river/src/view.zig

const std = @import("std");
const c = @import("c.zig");

const Box = @import("box.zig");
const Log = @import("log.zig").Log;
const Output = @import("output.zig").Output;
const Root = @import("root.zig").Root;
const ViewStack = @import("view_stack.zig").ViewStack;
const XdgToplevel = @import("xdg_toplevel.zig");

pub const View = struct {
    const Self = @This();

    const ViewImpl = union(enum) {
        xdg_toplevel: XdgToplevel,
    };

    /// The implementation of this view
    impl: ViewImpl,

    /// The output this view is currently associated with
    output: *Output,

    /// This is non-null exactly when the view is mapped
    wlr_surface: ?*c.wlr_surface,

    /// If the view is floating or not
    floating: bool,

    /// True if the view is currentlt focused by at lease one seat
    focused: bool,

    /// The current output-relative coordinates and dimensions of the view
    current_box: Box,
    pending_box: ?Box,

    /// The dimensions the view would have taken if we didn't force it to tile
    natural_width: u32,
    natural_height: u32,

    current_tags: u32,
    pending_tags: ?u32,

    pending_serial: ?u32,

    // This is what we render while a transaction is in progress
    stashed_buffer: ?*c.wlr_buffer,

    pub fn init_xdg_toplevel(
        self: *Self,
        output: *Output,
        tags: u32,
        wlr_xdg_surface: *c.wlr_xdg_surface,
    ) void {
        self.output = output;

        self.wlr_surface = null;

        self.focused = false;

        self.current_box = Box{
            .x = 0,
            .y = 0,
            .height = 0,
            .width = 0,
        };
        self.pending_box = null;

        self.current_tags = tags;
        self.pending_tags = null;

        self.pending_serial = null;

        self.stashed_buffer = null;

        self.impl = .{ .xdg_toplevel = undefined };
        self.impl.xdg_toplevel.init(self, wlr_xdg_surface);
    }

    pub fn deinit(self: *Self) void {
        if (self.stashed_buffer) |buffer| {
            c.wlr_buffer_unref(buffer);
        }
    }

    pub fn needsConfigure(self: Self) bool {
        if (self.pending_box) |pending_box| {
            return pending_box.width != self.current_box.width or
                pending_box.height != self.current_box.height;
        } else {
            return false;
        }
    }

    pub fn configure(self: Self) void {
        if (self.pending_box) |pending_box| {
            switch (self.impl) {
                .xdg_toplevel => |xdg_toplevel| xdg_toplevel.configure(pending_box),
            }
        } else {
            Log.Error.log("Configure called on a View with no pending box", .{});
        }
    }

    pub fn sendFrameDone(self: Self) void {
        var now: c.timespec = undefined;
        _ = c.clock_gettime(c.CLOCK_MONOTONIC, &now);
        c.wlr_surface_send_frame_done(self.wlr_surface.?, &now);
    }

    pub fn dropStashedBuffer(self: *Self) void {
        // TODO: log debug error
        if (self.stashed_buffer) |buffer| {
            c.wlr_buffer_unref(buffer);
            self.stashed_buffer = null;
        }
    }

    pub fn stashBuffer(self: *Self) void {
        // TODO: log debug error if there is already a saved buffer
        if (self.wlr_surface) |wlr_surface| {
            if (c.wlr_surface_has_buffer(wlr_surface)) {
                _ = c.wlr_buffer_ref(wlr_surface.buffer);
                self.stashed_buffer = wlr_surface.buffer;
            }
        }
    }

    /// Set the focued bool and the active state of the view if it is a toplevel
    pub fn setFocused(self: *Self, focused: bool) void {
        self.focused = focused;
        switch (self.impl) {
            .xdg_toplevel => |xdg_toplevel| xdg_toplevel.setActivated(focused),
        }
    }

    /// If true is passsed, make the view float. If false, return it to the tiled
    /// layout.
    pub fn setFloating(self: *Self, float: bool) void {
        if (float and !self.floating) {
            self.floating = true;
            self.pending_box = Box{
                .x = std.math.max(0, @divTrunc(@intCast(i32, self.output.usable_box.width) -
                    @intCast(i32, self.natural_width), 2)),
                .y = std.math.max(0, @divTrunc(@intCast(i32, self.output.usable_box.height) -
                    @intCast(i32, self.natural_height), 2)),
                .width = self.natural_width,
                .height = self.natural_height,
            };
        } else if (!float and self.floating) {
            self.floating = false;
        }
    }

    /// Move a view from one output to another, sending the required enter/leave
    /// events.
    pub fn sendToOutput(self: *Self, destination_output: *Output) void {
        const node = @fieldParentPtr(ViewStack(View).Node, "view", self);

        self.output.views.remove(node);
        destination_output.views.push(node);

        c.wlr_surface_send_leave(self.wlr_surface, self.output.wlr_output);
        c.wlr_surface_send_enter(self.wlr_surface, destination_output.wlr_output);

        self.output = destination_output;
    }

    pub fn close(self: Self) void {
        switch (self.impl) {
            .xdg_toplevel => |xdg_toplevel| xdg_toplevel.close(),
        }
    }

    pub fn forEachSurface(
        self: Self,
        iterator: c.wlr_surface_iterator_func_t,
        user_data: ?*c_void,
    ) void {
        switch (self.impl) {
            .xdg_toplevel => |xdg_toplevel| xdg_toplevel.forEachSurface(iterator, user_data),
        }
    }
};