signal-desktop/ts/components/GroupCallRemoteParticipants.tsx
2022-05-23 10:16:13 -07:00

538 lines
18 KiB
TypeScript

// Copyright 2020-2022 Signal Messenger, LLC
// SPDX-License-Identifier: AGPL-3.0-only
import React, { useCallback, useState, useMemo, useEffect } from 'react';
import Measure from 'react-measure';
import { takeWhile, clamp, chunk, maxBy, flatten, noop } from 'lodash';
import type { VideoFrameSource } from 'ringrtc';
import { GroupCallRemoteParticipant } from './GroupCallRemoteParticipant';
import {
GroupCallOverflowArea,
OVERFLOW_PARTICIPANT_WIDTH,
} from './GroupCallOverflowArea';
import type {
GroupCallRemoteParticipantType,
GroupCallVideoRequest,
} from '../types/Calling';
import { useGetCallingFrameBuffer } from '../calling/useGetCallingFrameBuffer';
import type { LocalizerType } from '../types/Util';
import { usePageVisibility } from '../hooks/usePageVisibility';
import { useDevicePixelRatio } from '../hooks/useDevicePixelRatio';
import { nonRenderedRemoteParticipant } from '../util/ringrtc/nonRenderedRemoteParticipant';
import { missingCaseError } from '../util/missingCaseError';
import { SECOND } from '../util/durations';
import { filter, join } from '../util/iterables';
import * as setUtil from '../util/setUtil';
import * as log from '../logging/log';
import { MAX_FRAME_HEIGHT, MAX_FRAME_WIDTH } from '../calling/constants';
const MIN_RENDERED_HEIGHT = 180;
const PARTICIPANT_MARGIN = 10;
const TIME_TO_STOP_REQUESTING_VIDEO_WHEN_PAGE_INVISIBLE = 20 * SECOND;
// We scale our video requests down for performance. This number is somewhat arbitrary.
const VIDEO_REQUEST_SCALAR = 0.75;
type Dimensions = {
width: number;
height: number;
};
type GridArrangement = {
rows: Array<Array<GroupCallRemoteParticipantType>>;
scalar: number;
};
type PropsType = {
getGroupCallVideoFrameSource: (demuxId: number) => VideoFrameSource;
i18n: LocalizerType;
isInSpeakerView: boolean;
remoteParticipants: ReadonlyArray<GroupCallRemoteParticipantType>;
setGroupCallVideoRequest: (_: Array<GroupCallVideoRequest>) => void;
remoteAudioLevels: Map<number, number>;
};
enum VideoRequestMode {
Normal = 'Normal',
LowResolution = 'LowResolution',
NoVideo = 'NoVideo',
}
// This component lays out group call remote participants. It uses a custom layout
// algorithm (in other words, nothing that the browser provides, like flexbox) in
// order to animate the boxes as they move around, and to figure out the right fits.
//
// It's worth looking at the UI (or a design of it) to get an idea of how it works. Some
// things to notice:
//
// * Participants are arranged in 0 or more rows.
// * Each row is the same height, but each participant may have a different width.
// * It's possible, on small screens with lots of participants, to have participants
// removed from the grid. This is because participants have a minimum rendered height.
//
// There should be more specific comments throughout, but the high-level steps are:
//
// 1. Figure out the maximum number of possible rows that could fit on the screen; this is
// `maxRowCount`.
// 2. Split the participants into two groups: ones in the main grid and ones in the
// overflow area. The grid should prioritize participants who have recently spoken.
// 3. For each possible number of rows (starting at 0 and ending at `maxRowCount`),
// distribute participants across the rows at the minimum height. Then find the
// "scalar": how much can we scale these boxes up while still fitting them on the
// screen? The biggest scalar wins as the "best arrangement".
// 4. Lay out this arrangement on the screen.
export const GroupCallRemoteParticipants: React.FC<PropsType> = ({
getGroupCallVideoFrameSource,
i18n,
isInSpeakerView,
remoteParticipants,
setGroupCallVideoRequest,
remoteAudioLevels,
}) => {
const [containerDimensions, setContainerDimensions] = useState<Dimensions>({
width: 0,
height: 0,
});
const [gridDimensions, setGridDimensions] = useState<Dimensions>({
width: 0,
height: 0,
});
const devicePixelRatio = useDevicePixelRatio();
const getFrameBuffer = useGetCallingFrameBuffer();
const { invisibleDemuxIds, onParticipantVisibilityChanged } =
useInvisibleParticipants(remoteParticipants);
// 1. Figure out the maximum number of possible rows that could fit on the screen.
