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Image Compression Dialog Options

Q Our codec needs to provide more options to the user than the normal Image Compression dialog contains. Inside Macintosh suggests that it's possible to provide an extra Options button in the dialog, but this seems to be a function of the application, not the codec. However, I have seen some applications that do provide an Options button for some codecs. How does the application know to do this?

A If your codec component has an exported function named CDRequestSettings, the Standard Compression dialog is smart enough to provide the specific button. In other words, the QuickTime code checks the codec component, adds the button (provided it is available), tests the button status, and calls CDRequestSettings. You get the rect of the displayed Rect with the coordinates if you want to display your dialog inside the other one. In many cases, it makes sense to provide a filterProc as well to process update events (with the exception of a totally modal dialog box).

To test if this works for your codec, put a DebugStr inside your CDRequestSettings, and check the Standard Dialog to see if it displays the button and to see if your function is called.

If you need additional information, CDRequestSettings is documented in the QuickTime Technote QT4andQuickTime 1.6.1 Features, which is on the Developer CDs.

[Aug 01 1995]

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