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Base SVG Filters Reference ​

Visual filters for base SVG layer Apply opacity, blur, brightness, tint, and other effects to make overlays more prominent

Overview ​

Apply visual filters to the base SVG layer to make overlays more prominent while keeping overlays crisp and clear.

Quick Start ​

Simple filters (legacy object format, CSS filters only):

yaml
base_svg:
  source: builtin:ncc-1701-a-blue
  filters:
    opacity: 0.5
    blur: "3px"

Stackable filters (array format, supports CSS and SVG filter primitives):

yaml
base_svg:
  source: builtin:ncc-1701-a-blue
  filters:
    - { mode: css, type: opacity, value: 0.5 }
    - { mode: svg, type: tint, value: { color: 'rgba(180,0,0,0.35)' } }

Filter Types ​

Opacity ​

Controls transparency of base SVG (0.0 = invisible, 1.0 = fully opaque).

yaml
filters:
  opacity: 0.5  # 50% transparent

Use cases: Dim background artwork to emphasize overlays.

Blur ​

Applies Gaussian blur (softens focus).

yaml
filters:
  blur: "3px"  # Moderate blur

Use cases: Create depth, de-emphasize background detail.

Brightness ​

Adjusts brightness level (1.0 = normal, <1.0 = darker, >1.0 = brighter).

yaml
filters:
  brightness: 0.7  # 30% darker

Use cases: Darken background, adjust visibility.

Contrast ​

Adjusts contrast (1.0 = normal, <1.0 = lower contrast, >1.0 = higher contrast).

yaml
filters:
  contrast: 0.8  # Reduce contrast

Use cases: Soften harsh edges, mute colors.

Grayscale ​

Converts to grayscale (0.0 = full color, 1.0 = completely gray).

yaml
filters:
  grayscale: 0.5  # 50% desaturated

Use cases: Monochrome displays, reduced visual weight.

Sepia ​

Applies sepia tone (warm brown tint).

yaml
filters:
  sepia: 0.3  # Slight warmth

Use cases: Vintage aesthetic, warm backgrounds.

Hue Rotate ​

Rotates colors around the color wheel (in degrees).

yaml
filters:
  hue_rotate: 45  # Shift hues by 45 degrees

Use cases: Color theme adjustments, alert states.

Saturate ​

Adjusts color saturation (1.0 = normal, <1.0 = less saturated, >1.0 = more saturated).

yaml
filters:
  saturate: 0.6  # Reduce saturation

Use cases: Mute vibrant colors, adjust visual intensity.

Invert ​

Inverts colors (0.0 = normal, 1.0 = fully inverted).

yaml
filters:
  invert: 0.2  # Slight inversion

Use cases: High-contrast themes, special effects.

Drop Shadow ​

Creates a drop shadow behind the element.

yaml
filters:
  - { mode: css, type: drop-shadow, value: { x: 2, y: 2, blur: '4px', color: '#000000' } }

Use cases: Depth/emphasis via a classic drop shadow.

SVG Filter Primitives ​

Lower-level SVG <filter> primitives, for effects the CSS filter list above can't express. Requires array format with mode: svg — SVG filters need an <svg> root, so these aren't available on non-SVG cards like data-grid. Chain multiple primitives in the same filters: array to compose more complex effects (each primitive's output feeds the next).

feGaussianBlur ​

SVG blur filter — smoother than CSS blur, chains with other SVG filters.

yaml
filters:
  - { mode: svg, type: feGaussianBlur, value: { stdDeviation: 4 } }

Use cases: Softening, glow bases, chaining with feOffset for shadows.

feColorMatrix ​

Powerful color transformation using matrix operations. Supports hue rotation, saturation, luminance-to-alpha, and custom 4x5 color mapping matrices.

yaml
filters:
  - { mode: svg, type: feColorMatrix, value: { type: saturate, values: 1.5 } }

Use cases: Advanced color remapping beyond CSS saturate/hue-rotate.

feOffset ​

Shifts the filter result by dx/dy pixels. Essential for creating shadow effects when combined with blur.

yaml
filters:
  - { mode: svg, type: feOffset, value: { dx: 3, dy: 3 } }

Use cases: Building custom shadow effects when chained with feGaussianBlur/feBlend.

