the Pen Tinted Image w/ Multiple Backgrounds by Chris Coyier (@chriscoyier) on CodePen.


CSS Basics: Using Multiple Backgrounds is a post from CSS-Tricks