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Windows Driver Kit DDI reference (nf-d3dkmdt-d3dkmdt_vppr_get_content_rotation_part)

D3DKMDT_VPPR_GET_CONTENT_ROTATION_PART function

Description

A helper function that extracts the rotation angle from a given value of the D3DKMDT_VIDPN_PRESENT_PATH_ROTATION enumeration. Only drivers that support path-independent rotation (DXGKDDI_INTERFACE_VERSION >= DXGKDDI_INTERFACE_VERSION_WDDM1_3_PATH_INDEPENDENT_ROTATION) should call this function.

Parameters

`Rotation`

On input, a value from the D3DKMDT_VIDPN_PRESENT_PATH_ROTATION enumeration.

On output, a value between 1 and 4, inclusive, that corresponds to the ROTATION portion of the D3DKMDT_VIDPN_PRESENT_PATH_ROTATION constant values. An output value of 1 (identity) represents 0 degrees of rotation, 2 represents 90 degrees, and so on. An output value of 0 indicates that the VidPN path is not initialized.

Return value

The returned value corresponds to the rotation angle as follows:

Input enumeration value	Input enumeration constant	Rotation in degrees	Output Rotation value
0	D3DKMDT_VPPR_UNINITIALIZED	-	0
1	D3DKMDT_VPPR_IDENTITY	0	1
2	D3DKMDT_VPPR_ROTATE90	90	2
3	D3DKMDT_VPPR_ROTATE180	180	3
4	D3DKMDT_VPPR_ROTATE270	270	4
5	D3DKMDT_VPPR_IDENTITY_OFFSET90	0	1
6	D3DKMDT_VPPR_ROTATE90_OFFSET90	90	2
7	D3DKMDT_VPPR_ROTATE180_OFFSET90	180	3
8	D3DKMDT_VPPR_ROTATE270_OFFSET90	270	4
9	D3DKMDT_VPPR_IDENTITY_OFFSET180	0	1
10	D3DKMDT_VPPR_ROTATE90_OFFSET180	90	2
11	D3DKMDT_VPPR_ROTATE180_OFFSET180	180	3
12	D3DKMDT_VPPR_ROTATE270_OFFSET180	270	4
13	D3DKMDT_VPPR_IDENTITY_OFFSET270	0	1
14	D3DKMDT_VPPR_ROTATE90_OFFSET270	90	2
15	D3DKMDT_VPPR_ROTATE180_OFFSET270	180	3
16	D3DKMDT_VPPR_ROTATE270_OFFSET270	270	4

Remarks

This function is declared inline in D3dkmdt.h as:

__inline
D3DKMDT_VIDPN_PRESENT_PATH_ROTATION
    D3DKMDT_VPPR_GET_CONTENT_ROTATION_PART(
        D3DKMDT_VIDPN_PRESENT_PATH_ROTATION Rotation)
{
    if ((Rotation >= D3DKMDT_VPPR_IDENTITY_OFFSET90) &&
        (Rotation <= D3DKMDT_VPPR_ROTATE270_OFFSET270))
    {
        Rotation =
            (D3DKMDT_VIDPN_PRESENT_PATH_ROTATION)(
                ((Rotation - 1) % 4) + 1);
    }
    return Rotation;
}

Your driver typically won't need to call this function.

D3DKMDT_VPPR_GET_CONTENT_ROTATION_PART - NtDoc