Image Drawing and Overlay

Drawing uses Windows GDIGraphics Device Interface system calls.
MFCMicrosoft Foundation Class applications normally use OnDraw event handler to draw, where a pointer to a device context is available.
Borland/CodeGear's OWL or VCL use a Paint event handler.
The color palette in 256-color display mode gives optimal rendering. Gray-level images can be improved using LUTLookUp Tabless (using histogram stretching techniques or pseudo-coloring).
The zoom can be different horizontally and vertically.
DrawFrameWithCurrentPen method draws a frame.
Non-destructive overlaying drawing operations do not alter the image contents, such as MoveTo/LineTo.
Destructive overlaying drawing operations alter the image contents by drawing inside the image such as Easy::.OpenImageGraphicContext. Gray-level [color] images can only receive a gray-level [color] overlay.