add editor-scroll-to method of editor<%>

svn: r10860

original commit: 6c43d23bc47c8e811ee77831a965592d0f849a25

collects/mred/edit.ss

@@ -36,7 +36,7 @@
 			     "MrEdIt" #f 620 450))
       (define c (make-object editor-canvas% f))
       (define e (make-object (class editor%
-			       (define/override (set-modified mod?)
+                               (define/override (set-modified mod?)
 				 (send f modified mod?)
 				 (super set-modified mod?))
 			       (super-new))))

collects/mred/private/kernel.ss

@@ -252,6 +252,7 @@
     release-snip
     on-snip-modified
     set-modified
+    scroll-editor-to
     set-snip-data
     get-snip-data
     needs-update
@@ -928,6 +929,7 @@
     release-snip
     on-snip-modified
     set-modified
+    scroll-editor-to
     set-snip-data
     get-snip-data
     needs-update
@@ -1141,6 +1143,7 @@
     release-snip
     on-snip-modified
     set-modified
+    scroll-editor-to
     set-snip-data
     get-snip-data
     needs-update

collects/scribblings/gui/editor-intf.scrbl

@@ -1988,6 +1988,30 @@ The @scheme[show-errors?] argument is no longer used.
 }
 
 
+@defmethod[(scroll-editor-to [localx real?]
+                             [localy real?]
+                             [width (and/c real? (not/c negative?))]
+                             [height (and/c real? (not/c negative?))]
+                             [refresh? any/c]
+                             [bias (one-of/c 'start 'end 'none)])
+           boolean?]{
+
+Causes the editor to be scrolled so that a given @techlink{location}
+ is visible. If the editor is scrolled, @scheme[#t] is returned,
+ otherwise @scheme[#f] is returned.
+
+This method is normally called indirectly by @method[editor<%>
+ scroll-to] or @xmethod[text% scroll-to-position] to implement
+ scrolling.
+
+The default implementation forwards the request to the
+@method[editor-admin% scroll-to] method of the current administrator,
+if any (see @method[editor<%> get-admin]). If the editor has no
+administrator, @scheme[#f] is returned.
+
+}
+
+
 @defmethod[(scroll-line-location [pos (and/c exact? integer?)])
            (and/c real? (not/c negative?))]{
 
@@ -2010,8 +2034,13 @@ For @scheme[text%] objects: @|FCA| @|EVD|
 
 Called (indirectly) by snips within the editor: it causes the editor
  to be scrolled so that a given @techlink{location} range within a
- given snip is visible. If the editor is scrolled, @scheme[#t] is
- returned, otherwise @scheme[#f] is returned.
+ given snip is visible. If the editor is scrolled immediately,
+ @scheme[#t] is returned, otherwise @scheme[#f] is returned.
+
+If refreshing is delayed (see @method[editor<%> refresh-delayed?]),
+ then the scroll request is saved until the delay has ended. The
+ scroll is performed (immediately or later) by calling
+ @method[editor<%> scroll-editor-to].
 
 The @scheme[localx], @scheme[localy], @scheme[width], and @scheme[height]
  arguments specify the area that needs to be visible in @scheme[snip]'s

collects/scribblings/gui/text-class.scrbl

@@ -1706,12 +1706,18 @@ When the specified range cannot fit in the visible area, @scheme[bias]
  displayed. Otherwise, @scheme[bias] must be @scheme['none].
 
 If the editor is scrolled, then the editor is redrawn and the return
- value is @scheme[#t]; otherwise, the return value is @scheme[#f].
+ value is @scheme[#t]; otherwise, the return value is @scheme[#f].  If
+ refreshing is delayed (see @method[editor<%> refresh-delayed?]), then
+ the scroll request is saved until the delay has ended. The scroll is
+ performed (immediately or later) by calling @method[editor<%>
+ scroll-editor-to].
 
 Scrolling is disallowed when the editor is internally locked for
  reflowing (see also @|lockdiscuss|). 
 
-The system may scroll the editor without calling this method.
+The system may scroll the editor without calling this method. For
+ example, a canvas displaying an editor might scroll the editor to
+ handle a scrollbar event.
 
 }