element-web/res/css/views/messages/_MImageBody.scss

/*
Copyright 2015, 2016 OpenMarket Ltd
Copyright 2021 The Matrix.org Foundation C.I.C.

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
*/

$timeline-image-border-radius: 8px;

.mx_MImageBody_placeholder {
    // Position the placeholder on top of the thumbnail, so that the reveal animation can work
    position: absolute;
    left: 0;
    top: 0;
    height: 100%;
    width: 100%;

    background-color: $background;

    .mx_Blurhash > canvas {
        animation: mx--anim-pulse 1.75s infinite cubic-bezier(.4, 0, .6, 1);
    }
}

.mx_MImageBody_thumbnail_container {
    border-radius: $timeline-image-border-radius;

    // Necessary for the border radius to apply correctly to the placeholder
    overflow: hidden;
    contain: paint;

    min-height: $font-44px;
    min-width: $font-44px;
    display: flex;
    justify-content: center;
    align-items: center;
}

.mx_MImageBody_thumbnail {
    display: block;

    // Force the image to be the full size of the container, even if the
    // pixel size is smaller. The problem here is that we don't know what
    // thumbnail size the HS is going to give us, but we have to commit to
    // a container size immediately and not change it when the image loads
    // or we'll get a scroll jump (or have to leave blank space).
    // This will obviously result in an upscaled image which will be a bit
    // blurry. The best fix would be for the HS to advertise what size thumbnails
    // it guarantees to produce.
    height: 100%;
    width: 100%;
}

.mx_MImageBody_gifLabel {
    position: absolute;
    display: block;
    top: 0px;
    left: 14px;
    padding: 5px;
    border-radius: 5px;
    background: $imagebody-giflabel;
    border: 2px solid $imagebody-giflabel-border;
    color: $imagebody-giflabel-color;
    pointer-events: none;
}

.mx_HiddenImagePlaceholder {
    position: absolute;
    left: 0;
    top: 0;
    bottom: 0;
    right: 0;

    // To center the text in the middle of the frame
    display: flex;
    align-items: center;
    justify-content: center;
    text-align: center;

    cursor: pointer;
    background-color: $header-panel-bg-color;

    .mx_HiddenImagePlaceholder_button {
        color: $accent;

        span.mx_HiddenImagePlaceholder_eye {
            margin-right: 8px;

            background-color: $accent;
            mask-image: url('$(res)/img/feather-customised/eye.svg');
            display: inline-block;
            width: 18px;
            height: 14px;
        }

        span:not(.mx_HiddenImagePlaceholder_eye) {
            vertical-align: text-bottom;
        }
    }
}

.mx_EventTile:hover .mx_HiddenImagePlaceholder {
    background-color: $background;
}