getDeviceNAlphaPicture

Get a Picture object for the DeviceN alpha channel.
getDeviceNAlphaPicture([out, retval] IUnknown **pic)
This function retrieves the Picture object (OLE IPicture interface) for the alpha channel generated by the last call to convertPageToDeviceNImageWithAlpha.

The Picture will be an 8-bit grayscale bitmap, indicating the alpha value at each pixel. Note: this function is only useful with convertPageToDeviceNImageWithAlpha and convertRegionToDeviceNImageWithAlpha.

VB6:
rast.convertPageToDeviceNImage page, dpi nChannels = rast.getNumDeviceNChannels For i = 0 To nChannels-1 channelName = rast.getDeviceNChannelName(i) channelCMYK = rast.getDeviceNChannelCMYK(i) pic = rast.getDeviceNPicture(i) ' each channel has an 8-bit grayscale bitmap, similar to what ' is returned by convertPageToPicture in imageGray mode ... Next i pic = rast.getDeviceNAlphaPicture ' the returned image is similar to the color channel images ... rast.clearDeviceNImage
convertPageToDeviceNImage
convertRegionToDeviceNImage
getNumDeviceNChannels
getDeviceNChannelName
getDeviceNChannelCMYK
clearDeviceNImage