river: remove opacity command

This code is complex and increases maintenance burden but doesn't
add any functionality, only eye-candy.

Futhermore, neither I nor any of the core contributors use it.

There may be a place in river for such eye-candy down the line, in which
case this code could be revived. Currently river is early enough in its
development that our focus should be on core functionality instead.

13 files changed, 6 insertions, 240 deletions

diff --git a/completions/bash/riverctl b/completions/bash/riverctl
index 4dec1c5..a0a429e 100644
--- a/completions/bash/riverctl
+++ b/completions/bash/riverctl
@@ -42,7 +42,6 @@ function __riverctl_completion ()
 			border-color-unfocused \
 			border-width \
 			focus-follows-cursor \
-			opacity \
 			set-repeat \
 			set-cursor-warp \
 			xcursor-theme"
diff --git a/completions/fish/riverctl.fish b/completions/fish/riverctl.fish
index eca0c25..d9bb475 100644
--- a/completions/fish/riverctl.fish
+++ b/completions/fish/riverctl.fish
@@ -4,7 +4,7 @@ end
 
 function __fish_riverctl_complete_no_subcommand
     for i in (commandline -opc)
-        if contains -- $i close csd-filter-add exit float-filter-add focus-output focus-view input list-inputs list-input-configs move resize snap send-to-output spawn swap toggle-float toggle-fullscreen zoom default-layout output-layout set-layout-value mod-layout-value set-focused-tags set-view-tags toggle-focused-tags toggle-view-tags spawn-tagmask declare-mode enter-mode map map-pointer unmap unmap-pointer attach-mode background-color border-color-focused border-color-unfocused border-width focus-follows-cursor opacity set-repeat set-cursor-warp xcursor-theme
+        if contains -- $i close csd-filter-add exit float-filter-add focus-output focus-view input list-inputs list-input-configs move resize snap send-to-output spawn swap toggle-float toggle-fullscreen zoom default-layout output-layout set-layout-value mod-layout-value set-focused-tags set-view-tags toggle-focused-tags toggle-view-tags spawn-tagmask declare-mode enter-mode map map-pointer unmap unmap-pointer attach-mode background-color border-color-focused border-color-unfocused border-width focus-follows-cursor set-repeat set-cursor-warp xcursor-theme
             return 1
         end
     end
@@ -79,7 +79,6 @@ complete -c riverctl -x -n '__fish_riverctl_complete_no_subcommand' -a border-co
 complete -c riverctl -x -n '__fish_riverctl_complete_no_subcommand' -a border-color-unfocused -d 'Set the border color of unfocused views'
 complete -c riverctl -x -n '__fish_riverctl_complete_no_subcommand' -a border-width           -d 'Set the border width to pixels'
 complete -c riverctl -x -n '__fish_riverctl_complete_no_subcommand' -a focus-follows-cursor   -d 'Configure the focus behavior when moving cursor'
-complete -c riverctl -x -n '__fish_riverctl_complete_no_subcommand' -a opacity                -d 'Configure server-side opacity of views'
 complete -c riverctl -x -n '__fish_riverctl_complete_no_subcommand' -a set-repeat             -d 'Set the keyboard repeat rate and repeat delay'
 complete -c riverctl -x -n '__fish_riverctl_complete_no_subcommand' -a set-cursor-warp        -d 'Set the cursor warp mode.'
 complete -c riverctl -x -n '__fish_riverctl_complete_no_subcommand' -a xcursor-theme          -d 'Set the xcursor theme'
diff --git a/completions/zsh/_riverctl b/completions/zsh/_riverctl
index e7fdaa2..625964b 100644
--- a/completions/zsh/_riverctl
+++ b/completions/zsh/_riverctl
@@ -48,7 +48,6 @@ _riverctl_subcommands()
         'border-color-unfocused:Set the border color of unfocused views'
         'border-width:Set the border width to pixels'
         'focus-follows-cursor:Configure the focus behavior when moving cursor'
-        'opacity:Configure server-side opacity of views'
         'set-repeat:Set the keyboard repeat rate and repeat delay'
         'set-cursor-warp:Set the cursor warp mode.'
         'xcursor-theme:Set the xcursor theme'
diff --git a/doc/riverctl.1.scd b/doc/riverctl.1.scd
index d8f8bca..a485a73 100644
--- a/doc/riverctl.1.scd
+++ b/doc/riverctl.1.scd
@@ -259,26 +259,6 @@ A complete list may be found in _/usr/include/linux/input-event-codes.h_
 	- _on-output-change_: When a different output is focused, the cursor will be
 	  warped to its center.
 
