Implement configurable view opacity with fade effect

10 files changed, 228 insertions, 5 deletions

diff --git a/contrib/config.sh b/contrib/config.sh
index 620b29f..3b51bbe 100755
--- a/contrib/config.sh
+++ b/contrib/config.sh
@@ -100,3 +100,5 @@ 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
diff --git a/doc/riverctl.1.scd b/doc/riverctl.1.scd
index bbbbafa..143d57e 100644
--- a/doc/riverctl.1.scd
+++ b/doc/riverctl.1.scd
@@ -162,6 +162,21 @@ that tag 1 through 9 are visible.
 	- move-view
 	- resize-view
 
+*opacity* _focused-opacity_ _unfocused-opacity_ _starting-opacity_ _opacity-step_ _opacity-delta-t_
+	Set the server side opacity of views.
+
+	_focused-opacity_ sets the opacity of the focused window, _unfocused-opacity_
+	the opacity of every unfocused window while _starting-opacity_ sets the
+	opacity a window will have at startup before immediately transitioning to
+	either the focused or unfocused opacity. These settings require a floating
+	point number from 0.0 (fully transparent) to 1.0 (fully opaque).
+
+	Opacity transitions can be animated. _opacity-step_ sets the amount the
+	opacity should be increased or decreased per step of the transition. It
+	requires a floating point number from 0.05 to 1.0. If set to 1.0, animations
+	are disabled. _opacity-delta-t_ sets the time between the transition steps
+	in milliseconds.
+
 *outer-padding* _pixels_
 	Set the padding around the edge of the screen to _pixels_.
 
diff --git a/river/Config.zig b/river/Config.zig
index bb9b7a6..04b1893 100644
--- a/river/Config.zig
+++ b/river/Config.zig
@@ -66,6 +66,21 @@ csd_filter: std.ArrayList([]const u8),
 /// The selected focus_follows_cursor mode
 focus_follows_cursor: FocusFollowsCursorMode = .disabled,
 
+/// The opacity of the focused view
+view_opacity_focused: f32 = 1.0,
+
+/// The opacity of unfocused views
+view_opacity_unfocused: f32 = 1.0,
+
+/// The starting opacity of new views
+view_opacity_initial: f32 = 1.0,
+
+/// View opacity transition step
+view_opacity_delta: f32 = 1.0,
+
+/// Time between view opacity transition steps in msec
+view_opacity_delta_t: u31 = 20,
+
 pub fn init() !Self {
     var self = Self{
         .mode_to_id = std.StringHashMap(usize).init(util.gpa),
diff --git a/river/Root.zig b/river/Root.zig
index 5705ea3..d07884e 100644
--- a/river/Root.zig
+++ b/river/Root.zig
@@ -250,6 +250,8 @@ 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 77bfed8..bb6e557 100644
--- a/river/Seat.zig
+++ b/river/Seat.zig
@@ -188,6 +188,9 @@ pub fn setFocusRaw(self: *Self, new_focus: FocusTarget) void {
             // activated state.
             if (build_options.xwayland and self.focused.view.impl == .xwayland_view)
                 c.wlr_xwayland_surface_activate(self.focused.view.impl.xwayland_view.wlr_xwayland_surface, false);
+            if (self.focused.view.pending.focus == 0) {
+                self.focused.view.pending.target_opacity = self.input_manager.server.config.view_opacity_unfocused;
+            }
         }
         c.wlr_seat_keyboard_clear_focus(self.wlr_seat);
 
