X11: Use cursor themes

This changes to getting cursors by name from the cursor theme, which makes the
cursor match the ones used in modern desktop environments.  As far as I can
tell, there is no real standard for names, these ones seem to work for me in
GNOME, KDE, and Xfce.

I am not sure about the compatibility concerns here, but X11 without Xcursor
themes strikes me as either too esoteric or too ancient to worry about,
especially since cursor switching isn't critical functionality anyway.

2 files changed, 42 insertions, 29 deletions

diff --git a/src/x11.c b/src/x11.c
index cce1f8c..ca23a76 100644
--- a/src/x11.c
+++ b/src/x11.c
@@ -28,7 +28,6 @@
 
 #ifdef HAVE_XCURSOR
 #  include <X11/Xcursor/Xcursor.h>
-#  include <X11/cursorfont.h>
 #endif
 
 #include <sys/select.h>
@@ -65,6 +64,18 @@ enum WmClientStateMessageAction {
   WM_STATE_TOGGLE
 };
 
+#define NUM_CURSORS ((unsigned)PUGL_CURSOR_UP_DOWN + 1u)
+
+static const char* const cursor_names[NUM_CURSORS] = {
+  "default",           // ARROW
+  "text",              // CARET
+  "crosshair",         // CROSSHAIR
+  "pointer",           // HAND
+  "not-allowed",       // NO
+  "sb_h_double_arrow", // LEFT_RIGHT
+  "sb_v_double_arrow"  // UP_DOWN
+};
+
 static bool
 initXSync(PuglWorldInternals* const impl)
 {
@@ -150,7 +161,7 @@ puglInitViewInternals(void)
   PuglInternals* impl = (PuglInternals*)calloc(1, sizeof(PuglInternals));
 
 #ifdef HAVE_XCURSOR
-  impl->cursorShape = XC_arrow;
+  impl->cursorName = cursor_names[PUGL_CURSOR_ARROW];
 #endif
 
   return impl;
@@ -246,20 +257,36 @@ updateSizeHints(const PuglView* const view)
 
 #ifdef HAVE_XCURSOR
 static PuglStatus
-defineCursorShape(PuglView* const view, const unsigned shape)
+defineCursorName(PuglView* const view, const char* const name)
 {
   PuglInternals* const impl    = view->impl;
   PuglWorld* const     world   = view->world;
   Display* const       display = world->impl->display;
-  const Cursor         cur     = XcursorShapeLoadCursor(display, shape);
 
-  if (cur) {
-    XDefineCursor(display, impl->win, cur);
-    XFreeCursor(display, cur);
-    return PUGL_SUCCESS;
+  // Load cursor theme
+  char* const theme = XcursorGetTheme(display);
+  if (!theme) {
+    return PUGL_FAILURE;
   }
 
-  return PUGL_FAILURE;
+  // Get the default size and cursor image from it
+  const int           size  = XcursorGetDefaultSize(display);
+  XcursorImage* const image = XcursorLibraryLoadImage(name, theme, size);
+  if (!image) {
+    return PUGL_BAD_PARAMETER;
+  }
+
+  // Load a cursor from the image
+  const Cursor cur = XcursorImageLoadCursor(display, image);
+  XcursorImageDestroy(image);
+  if (!cur) {
+    return PUGL_UNKNOWN_ERROR;
+  }
+
+  // Set the view's cursor to the new loaded one
+  XDefineCursor(display, impl->win, cur);
+  XFreeCursor(display, cur);
+  return PUGL_SUCCESS;
 }
 #endif
 
@@ -1436,37 +1463,25 @@ puglSetClipboard(PuglView* const   view,
   return st;
 }
 
-#ifdef HAVE_XCURSOR
-static const unsigned cursor_nums[] = {
-  XC_arrow,             // ARROW
-  XC_xterm,             // CARET
-  XC_crosshair,         // CROSSHAIR
-  XC_hand2,             // HAND
-  XC_pirate,            // NO
-  XC_sb_h_double_arrow, // LEFT_RIGHT
-  XC_sb_v_double_arrow, // UP_DOWN
-};
-#endif
-
 PuglStatus
 puglSetCursor(PuglView* const view, const PuglCursor cursor)
 {
 #ifdef HAVE_XCURSOR
   PuglInternals* const impl  = view->impl;
   const unsigned       index = (unsigned)cursor;
-  const unsigned       count = sizeof(cursor_nums) / sizeof(cursor_nums[0]);
+  const unsigned       count = sizeof(cursor_names) / sizeof(cursor_names[0]);
   if (index >= count) {
     return PUGL_BAD_PARAMETER;
   }
 
-  const unsigned shape = cursor_nums[index];
-  if (!impl->win || impl->cursorShape == shape) {
+  const char* const name = cursor_names[index];
+  if (!impl->win || impl->cursorName == name) {
     return PUGL_SUCCESS;
   }
 
-  impl->cursorShape = cursor_nums[index];
+  impl->cursorName = cursor_names[index];
 
-  return defineCursorShape(view, impl->cursorShape);
+  return defineCursorName(view, impl->cursorName);
 #else
   (void)view;
   (void)cursor;
diff --git a/src/x11.h b/src/x11.h
index f85b227..720dbeb 100644
--- a/src/x11.h
+++ b/src/x11.h
@@ -56,9 +56,7 @@ struct PuglInternalsImpl {
   PuglEvent    pendingConfigure;
   PuglEvent    pendingExpose;
   int          screen;
-#ifdef HAVE_XCURSOR
-  unsigned cursorShape;
-#endif
+  const char*  cursorName;
 };
 
 PUGL_WARN_UNUSED_RESULT