feBlend ​

Blends the current filter result with another input (SourceGraphic by default) using any of the 16 standard CSS blend modes (multiply, screen, overlay, etc.).

yaml
filters:
  - { mode: svg, type: feBlend, value: { mode: screen } }

Use cases: Glow effects — try screen/lighten mode after a blur.

feComposite ​

Combines two inputs (the previous filter result and SourceGraphic by default) using Porter-Duff compositing operators, or a custom arithmetic formula.

yaml
filters:
  - { mode: svg, type: feComposite, value: { operator: over } }

Use cases: Advanced layering/compositing beyond simple blend modes.

feMorphology ​

Erodes (thins) or dilates (fattens) shapes. Useful for creating outline effects or adjusting edge thickness.

yaml
filters:
  - { mode: svg, type: feMorphology, value: { operator: dilate, radius: 2 } }

Use cases: Outline/edge-thickness effects.

feTurbulence ​

Generates Perlin noise patterns for organic textures. Commonly used with feDisplacementMap for distortion/warping effects.

yaml
filters:
  - { mode: svg, type: feTurbulence, value: { baseFrequency: 0.02, numOctaves: 3 } }

Use cases: Organic noise textures, paired with feDisplacementMap.

feDisplacementMap ​

Warps/distorts the image based on color values from another source. Perfect for wavy, liquid, or turbulent effects.

yaml
filters:
  - { mode: svg, type: feTurbulence, value: { baseFrequency: 0.02, numOctaves: 3 } }
  - { mode: svg, type: feDisplacementMap, value: { scale: 20 } }

Use cases: Wavy, liquid, or turbulent distortion effects.

TIP

Add a Turbulence filter right before this one — Turbulence generates the displacement map this filter distorts by.

Tint ​

The one friendly compound SVG type — internally expands to a chained feFlood+feComposite pair, so it composites a flat color wash over the base SVG (a real color tint, not an approximation) from a single filter entry. Same SVG-only requirement as the primitives above — not available on non-SVG cards like data-grid. The color's alpha channel controls how much of the artwork shows through.

yaml
filters:
  - { mode: svg, type: tint, value: { color: 'rgba(180,0,0,0.35)' } }

Use cases: Alert/status washes, theme-colored overlays, quick visual state changes.

Common Filter Recipes ​

Copy-paste filters: arrays for common effects.

Dimmed ​

Reduces opacity and brightness for a subtle background.

yaml
filters:
  opacity: 0.5
  brightness: 0.8

Best for: General use, balanced visibility.

Subtle ​

Light dimming with slight blur and desaturation.

yaml
filters:
  opacity: 0.6
  blur: "1px"
  grayscale: 0.2

Best for: Maintaining detail while reducing emphasis.

Backdrop ​

Heavy dimming with blur for strong overlay emphasis.

yaml
filters:
  opacity: 0.3
  blur: "3px"
  brightness: 0.6

Best for: Data-heavy displays, prominent overlays.

Faded ​

Desaturated and dimmed for a muted background.

yaml
filters:
  opacity: 0.4
  grayscale: 0.5
  contrast: 0.7

Best for: Minimal aesthetic, reduced visual clutter.

Red Wash (alert) ​

A real red color tint using the SVG tint filter, rather than the old red-alert preset's hue-rotate approximation.

yaml
filters:
  - { mode: svg, type: tint, value: { color: 'rgba(180,0,0,0.35)' } }

Best for: Alert states, emergency displays.

Monochrome ​

Full grayscale with reduced contrast.

yaml
filters:
  opacity: 0.6
  grayscale: 1.0
  contrast: 0.8

Best for: Professional displays, reduced color distraction.

Clear all filters ​

yaml
filters: []

Overlay-Only Mode ​

Create cards without any base SVG (pure overlay displays).

yaml
base_svg:
  source: "none"
view_box: [0, 0, 1920, 1200]  # REQUIRED when source is "none"

overlays:
  - type: control
    id: main_display
    # ... overlay config

Requirements:

  • view_box must be explicitly defined (4-element array)
  • No anchor extraction (all overlays need explicit coordinates)

Use cases:

  • Pure data displays
  • Custom overlay compositions
  • Testing/prototyping

See Also ​