android, desktop, ios: remove right gap on received messages in channels (#7106)

* android, desktop, ios: remove right gap on received messages in channels

In channels received messages now use the full row width instead of the chat-bubble right gap, matching the broadcast/feed style. Gated on ChatInfo.isChannel (useRelays), the always-present channel flag used across the channel UI; sent messages and non-channel groups, business and direct chats are unchanged.

* docs: add plan justifying removing right gap on received messages in channels

---------

Co-authored-by: Evgeny Poberezkin <evgeny@poberezkin.com>

apps/ios/Shared/Views/Chat/ChatView.swift

@@ -895,8 +895,9 @@ struct ChatView: View {
                         }
                     } else {
                         let voiceNoFrame = voiceWithoutFrame(ci)
+                        let channelReceived = !ci.chatDir.sent && cInfo.isChannel
                         let maxWidth = cInfo.chatType == .group
-                        ? voiceNoFrame
+                        ? voiceNoFrame || channelReceived
                         ? (g.size.width - 28) - 42
                         : (g.size.width - 28) * 0.84 - 42
                         : voiceNoFrame

apps/multiplatform/common/src/commonMain/kotlin/chat/simplex/common/views/chat/ChatView.kt

@@ -2000,7 +2000,7 @@ fun BoxScope.ChatItemsList(
                 Column(
                   Modifier
                     .padding(top = 8.dp)
-                    .padding(start = 8.dp, end = if (voiceWithTransparentBack) 12.dp else adjustTailPaddingOffset(66.dp, start = false))
+                    .padding(start = 8.dp, end = if (voiceWithTransparentBack || chatInfo.isChannel) 12.dp else adjustTailPaddingOffset(66.dp, start = false))
                     .fillMaxWidth()
                     .then(swipeableModifier),
                   verticalArrangement = Arrangement.spacedBy(4.dp),
@@ -2079,7 +2079,7 @@ fun BoxScope.ChatItemsList(
                   }
                   Row(
                     Modifier
-                      .padding(start = 8.dp + (MEMBER_IMAGE_SIZE * fontSizeSqrtMultiplier) + 4.dp, end = if (voiceWithTransparentBack) 12.dp else adjustTailPaddingOffset(66.dp, start = false))
+                      .padding(start = 8.dp + (MEMBER_IMAGE_SIZE * fontSizeSqrtMultiplier) + 4.dp, end = if (voiceWithTransparentBack || chatInfo.isChannel) 12.dp else adjustTailPaddingOffset(66.dp, start = false))
                       .chatItemOffset(cItem, itemSeparation.largeGap, revealed = revealed.value)
                       .then(swipeableOrSelectionModifier)
                   ) {
@@ -2092,7 +2092,7 @@ fun BoxScope.ChatItemsList(
                 Column(
                   Modifier
                     .padding(top = 8.dp)
-                    .padding(start = 8.dp, end = if (voiceWithTransparentBack) 12.dp else adjustTailPaddingOffset(66.dp, start = false))
+                    .padding(start = 8.dp, end = if (voiceWithTransparentBack || chatInfo.isChannel) 12.dp else adjustTailPaddingOffset(66.dp, start = false))
                     .fillMaxWidth()
                     .then(swipeableModifier),
                   verticalArrangement = Arrangement.spacedBy(4.dp),
@@ -2162,7 +2162,7 @@ fun BoxScope.ChatItemsList(
                   }
                   Row(
                     Modifier
-                      .padding(start = 8.dp + (MEMBER_IMAGE_SIZE * fontSizeSqrtMultiplier) + 4.dp, end = if (voiceWithTransparentBack) 12.dp else adjustTailPaddingOffset(66.dp, start = false))
+                      .padding(start = 8.dp + (MEMBER_IMAGE_SIZE * fontSizeSqrtMultiplier) + 4.dp, end = if (voiceWithTransparentBack || chatInfo.isChannel) 12.dp else adjustTailPaddingOffset(66.dp, start = false))
                       .chatItemOffset(cItem, itemSeparation.largeGap, revealed = revealed.value)
                       .then(swipeableOrSelectionModifier)
                   ) {

