WindowManager: Support Dynamic tooltips when dragging.

Originally the operator name was drawn next to the dragging content.
After that there was an option to add custom, static text with the
dragging content. This patch allows dynamic text to be drawn.

The custom text was implemented as out parameter of the poll function
what made the code unclear. This patch introduces a tooltip function
that separates tooltip generation from the poll function.

NOTE: the text should always be returned in its own memory block. This
block will be freed after it is copied in the drag struct.

Reviewed By: Severin

Differential Revision: https://developer.blender.org/D12104

1 files changed, 46 insertions, 36 deletions

diff --git a/source/blender/windowmanager/intern/wm_dragdrop.c b/source/blender/windowmanager/intern/wm_dragdrop.c
index db72dd2a819..c58d3c53e03 100644
--- a/source/blender/windowmanager/intern/wm_dragdrop.c
+++ b/source/blender/windowmanager/intern/wm_dragdrop.c
@@ -96,14 +96,16 @@ ListBase *WM_dropboxmap_find(const char *idname, int spaceid, int regionid)
 
 wmDropBox *WM_dropbox_add(ListBase *lb,
                           const char *idname,
-                          bool (*poll)(bContext *, wmDrag *, const wmEvent *, const char **),
+                          bool (*poll)(bContext *, wmDrag *, const wmEvent *),
                           void (*copy)(wmDrag *, wmDropBox *),
-                          void (*cancel)(struct Main *, wmDrag *, wmDropBox *))
+                          void (*cancel)(struct Main *, wmDrag *, wmDropBox *),
+                          WMDropboxTooltipFunc tooltip)
 {
   wmDropBox *drop = MEM_callocN(sizeof(wmDropBox), "wmDropBox");
   drop->poll = poll;
   drop->copy = copy;
   drop->cancel = cancel;
+  drop->tooltip = tooltip;
   drop->ot = WM_operatortype_find(idname, 0);
   drop->opcontext = WM_OP_INVOKE_DEFAULT;
 
@@ -218,22 +220,36 @@ void WM_drag_free_list(struct ListBase *lb)
   }
 }
 
-static const char *dropbox_active(bContext *C,
-                                  ListBase *handlers,
-                                  wmDrag *drag,
-                                  const wmEvent *event)
+static char *dropbox_tooltip(bContext *C,
+                             wmDrag *drag,
+                             const wmEvent *event,
+                             const wmDropBox *drop)
+{
+  char *tooltip = NULL;
+  if (drop->tooltip) {
+    tooltip = drop->tooltip(C, drag, event);
+  }
+  if (!tooltip) {
+    tooltip = BLI_strdup(WM_operatortype_name(drop->ot, drop->ptr));
+  }
+  /* XXX Doing translation here might not be ideal, but later we have no more
+   *     access to ot (and hence op context)... */
+  return tooltip;
+}
+
+static wmDropBox *dropbox_active(bContext *C,
+                                 ListBase *handlers,
+                                 wmDrag *drag,
+                                 const wmEvent *event)
 {
   LISTBASE_FOREACH (wmEventHandler *, handler_base, handlers) {
     if (handler_base->type == WM_HANDLER_TYPE_DROPBOX) {
       wmEventHandler_Dropbox *handler = (wmEventHandler_Dropbox *)handler_base;
       if (handler->dropboxes) {
         LISTBASE_FOREACH (wmDropBox *, drop, handler->dropboxes) {
-          const char *tooltip = NULL;
-          if (drop->poll(C, drag, event, &tooltip) &&
+          if (drop->poll(C, drag, event) &&
               WM_operator_poll_context(C, drop->ot, drop->opcontext)) {
-            /* XXX Doing translation here might not be ideal, but later we have no more
-             *     access to ot (and hence op context)... */
-            return (tooltip) ? tooltip : WM_operatortype_name(drop->ot, drop->ptr);
+            return drop;
           }
         }
       }
@@ -242,29 +258,22 @@ static const char *dropbox_active(bContext *C,
   return NULL;
 }
 
-/* return active operator name when mouse is in box */
-static const char *wm_dropbox_active(bContext *C, wmDrag *drag, const wmEvent *event)
+/* return active operator tooltip/name when mouse is in box */
+static char *wm_dropbox_active(bContext *C, wmDrag *drag, const wmEvent *event)
 {
   wmWindow *win = CTX_wm_window(C);
-  ScrArea *area = CTX_wm_area(C);
-  ARegion *region = CTX_wm_region(C);
-  const char *name;
-
-  name = dropbox_active(C, &win->handlers, drag, event);
-  if (name) {
-    return name;
+  wmDropBox *drop = dropbox_active(C, &win->handlers, drag, event);
+  if (!drop) {
+    ScrArea *area = CTX_wm_area(C);
+    drop = dropbox_active(C, &area->handlers, drag, event);
   }
-
-  name = dropbox_active(C, &area->handlers, drag, event);
-  if (name) {
-    return name;
+  if (!drop) {
+    ARegion *region = CTX_wm_region(C);
+    drop = dropbox_active(C, &region->handlers, drag, event);
   }
-
-  name = dropbox_active(C, &region->handlers, drag, event);
-  if (name) {
-    return name;
+  if (drop) {
+    return dropbox_tooltip(C, drag, event, drop);
   }
-
   return NULL;
 }
 
@@ -279,17 +288,18 @@ static void wm_drop_operator_options(bContext *C, wmDrag *drag, const wmEvent *e
     return;
   }
 
-  drag->opname[0] = 0;
+  drag->tooltip[0] = 0;
 
   /* check buttons (XXX todo rna and value) */
   if (UI_but_active_drop_name(C)) {
-    BLI_strncpy(drag->opname, IFACE_("Paste name"), sizeof(drag->opname));
+    BLI_strncpy(drag->tooltip, IFACE_("Paste name"), sizeof(drag->tooltip));
   }
   else {
-    const char *opname = wm_dropbox_active(C, drag, event);
+    char *tooltip = wm_dropbox_active(C, drag, event);
 
-    if (opname) {
-      BLI_strncpy(drag->opname, opname, sizeof(drag->opname));
+    if (tooltip) {
+      BLI_strncpy(drag->tooltip, tooltip, sizeof(drag->tooltip));
+      MEM_freeN(tooltip);
       // WM_cursor_modal_set(win, WM_CURSOR_COPY);
     }
     // else
@@ -584,7 +594,7 @@ void wm_drags_draw(bContext *C, wmWindow *win, rcti *rect)
     }
 
     /* operator name with roundbox */
-    if (drag->opname[0]) {
+    if (drag->tooltip[0]) {
       if (drag->imb) {
         x = cursorx - drag->sx / 2;
 
@@ -611,7 +621,7 @@ void wm_drags_draw(bContext *C, wmWindow *win, rcti *rect)
         drag_rect_minmax(rect, x, y, x + w, y + iconsize);
       }
       else {
-        wm_drop_operator_draw(drag->opname, x, y);
+        wm_drop_operator_draw(drag->tooltip, x, y);
       }
     }
   }