move and rename pict `convert' support

Renamed `convert' to `pict-convert', etc., to avoid confusion
with `file/convert' bindings.

Moved out of `slideshow/pict' to `slideshow/pict-convert', because
most `slideshow/pict' clients do not need it.

collects/drracket/private/language.rkt

@@ -373,7 +373,7 @@
       (define convert-table (make-hasheq))
       (define pict:convertible?
         (with-handlers ((exn:fail? (λ (exn) (λ (val) #f))))
-          (dynamic-require 'texpict/mrpict 'convertible?)))
+          (dynamic-require 'slideshow/pict-convert 'pict-convertible?)))
       (parameterize ([pretty-print-pre-print-hook (λ (val port) (void))]
                      [pretty-print-post-print-hook (λ (val port) (void))]
                      [pretty-print-exact-as-decimal #f]
@@ -469,8 +469,9 @@
   (define (mk-pict-snip convertible)
     (define-syntax-rule 
       (dyn name args ...)
-      ((dynamic-require 'texpict/mrpict 'name) args ...))
-    (define pict (dyn convert convertible))
+      ((dynamic-require 'slideshow/pict 'name) args ...))
+    (define pict ((dynamic-require 'slideshow/pict-convert 'pict-convert) 
+                  convertible))
     (define w (dyn pict-width pict))
     (define h (dyn pict-height pict))
     (define a (dyn pict-ascent pict))

collects/scribblings/slideshow/picts.scrbl

@@ -1,7 +1,7 @@
 #lang scribble/doc
 @(require "ss.rkt" "pict-diagram.rkt"
           (for-label racket/gui slideshow/code slideshow/flash slideshow/face
-                     slideshow/balloon))
+                     slideshow/balloon slideshow/pict-convert))
 
 @title[#:style 'toc]{Making Pictures}
 
@@ -21,7 +21,8 @@ PostScript for inclusion into a larger document. The
 
 @section{Pict Datatype}
 
-A picture is a @racket[pict] structure. Some functions, such as
+A @deftech{pict} is a @racket[pict] structure representing an image.
+Some functions, such as
 @racket[hline], create new simple picts. Other functions, such as
 @racket[ht-append], build new picts out of existing picts. In the
 latter case, the embedded picts retain their identity, so that
@@ -1130,23 +1131,26 @@ A parameter used to refine text measurements to better match an
 expected scaling of the image. The @racket[scale/improve-new-text]
 form sets this parameter while also scaling the resulting pict.}
 
-@section{Convertion to @racket[pict?]s}
+@;----------------------------------------
 
-This section describes a protocol for values to be
-able to convert themselves to @racket[pict?]s. The 
-protocol is used by DrRacket's REPL to render values
-that it prints out.
+@section{Conversion to Picts}
 
-@defthing[prop:convertible struct-type-property?]{
+@defmodule[slideshow/pict-convert]{The
+@racketmodname[slideshow/pict-convert] library defines a protocol for
+values to convert themselves to @tech{picts}. The protocol
+is used by DrRacket's interactions window, for example, to render
+values that it prints}
+
+@defthing[prop:pict-convertible struct-type-property?]{
 
 A property whose value should be a procedure matching the
 contract @racket[(-> any/c pict?)]. The
 procedure is called when a structure with the property is passed to
-@racket[convert]; the argument to the procedure is the
+@racket[pict-convert]; the argument to the procedure is the
 structure, and the procedure's result should be a pict.
 }
 
-@defthing[prop:convertible? struct-type-property?]{
+@defthing[prop:pict-convertible? struct-type-property?]{
 A property whose value should be a predicate procedure
 (i.e., matching the contract @racket[predicate/c]).
 
@@ -1154,18 +1158,18 @@ If this property is not set, then it is assumed to be
 the function @racket[(λ (x) #t)]. 
 
 If this property is set, then this procedure is called
-by @racket[convertible?] to determine if this particular
+by @racket[pict-convertible?] to determine if this particular
 value is convertible (thereby supporting situations
 where some instances of a given struct are convertible
 to picts, but others are not).
 }
 
-@defproc[(convertible? [v any/c]) boolean?]{
+@defproc[(pict-convertible? [v any/c]) boolean?]{
 Returns @racket[#t] if @racket[v] supports the conversion protocol
-(by being a struct with the @racket[prop:convertible] property)
+(by being a struct with the @racket[prop:pict-convertible] property)
 and @racket[#f] otherwise.
 }
 
-@defproc[(convert [v convertible?]) pict?]{
-  Requests a data conversion from @racket[v] to a @racket[pict?].
+@defproc[(pict-convert [v pict-convertible?]) pict?]{
+  Requests a data conversion from @racket[v] to a pict.
 }

collects/slideshow/pict-convert.rkt

@@ -0,0 +1,10 @@
+#lang racket/base
+(require "pict.rkt"
+         racket/contract
+         texpict/private/convertible)
+
+
+(provide pict-convert pict-convertible?)
+(provide/contract
+ [prop:pict-convertible (struct-type-property/c (-> pict-convertible? pict?))]
+ [prop:pict-convertible? (struct-type-property/c predicate/c)])

collects/texpict/mrpict.rkt

@@ -8,7 +8,6 @@
            racket/draw/draw-unit
            "private/mrpict-sig.rkt"
            "private/common-sig.rkt"
-           "private/convertible.rkt"
            "mrpict-sig.rkt"
            "mrpict-unit.rkt")
 
@@ -53,7 +52,3 @@
               pict?)])
   
   (provide text-style/c)
-
-  (provide convert convertible?)
-  (provide/contract
-   [prop:convertible (struct-type-property/c (-> convertible? pict?))])

collects/texpict/private/common-unit.rkt

@@ -23,7 +23,7 @@
 			   panbox     ; panorama box, computed on demand
                            last)      ; a descendent for the bottom-right
         #:mutable
-        #:property prop:convertible (λ (v) v)
+        #:property prop:pict-convertible (λ (v) v)
         #:property file:prop:convertible (lambda (v mode default)
                                            (convert-pict v mode default)))
       (define-struct child (pict dx dy sx sy syx sxy))

collects/texpict/private/convertible.rkt

@@ -1,19 +1,19 @@
 #lang racket/base
-(provide prop:convertible prop:convertible? convertible? convert)
+(provide prop:pict-convertible prop:pict-convertible? pict-convertible? pict-convert)
 
-(define-values (prop:convertible -convertible? convertible-ref)
-  (make-struct-type-property 'convertible))
+(define-values (prop:pict-convertible -pict-convertible? pict-convertible-ref)
+  (make-struct-type-property 'pict-convertible))
 
-(define-values (prop:convertible? convertible?? convertible?-ref)
-  (make-struct-type-property 'convertible?))
+(define-values (prop:pict-convertible? pict-convertible?? pict-convertible?-ref)
+  (make-struct-type-property 'pict-convertible?))
 
-(define (convertible? x)
-  (and (-convertible? x)
-       (if (convertible?? x)
-           ((convertible?-ref x) x)
+(define (pict-convertible? x)
+  (and (-pict-convertible? x)
+       (if (pict-convertible?? x)
+           ((pict-convertible?-ref x) x)
            #t)))
 
-(define (convert v)
-  (unless (convertible? v)
-    (raise-type-error 'convert "convertible" v))
-  ((convertible-ref v) v))
+(define (pict-convert v)
+  (unless (pict-convertible? v)
+    (raise-type-error 'pict-convert "pict-convertible" v))
+  ((pict-convertible-ref v) v))