What is Monitor Geometry?
Geometry testing checks whether straight lines are rendered as visually straight lines across the full panel — and whether the overall image is undistorted and correctly proportioned. On modern flat LCD panels, geometric distortion is uncommon but can occur in the panel circuitry, signal processing pipeline, or due to panel mounting stress.
Curved monitors intentionally distort geometry — the curvature is designed to compensate for the natural perception of a flat screen viewed at an angle. Geometry testing on curved panels checks for unintended distortion within the curve, not the curve itself.
How to Use the Geometry Test
Step 1 — Launch and go fullscreen. Press Launch Test, then F for fullscreen. Navigate to the grid or cross-hatch line pattern.
Step 2 — Check horizontal lines. Horizontal lines at the top, middle, and bottom of the screen should all be perfectly straight. Any bow or wave is a geometry defect.
Step 3 — Check vertical lines. Repeat along the left, centre, and right. Barrel distortion (lines bowing outward) and pincushion distortion (lines bowing inward) are the most common patterns.
Step 4 — Check the corners. Look for any compression or stretching of the grid at the corners — corner geometry issues are less common on LCD than on CRT but can appear.
Geometry Defect Types
| Defect | Appearance |
|---|---|
| Barrel distortion | Lines bow outward — convex shape |
| Pincushion distortion | Lines bow inward — concave shape |
| Trapezoid distortion | Image is wider at top or bottom |
| Tilt | Entire image is rotated slightly |
| Corner warp | Corners pulled up or down |
Causes of LCD Geometry Issues
Unlike CRT monitors — which required extensive geometry adjustment — modern LCD panels drive pixels directly, so most geometric distortion originates in:
- Signal processing: GPU or display scaler distorting the image in the processing pipeline
- Incorrect aspect ratio: Content at 4:3 stretched to 16:9, or vice versa — check display scaling settings
- Panel mounting stress: Mechanical stress from the frame warping the panel substrate in severe cases
- Curved panel anomalies: Unintended distortion within the panel's curve radius
Most geometry issues on modern monitors are caused by incorrect display settings rather than hardware defects. Confirm the correct resolution and aspect ratio in OS display settings before assessing hardware.
Frequently Asked Questions
Why do straight lines look curved on my monitor? First check that the display resolution matches the panel's native resolution and that the aspect ratio is set correctly. If lines appear curved at correct settings, the panel may have geometric distortion in the processing pipeline. Some monitors offer keystone or geometric correction in the OSD.
Can I correct geometry distortion in software? Some GPU control panels (NVIDIA Control Panel, AMD Software) offer digital vibrance and distortion correction tools. Windows and macOS also offer limited display geometry correction. For significant distortion, a hardware-level correction is preferred.
Do curved monitors have geometry issues? Curved monitors have intentional horizontal curvature. This test evaluates whether lines are straight within the curved surface — they should appear straight when viewed from the intended seating distance. If a curved panel shows additional vertical warp or irregular distortion, that is a defect.
Is geometry testing relevant for gaming? For most games, minor geometry distortion is imperceptible during play. It is most noticeable in productivity contexts: spreadsheets with long rows, CAD drawing lines, architectural visualization, and UI design. If straight lines matter to your use case, test before the return window closes.