From 8308c203b6ea2dbf7ba32755f084c7105ea213f6 Mon Sep 17 00:00:00 2001
From: Robby Findler <robby@racket-lang.org>
Date: Mon, 3 Dec 2001 19:00:35 +0000
Subject: [PATCH] added delegate canvas to help when delegatee window is hidden
 completely

original commit: 048b3a19ffb842163d2a46c269a56d423519fe0d
---
 collects/framework/private/canvas.ss | 12 ++++++++++
 collects/framework/private/frame.ss  | 34 +++++++++++++++++++---------
 collects/framework/private/sig.ss    |  3 +++
 3 files changed, 38 insertions(+), 11 deletions(-)

diff --git a/collects/framework/private/canvas.ss b/collects/framework/private/canvas.ss
index 679c97d4..3f005ff7 100644
--- a/collects/framework/private/canvas.ss
+++ b/collects/framework/private/canvas.ss
@@ -18,6 +18,17 @@
 	(mixin ((class->interface editor-canvas%)) (basic<%>)
           (super-instantiate ())))
       
+      (define delegate<%> (interface (basic<%>)))
+
+      (define delegate-mixin
+        (mixin (basic<%>) (delegate<%>)
+          (rename [super-on-superwindow-show on-superwindow-show])
+          (inherit get-top-level-window)
+          (define/override (on-superwindow-show shown?)
+            (send (send (get-top-level-window) get-delegatee) set-start/end-para #f #f)
+            (super-on-superwindow-show shown?))
+          (super-instantiate ())))
+      
       (define info<%> (interface (basic<%>)))
       ;; (basic<%> -> (class (is-a? (send this get-top-level-window) frame:info<%>)))
       (define info-mixin 
@@ -169,4 +180,5 @@
 
       (define basic% (basic-mixin editor-canvas%))
       (define info% (info-mixin basic%))
+      (define delegat% (delegate-mixin basic%))
       (define wide-snip% (wide-snip-mixin basic%)))))
diff --git a/collects/framework/private/frame.ss b/collects/framework/private/frame.ss
index def4fba6..32886bf0 100644
--- a/collects/framework/private/frame.ss
+++ b/collects/framework/private/frame.ss
@@ -888,6 +888,10 @@
           (rename [super-on-event on-event])
           (init-field delegate-frame)
           (inherit get-editor get-dc)
+          (rename [super-on-superwindow-show on-superwindow-show])
+          (define/override (on-superwindow-show shown?)
+            (send (send delegate-frame get-delegatee) set-start/end-para #f #f)
+            (super-on-superwindow-show shown?))
           (define/override (on-event evt)
             (super-on-event evt)
             (when (and delegate-frame
@@ -908,27 +912,33 @@
         (class text:basic%
           (rename [super-on-paint on-paint])
           (inherit get-admin)
-          (define start-para 0)
-          (define end-para 0)
+          (define start-para #f)
+          (define end-para #f)
           (define view-x-b (box 0))
           (define view-width-b (box 0))
           (inherit paragraph-start-position position-location invalidate-bitmap-cache)
+
+          ;; set-start/end-para : (union (#f #f -> void) (number number -> void))
           (define/public (set-start/end-para _start-para _end-para)
-            (unless (and (= _start-para start-para)
-                         (= _end-para end-para))
+            (unless (and (equal? _start-para start-para)
+                         (equal? _end-para end-para))
               (let ([old-start-para start-para]
                     [old-end-para end-para])
                 (set! start-para _start-para)
                 (set! end-para _end-para)
-                (let-values ([(x y w h) (get-rectangle old-start-para old-end-para)])
-                  (when x
-                    (invalidate-bitmap-cache x y w h)))
-                (let-values ([(x y w h) (get-rectangle start-para end-para)])
-                  (when x
-                    (invalidate-bitmap-cache x y w h))))))
+                (when (and old-start-para old-end-para)
+                  (let-values ([(x y w h) (get-rectangle old-start-para old-end-para)])
+                    (when x
+                      (invalidate-bitmap-cache x y w h))))
+                (when (and start-para end-para)
+                  (let-values ([(x y w h) (get-rectangle start-para end-para)])
+                    (when x
+                      (invalidate-bitmap-cache x y w h)))))))
 
           (define/override (on-paint before? dc left top right bottom dx dy draw-caret)
-            (when before?
+            (when (and before?
+                       start-para
+                       end-para)
               (let ([old-pen (send dc get-pen)]
                     [old-brush (send dc get-brush)])
                 (send dc set-pen
@@ -1038,6 +1048,8 @@
                     (send delegate-text position-paragraph (unbox startb)) 
                     (send delegate-text position-paragraph (unbox endb)))))
 
+          (define/public (get-delegatee) delegatee)
+
           (super-instantiate ())
           
           (define delegatee (instantiate delegatee-text% ()))
diff --git a/collects/framework/private/sig.ss b/collects/framework/private/sig.ss
index 0eb38d1e..6562a147 100644
--- a/collects/framework/private/sig.ss
+++ b/collects/framework/private/sig.ss
@@ -163,6 +163,9 @@
     (basic-mixin
      basic<%>
 
+     delegate-mixin
+     delegate<%>
+     
      info-mixin
      info<%>