[WIP] Add support for drag and dropdragdrop

1 files changed, 38 insertions, 2 deletions

diff --git a/include/pugl/pugl.h b/include/pugl/pugl.h
index e57f6aa..89415f6 100644
--- a/include/pugl/pugl.h
+++ b/include/pugl/pugl.h
@@ -152,10 +152,12 @@ typedef enum {
    A system clipboard.
 
    A clipboard provides a mechanism for transferring data between views,
-   including views in different processes.
+   including views in different processes.  Clipboards are used for both "copy
+   and paste" and "drag and drop" interactions.
 */
 typedef enum {
   PUGL_CLIPBOARD_GENERAL, ///< General clipboard for copy/pasted data
+  PUGL_CLIPBOARD_DRAG,    ///< Drag clipboard for drag and drop data
 } PuglClipboard;
 
 /**
@@ -977,10 +979,11 @@ typedef enum {
   PUGL_REFRESH_RATE,          ///< Refresh rate in Hz
   PUGL_VIEW_TYPE,             ///< View type (a #PuglViewType)
   PUGL_DARK_FRAME,            ///< True if window frame should be dark
+  PUGL_ACCEPT_DROP,           ///< True if view accepts dropped data
 } PuglViewHint;
 
 /// The number of #PuglViewHint values
-#define PUGL_NUM_VIEW_HINTS ((unsigned)PUGL_DARK_FRAME + 1U)
+#define PUGL_NUM_VIEW_HINTS ((unsigned)PUGL_ACCEPT_DROP + 1U)
 
 /// A special view hint value
 typedef enum {
@@ -1195,6 +1198,16 @@ double
 puglGetScaleFactor(const PuglView* view);
 
 /**
+   Register a type as supported for drag and drop.
+
+   Before realizing the view, this function should be called for every type the
+   view may accept as a drop target.
+*/
+PUGL_API
+PuglStatus
+puglRegisterDragType(PuglView* view, const char* type);
+
+/**
    @}
    @defgroup pugl_frame Frame
    Functions for working with the position and size of a view.
@@ -1569,6 +1582,29 @@ puglAcceptOffer(PuglView*                 view,
                 PuglRect                  region);
 
 /**
+   Reject data offered from a clipboard.
+
+   This can be called instead of puglAcceptOffer() to explicitly reject the
+   offer.  Note that drag-and-drop will still work if this isn't called, but
+   applications should always explicitly accept or reject each data offer for
+   optimal behaviour.
+
+   @param view The view.
+
+   @param offer The data offer event.
+
+   @param region The region of the view that will refuse this drop.  This may
+   be used by the system to avoid sending redundant events when the item is
+   dragged within the region.  This is only an optimization, an all-zero region
+   can safely be passed.
+*/
+PUGL_API
+PuglStatus
+puglRejectOffer(PuglView*                 view,
+                const PuglDataOfferEvent* offer,
+                PuglRect                  region);
+
+/**
    Set the clipboard contents.
 
    This sets the system clipboard contents, which can be retrieved with