//
// We choose the smaller of these two options:
//
// - The number of participants, which means there'd be one participant per row.
// - The number of possible rows in the container, assuming all participants were
// rendered at minimum height. Doesn't rely on the number of participants—it's some
// simple division.
//
// Could be 0 if (a) there are no participants (b) the container's height is small.
const maxRowCount = Math.min(
remoteParticipants.length,
Math.floor(
containerDimensions.height / (MIN_RENDERED_HEIGHT + PARTICIPANT_MARGIN)
)
);
// 2. Split participants into two groups: ones in the main grid and ones in the overflow
// sidebar.
//
// We start by sorting by `presenting` first since presenters should be on the main grid
// then we sort by `speakerTime` so that the most recent speakers are next in
// line for the main grid. Then we split the list in two: one for the grid and one for
// the overflow area.
//
// Once we've sorted participants into their respective groups, we sort them on
// something stable (the `demuxId`, but we could choose something else) so that people
// don't jump around within the group.
//
// These are primarily memoized for clarity, not performance.
const sortedParticipants: Array<GroupCallRemoteParticipantType> = useMemo(
() =>
remoteParticipants
.concat()
.sort(
(a, b) =>
Number(b.presenting || 0) - Number(a.presenting || 0) ||
(b.speakerTime || -Infinity) - (a.speakerTime || -Infinity)
),
[remoteParticipants]
);
const gridParticipants: Array<GroupCallRemoteParticipantType> =
useMemo(() => {
if (!sortedParticipants.length) {
return [];
}
const candidateParticipants = isInSpeakerView
? [sortedParticipants[0]]
: sortedParticipants;
// Imagine that we laid out all of the rows end-to-end. That's the maximum total
// width. So if there were 5 rows and the container was 100px wide, then we can't
// possibly fit more than 500px of participants.
const maxTotalWidth = maxRowCount * containerDimensions.width;
// We do the same thing for participants, "laying them out end-to-end" until they
// exceed the maximum total width.
let totalWidth = 0;
return takeWhile(candidateParticipants, remoteParticipant => {
totalWidth += remoteParticipant.videoAspectRatio * MIN_RENDERED_HEIGHT;
return totalWidth < maxTotalWidth;
}).sort(stableParticipantComparator);
}, [
containerDimensions.width,
isInSpeakerView,
maxRowCount,
sortedParticipants,
]);
const overflowedParticipants: Array<GroupCallRemoteParticipantType> = useMemo(
() =>
sortedParticipants
.slice(gridParticipants.length)
.sort(stableParticipantComparator),
[sortedParticipants, gridParticipants.length]
);
// 3. For each possible number of rows (starting at 0 and ending at `maxRowCount`),
// distribute participants across the rows at the minimum height. Then find the
// "scalar": how much can we scale these boxes up while still fitting them on the
// screen? The biggest scalar wins as the "best arrangement".
const gridArrangement: GridArrangement = useMemo(() => {
let bestArrangement: GridArrangement = {
scalar: -1,
rows: [],
};
if (!gridParticipants.length) {
return bestArrangement;
}
for (let rowCount = 1; rowCount <= maxRowCount; rowCount += 1) {
// We do something pretty naïve here and chunk the grid's participants into rows.
// For example, if there were 12 grid participants and `rowCount === 3`, there
// would be 4 participants per row.
//
// This naïve chunking is suboptimal in terms of absolute best fit, but it is much
// faster and simpler than trying to do this perfectly. In practice, this works
// fine in the UI from our testing.
const numberOfParticipantsInRow = Math.ceil(
gridParticipants.length / rowCount
);
const rows = chunk(gridParticipants, numberOfParticipantsInRow);
// We need to find the scalar for this arrangement. Imagine that we have these
// participants at the minimum heights, and we want to scale everything up until
// it's about to overflow.
