DWORD SetViewportOrg(hDC,X,Y)
This function sets the viewport origin of the specified device context. The viewport, along with the device-context window, defines how GDI maps points in the logical coordinate system to points in the coordinate system of the actual device. In other words, they define how GDI converts logical coordinates into device coordinates.
The viewport origin marks the point in the device coordinate system to which GDI maps the window origin, a point in the logical coordinate system specified by the SetWindow-Org function. GDI maps all other points by following the same process required to map the window origin to the viewport origin. For example, all points in a circle around the point at the window origin will be in a circle around the point at the viewport origin. Similarly, all points in a line that passes through the window origin will be in a line that passes through the viewport origin.
| Parameter | Type/Description |
| hDC | HDC Identifies the device context. | |
| X | int Specifies the x-coordinate (in device units) of the origin of the viewport. The value must be within the range of the device coordinate system. | |
| Y | int Specifies the y-coordinate (in device units) of the origin of the viewport. The value must be within the range of the device coordinate system. |
The return value specifies the previous origin of the viewport (in device coordinates). The y-coordinate is in the high-order word; the x-coordinate is in the low-order word.