element-web/res/css/views/rooms/_VoiceRecordComposerTile.scss

/*
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.
*/

.mx_VoiceRecordComposerTile_stop {
    // 28px plus a 2px border makes this a 32px square (as intended)
    width: 28px;
    height: 28px;
    border: 2px solid $voice-record-stop-border-color;
    border-radius: 32px;
    margin-right: 16px; // between us and the send button
    position: relative;

    &::after {
        content: '';
        width: 14px;
        height: 14px;
        position: absolute;
        top: 7px;
        left: 7px;
        border-radius: 2px;
        background-color: $voice-record-stop-symbol-color;
    }
}

.mx_VoiceRecordComposerTile_delete {
    width: 24px;
    height: 24px;
    vertical-align: middle;
    margin-right: 8px; // distance from left edge of waveform container (container has some margin too)
    background-color: $voice-record-icon-color;
    mask-repeat: no-repeat;
    mask-size: contain;
    mask-image: url('$(res)/img/element-icons/trashcan.svg');
}

.mx_MessageComposer_row .mx_VoiceMessagePrimaryContainer {
    // Note: remaining class properties are in the PlayerContainer CSS.

    margin: 6px; // force the composer area to put a gutter around us
    margin-right: 12px; // isolate from stop/send button

    position: relative; // important for the live circle

    &.mx_VoiceRecordComposerTile_recording {
        // We are putting the circle in this padding, so we need +10px from the regular
        // padding on the left side.
        padding-left: 22px;

        &::before {
            animation: recording-pulse 2s infinite;

            content: '';
            background-color: $voice-record-live-circle-color;
            width: 10px;
            height: 10px;
            position: absolute;
            left: 12px; // 12px from the left edge for container padding
            top: 18px; // vertically center (middle align with clock)
            border-radius: 10px;
        }
    }
}

// The keyframes are slightly weird here to help make a ramping/punch effect
// for the recording dot. We start and end at 100% opacity to help make the
// dot feel a bit like a real lamp that is blinking: the animation ends up
// spending a lot of its time showing a steady state without a fade effect.
// This lamp effect extends into why the 0% opacity keyframe is not in the
// midpoint: lamps take longer to turn off than they do to turn on, and the
// extra frames give it a bit of a realistic punch for when the animation is
// ramping back up to 100% opacity.
//
// Target animation timings: steady for 1.5s, fade out for 0.3s, fade in for 0.2s
// (intended to be used in a loop for 2s animation speed)
@keyframes recording-pulse {
    0% {
        opacity: 1;
    }
    35% {
        opacity: 0;
    }
    65% {
        opacity: 1;
    }
}