-*opacity* _focused_ _unfocused_ _initial_ _step-size_ _delta-t_
-	Configure server-side opacity of views, including transition
-	animations. A value of 0.0 is fully transparent while 1.0 is fully
-	opaque. By default all views are fully opaque and there are no
-	animations.
-
-	- _focused_: opacity of focused views [0.0, 1.0]
-	- _unfocused_: opacity of unfocused views [0.0, 1.0]
-	- _initial_: opacity of views when they are created before immediately
-	  transitioning to either _focused_ or _unfocused_ [0.0, 1.0]
-	- _step-size_: opacity change per step [0.05, 1.0]
-	- _delta-t_: step time in milliseconds
-
-	A transition animation may occur when changing between states with
-	different opacity values configured. Instead of setting the view's
-	opacity to the value for the new state immediately, it is changed
-	incrementally in steps of _step-size_ every _delta-t_ milliseconds.
-	Setting _step-size_ to 1.0 disables transitions fully regardless of
-	the value of _delta-t_.
-
 *set-repeat* _rate_ _delay_
 	Set the keyboard repeat rate to _rate_ key repeats per second and
 	repeat delay to _delay_ milliseconds.
diff --git a/example/init b/example/init
index 44532c4..07e0347 100755
--- a/example/init
+++ b/example/init
@@ -150,9 +150,6 @@ riverctl float-filter-add "popup"
 # Set app-ids of views which should use client side decorations
 riverctl csd-filter-add "gedit"
 
-# Set opacity and fade effect
-# riverctl opacity 1.0 0.75 0.0 0.1 20
-
 # Set and exec into the default layout generator, rivertile.
 # River will send the process group of the init executable SIGTERM on exit.
 riverctl default-layout rivertile
diff --git a/river/Config.zig b/river/Config.zig
index dbc7c39..63fef65 100644
--- a/river/Config.zig
+++ b/river/Config.zig
@@ -76,19 +76,6 @@ default_layout_namespace: []const u8 = &[0]u8{},
 /// Determines where new views will be attached to the view stack.
 attach_mode: AttachMode = .top,
 
-opacity: struct {
-    /// The opacity of focused views
-    focused: f32 = 1.0,
-    /// The opacity of unfocused views
-    unfocused: f32 = 1.0,
-    /// The initial opacity of new views
-    initial: f32 = 1.0,
-    /// View opacity transition step
-    delta: f32 = 1.0,
-    /// Time between view opacity transition steps in milliseconds
-    delta_t: u31 = 20,
-} = .{},
-
 /// Keyboard repeat rate in characters per second
 repeat_rate: u31 = 25,
 
diff --git a/river/Root.zig b/river/Root.zig
index f39f6f2..aad7541 100644
--- a/river/Root.zig
+++ b/river/Root.zig
@@ -399,8 +399,6 @@ fn commitTransaction(self: *Self) void {
             view.current = view.pending;
 
             view.dropSavedBuffers();
-
-            view.commitOpacityTransition();
         }
 
