Represents a pointer to the upper left corner of the image buffer for the main image (a 32bpp bitmap containing color and mask (opacity) information).
This property is there to provide a means of direct access to the image buffer for plugins etc.
It is returned as an integer type, but for plugins etc., cast it to an appropriate type (const unsigned long * etc.) and use it.
Do not write a value to the pointer obtained by this property.
Any pointer obtained by Layer.mainImageBufferForWrite can be written.
Returns NULL (0) if no image has been assigned to the layer.
The size of the image is represented by the Layer.imageWidth and Layer.imageHeight properties.
See Layer.mainImageBufferPitch for how to calculate the pointer.