UI code for supporting workspace drags

Not used yet.

src/dnd.rs

@@ -10,7 +10,6 @@ use crate::backend::{ZcosmicToplevelHandleV1, ZcosmicWorkspaceHandleV1};
 
 // Include `pid` in mime. Want to drag between our surfaces, but not another
 // process, if we use Wayland object ids.
-#[allow(dead_code)]
 static WORKSPACE_MIME: LazyLock<String> =
     LazyLock::new(|| format!("text/x.cosmic-workspace-id-{}", std::process::id()));
 
@@ -59,11 +58,47 @@ impl TryFrom<(Vec<u8>, std::string::String)> for DragToplevel {
     }
 }
 
+#[derive(Clone, Debug)]
+pub struct DragWorkspace {}
+
+impl AsMimeTypes for DragWorkspace {
+    fn available(&self) -> Cow<'static, [String]> {
+        vec![WORKSPACE_MIME.clone()].into()
+    }
+
+    fn as_bytes(&self, mime_type: &str) -> Option<Cow<'static, [u8]>> {
+        if mime_type == *WORKSPACE_MIME {
+            Some(Vec::new().into())
+        } else {
+            None
+        }
+    }
+}
+
+impl cosmic::iced::clipboard::mime::AllowedMimeTypes for DragWorkspace {
+    fn allowed() -> Cow<'static, [String]> {
+        vec![WORKSPACE_MIME.clone()].into()
+    }
+}
+
+impl TryFrom<(Vec<u8>, std::string::String)> for DragWorkspace {
+    type Error = ();
+    fn try_from((_bytes, mime_type): (Vec<u8>, String)) -> Result<Self, ()> {
+        if mime_type == *WORKSPACE_MIME {
+            Ok(Self {})
+        } else {
+            Err(())
+        }
+    }
+}
+
 #[derive(Clone, Debug, PartialEq)]
 #[repr(u8)]
 pub enum DropTarget {
     WorkspaceSidebarEntry(ZcosmicWorkspaceHandleV1, wl_output::WlOutput),
     OutputToplevels(ZcosmicWorkspaceHandleV1, wl_output::WlOutput),
+    #[allow(dead_code)]
+    WorkspacesBar(wl_output::WlOutput),
 }
 
 impl DropTarget {
@@ -81,6 +116,10 @@ impl DropTarget {
                 let id = output.id().protocol_id();
                 (u64::from(discriminant) << 32) | u64::from(id)
             }
+            Self::WorkspacesBar(output) => {
+                let id = output.id().protocol_id();
+                (u64::from(discriminant) << 32) | u64::from(id)
+            }
         }
     }
 }

src/main.rs

@@ -47,7 +47,7 @@ use backend::{ToplevelInfo, ZcosmicToplevelHandleV1, ZcosmicWorkspaceHandleV1};
 mod dnd;
 mod utils;
 mod widgets;
-use dnd::{DragSurface, DragToplevel, DropTarget};
+use dnd::{DragSurface, DragToplevel, DragWorkspace, DropTarget};
 
 #[derive(Clone, Debug, Default, PartialEq, CosmicConfigEntry)]
 struct CosmicWorkspacesConfig {
@@ -98,6 +98,10 @@ enum Msg {
     DndEnter(DropTarget, f64, f64, Vec<String>),
     DndLeave(DropTarget),
     DndToplevelDrop(DragToplevel),
+    #[allow(dead_code)]
+    DndWorkspaceDrag,
+    #[allow(dead_code)]
+    DndWorkspaceDrop(DragWorkspace),
     SourceFinished,
     #[allow(dead_code)]
     NewWorkspace,
@@ -109,7 +113,7 @@ enum Msg {
     Ignore,
 }
 