         if (view_tags_changed) output.sendViewTags();
diff --git a/river/Seat.zig b/river/Seat.zig
index e741617..0d25860 100644
--- a/river/Seat.zig
+++ b/river/Seat.zig
@@ -199,12 +199,7 @@ pub fn setFocusRaw(self: *Self, new_focus: FocusTarget) void {
         switch (self.focused) {
             .view => |view| {
                 view.pending.focus -= 1;
-                if (view.pending.focus == 0) {
-                    view.setActivated(false);
-                    if (!view.pending.fullscreen) {
-                        view.pending.target_opacity = server.config.opacity.unfocused;
-                    }
-                }
+                if (view.pending.focus == 0) view.setActivated(false);
             },
             .layer, .none => {},
         }
@@ -213,12 +208,7 @@ pub fn setFocusRaw(self: *Self, new_focus: FocusTarget) void {
         switch (new_focus) {
             .view => |target_view| {
                 std.debug.assert(self.focused_output == target_view.output);
-                if (target_view.pending.focus == 0) {
-                    target_view.setActivated(true);
-                    if (!target_view.pending.fullscreen) {
-                        target_view.pending.target_opacity = server.config.opacity.focused;
-                    }
-                }
+                if (target_view.pending.focus == 0) target_view.setActivated(true);
                 target_view.pending.focus += 1;
             },
             .layer => |target_layer| std.debug.assert(self.focused_output == target_layer.output),
diff --git a/river/View.zig b/river/View.zig
index acc6f25..79ddc1a 100644
--- a/river/View.zig
+++ b/river/View.zig
@@ -71,9 +71,6 @@ const State = struct {
 
     float: bool = false,
     fullscreen: bool = false,
-
-    /// Opacity the view is transitioning to
-    target_opacity: f32,
 };
 
 const SavedBuffer = struct {
@@ -124,12 +121,6 @@ float_box: Box = undefined,
 /// and for more intuitive behavior if there is no active layout for the output.
 post_fullscreen_box: Box = undefined,
 
-/// The current opacity of this view
-opacity: f32,
-
-/// Opacity change timer event source
-opacity_timer: ?*wl.EventSource = null,
-
 draw_borders: bool = true,
 
 /// This is created when the view is mapped and destroyed with the view
@@ -144,16 +135,9 @@ foreign_close: wl.Listener(*wlr.ForeignToplevelHandleV1) =
 pub fn init(self: *Self, output: *Output, tags: u32, surface: anytype) void {
     self.* = .{
         .output = output,
-        .current = .{
-            .tags = tags,
-            .target_opacity = server.config.opacity.initial,
-        },
-        .pending = .{
-            .tags = tags,
-            .target_opacity = server.config.opacity.initial,
-        },
+        .current = .{ .tags = tags },
+        .pending = .{ .tags = tags },
         .saved_buffers = std.ArrayList(SavedBuffer).init(util.gpa),
-        .opacity = server.config.opacity.initial,
     };
 
     if (@TypeOf(surface) == *wlr.XdgSurface) {
@@ -213,7 +197,6 @@ pub fn applyPending(self: *Self) void {
         self.setFullscreen(true);
         self.post_fullscreen_box = self.current.box;
 
-        self.pending.target_opacity = 1.0;
         const layout_box = server.root.output_layout.getBox(self.output.wlr_output).?;
         self.pending.box = .{
             .x = 0,
@@ -226,12 +209,6 @@ pub fn applyPending(self: *Self) void {
     if (self.current.fullscreen and !self.pending.fullscreen) {
         self.setFullscreen(false);
         self.pending.box = self.post_fullscreen_box;
-
-        // Restore configured opacity
-        self.pending.target_opacity = if (self.pending.focus > 0)
-            server.config.opacity.focused
-        else
-            server.config.opacity.unfocused;
     }
 
     if (arrange_output) self.output.arrangeViews();
@@ -449,8 +426,6 @@ pub fn shouldTrackConfigure(self: Self) bool {
 
