Changes between Version 2 and Version 3 of CocoaBridge

Timestamp:

Oct 13, 2007, 2:14:18 AM (13 years ago)

Author:

rme

Comment:

--

CocoaBridge

@@ -5 +5 @@
 A good introductory Cocoa text is Aaron Hillegass's
 [http://www.amazon.com/Cocoa-Programming-Mac-OS-2nd/dp/0321213149 Cocoa Programming for Mac OS X].
+
+== Elementary Usage ==
+
+Here's a very simple example of how to create a window and draw to it.
+
+{{{
+(in-package "CL-USER")
+
+(require "COCOA")
+
+(defclass red-view (ns:ns-view)
+  ()
+  (:metaclass ns:+ns-object))
+
+(objc:defmethod (#/drawRect: :void) ((self red-view) (rect :<NSR>ect))
+  (#/set (#/redColor ns:ns-color))
+  (#_NSRectFill (#/bounds self)))
+
+(defun show-red-window ()
+  (ccl::with-autorelease-pool
+   (let* ((rect (ns:make-ns-rect 0 0 300 300))
+          (w (make-instance 'ns:ns-window
+                            :with-content-rect rect
+                            :style-mask (logior #$NSTitledWindowMask
+                                               #$NSClosableWindowMask
+                                               #$NSMiniaturizableWindowMask)
+                            :backing #$NSBackingStoreBuffered
+                            :defer t)))
+     (#/setTitle: w "Red")
+     (#/setContentView: w (make-instance 'red-view))
+     (#/center w)
+     (#/makeKeyAndOrderFront: w nil)
+     (#/contentView w))))
+}}}
+
+Load the file containing these forms, evaluate `(show-red-window)`, and you'll see a red window.
+
+=== More drawing ===
+
+The general assumption in Cocoa is that you will do your drawing in your custom
+view's `drawRect:` method.  It's often nice, though, to be able to draw by evaluating
+forms at the lisp top-level.
+
+One problem with that, at least in OpenMCL, is that parts of Cocoa are not
+thread-safe.  Fortunately, creating windows on secondary threads is supported.
+So is drawing to a view, provided that the drawing is bracketed with calls to
+`lockFocusIfCanDraw` and `unlockFocus`.
+
+So, to keep from forgetting to `unlockFocus`, define this simple macro.
+(If you forget to `unlockFocus`, you'll get a spinning beach ball and have
+to kill the lisp.)
+
+{{{
+(defmacro with-focused-view (view &body forms)
+  `(when (#/lockFocusIfCanDraw ,view)
+     ,@forms
+     (#/unlockFocus ,view)))
+}}}
+
+Now, you can draw.  Notice that `show-red-view` returns a view instance.
+
+{{{
+(setf *v* (show-red-view))
+(with-focused-view *v*
+    (let* ((path (#/bezierPath ns:ns-bezier-path)))
+      (#/moveToPoint: path (ns:make-ns-point 10 10))
+      (#/lineToPoint: path (ns:make-ns-point 100 100))
+      (#/stroke path)))
+}}}
+