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From: gareth@vcn.bc.ca (Gareth Jones)
Newsgroups: comp.sys.apple2
Subject: HCGS Article 3
Date: 2 Jul 1996 17:25:23 GMT
Organization: Vancouver CommunityNet
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Message-ID: <4rbm23$jo6@milo.vcn.bc.ca>
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Here is another article on HyperCard GS by yours truly.
++++++++++++
Getting the Whole Picture with the "Picture" XCMD
Gareth Jones
10 November 1995
One of the most intriguing tools in the "Scripter's Tools" stack
that is part of HyperCard IIgs is the "Picture" external command (XCMD).
When installed in a stack, the XCMD provides a command that will display
a GS paint document, the top left part of a MacPaint document (320 by 200
pixels), or a graphic held as a resource or in the Clipboard. The style
of window can also be specified by the user.
The Picture XCMD has many uses, from a simple picture viewer to the
engine of a stack that loads pictures to modify them, to displaying fancy
"About..." and "Help" dialogue boxes stored as resources in the stack by
the program Genesys. It is also a useful addition to your Home stack, as
you can then view graphics by simply typing "Picture" into the message box.
Syntax
Picture commands have the following syntax:
picture [sourceName [, type [, windowStyle [, visible [, rect]]]]]
If you call picture with no parameters, HyperCard displays the
directory dialog box and asks you to locate a paint file to display. If
you cancel the dialog box, picture sets the result to "cancel".
If you decide to use parameters, the "Type" parameter should be one
of the following words: "file", "resource", or "clipboard." The default
is "file".
"WindowStyle" should be "dialog", "document", "rect", "shadow", or
"windoid". The default is "document", which creates a movable window with
horizontal and vertical scrollbars.
"Visible" is an expression that evaluates to "true" or "false". It
determines whether the picture XCMD initially creates a visible or
invisible window. The default value is "true".
"Rect" is an expression that specifies the location of the window on
the screen. The following are examples of legal commands:
picture
picture "My.Hard.Drive:PicName"
picture "PicName",file
picture "PicName",resource
picture "Picture Window's Name",clipboard
picture "PicName",file,shadow, true,"50,60,280,120"
The "SourceName" parameter of this XCMD is defined as a string that
evaluates to:
1. the name of an Apple Preferred format picture file or MacPaint
compatible file (for source type "file"),
2. the name or number of a PICT resource (for source type
"resource"), or
3. any name at all (for source type "clipboard").
In theory, the source name also becomes the name of the picture
window, so that if you display a picture file with the pathname
":MyHardDrive:Paintings:NumberOne", the window displaying the picture
would also be ":MyHardDrive:Paintings:NumberOne".
A Bug
Unfortunately, there is a serious bug in this XCMD that corrupts the
last part of the window name if the name is 32 characters long or longer.
You can verify this by putting the following script into a button and
then clicking the button:
on mouseUp
global filename
answer file "Select a picture:" of type 192
put it into filename
picture filename
put filename -- this shows the complete pathname in msg box
wait five seconds
close window filename -- this won't work, under either System
6.0.1 or 5.0.4
end mouseUp
The window does not close when it should, and the reason is that the
final characters of the window's name have been mangled into garbage,
represented on screen as inverse question marks.
A Fix
Obviously, a way has to be found to close the window under control
of a script, or the picture window, windoid, or dialogue will clutter the
screen until you quit the stack. Since addressing it by name is useless,
use the following script to do the job.
on mouseUp
REPEAT with i = 1 to the number of windows
put first character of the name of window i into winName
if winName is ":" then
put the id of window i into IDnumber
do "close window id" && IDnumber
exit repeat
end if
end repeat
end mouseUp
The script depends on the fact that the picture window is almost
certainly the only one whose name begins with a colon. It finds the
window whose name begins that way and asks for its "ID number." Finally,
it orders that the window with that ID number be closed.
It is unfortunate that Apple never fixed the bug I've described.
However, you can work around it -- completely avoid it, in fact -- with a
few lines of script.
Thanks to Lorne Walton for verifying the bug.