High Level interface in the current version is made of the base class TBaseImage and its two descendants TSingleImage and TMultiImage. More information on the current state of high level interface can be found in Usage/High Level Interface section.
You can learn how to use high level interface from the following code fragments or (more useful) high level Pascal Demos.
// high level interface test uses ImagingTypes, // high level classes are declared in this unit ImagingClasses; var // this is one level image container SImg: TSingleImage; // this is multi level image container MImg: TMultiImage; begin // new 400x300x24 image is created SImg := TSingleImage.CreateFromParams(400, 300, ifR8G8B8); // resize image SImg.Resize(512, 384, rfBicubic); // you can find out whether image is valid or not this way: if SImg.Valid then WriteLn('Image is valid!'); // you are free to use low level functions on high level classes // you can use ImageData property to get access to underlying structure SwapChannels(SImg.ImageDataPointer^, ChannelRed, ChannelGreen); // image can be converted to another format by simply setting Format property SImg.Format := ifIndex8; // extended format info is accessible trough FormatInfo property WriteLn('Image has ', SImg.FormatInfo.PaletteEntries, ' palette entries'); // new multi image without parameters is created (default sized 1 level image // will be created) MImg := TMultiImage.Create; // single image is assigned to multi image - multi image will now have // one level identical to source single image MImg.Assign(SImg); // single image is resized SImg.Width := SImg.Width * 2; // new level is added to multi image (SImg is cloned) MImg.AddLevel(SImg); // single image is converted SImg.Format := ifR32F; // new level is inserted to multi image at index 0 (SImg is cloned) MImg.InsertLevel(0, SImg); // all levels of multi image are written to stream MImg.SaveMultiToStream('tga', SomeStream); // images are freed SImg.Free; MImg.Free; end.