@@ -200,6 +203,7 @@ pub fn setFocusRaw(self: *Self, new_focus: FocusTarget) void {
                 // activated state.
                 if (build_options.xwayland and target_view.impl == .xwayland_view)
                     c.wlr_xwayland_surface_activate(target_view.impl.xwayland_view.wlr_xwayland_surface, true);
+                target_view.pending.target_opacity = self.input_manager.server.config.view_opacity_focused;
             },
             .layer => |target_layer| std.debug.assert(self.focused_output == target_layer.output),
             .none => {},
@@ -281,7 +285,7 @@ pub fn handleMapping(self: *Self, keysym: c.xkb_keysym_t, modifiers: u32, releas
             if (out) |s| {
                 const stdout = std.io.getStdOut().outStream();
                 stdout.print("{}", .{s}) catch
-                    |err| log.err(.command, "{}: write to stdout failed {}", .{ args[0], err });
+                |err| log.err(.command, "{}: write to stdout failed {}", .{ args[0], err });
             }
             return true;
         }
diff --git a/river/View.zig b/river/View.zig
index 3bcc684..df23d12 100644
--- a/river/View.zig
+++ b/river/View.zig
@@ -1,6 +1,7 @@
 // This file is part of river, a dynamic tiling wayland compositor.
 //
 // Copyright 2020 Isaac Freund
+// Copyright 2020 Leon Henrik Plickat
 //
 // 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
@@ -65,6 +66,9 @@ const State = struct {
 
     float: bool = false,
     fullscreen: bool = false,
+
+    /// Opacity the view is transitioning to
+    target_opacity: f32,
 };
 
 const SavedBuffer = struct {
@@ -109,14 +113,27 @@ saved_buffers: std.ArrayList(SavedBuffer),
 /// view returns to floating mode.
 float_box: Box = undefined,
 
+/// The current opacity of this view
+opacity: f32,
+
+/// Opacity change timer event source
+opacity_timer: ?*c.wl_event_source = null,
+
 draw_borders: bool = true,
 
 pub fn init(self: *Self, output: *Output, tags: u32, surface: anytype) void {
     self.* = .{
         .output = output,
-        .current = .{ .tags = tags },
-        .pending = .{ .tags = tags },
+        .current = .{
+            .tags = tags,
+            .target_opacity = output.root.server.config.view_opacity_initial,
+        },
+        .pending = .{
+            .tags = tags,
+            .target_opacity = output.root.server.config.view_opacity_initial,
+        },
         .saved_buffers = std.ArrayList(SavedBuffer).init(util.gpa),
+        .opacity = output.root.server.config.view_opacity_initial,
     };
 
     if (@TypeOf(surface) == *c.wlr_xdg_surface) {
@@ -337,6 +354,8 @@ pub fn shouldTrackConfigure(self: Self) bool {
 pub fn map(self: *Self) void {
     const root = self.output.root;
 
+    self.pending.target_opacity = self.output.root.server.config.view_opacity_unfocused;
+
     log.debug(.server, "view '{}' mapped", .{self.getTitle()});
 
     // Add the view to the stack of its output
@@ -365,6 +384,10 @@ pub fn unmap(self: *Self) void {
 
     self.destroying = true;
 
+    if (self.opacity_timer != null) {
+        self.killOpacityTimer();
+    }
+
     // Inform all seats that the view has been unmapped so they can handle focus
     var it = root.server.input_manager.seats.first;
     while (it) |node| : (it = node.next) {
@@ -379,3 +402,72 @@ pub fn unmap(self: *Self) void {
 