plans/2026-06-19-channel-received-remove-right-gap.md

@@ -0,0 +1,95 @@
+# Remove the right gap on received messages in channels
+
+## Problem
+
+In groups, received messages are laid out as left-aligned chat bubbles whose
+maximum width is capped well short of the right edge, leaving a large empty gap
+on the right so long content wraps early. In channels this wastes horizontal
+space — channel posts are broadcast/feed-style content that reads better using
+nearly the full row width.
+
+## Change
+
+For channels only, received messages drop the right-side gap so content can use
+nearly the full row width (a small edge margin remains). This only changes the
+maximum available width: long text uses more of the row, short messages still
+size to content, and media stays within its existing cap. Sent messages keep
+their existing layout.
+
+### Android / desktop (`apps/multiplatform`)
+
+The `end` padding becomes `12.dp` (the same edge margin sent messages use)
+instead of `adjustTailPaddingOffset(66.dp, …)`, at the four received-message
+layout sites in `ChatItemsList` (`ChatView.kt`): the `GroupRcv`
+(member-attributed) and `ChannelRcv` (unattributed) branches, each with and
+without an avatar.
+
+```kotlin
+end = if (voiceWithTransparentBack || chatInfo.isChannel) 12.dp
+      else adjustTailPaddingOffset(66.dp, start = false)
+```
+
+### iOS (`apps/ios`)
+
+iOS computes one per-message `maxWidth` in `ChatView.swift` and applies it to
+every bubble; the `* 0.84` factor is the gap. For a received message in a
+channel that factor is dropped (full width minus the avatar inset) — the same
+geometry the voice-message case already uses:
+
+```swift
+let channelReceived = !ci.chatDir.sent && cInfo.isChannel
+let maxWidth = cInfo.chatType == .group
+? voiceNoFrame || channelReceived
+? (g.size.width - 28) - 42
+: (g.size.width - 28) * 0.84 - 42
+: ...
+```
+
+The received check (`!ci.chatDir.sent`) is explicit here because, unlike the
+Kotlin layout (which has a separate received branch), iOS shares one `maxWidth`
+between sent and received.
+
+## Why gate on `ChatInfo.isChannel` (`useRelays`)
+
+The change is gated per chat on `ChatInfo.isChannel`, which is
+`groupInfo?.useRelays == true` — `chatInfo.isChannel` on both Android/desktop and
+iOS (`cInfo.isChannel`).
+
+This is the robust signal. The whole channel feature on both platforms keys on
+`useRelays` (channel preferences, member management, info view, broadcast
+compose, etc.); `useRelays` is a non-optional `Bool` that is always present on a
+group.
+
+- **Not on the group-type `isChannel`** (`publicGroup?.groupType == channel`).
+  This was the first attempt and it left the gap in place on iOS. The likely
+  mechanism: `publicGroup` is an optional reconstructed from nullable DB columns
+  (`src/Simplex/Chat/Store/Groups.hs` `toGroupProfile`, plus a creation path that
+  sets `publicGroup = Nothing`), so when it is not populated for a chat the
+  optional chain silently evaluates to `false` and the gap is never removed.
+  `useRelays` cannot fail this way — it is a required `Bool` set at group
+  creation (`useRelays = not direct`, `Commands.hs:2080`). Independent of the
+  exact mechanism, `useRelays` is the safer signal. It is also as precise: the
+  only group type ever constructed is `GTChannel` (`GTGroup` is defined but never
+  instantiated), and `useRelays == true` is set on exactly that same
+  public-group/channel path, so `useRelays == true` ⟺ "is a channel" for every
+  chat today — regular groups, business chats and direct chats all have
+  `useRelays` false/absent (verified: no non-channel path sets it true).
+- **Not on the item direction.** The unattributed `ChannelRcv` direction is
+  produced for any group message without an attributed member, not only in
+  channels, and channels also contain member-attributed (`GroupRcv`) posts.
+  Gating on direction would both over- and under-match, so the gate is the
+  per-chat `isChannel`.
+
+## Scope
+
+Regular groups, business chats, and direct chats are unchanged (`isChannel` is
+false for them). Sent messages are untouched.
+
+## Verification
+
+- Android/desktop: `:common:compileKotlinDesktop` compiles clean.
+- iOS: change is a small, type-safe Swift expression; build/verify on macOS
+  (Xcode) — not compilable on the Linux build host used here.
+- Visual (both platforms): in a channel, long received messages widen toward the
+  right edge; in a regular group and in direct chats the right gap is unchanged;
+  sent messages are unchanged everywhere.