flFlags (ULONG) - input

Flags.

A set of flags that pass information regarding the complexity of the 2x2 matrix of the M11, M12, M21, and M22 components (of the composite transform from world coordinates to device coordinates). These flags indicate if a translation is required. If the MATRIX_SIMPLE flag is not set, none of the other flags are valid.

MATRIX_SIMPLE

Two entries are 0.
MATRIX_UNITS
All entries are +1 or -1.
MATRIX_XY_EXCHANGE
Zeros are on the diagonal.
MATRIX_X_NEGATE
X is hit by negative (see Note).
MATRIX_Y_NEGATE
Y is hit by negative (see Note).
MATRIX_TRANSLATION
Non-zero translation.
Note: MATRIX_X_NEGATE and MATRIX_Y_NEGATE are only meaningful when both MATRIX_SIMPLE and MATRIX_UNITS are set.

Examples:

Matrix = { 1.0, 0.0, 0.0, 1.0, 0, 0 } =>
Flags = MATRIX_SIMPLE | MATRIX_UNITS

Matrix = { 1.0, 0.0, 0.0, 1.0, 5, 10 } =>
Flags = MATRIX_SIMPLE | MATRIX_UNITS | MATRIX_TRANSLATION

Matrix = { 0.0, -1.0, 1.0, 0.0, 17, 5 } =>
Flags = MATRIX_SIMPLE | MATRIX_UNITS | MATRIX_XY_EXCHANGE |
MATRIX_Y_NEGATE | MATRIX_TRANSLATION