     root.startTransaction();
 }
+
+/// Change the opacity of a view by config.view_opacity_delta.
+/// If the target opacity was reached, return true.
+fn incrementOpacity(self: *Self) bool {
+    // TODO damage view when implementing damage based rendering
+    const config = &self.output.root.server.config;
+    if (self.opacity < self.current.target_opacity) {
+        self.opacity += config.view_opacity_delta;
+        if (self.opacity < self.current.target_opacity) return false;
+    } else {
+        self.opacity -= config.view_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 {
+    if (c.wl_event_source_remove(self.opacity_timer) < 0) unreachable;
+    self.opacity_timer = null;
+}
+
+/// Set the timeout on a views opacity timer
+fn armOpacityTimer(self: *Self) void {
+    const delta_t = self.output.root.server.config.view_opacity_delta_t;
+    if (c.wl_event_source_timer_update(self.opacity_timer, delta_t) < 0) {
+        log.err(.view, "failed to update opacity timer", .{});
+        self.killOpacityTimer();
+    }
+}
+
+/// Called by the opacity timer
+fn handleOpacityTimer(data: ?*c_void) callconv(.C) c_int {
+    const self = util.voidCast(Self, data.?);
+    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 server = self.output.root.server;
+    self.opacity_timer = c.wl_event_loop_add_timer(
+        c.wl_display_get_event_loop(server.wl_display),
+        handleOpacityTimer,
+        self,
+    ) orelse {
+        log.err(.view, "failed to create opacity timer for view '{}'", .{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();
+    }
+}
diff --git a/river/XdgToplevel.zig b/river/XdgToplevel.zig
index fcd74f4..1693271 100644
--- a/river/XdgToplevel.zig
+++ b/river/XdgToplevel.zig
@@ -251,8 +251,10 @@ fn handleCommit(listener: ?*c.wl_listener, data: ?*c_void) callconv(.C) void {
             view.pending_serial = null;
             if (view.shouldTrackConfigure())
                 view.output.root.notifyConfigured()
-            else
+            else {
                 view.current = view.pending;
+                view.commitOpacityTransition();
+            }
         } else {
             // If the client has not yet acked our configure, we need to send a
             // frame done event so that it commits another buffer. These
diff --git a/river/command.zig b/river/command.zig
index bfe0727..c9935d5 100644
--- a/river/command.zig
+++ b/river/command.zig
@@ -49,6 +49,7 @@ const str_to_impl_fn = [_]struct {
     .{ .name = "map-pointer",            .impl = @import("command/map.zig").mapPointer },
     .{ .name = "mod-master-count",       .impl = @import("command/mod_master_count.zig").modMasterCount },
     .{ .name = "mod-master-factor",      .impl = @import("command/mod_master_factor.zig").modMasterFactor },
+    .{ .name = "opacity",                .impl = @import("command/opacity.zig").opacity },
     .{ .name = "outer-padding",          .impl = @import("command/config.zig").outerPadding },
     .{ .name = "send-to-output",         .impl = @import("command/send_to_output.zig").sendToOutput },
     .{ .name = "set-focused-tags",       .impl = @import("command/tags.zig").setFocusedTags },
@@ -73,6 +74,7 @@ pub const Error = error{
     InvalidCharacter,
     InvalidDirection,
     InvalidRgba,
+    InvalidValue,
     UnknownOption,
     OutOfMemory,
     Other,
@@ -113,6 +115,7 @@ pub fn errToMsg(err: Error) [:0]const u8 {
         Error.InvalidCharacter => "invalid character in argument",
         Error.InvalidDirection => "invalid direction. Must be 'next' or 'previous'",
         Error.InvalidRgba => "invalid color format, must be #RRGGBB or #RRGGBBAA",
+        Error.InvalidValue => "invalid value",
         Error.OutOfMemory => "out of memory",
         Error.Other => unreachable,
     };
diff --git a/river/command/opacity.zig b/river/command/opacity.zig
new file mode 100644
index 0000000..7cf8e86
--- /dev/null
+++ b/river/command/opacity.zig
@@ -0,0 +1,79 @@
+// This file is part of river, a dynamic tiling wayland compositor.
+//
+// Copyright 2020 Leon Henrik Plickat
+//
+// 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 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 []const u8,
+    out: *?[]const u8,
+) Error!void {
+    if (args.len < 6) return Error.NotEnoughArguments;
+    if (args.len > 6) return Error.TooManyArguments;
+
+    const server = seat.input_manager.server;
+
+    // Focused opacity
+    server.config.view_opacity_focused = try std.fmt.parseFloat(f32, args[1]);
+    if (server.config.view_opacity_focused < 0.0 or server.config.view_opacity_focused > 1.0)
+        return Error.InvalidValue;
+
+    // Unfocused opacity
+    server.config.view_opacity_unfocused = try std.fmt.parseFloat(f32, args[2]);
+    if (server.config.view_opacity_unfocused < 0.0 or server.config.view_opacity_unfocused > 1.0)
+        return Error.InvalidValue;
+
+    // Starting opacity for new views
+    server.config.view_opacity_initial = try std.fmt.parseFloat(f32, args[3]);
+    if (server.config.view_opacity_initial < 0.0 or server.config.view_opacity_initial > 1.0)
+        return Error.InvalidValue;
+
+    // Opacity transition step
+    server.config.view_opacity_delta = try std.fmt.parseFloat(f32, args[4]);
+    if (server.config.view_opacity_delta < 0.0 or server.config.view_opacity_delta > 1.0)
+        return Error.InvalidValue;
+
+    // Time between step
+    server.config.view_opacity_delta_t = try std.fmt.parseInt(u31, args[5], 10);
+    if (server.config.view_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.view_opacity_focused;
+            } else {
+                vnode.pending.target_opacity = server.config.view_opacity_unfocused;
+            }
+        }
+    }
+    server.root.startTransaction();
+}
diff --git a/river/render.zig b/river/render.zig
index 65a4ab6..857478b 100644
--- a/river/render.zig
+++ b/river/render.zig
@@ -36,6 +36,8 @@ const SurfaceRenderData = struct {
     output_y: i32,
 
