Masks & Effects
OpenGPEX supports non-destructive masking and adjustment effects that preserve original pixel data.
Non-Destructive Philosophy
All masks and effects are metadata operations — the original image is never modified:
Original Asset (immutable) → Layer Metadata (masks, adjustments) → Rendered Output
Masks and adjustments can be toggled, modified, or removed at any time without data loss.
Mask Types
Vector Masks (Shape-based)
Constrain visible regions to a geometric shape (rectangle or ellipse):
- Feather: soft edge blur radius
- Invert: swap visible/hidden regions
- Enable/Disable: toggle without deleting
Bitmap Masks (Painted)
Grayscale transparency maps created with the Eraser tool:
- White = fully visible
- Black = fully hidden
- Gray = semi-transparent
- Supports feather and inversion
Adjustments
Per-layer non-destructive adjustments applied in real-time:
Basic (5 sliders)
| Parameter | Range | Default |
|---|---|---|
| Brightness | 0–200 | 100 |
| Contrast | 0–200 | 100 |
| Saturation | 0–200 | 100 |
| Hue Rotate | 0–360° | 0 |
| Blur | 0–20px | 0 |
Advanced Filters
| Filter | Description |
|---|---|
| Curves | RGB + per-channel (R/G/B) tonal adjustment via cubic spline |
| Levels | Histogram-based input/output with shadows/gamma/highlights + Auto |
| Channel Mixer | 3×3 matrix controlling R/G/B cross-contribution (7 presets + monochrome) |
| Color Balance | Per-tonal-range (shadows/midtones/highlights) color shift on Cyan↔Red, Magenta↔Green, Yellow↔Blue axes with optional preserve-luminosity |
All filters are cached by content hash for performance and rendered non-destructively — original pixels are never modified.
Blend Modes (16)
| Group | Modes |
|---|---|
| Normal | Normal |
| Darken | Multiply, Darken, Color Burn |
| Lighten | Screen, Lighten, Color Dodge |
| Contrast | Overlay, Soft Light, Hard Light |
| Inversion | Difference, Exclusion |
| Component | Hue, Saturation, Color, Luminosity |
Blend modes are applied consistently between viewport preview and export output via the isomorphic painter.
Last updated: 2026-07-30