[DirectX 7 Programmer's Reference] Transparent Blitting (100%)

Microsoft DirectX 7.0 > DirectDraw > DirectDraw Essentials > Surfaces > Blitting to Surfaces

[DirectX 5 Programmer's Reference] Transparent Blitting and Color Keys (34.9404761904762%)

DirectX Foundation > DirectDraw > Getting Started: Basic Graphics Concepts > Sprite Concepts