[DirectX 7 Programmer's Reference] Viewport Rectangle (58.8235294117647%)

Microsoft DirectX 7.0 > Direct3D > Direct3D Immediate Mode > Direct3D Immediate Mode Essentials > Geometry Pipeline > Viewports and Clipping

[DirectX 7 Programmer's Reference] Viewport Scaling (49.1013071895425%)

Microsoft DirectX 7.0 > Direct3D > Direct3D Immediate Mode > Direct3D Immediate Mode Essentials > Geometry Pipeline > Viewports and Clipping

[DirectX 6 Programmer's Reference] Viewport Scaling (29.2388167388167%)

DirectX Foundation > Direct3D Immediate Mode > Direct3D Immediate Mode Essentials > The Geometry Pipeline > Viewports and Clipping > Clipping Volumes

[DirectX October 2006 Documentation] Viewport (27.7452123040358%)

DirectX SDK > Introducing DirectX 9.0 > Namespaces > Microsoft.DirectX.Direct3D > Structures

[DirectX October 2006 Documentation] Viewport (23.6397589338766%)

DirectX SDK > Introducing DirectX 9.0 > Namespaces > Microsoft.DirectX.Direct3D > Classes > Device > Properties

[DirectX October 2006 Documentation] Viewport (22.8185213479331%)

DirectX SDK > Introducing DirectX 9.0 > Namespaces > Microsoft.DirectX.Direct3D > Structures > Viewport > Methods