 /// Called by the impl when the surface is ready to be displayed
 pub fn map(self: *Self) void {
-    self.pending.target_opacity = server.config.opacity.unfocused;
-
     log.debug("view '{s}' mapped", .{self.getTitle()});
 
     if (self.foreign_toplevel_handle == null) {
@@ -499,10 +474,6 @@ pub fn unmap(self: *Self) void {
 
     if (self.saved_buffers.items.len == 0) self.saveBuffers();
 
-    if (self.opacity_timer != null) {
-        self.killOpacityTimer();
-    }
-
     // Inform all seats that the view has been unmapped so they can handle focus
     var it = server.input_manager.seats.first;
     while (it) |node| : (it = node.next) {
@@ -540,69 +511,6 @@ pub fn notifyAppId(self: Self) void {
     }
 }
 
-/// Change the opacity of a view by config.opacity.delta.
-/// If the target opacity was reached, return true.
-fn incrementOpacity(self: *Self) bool {
-    self.output.damage.addWhole();
-    if (self.opacity < self.current.target_opacity) {
-        self.opacity += server.config.opacity.delta;
-        if (self.opacity < self.current.target_opacity) return false;
-    } else {
-        self.opacity -= server.config.opacity.delta;
-        if (self.opacity > self.current.target_opacity) return false;
-    }
-    self.opacity = self.current.target_opacity;
-    return true;
-}
-
-/// Destroy a views opacity timer
-fn killOpacityTimer(self: *Self) void {
-    self.opacity_timer.?.remove();
-    self.opacity_timer = null;
-}
-
-/// Set the timeout on a views opacity timer
-fn armOpacityTimer(self: *Self) void {
-    const delta_t = server.config.opacity.delta_t;
-    self.opacity_timer.?.timerUpdate(delta_t) catch |err| {
-        log.err("failed to update opacity timer: {s}", .{err});
-        self.killOpacityTimer();
-    };
-}
-
-/// Called by the opacity timer
-fn handleOpacityTimer(self: *Self) callconv(.C) c_int {
-    if (self.incrementOpacity()) {
-        self.killOpacityTimer();
-    } else {
-        self.armOpacityTimer();
-    }
-    return 0;
-}
-
-/// Create an opacity timer for a view and arm it
-fn attachOpacityTimer(self: *Self) void {
-    const event_loop = server.wl_server.getEventLoop();
-    self.opacity_timer = event_loop.addTimer(*Self, handleOpacityTimer, self) catch {
-        log.err("failed to create opacity timer for view '{s}'", .{self.getTitle()});
-        return;
-    };
-    self.armOpacityTimer();
-}
-
-/// Commit an opacity transition
-pub fn commitOpacityTransition(self: *Self) void {
-    if (self.opacity == self.current.target_opacity) return;
-
-    // A running timer can handle a target_opacity change
-    if (self.opacity_timer != null) return;
-
-    // Do the first step now, if that step was not enough, attach timer
-    if (!self.incrementOpacity()) {
-        self.attachOpacityTimer();
-    }
-}
-
 /// Only honors the request if the view is already visible on the seat's
 /// currently focused output. TODO: consider allowing this request to switch
 /// output/tag focus.
diff --git a/river/XdgToplevel.zig b/river/XdgToplevel.zig
index b56ed08..c74a0f0 100644
--- a/river/XdgToplevel.zig
+++ b/river/XdgToplevel.zig
@@ -280,7 +280,6 @@ fn handleCommit(listener: *wl.Listener(*wlr.Surface), surface: *wlr.Surface) voi
             } else {
                 const self_tags_changed = view.pending.tags != view.current.tags;
                 view.current = view.pending;
-                view.commitOpacityTransition();
                 if (self_tags_changed) view.output.sendViewTags();
                 view.output.damage.addWhole();
             }
diff --git a/river/command.zig b/river/command.zig
index 315d300..b3fc953 100644
--- a/river/command.zig
+++ b/river/command.zig
@@ -66,7 +66,6 @@ const str_to_impl_fn = [_]struct {
     .{ .name = "map-pointer",            .impl = @import("command/map.zig").mapPointer },
     .{ .name = "mod-layout-value",       .impl = @import("command/layout.zig").modLayoutValue },
     .{ .name = "move",                   .impl = @import("command/move.zig").move },
