txtfx docs
txtfx docs
EditorHomeGetting started

Editor

EffectsASCII settingsMasksTimeline

Export & share

ExportingSharingEmbedding

Masks

Paint foreground and background regions to control where effects appear

This page covers painting masks and pointing effects at the regions you paint.

Masks split the image into a foreground and a background region. Each effect can then target one region — snow behind a subject, fire only on it, and so on.

Painting a mask

Pick a brush

Press B for the foreground brush or N for the background brush, or click them in the left panel.

Paint the region

Paint over the image. Foreground strokes show as a tint. Adjust brush size with [ and ] or the slider, and edge softness with the Feather slider (0–20, default 4).

Point effects at a region

In each effect's controls, set Region to Foreground, Background, or Both. New effects default to Background.

Region options

  • Background — the effect only appears in unpainted areas (default)
  • Foreground — the effect only appears in painted areas
  • Both — the effect ignores the mask entirely

Tips

  • Press M to toggle the mask overlay and check what you have painted.
  • Use a large, feathered brush for soft transitions between regions.
  • Mask strokes are undoable with Cmd/Ctrl + Z.
  • Clear mask in the left panel resets everything to background.

Clear mask is destructive

Clearing the mask resets the entire canvas to background and cannot be selectively undone from the confirmation dialog — painted foreground regions are lost.

ASCII settings

Configure the character grid — font size, spacing, color, blend mode, and the brightness ramp

Timeline

Playback controls, effect timing bars, and one-shot vs continuous modes

On this page

Painting a maskPick a brushPaint the regionPoint effects at a regionRegion optionsTips