When the RasterPaintEngine.Gdi engine is used, the RasterImage.Paint method internally will call the Win32 API functions to paint the image.

When the RasterPaintEngine.GdiPlus engine is used, the RasterImage.Paint method internally will call GDI+ Graphics.DrawImage methods to paint the image. Note that if the RasterImage object is not fully compatible with GDI+, the framework will internally makes a copy of parts of the image data (bands) and paints them to the destination device. The original data is not converted and no changes will be made to the original image.

RasterPaintEngine.GdiPlus2 engine is deprecated as of LEADTOOLS v16.5. The functionality of this paint engine is merged with RasterPaintEngine.GdiPlus and you should convert your code to use RasterPaintEngine.GdiPlus whenever RasterPaintEngine.GdiPlus2 was used.

Using a particular paint engine depends on the RasterImage object and your specific needs:

• RasterPaintEngine.Gdi is generally faster than RasterPaintEngine.GdiPlus since painting in Windows is faster using the Windows GDI is faster than using GDI+.
• If you need to use GDI+ specific features (for example, if the RasterImage has a transparent color or is a 32-bit image with an alpha channel), then use RasterPaintEngine.GdiPlus. RasterPaintEngine.GdiPlus does not support transparency nor painting the alpha channel values of an image.

When the RasterPaintEngine.GdiPlus engine is used, the following properties are ignored when painting images:

Property	Notes
RasterPaintProperties.RasterOperation	Raster operations (ROP) are not supported in GDI+
RasterPaintProperties.UsePaintPalette	Palette is automatically used.