-    .{ .name = "opacity",                .impl = @import("command/opacity.zig").opacity },
     .{ .name = "output-layout",          .impl = @import("command/layout.zig").outputLayout },
     .{ .name = "resize",                 .impl = @import("command/move.zig").resize },
     .{ .name = "send-to-output",         .impl = @import("command/output.zig").sendToOutput },
diff --git a/river/command/opacity.zig b/river/command/opacity.zig
deleted file mode 100644
index c4de30b..0000000
--- a/river/command/opacity.zig
+++ /dev/null
@@ -1,79 +0,0 @@
-// This file is part of river, a dynamic tiling wayland compositor.
-//
-// Copyright 2020 The River Developers
-//
-// This program is free software: you can redistribute it and/or modify
-// it under the terms of the GNU General Public License as published by
-// the Free Software Foundation, either version 3 of the License, or
-// (at your option) any later version.
-//
-// This program is distributed in the hope that it will be useful,
-// but WITHOUT ANY WARRANTY; without even the implied warranty of
-// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
-// GNU General Public License for more details.
-//
-// You should have received a copy of the GNU General Public License
-// along with this program. If not, see <https://www.gnu.org/licenses/>.
-
-const std = @import("std");
-
-const server = &@import("../main.zig").server;
-
-const Error = @import("../command.zig").Error;
-const Seat = @import("../Seat.zig");
-const View = @import("../View.zig");
-const ViewStack = @import("../view_stack.zig").ViewStack;
-
-fn opacityUpdateFilter(view: *View, context: void) bool {
-    // We want to update all views
-    return true;
-}
-
-pub fn opacity(
-    allocator: *std.mem.Allocator,
-    seat: *Seat,
-    args: []const [:0]const u8,
-    out: *?[]const u8,
-) Error!void {
-    if (args.len < 6) return Error.NotEnoughArguments;
-    if (args.len > 6) return Error.TooManyArguments;
-
-    // Focused opacity
-    server.config.opacity.focused = try std.fmt.parseFloat(f32, args[1]);
-    if (server.config.opacity.focused < 0.0 or server.config.opacity.focused > 1.0)
-        return Error.InvalidValue;
-
-    // Unfocused opacity
-    server.config.opacity.unfocused = try std.fmt.parseFloat(f32, args[2]);
-    if (server.config.opacity.unfocused < 0.0 or server.config.opacity.unfocused > 1.0)
-        return Error.InvalidValue;
-
-    // Starting opacity for new views
-    server.config.opacity.initial = try std.fmt.parseFloat(f32, args[3]);
-    if (server.config.opacity.initial < 0.0 or server.config.opacity.initial > 1.0)
-        return Error.InvalidValue;
-
-    // Opacity transition step
-    server.config.opacity.delta = try std.fmt.parseFloat(f32, args[4]);
-    if (server.config.opacity.delta < 0.0 or server.config.opacity.delta > 1.0)
-        return Error.InvalidValue;
-
-    // Time between step
-    server.config.opacity.delta_t = try std.fmt.parseInt(u31, args[5], 10);
-    if (server.config.opacity.delta_t < 1) return Error.InvalidValue;
-
-    // Update opacity of all views
-    // Unmapped views will be skipped, however their opacity gets updated on map anyway
-    var oit = server.root.outputs.first;
-    while (oit) |onode| : (oit = onode.next) {
-        var vit = ViewStack(View).iter(onode.data.views.first, .forward, {}, opacityUpdateFilter);
-        while (vit.next()) |vnode| {
-            if (vnode.current.focus > 0) {
-                vnode.pending.target_opacity = server.config.opacity.focused;
-            } else {
-                vnode.pending.target_opacity = server.config.opacity.unfocused;
-            }
-        }
-    }
-    server.root.startTransaction();
-}
diff --git a/river/render.zig b/river/render.zig
index aedeccf..2b25bde 100644
--- a/river/render.zig
+++ b/river/render.zig
@@ -43,8 +43,6 @@ const SurfaceRenderData = struct {
     output_y: i32,
 
     when: *os.timespec,
-
-    opacity: f32,
 };
 
