Creates a graphics context to draw the preview in.
- macOS 10.0–10.15Deprecated
The preview request object.
The size of the preview; if
truethe size is in pixels, otherwise it is in points.
trueif the preview uses a bitmap-based graphics context,
falseotherwise. This value of this parameter affects the interpretation of the
A dictionary containing properties for the preview response. Preview Properties lists the current property keys and describes their values.
A Core Graphics graphics-context object that you can draw your preview image in. You should explicitly release this object when it is no longer needed.
You can directly draw your preview data in the graphics-context object created by this function. After calling this function, you should flush the context with
QLPreview. Also be sure to release the
Quick Look provides three types of graphics contexts for drawing previews: bitmap, single-page vector-based, and multi-page vector-based (for PDF previews). You use this function to acquire a context for bitmap and single-page vector drawing; the
is parameter is used to distinguish between them. For multi-page contexts, use the
Thread-safety: This function should be called in the same thread as the preview request is made in; generally, this is the same thread in which the GeneratePreviewForURL callback was invoked.