Maintain Aspect Ratio Mixin on Open Event Frontend

The welcome page of the Open-Event-Frontend is designed to contain cards that represent an event. A user is directed to the event-details page by clicking on the corresponding card. The page consists of an image that serves as the banner for the event and an overlapping div to provide some contrast against the image. A comment may also be added onto the image and along with the overlapping div it is wrapped in a container div.

Since we have given a specific height to the contrasting div, the background image shrinks according to the screen size but the contrasting div does not whenever we go from a large screen to a smaller screen.

Mobile view (before):-

We want our contrasting div also to resize in accordance to the image. To do it, we first define a sass mixin to maintain a common aspect ratio for image and overlapping div. Let us see it’s code.

 @mixin aspect-ratio($width, $height) {
    position: relative;
    &:before {
      display: block;
      content: "";
      width: 100%;
      padding-top: ($height / $width) * 100%;
    }
    > .content {
      position: absolute;
      top: 0;
      left: 0;
      right: 0;
      bottom: 0;
    }
    > img {
      position: absolute;
      top: 0;
      left: 0;
      right: 0;
      bottom: 0;
    }
  }

So what does this mixin actually doing is we are passing the height and width of the image and we are defining a pseudo element for our image and give it a margin top of (height/width)*100 since this value is related to image width (height: 0; padding-bottom: 100%; would also work, but then we have to adjust the padding-bottom value every time we change the width). Now we just position the content element and image as absolute with all four orientations set to 0. This just covers the parent element completely, no matter which size it has.

Now we can simply use our mixin by adding the following line of code in out container div

@include aspect-ratio(2, 1);

Here we want to maintain a 2:1 aspect ratio and the user is also expected to upload the image in the same aspect ratio. Therefore, we pass width as 2 and height as 1 to our mixin.

Now when we resize our screen both the image and the overlapping div resize maintaining 2:1 aspect ratio.

Mobile view (after):-

Resources

  • mademyday blog describes a method of using pseudo elements to maintain an element’s aspect ratio.
  • css-tricks snippet.

Resizing Uploaded Image (Python)

While we make websites were we need to upload images such as in event organizing server, the image for the event needs to be shown in various different sizes in different pages. But an image with high resolution might be an overkill for using at a place where we just need it to be shown as a thumbnail. So what most CMS websites do is re-size the image uploaded and store a smaller image as thumbnail. So how do we do that? Let’s find out.

Continue reading Resizing Uploaded Image (Python)