What does HRESULT 0x80400007 (INPUT_E_TRANSFORM) mean?

INPUT_E_TRANSFORM

The scope of INPUT_E_TRANSFORM is pointer coordinate transformation. The coordinate transform required to map pointer data into the target coordinate system failed. Keep 0x80400007 beside the returning method because a wrapper can replace this distinction with a generic subsystem message.

Where the failure occurs

Pointer coordinates can pass through physical-device units, desktop coordinates, per-monitor DPI scaling, client coordinates, rotation, and an application transform. Each stage must produce finite values and an invertible mapping where an inverse is required. Logging only the final x and y values hides singular matrices, stale HWND geometry, mixed units, and overflow introduced earlier.

Pointer input can cross device, screen, client, logical, DPI-scaled, rotated, and application-defined spaces. A singular matrix, invalid calibration, stale window geometry, overflow, or mismatched units can make the mapping impossible or non-finite.

Avoid broad resets

INPUT_E_PACKET may flag invalid source coordinates; this result indicates that valid-looking data could not be converted through the requested mapping. Do not clamp every failed result into the window bounds. Clamping hides a broken matrix and can synthesize clicks at an unrelated edge.

Evidence to preserve

• Source and destination coordinate spaces with DPI and orientation
• Full transform matrix and determinant
• Raw and transformed coordinates around the failure
• Window bounds, monitor identity, and display-change generation

Smallest faithful reproducer

Start with identity transforms and a stable window on one monitor. Add DPI conversion, rotation, calibration, and application matrices one at a time while retaining both the source and destination rectangles used for each conversion.

1. Test the identity transform with the same packets.
2. Apply translation and scale before adding rotation or calibration.
3. reject NaN, infinity, and singular matrices at construction time.
4. Rebuild transforms after DPI, orientation, monitor, or window changes.

Technical references

• Microsoft: COM error codes for Input and graphics.
• Microsoft: Pointer Input Messages and Notifications.
• Microsoft: POINTER_INFO structure and pointer lifetime.
• Microsoft: GetPointerFrameInfoHistory.
• Microsoft: Interaction Context API.