//
// We don't want it to overflow horizontally or vertically, so we calculate a
// "width scalar" and "height scalar" and choose the smaller of the two. (Choosing
// the LARGER of the two could cause overflow.)
const widestRow = maxBy(rows, totalRemoteParticipantWidthAtMinHeight);
if (!widestRow) {
log.error('Unable to find the widest row, which should be impossible');
continue;
}
const widthScalar =
(gridDimensions.width - (widestRow.length + 1) * PARTICIPANT_MARGIN) /
totalRemoteParticipantWidthAtMinHeight(widestRow);
const heightScalar =
(gridDimensions.height - (rowCount + 1) * PARTICIPANT_MARGIN) /
(rowCount * MIN_RENDERED_HEIGHT);
const scalar = Math.min(widthScalar, heightScalar);
// If this scalar is the best one so far, we use that.
if (scalar > bestArrangement.scalar) {
bestArrangement = { scalar, rows };
}
}
return bestArrangement;
}, [
gridParticipants,
maxRowCount,
gridDimensions.width,
gridDimensions.height,
]);
// 4. Lay out this arrangement on the screen.
const gridParticipantHeight = Math.floor(
gridArrangement.scalar * MIN_RENDERED_HEIGHT
);
const gridParticipantHeightWithMargin =
gridParticipantHeight + PARTICIPANT_MARGIN;
const gridTotalRowHeightWithMargin =
gridParticipantHeightWithMargin * gridArrangement.rows.length;
const gridTopOffset = Math.floor(
(gridDimensions.height - gridTotalRowHeightWithMargin) / 2
);
const rowElements: Array<Array<JSX.Element>> = gridArrangement.rows.map(
(remoteParticipantsInRow, index) => {
const top = gridTopOffset + index * gridParticipantHeightWithMargin;
const totalRowWidthWithoutMargins =
totalRemoteParticipantWidthAtMinHeight(remoteParticipantsInRow) *
gridArrangement.scalar;
const totalRowWidth =
totalRowWidthWithoutMargins +
PARTICIPANT_MARGIN * (remoteParticipantsInRow.length - 1);
const leftOffset = Math.floor((gridDimensions.width - totalRowWidth) / 2);
let rowWidthSoFar = 0;
return remoteParticipantsInRow.map(remoteParticipant => {
const { demuxId, videoAspectRatio } = remoteParticipant;
const audioLevel = remoteAudioLevels.get(demuxId) ?? 0;
const renderedWidth = Math.floor(
videoAspectRatio * gridParticipantHeight
);
const left = rowWidthSoFar + leftOffset;
rowWidthSoFar += renderedWidth + PARTICIPANT_MARGIN;
return (
<GroupCallRemoteParticipant
key={demuxId}
getFrameBuffer={getFrameBuffer}
getGroupCallVideoFrameSource={getGroupCallVideoFrameSource}
height={gridParticipantHeight}
i18n={i18n}
audioLevel={audioLevel}
left={left}
remoteParticipant={remoteParticipant}
top={top}
width={renderedWidth}
/>
);
});
}
);
const videoRequestMode = useVideoRequestMode();
useEffect(() => {
log.info(`Group call now using ${videoRequestMode} video request mode`);
}, [videoRequestMode]);
useEffect(() => {
let videoRequest: Array<GroupCallVideoRequest>;
switch (videoRequestMode) {
case VideoRequestMode.Normal:
videoRequest = [
...gridParticipants.map(participant => {
let scalar: number;
if (participant.sharingScreen) {
// We want best-resolution video if someone is sharing their screen.
scalar = Math.max(devicePixelRatio, 1);
} else {
scalar = VIDEO_REQUEST_SCALAR;
}
return {
demuxId: participant.demuxId,
width: clamp(
Math.floor(
gridParticipantHeight * participant.videoAspectRatio * scalar
),
1,
MAX_FRAME_WIDTH
),
height: clamp(
Math.floor(gridParticipantHeight * scalar),
1,
MAX_FRAME_HEIGHT
),
};
}),
...overflowedParticipants.map(participant => {
if (invisibleDemuxIds.has(participant.demuxId)) {
return nonRenderedRemoteParticipant(participant);
}
return {
demuxId: participant.demuxId,
width: clamp(
Math.floor(OVERFLOW_PARTICIPANT_WIDTH * VIDEO_REQUEST_SCALAR),
1,
MAX_FRAME_WIDTH
),
height: clamp(
Math.floor(
(OVERFLOW_PARTICIPANT_WIDTH / participant.videoAspectRatio) *
VIDEO_REQUEST_SCALAR
),
1,
MAX_FRAME_HEIGHT
),
};
}),
];
break;
case VideoRequestMode.LowResolution:
videoRequest = remoteParticipants.map(participant =>
participant.hasRemoteVideo
? {