 /// The rendering order in this function must be kept in sync with Cursor.surfaceAt()
@@ -186,7 +184,6 @@ fn renderLayer(
             .output_x = layer_surface.box.x,
             .output_y = layer_surface.box.y,
             .when = now,
-            .opacity = 1.0,
         };
         switch (role) {
             .toplevels => layer_surface.wlr_layer_surface.surface.forEachSurface(
@@ -218,7 +215,6 @@ fn renderView(output: *const Output, view: *View, now: *os.timespec) void {
                     .height = @intCast(c_int, saved_buffer.box.height),
                 },
                 saved_buffer.transform,
-                view.opacity,
             );
     } else {
         // Since there is no stashed buffer, we are not in the middle of
@@ -228,7 +224,6 @@ fn renderView(output: *const Output, view: *View, now: *os.timespec) void {
             .output_x = view.current.box.x - view.surface_box.x,
             .output_y = view.current.box.y - view.surface_box.y,
             .when = now,
-            .opacity = view.opacity,
         };
 
         view.surface.?.forEachSurface(*SurfaceRenderData, renderSurfaceIterator, &rdata);
@@ -241,7 +236,6 @@ fn renderViewPopups(output: *const Output, view: *View, now: *os.timespec) void
         .output_x = view.current.box.x - view.surface_box.x,
         .output_y = view.current.box.y - view.surface_box.y,
         .when = now,
-        .opacity = view.opacity,
     };
     view.forEachPopupSurface(*SurfaceRenderData, renderSurfaceIterator, &rdata);
 }
@@ -260,7 +254,6 @@ fn renderDragIcons(output: *const Output, now: *os.timespec) void {
             .output_y = @floatToInt(i32, drag_icon.seat.cursor.wlr_cursor.y) +
                 drag_icon.wlr_drag_icon.surface.sy - output_box.y,
             .when = now,
-            .opacity = 1.0,
         };
         drag_icon.wlr_drag_icon.surface.forEachSurface(*SurfaceRenderData, renderSurfaceIterator, &rdata);
     }
@@ -279,7 +272,6 @@ fn renderXwaylandUnmanaged(output: *const Output, now: *os.timespec) void {
             .output_x = xwayland_surface.x - output_box.x,
             .output_y = xwayland_surface.y - output_box.y,
             .when = now,
-            .opacity = 1.0,
         };
         xwayland_surface.surface.?.forEachSurface(*SurfaceRenderData, renderSurfaceIterator, &rdata);
     }
@@ -302,7 +294,6 @@ fn renderSurfaceIterator(
             .height = surface.current.height,
         },
         surface.current.transform,
-        rdata.opacity,
     );
 
     surface.sendFrameDone(rdata.when);
@@ -315,7 +306,6 @@ fn renderTexture(
     texture: *wlr.Texture,
     wlr_box: wlr.Box,
     transform: wl.Output.Transform,
-    opacity: f32,
 ) void {
     var box = wlr_box;
 
@@ -333,7 +323,7 @@ fn renderTexture(
     // This takes our matrix, the texture, and an alpha, and performs the actual
     // rendering on the GPU.
     const renderer = output.wlr_output.backend.getRenderer().?;
-    renderer.renderTextureWithMatrix(texture, &matrix, opacity) catch return;
+    renderer.renderTextureWithMatrix(texture, &matrix, 1.0) catch return;
 }
 
 fn renderBorders(output: *const Output, view: *View, now: *os.timespec) void {