CT Workflow — Krita Docker Plugin

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A lightweight canvas thumbnail preview panel for Krita with real-time effects across Readability, Value, and Color observation.

Built for speed and stability — handles 4K+ documents without lag.

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Why

CT Workflow is designed as a visual self-check tool for painters and concept artists.

Instead of judging composition quality, it helps artists quickly inspect:

• Readability — mass grouping, silhouette separation, visual balance, attention flow
• Value — value readability, squint simulation, depth hierarchy
• Color — color harmony, squint blur observation, palette mixing

through simple transformations like flip, desaturation, inversion, binarization, and squint blur.

The goal is not evaluation.

The goal is visibility.

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Features

Three Observation Stages (Accordion)

Only one stage expanded at a time. Zooming a preview does not shift the other stage headers.

Stage	Purpose	Effects
Readability	Composition readability check	H-Flip, V-Flip, Desaturate, Invert, Binarize + Threshold
Value	Value organization & squint	Auto-desaturate, Depth slider (0–8) for squint blur
Color	Color harmony & mixing	Original / Squint Blur, Palette Board freehand paint

Palette Board (Color Tab)

• Freehand paint — brush strokes on a fixed-height canvas (120px), width expands with panel
• Krita color sync — auto-reads Krita foreground color for painting
• Shift+click pick — pick any color from the Board and sync it back to Krita foreground
• Brush size buttons — 4 fixed sizes (80 / 60 / 40 / 20 px), mutually exclusive
• Color indicator — live sync with Krita foreground color (polled, updates automatically)
• Freeze / Hold — snapshot the Board canvas alongside the preview for comparison
• Clear — one-click reset

Shared Controls

• Capture — Snapshot current canvas for CT inspection
• Freeze — Lock current preview + Board state
• Hold — Momentarily compare frozen snapshot against live view
• Mouse Wheel — Zoom preview 20%–500% (observation distance, not navigator magnification)
• Scrub Zoom — Press-and-drag horizontally on the preview to zoom in/out. Cursor changes to a magnifying glass (+ / − while dragging)
• Fit — Reset zoom to fit panel
• Resize bars — Custom 8px grip on right and bottom edges

Pen / Tablet Scrub Zoom

Input device	Trigger
Mouse / touch	Press on preview → drag horizontally
Pen (Windows Ink)	Pen tip down on preview → drag horizontally
Pen (Wintab / Wacom)	Hold Spacebar → drag pen horizontally on preview

Wintab drivers on Windows bypass the OS mouse layer, so the pen tip alone cannot be detected inside a Krita docker. The Spacebar fallback uses the keyboard subsystem, which Krita does not intercept.

Tip: Keep the Spacebar held while dragging; release it when you reach the desired zoom.

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Quick Install

Note for developers: Krita loads from %APPDATA%\krita\pykrita\ (Windows), not from your git clone. After editing files, copy them to the Krita path and restart Krita.

Windows (One-Liner)

$dest = "$env:APPDATA\krita\pykrita"; New-Item -ItemType Directory -Force -Path $dest | Out-Null; Copy-Item -Recurse -Force "ct_navigator.desktop","ct_navigator" $dest

Manual (All Platforms)

Copy ct_navigator.desktop and the ct_navigator/ folder into Krita's pykrita directory:

OS	Path
Windows	%APPDATA%\krita\pykrita\
Linux	~/.local/share/krita/pykrita/
macOS	~/Library/Application Support/Krita/pykrita/

Expected result:

pykrita/
  ct_navigator.desktop
  ct_navigator/
    __init__.py
    docker.py
    effects.py
    palette_board.py
    utils.py

Enable

1. Restart Krita
2. Settings > Configure Krita > Python Plugin Manager → check CT Workflow
3. Restart Krita again
4. Settings > Dockers > CT Workflow to show the panel

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Usage

Readability Stage

Control	Action
Capture	Snapshot current canvas
H-Flip	Mirror preview horizontally
V-Flip	Mirror preview vertically
Desat	Grayscale (luminance)
Invert	Negative / invert colors
Binarize	Black & white with threshold slider
Freeze	Lock current preview state
Hold	Flick compare frozen vs live

Value Stage

Control	Action
Depth	0 = clear desaturated, 8 = deep squint blur

Color Stage

Control	Action
Mode	Original / Squint Blur
Board click	Paint with current Krita foreground color
Board Shift+click	Pick Board color → sync to Krita foreground (🖉 icon tooltip)
Brush buttons	80 / 60 / 40 / 20 px (mutually exclusive)
Color indicator	Live Krita foreground color preview
Clear	Reset Board canvas
Freeze / Hold	Snapshot and compare Board + preview

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CT Workflow

Painting
  ↓
Capture
  ↓
Readability CT Inspection (Flip / Invert / Binarize)
  ↓
Value CT Inspection (Desaturate + Squint Depth)
  ↓
Color CT Inspection (Squint Blur / Palette Board Mixing)
  ↓
Freeze
  ↓
Continue Painting
  ↓
Hold (flick compare)
  ↓
Judge drift across Readability / Value / Color

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What CT Workflow Is NOT

CT Workflow is not a live navigator.

It is a snapshot-based structure inspection tool.

The preview updates only when the user explicitly clicks Capture.

This preserves:

• inspection stability
• structure freezing
• flick-comparison consistency
• low-overhead performance

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Performance Notes

• Large documents: A 4K canvas is pre-scaled to ≤1024 px before any effect runs, so toggling effects stays instant.
• Rendering pipeline: Scale first → apply effects on the small thumb → display. No full-resolution pixel loops.
• Invert: Uses QImage.invertPixels() (C++ native), zero Python overhead.
• Desaturate / Binarize: Use bytearray batch ops instead of slow pixel() / setPixel().
• Resize: Debounced at 100 ms; dragging the panel edge does not spam redraws.
• Board canvas: Fixed 120px height, dynamic width; resize preserves content via top-left align (no stretch).
• Scrub zoom: Polls at 50 fps with a 5 px dead-zone and 3% zoom threshold to suppress frame-to-frame jitter.

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File Structure

ct_navigator/
  ct_navigator.desktop       # Plugin metadata
  ct_navigator/
    __init__.py              # Entry point (registers Docker)
    docker.py                # Panel UI, tabs, capture, zoom, resize, freeze/hold
    effects.py               # Fast pixel effects (batch byte ops + native invert)
    palette_board.py         # Freehand paintable board with Krita color sync
    utils.py                 # Logging & helpers

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Known Limitations

• Wintab pen taps on toolbar buttons (Capture / Freeze / Hold) may occasionally miss because Wintab events are not always converted to Qt mouse events inside Krita. Mouse clicks remain fully responsive.

Compatibility

• Krita 5.2+
• Python 3.10+ (bundled with Krita)
• PyQt5 (bundled with Krita)
• No external dependencies