demuxId: participant.demuxId,
width: 1,
height: 1,
}
: nonRenderedRemoteParticipant(participant)
);
break;
case VideoRequestMode.NoVideo:
videoRequest = remoteParticipants.map(nonRenderedRemoteParticipant);
break;
default:
log.error(missingCaseError(videoRequestMode));
videoRequest = remoteParticipants.map(nonRenderedRemoteParticipant);
break;
}
setGroupCallVideoRequest(videoRequest);
}, [
devicePixelRatio,
gridParticipantHeight,
gridParticipants,
invisibleDemuxIds,
overflowedParticipants,
remoteParticipants,
setGroupCallVideoRequest,
videoRequestMode,
]);
return (
<Measure
bounds
onResize={({ bounds }) => {
if (!bounds) {
log.error('We should be measuring the bounds');
return;
}
setContainerDimensions(bounds);
}}
>
{containerMeasure => (
<div
className="module-ongoing-call__participants"
ref={containerMeasure.measureRef}
>
<Measure
bounds
onResize={({ bounds }) => {
if (!bounds) {
log.error('We should be measuring the bounds');
return;
}
setGridDimensions(bounds);
}}
>
{gridMeasure => (
<div
className="module-ongoing-call__participants__grid"
ref={gridMeasure.measureRef}
>
{flatten(rowElements)}
</div>
)}
</Measure>
<GroupCallOverflowArea
getFrameBuffer={getFrameBuffer}
getGroupCallVideoFrameSource={getGroupCallVideoFrameSource}
i18n={i18n}
onParticipantVisibilityChanged={onParticipantVisibilityChanged}
overflowedParticipants={overflowedParticipants}
remoteAudioLevels={remoteAudioLevels}
/>
</div>
)}
</Measure>
);
};
// This function is only meant for use with `useInvisibleParticipants`. It helps avoid
// returning new set instances when the underlying values are equal.
function pickDifferentSet<T>(a: Readonly<Set<T>>, b: Readonly<Set<T>>): Set<T> {
return a.size === b.size ? a : b;
}
function useInvisibleParticipants(
remoteParticipants: ReadonlyArray<GroupCallRemoteParticipantType>
): Readonly<{
invisibleDemuxIds: Set<number>;
onParticipantVisibilityChanged: (demuxId: number, isVisible: boolean) => void;
}> {
const [invisibleDemuxIds, setInvisibleDemuxIds] = useState(new Set<number>());
const onParticipantVisibilityChanged = useCallback(
(demuxId: number, isVisible: boolean) => {
setInvisibleDemuxIds(oldInvisibleDemuxIds => {
const toggled = setUtil.toggle(
oldInvisibleDemuxIds,
demuxId,
!isVisible
);
return pickDifferentSet(oldInvisibleDemuxIds, toggled);
});
},
[]
);
useEffect(() => {
log.info(
`Invisible demux IDs changed to [${join(invisibleDemuxIds, ',')}]`
);
}, [invisibleDemuxIds]);
useEffect(() => {
const remoteParticipantDemuxIds = new Set<number>(
remoteParticipants.map(r => r.demuxId)
);
setInvisibleDemuxIds(oldInvisibleDemuxIds => {
const staleIds = filter(
oldInvisibleDemuxIds,
id => !remoteParticipantDemuxIds.has(id)
);
const withoutStaleIds = setUtil.remove(oldInvisibleDemuxIds, ...staleIds);
return pickDifferentSet(oldInvisibleDemuxIds, withoutStaleIds);
});
}, [remoteParticipants]);
return {
invisibleDemuxIds,
onParticipantVisibilityChanged,
};
}
function useVideoRequestMode(): VideoRequestMode {
const isPageVisible = usePageVisibility();
const [result, setResult] = useState<VideoRequestMode>(
isPageVisible ? VideoRequestMode.Normal : VideoRequestMode.LowResolution
);
useEffect(() => {
if (isPageVisible) {
setResult(VideoRequestMode.Normal);
return noop;
}
setResult(VideoRequestMode.LowResolution);
const timeout = setTimeout(() => {
setResult(VideoRequestMode.NoVideo);
}, TIME_TO_STOP_REQUESTING_VIDEO_WHEN_PAGE_INVISIBLE);
return () => {
clearTimeout(timeout);
};
}, [isPageVisible]);
return result;
}
function totalRemoteParticipantWidthAtMinHeight(
remoteParticipants: ReadonlyArray<GroupCallRemoteParticipantType>
): number {
return remoteParticipants.reduce(
(result, { videoAspectRatio }) =>
result + videoAspectRatio * MIN_RENDERED_HEIGHT,
0
);
}
function stableParticipantComparator(
a: Readonly<{ demuxId: number }>,
b: Readonly<{ demuxId: number }>
): number {
return a.demuxId - b.demuxId;
}