Post-Processing

Scanlines

Scanlines overlay horizontal lines that simulate the look of CRT monitors and old televisions. This effect adds authentic retro character to any visual, especially when combined with VHS or pixel art effects.

Example Configuration

scanlines.json

{
  "effect": {
    "postProcesses": [
      {
        "id": "pp_scanlines",
        "type": "scanlines",
        "enabled": true,
        "settings": {
          "intensity": 0.3,
          "count": 400
        }
      }
    ]
  }
}

Settings

Property	Type	Range	Default	Description
`intensity`	number	0-1	0.3	Darkness/visibility of scanlines
`count`	number	100-1000	400	Number of scanlines across the image

How It Works

CRT displays draw images line by line. Between each line of phosphors is a small gap. At close viewing distances, these gaps become visible as dark horizontal lines. The scanlines effect replicates this characteristic look.

Lines are drawn at regular intervals across the image
The intensity controls how dark the lines appear
Count determines the density of the lines (higher = more lines)
Lower intensity creates subtle texture, higher creates dramatic effect

Suggested Presets

Style	Settings
Subtle CRT	intensity: 0.15, count: 500
Classic TV	intensity: 0.3, count: 400
Heavy Retro	intensity: 0.5, count: 200

API Usage

render-request.json

POST /api/v1/render
{
  "state": {
    "canvas": {
      "aspectRatio": "16:9",
      "backgroundColor": "#1a1a1a"
    },
    "layers": [...],
    "selectedLayerId": null,
    "effect": {
      "effectId": "ascii-standard",
      "enabled": true,
      "postProcesses": [
        {
          "id": "pp_1",
          "type": "scanlines",
          "enabled": true,
          "settings": {
            "intensity": 0.4,
            "count": 300
          }
        }
      ]
    }
  },
  "format": "png",
  "width": 1920,
  "height": 1080
}

Tips

Combine with VHS glitch for authentic retro video look
Works great with ASCII and pixel art effects
Keep intensity low (0.1-0.3) for subtle texture
Match count to your output resolution for consistent appearance
Pair with curvature and vignette for full CRT monitor effect