Index: apps/diagram-viewer.man
==================================================================
--- apps/diagram-viewer.man
+++ apps/diagram-viewer.man
@@ -75,11 +75,14 @@
 [arg_def (handle) format in]
 
 This argument specifies the image format to convert the diagrams into
 when processing the input. The application recognizes all formats
 supported by the [package Img] package, i.e. for which it can load a
-package [package img::[var format]]
+package [package img::[var format]] (together with [package canvas::snap]),
+and all formats for which it can load a package
+[package canvas::[var format]]. These are (currently) [const mvg],
+and [const pdf].
 
 [arg_def path inputfile in]
 
 This argument specifies the path to the diagram file to process. It
 has to exist, must be readable, and written in [term diagram] format.

ADDED   modules/canvas/canvas_pdf.man
Index: modules/canvas/canvas_pdf.man
==================================================================
--- /dev/null
+++ modules/canvas/canvas_pdf.man
@@ -0,0 +1,36 @@
+[comment {-*- tcl -*- doctools manpage}]
+[manpage_begin canvas::pdf n 1]
+[keywords canvas]
+[keywords graphics]
+[keywords imagemagick]
+[keywords {portable document format}]
+[keywords pdf]
+[keywords {print screen}]
+[keywords serialization]
+[keywords {vector graphics}]
+[copyright {2014 Andreas Kupries, Arjen Markus}]
+[copyright {2014 Documentation, Andreas Kupries}]
+[moddesc   {Variations on a canvas}]
+[titledesc {Canvas to PDF}]
+[require Tcl 8.5]
+[require Tk 8.5]
+[require canvas::pdf [opt 1]]
+[require pdf4tcl]
+[description]
+
+This package provides a command to convert a canvas' contents to
+Adobe's PDF vector format.
+
+[section API]
+
+[list_begin definitions]
+
+[call [cmd ::canvas::pdf] [arg pathName]]
+
+Dump the contents of the canvas [arg pathName]. The result is a string
+in Adobe's PDF.
+
+[list_end]
+[vset CATEGORY canvas]
+[include ../../support/devel/doc/feedback.inc]
+[manpage_end]

ADDED   modules/canvas/canvas_pdf.tcl
Index: modules/canvas/canvas_pdf.tcl
==================================================================
--- /dev/null
+++ modules/canvas/canvas_pdf.tcl
@@ -0,0 +1,51 @@
+# *- tcl -*-
+# ### ### ### ######### ######### #########
+
+# Copyright (c) 2014 andreas Kupries, Arjen Markus
+# OLL licensed (http://wiki.tcl.tk/10892).
+
+# ### ### ### ######### ######### #########
+## Requisites
+
+package require Tcl 8.5
+package require Tk  8.5
+package require pdf4tcl
+package require fileutil
+
+namespace eval ::canvas {}
+
+# ### ### ### ######### ######### #########
+## Implementation.
+
+proc ::canvas::pdf {canvas} {
+    #raise [winfo toplevel $canvas] 
+    #update
+
+    set tmp [fileutil::tempfile canvas_pdf_]
+
+    # Note: The paper dimensions are hardcoded. A bit less than A7,
+    # looks like. This looks to be something which could be improved
+    # on.
+
+    # Note 2: We go through a temp file to write the pdf, and load it
+    # back into memory for the caller to use.
+
+    set pdf [::pdf4tcl::new %AUTO% -paper {9.5c 6.0c}]
+    $pdf canvas $canvas -width 9.2c
+    $pdf write -file $tmp
+    $pdf destroy
+
+    set data [fileutil::cat $tmp]
+    file delete $tmp
+
+    return $data
+}
+
+# ### ### ### ######### ######### #########
+## Helper commands. Internal.
+
+# ### ### ### ######### ######### #########
+## Ready
+
+package provide canvas::pdf 1.0.1
+return

Index: modules/canvas/pkgIndex.tcl
==================================================================
--- modules/canvas/pkgIndex.tcl
+++ modules/canvas/pkgIndex.tcl
@@ -7,8 +7,9 @@
 package ifneeded canvas::edit::polyline      0.1   [list source [file join $dir canvas_epolyline.tcl]]
 package ifneeded canvas::edit::quadrilateral 0.1   [list source [file join $dir canvas_equad.tcl]]
 package ifneeded canvas::gradient            0.2   [list source [file join $dir canvas_gradient.tcl]]
 package ifneeded canvas::highlight           0.1   [list source [file join $dir canvas_highlight.tcl]]
 package ifneeded canvas::mvg                 1     [list source [file join $dir canvas_mvg.tcl]]
+package ifneeded canvas::pdf                 1.0.1 [list source [file join $dir canvas_pdf.tcl]]
 package ifneeded canvas::snap                1.0.1 [list source [file join $dir canvas_snap.tcl]]
 package ifneeded canvas::tag                 0.1   [list source [file join $dir canvas_tags.tcl]]
 package ifneeded canvas::track::lines        0.1   [list source [file join $dir canvas_trlines.tcl]]

Index: modules/diagrams/application.tcl
==================================================================
--- modules/diagrams/application.tcl
+++ modules/diagrams/application.tcl
@@ -46,11 +46,17 @@
     return
 }
 
 proc ::diagram::application::showerror {text} {
     global argv0
-    puts stderr "$argv0: $text"
+    if {[catch {package present Tk}]} {
+        puts stderr "$argv0: $text"
+    } else {
+        tk_messageBox -type ok -icon error \
+	    -title "Error in application" \
+	    -message "$argv0: $text"
+    }
     exit 1
 }
 
 # # ## ### ##### ######## ############# #####################
 ## Internal data and status
@@ -464,7 +470,7 @@
     after 100
     return $dip
 }
 
 # # ## ### ##### ######## ############# #####################
-package provide diagram::application 1.2
+package provide diagram::application 1.3
 return

Index: modules/diagrams/pkgIndex.tcl
==================================================================
--- modules/diagrams/pkgIndex.tcl
+++ modules/diagrams/pkgIndex.tcl
@@ -9,7 +9,7 @@
 package ifneeded diagram::point       1 [list source [file join $dir point.tcl]]
 package ifneeded diagram::core        1 [list source [file join $dir core.tcl]]
 package ifneeded diagram::basic   1.0.1 [list source [file join $dir basic.tcl]]
 package ifneeded diagram              1 [list source [file join $dir diagram.tcl]]
 
-package ifneeded diagram::application 1.2 [list source [file join $dir application.tcl]]
+package ifneeded diagram::application 1.3 [list source [file join $dir application.tcl]]