-#[derive(Debug)]
+#[derive(Clone, Debug)]
 struct Workspace {
     name: String,
     // img_for_output: HashMap<wl_output::WlOutput, backend::CaptureImage>,
@@ -515,7 +519,7 @@ impl Application for App {
                                 output,
                             ));
                         }
-                        None => {}
+                        Some(DropTarget::WorkspacesBar(_)) | None => {}
                     }
                 }
             }
@@ -608,6 +612,8 @@ impl Application for App {
                     }
                 }
             }
+            Msg::DndWorkspaceDrag => {}
+            Msg::DndWorkspaceDrop(_workspace) => {}
             Msg::Ignore => {}
         }
 

src/view/mod.rs

@@ -19,7 +19,7 @@ use std::collections::HashMap;
 
 use crate::{
     backend::{self, CaptureImage},
-    dnd::{DragSurface, DragToplevel, DropTarget},
+    dnd::{DragSurface, DragToplevel, DragWorkspace, DropTarget},
     App, LayerSurface, Msg, Toplevel, Workspace,
 };
 
@@ -41,6 +41,25 @@ fn toplevel_dnd_destination<'a>(
     .into()
 }
 
+#[allow(dead_code)]
+fn workspace_dnd_destination<'a>(
+    target: DropTarget,
+    child: cosmic::Element<'a, Msg>,
+) -> cosmic::Element<'a, Msg> {
+    let target2 = target.clone();
+    cosmic::widget::dnd_destination::dnd_destination_for_data(
+        child,
+        |data: Option<DragWorkspace>, _action| match data {
+            Some(workspace) => Msg::DndWorkspaceDrop(workspace),
+            None => Msg::Ignore,
+        },
+    )
+    .drag_id(target.drag_id())
+    .on_enter(move |actions, mime, pos| Msg::DndEnter(target.clone(), actions, mime, pos))
+    .on_leave(move || Msg::DndLeave(target2.clone()))
+    .into()
+}
+
 pub(crate) fn layer_surface<'a>(
     app: &'a App,
     surface: &'a LayerSurface,
@@ -142,7 +161,7 @@ fn workspace_item<'a>(
     workspace: &'a Workspace,
     _output: &wl_output::WlOutput,
     is_drop_target: bool,
-) -> cosmic::Element<'a, Msg> {
+) -> cosmic::Element<'static, Msg> {
     let image = capture_image(workspace.img.as_ref(), 1.0);
     let is_active = workspace.is_active;
     // TODO editable name?
@@ -184,26 +203,32 @@ fn workspace_sidebar_entry<'a>(
         iced::mouse::Interaction::Idle
     };
     */
+    let item = workspace_item(workspace, output, is_drop_target);
     /* TODO allow moving workspaces (needs compositor support)
-    iced::widget::dnd_source(workspace_item(workspace, output))
-        .on_drag(|size| {
-            Msg::StartDrag(
-                size,
-                DragSurface::Workspace {
-                    handle: workspace.handle.clone(),
-                    output: output.clone(),
-                },
+    let workspace_clone = workspace.clone(); // TODO avoid clone
+    let output_clone = output.clone();
+    let source = cosmic::widget::dnd_source(item)
+        .drag_threshold(5.)
+        .drag_content(|| DragWorkspace {})
+        .drag_icon(move |offset| {
+            (
+                workspace_item(&workspace_clone, &output_clone, false).map(|_| ()),
+                cosmic::iced_core::widget::tree::State::None,
+                -offset,
             )
         })
-        .on_finished(Msg::SourceFinished)
-        .on_cancelled(Msg::SourceFinished)
-        .into()
+        .on_start(Some(Msg::StartDrag(DragSurface::Workspace(
+            workspace.handle.clone(),
+        ))))
+        .on_finish(Some(Msg::SourceFinished))
+        .on_cancel(Some(Msg::SourceFinished))
+        .into();
     */
     //crate::widgets::mouse_interaction_wrapper(
     //   mouse_interaction,
     toplevel_dnd_destination(
         DropTarget::WorkspaceSidebarEntry(workspace.handle.clone(), output.clone()),
-        workspace_item(workspace, output, is_drop_target),
+        item,
     )
 }