     when: *c.timespec,
+
+    opacity: f32,
 };
 
 pub fn renderOutput(output: *Output) void {
@@ -138,6 +140,7 @@ fn renderLayer(output: Output, layer: std.TailQueue(LayerSurface), now: *c.times
             .output_x = layer_surface.box.x,
             .output_y = layer_surface.box.y,
             .when = now,
+            .opacity = 1.0,
         };
         c.wlr_layer_surface_v1_for_each_surface(
             layer_surface.wlr_layer_surface,
@@ -162,6 +165,7 @@ fn renderView(output: Output, view: *View, now: *c.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
@@ -171,6 +175,7 @@ fn renderView(output: Output, view: *View, now: *c.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.forEachSurface(renderSurfaceIterator, &rdata);
@@ -191,6 +196,7 @@ fn renderDragIcons(output: Output, now: *c.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,
         };
         c.wlr_surface_for_each_surface(drag_icon.wlr_drag_icon.surface, renderSurfaceIterator, &rdata);
     }
@@ -209,6 +215,7 @@ fn renderXwaylandUnmanaged(output: Output, now: *c.timespec) void {
             .output_x = wlr_xwayland_surface.x - output_box.*.x,
             .output_y = wlr_xwayland_surface.y - output_box.*.y,
             .when = now,
+            .opacity = 1.0,
         };
         c.wlr_surface_for_each_surface(wlr_xwayland_surface.surface, renderSurfaceIterator, &rdata);
     }
@@ -233,6 +240,7 @@ fn renderSurfaceIterator(
             .height = surface.?.current.height,
         },
         surface.?.current.transform,
+        rdata.opacity,
     );
 
     c.wlr_surface_send_frame_done(surface, rdata.when);
@@ -245,6 +253,7 @@ fn renderTexture(
     wlr_texture: ?*c.wlr_texture,
     wlr_box: c.wlr_box,
     transform: c.wl_output_transform,
+    opacity: f32,
 ) void {
     const texture = wlr_texture orelse return;
     var box = wlr_box;
@@ -262,7 +271,7 @@ fn renderTexture(
 
     // This takes our matrix, the texture, and an alpha, and performs the actual
     // rendering on the GPU.
-    _ = c.wlr_render_texture_with_matrix(output.getRenderer(), texture, &matrix, 1.0);
+    _ = c.wlr_render_texture_with_matrix(output.getRenderer(), texture, &matrix, opacity);
 }
 
 fn renderBorders(output: Output, view: *View, now: *c.timespec) void {