Technical Note QD06

Every Picture [Comment] Tells Its Story, Don't It?

CONTENTS Introduction References Downloadables

Application-specific picture comment conflict and registration is addressed, along with Developer Technical Support's method for solving it. [Nov 01 1987]

Introduction

I will assume that the nature and usefulness of picture comments are already well known. The problem I am addressing is that, as it stands, developers must register their comments with us (Developer Technical Support) or run the risk of using the same comments as those used by Apple or within another third party product.

The idea here is to provide a "metacomment" which will contain information about which application owns the comment as well as the comment itself:

ApplicationComment (long comment)    kind = 100  size = n + 6
    data = application signature (i.e. 'MPNT' for MacPaint) = 4 bytes
           application "local" kind = 2 bytes
           comment data = n bytes

In this way each comment may be specific to an application. It is still up to a developer to publish information about the comments they have defined if they wish them to be understood and used by other programs.

Previously assigned and registered comments will still be valid. This means that those defined for the LaserWriter or MacDraw, for instance, will retain their normal meaning.

Suppose your application (creator = 'MYAP') wanted to define a comment. The appearance of the comment would be as follows (assuming you chose 128 to be the "local" kind for the comment):

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References

QuickDraw

Technical Note M.IM.gifComments -- Optimizing for the LaserWriter--Picture Comments

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Downloadables