(in-package :cl-smoke.qt.gui)

(defmacro qt:with-painter ((painter &optional paint-device) &body body)
  "Binds a PAINTER instance for PAINT-DEVICE to PAINTER
 during the evaluation of BODY. Or when PAINT-DEVICE is not
specified, saves and restored the state of PAINTER around BODY.

Makes sure the painter ends after BODY; thus preventing problems with 
still active and not yet garbage collected painters in CXX:PAINT-EVENT."
  (if paint-device
      `(let ((,painter (make-instance 'qt:painter :arg0 ,paint-device)))
         (assert (cxx:is-active ,painter)
                 (,painter)
                 "Painter ~A for ~A is not active"
                 ,painter ,paint-device)
         (unwind-protect
              (progn ,@body)
           (cxx:end ,painter)))
      `(progn (cxx:save ,painter)
              (unwind-protect
                   (progn ,@body)
                (cxx:restore ,painter)))))