Channel Context Info Support

Channel Context Interface.

• [plug imp]
• [extends IEditController]
• [released: 3.6.5]
• [optional]

Allows the host to inform the Plug-in about the context in which the Plug-in is instantiated, mainly channel based info (color, name, index,...). Index could be defined inside a namespace (for example index start from 1 to N for Type Input/Output Channel (Index namespace) and index start from 1 to M for Type Audio Channel).
As soon as the Plug-in provides this IInfoListener interface, the host will call setChannelContextInfos for each change occurring to this channel (new name, new color, new indexation,...)

Example

tresult PLUGIN_API MyPlugin::setChannelContextInfos (IAttributeList* list)
{
    if (list)
    {
        // optional we can ask for the Channel Name Length
        int64 length;
        if (list->getInt (ChannelContext::kChannelNameLengthKey, length) == kResultTrue)
        {
            ...
        }
        
        // get the Channel Name where we, as Plug-in, are instantiated
        String128 name;
        if (list->getString (ChannelContext::kChannelNameKey, name, sizeof (name)) == kResultTrue)
        {
            ...
        }

        // get the Channel UID
        if (list->getString (ChannelContext::kChannelUIDKey, name, sizeof (name)) == kResultTrue)
        {
            ...
        }
        
        // get Channel Index
        int64 index;
        if (list->getInt (ChannelContext::kChannelIndexKey, index) == kResultTrue)
        {
            ...
        }
        
        // get the Channel Color
        int64 color;
        if (list->getInt (ChannelContext::kChannelColorKey, color) == kResultTrue)
        {
            uint32 channelColor = (uint32)color;
            String str;
            str.printf ("%x%x%x%x", ChannelContext::GetAlpha (channelColor),
            ChannelContext::GetRed (channelColor),
            ChannelContext::GetGreen (channelColor),
            ChannelContext::GetBlue (channelColor));
            String128 string128;
            Steinberg::UString (string128, 128).fromAscii (str);
            ...
        }

        // get Channel Index Namespace Order of the current used index namespace
        if (list->getInt (ChannelContext::kChannelIndexNamespaceOrderKey, index) == kResultTrue)
        {
            ...
        }
    
        // get the channel Index Namespace Length
        if (list->getInt (ChannelContext::kChannelIndexNamespaceLengthKey, length) == kResultTrue)
        {
            ...
        }
        
        // get the channel Index Namespace
        String128 namespaceName;
        if (list->getString (ChannelContext::kChannelIndexNamespaceKey, namespaceName, sizeof (namespaceName)) == kResultTrue)
        {
            ...
        }

        // get Plug-in Channel Location
        int64 location;
        if (list->getInt (ChannelContext::kChannelPluginLocationKey, location) == kResultTrue)
        {
            String128 string128;
            switch (location)
            {
                case ChannelContext::kPreVolumeFader:
                    Steinberg::UString (string128, 128).fromAscii ("PreVolFader");
                break;
                case ChannelContext::kPostVolumeFader:
                    Steinberg::UString (string128, 128).fromAscii ("PostVolFader");
                break;
                case ChannelContext::kUsedAsPanner:
                    Steinberg::UString (string128, 128).fromAscii ("UsedAsPanner");
                break;
                default: Steinberg::UString (string128, 128).fromAscii ("unknown!");
                break;
            }
        }
        
        // do not forget to call addRef () if you want to keep this list
    }
}

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