Lightweight on-screen annotation tool for Windows, built with AutoHotkey v2 and GDI+.
Draw directly on top of any screen with multiple tools (freehand, line, rectangle, ellipse, circle, arrow), type text directly on the overlay, configurable hotkeys, background fill, and an INI-based settings system. Run it as source (.ahk) or as a compiled standalone .exe.
- Fast overlay drawing with GDI+ anti-aliased rendering
- Drawing tools: freehand, straight line, rectangle, ellipse, circle, arrow
- Text mode — type text directly on the overlay; click to place, Enter for new line, configurable font, size, and color
- Ortho mode (F8 by default) — locks line and arrow drawing to horizontal or vertical axis
- Background fill — fill the screen with a solid color using a modifier + color hotkey, creating whiteboard, blackboard, or colored canvas effects (undoable)
- Dynamic line width and opacity controls
- Color palette with single-key shortcuts (fully configurable via Settings)
- Built-in always-on-top help dialog with searchable hotkeys list (F1 by default, configurable)
- Undo / Redo support for all drawing actions including clear and fill — full linear history, no steps lost
- Clear all drawings with a single key; clear is itself undoable/redoable
- Right-click drawing toolbar: color picker, line width, opacity, quick actions, and per-control tooltips
- Pen cursor while drawing mode is active
- Always-on-top help and settings windows that don't get lost behind the overlay
- Multi-monitor support — starts on the monitor the mouse cursor is on
- Per-monitor DPI awareness with multiple fallbacks for mixed-scaling setups
- Shapes are preserved across drawing sessions (within the same monitor)
- Remembers last used drawing settings (color, line width, opacity) across restarts
- Windows
- AutoHotkey v2.x (for source usage only)
Gdip.ahkin the same folder as the main script
If you use the compiled .exe, AutoHotkey installation is not required.
- Install AutoHotkey v2.
- Keep these files in the same directory:
On Screen Drawing.ahkGdip.ahkAppLib.ahkCommonDialog.ahkSettings.ahkHelp.ahkDrawText.ahkCtrlToolTip.ahksettings.ini(optional — defaults are applied automatically)app_icon.ico(optional — used for the tray icon)
- Run
On Screen Drawing.ahk. - Press Ctrl+F9 (default) to start drawing mode.
- Download the latest release
.exefrom the Releases page. - Optionally place
settings.ininext to the.exefor custom settings. - Run the executable.
| Hotkey | Action |
|---|---|
| Ctrl+F9 | Toggle drawing mode on/off |
| F1 | Show hotkeys help |
| Ctrl+Shift+F12 | Exit the application |
| Hotkey / Action | Description |
|---|---|
| Esc | Clear all drawings (undoable) |
| Ctrl+Z | Undo last action (shape, clear or fill) |
| Ctrl+Y | Redo last undone action |
| XButton1 (Mouse Back) | Undo last action |
| XButton2 (Mouse Forward) | Redo last undone action |
| F8 | Toggle Ortho mode (line/arrow only) |
| t | Enter text mode |
| Ctrl+NumpadAdd | Increase line width |
| Ctrl+NumpadSub | Decrease line width |
| WheelUp / WheelDown | Increase / decrease line width |
| Right-click on overlay | Open drawing toolbar |
| Hotkey / Action | Description |
|---|---|
| Left-click on overlay | Commit current text (if any) and place cursor at new position |
| Enter | New line |
| Esc | Commit text and exit text mode |
| F2 | Decrease font size |
| F3 | Increase font size |
| F4 | Cycle through palette colors |
| Modifier | Tool |
|---|---|
| (none) | Freehand |
| Shift | Straight line |
| Ctrl | Rectangle |
| Alt | Ellipse |
| Ctrl+Alt | Circle (radius = max of X/Y drag distance) |
| Ctrl+Shift | Arrow (with auto-sized filled arrowhead) |
| Key | Color | Key | Color | Key | Color |
|---|---|---|---|---|---|
| r | Red | m | Magenta | s | Brown |
| g | Green | c | Cyan | w | White |
| b | Blue | o | Orange | n | Gray |
| y | Yellow | v | Violet | k | Black |
Color hotkeys are only active while drawing mode is on and the mouse cursor is on the active monitor. Press Shift + a color key (modifier configurable in Settings) to fill the entire background with that color — useful for whiteboard, blackboard, or colored canvas effects. The fill is undoable.
Press t (configurable) while in drawing mode to enter text mode. The cursor changes to an I-beam.
Click anywhere on the overlay to place a text cursor. Type your text — Enter inserts a new line. Clicking a different position commits the current text and starts a new one at the clicked location. Press Esc to commit and exit text mode. Committed text is added to the undo/redo history.
While in text mode:
- F2 / F3 decrease / increase the font size on the fly.
- F4 cycles through the configured color palette.
- Font, size, bold, italic, and underline are configured in Settings > Text tab.
Press the fill modifier key (default: Shift) together with a color hotkey to fill the screen background with a solid color — great for whiteboard, blackboard, or colored canvas effects. The fill is treated as a step in the undo/redo history — press Ctrl+Z to revert it.
The fill modifier key can be changed to Ctrl, Alt, or Win in Settings > Hotkeys.
When a fill is active, pressing Esc (Clear) preserves the background fill color and only removes the shapes drawn on top of it.
Press F8 (configurable) while in drawing mode to toggle Ortho mode on/off. A tooltip confirms the current state.
When Ortho mode is active, line and arrow tools are constrained to the dominant axis — horizontal if the horizontal drag distance is greater, vertical otherwise. All other tools (freehand, rect, ellipse, circle) are unaffected.
The undo/redo system treats every action — including Clear and Fill — as a step in a single linear history. You can freely undo and redo across clear and fill operations without losing any shapes.
The history size limit (MaxHistorySize, default 200) applies to the total number of entries including clear and fill markers.
Right-clicking anywhere on the overlay opens a compact floating toolbar:
- Color grid — configured colors in a 3-column grid. Active color marked with ✓; hotkey hints shown on each swatch (configurable).
- Line width — numeric edit field with up/down spinner.
- Opacity — numeric edit field with up/down spinner (0–255).
- Quick action buttons: Undo, Redo, Clear, Help, Stop Drawing, Exit App
- Tooltips: line width, opacity, and action buttons show hover hints; configured hotkeys are included where applicable
The toolbar snaps within the active monitor's bounds. Press Esc or click away to close it.
Right-clicking the tray icon shows:
- Help — displays the help window (app info, hotkeys, author links)
- Settings — opens the application settings window
- Restart Application — reloads the script
- Start / Stop Drawing — toggles drawing mode
- Exit — closes the app
Open via tray menu or the Settings button in the Help window. Changes to hotkeys or colors require a restart to take effect (the app will prompt you).
Tabs:
- General — numeric settings and behavior toggles
- Hotkeys — all configurable hotkeys
- Colors — color palette management (add, edit, delete entries)
- Text — font picker (family, size, bold, italic, underline) with live preview
The app reads settings.ini from the script/exe directory on startup. Missing keys fall back to defaults.
All settings can also be edited through the built-in Settings window (tray menu → Settings). Changes are saved back to
settings.iniautomatically.
| Key | Description | Default |
|---|---|---|
MinLineWidth |
Minimum allowed stroke width | 1 |
MaxLineWidth |
Maximum allowed stroke width | 10 |
DrawAlpha |
Drawing opacity (0–255) | 200 |
FrameIntervalMs |
Overlay redraw interval (ms) | 16 |
MinPointStep |
Min pixel distance between freehand points | 3 |
MaxHistorySize |
Maximum undo/redo steps | 200 |
ClearOnExitDraw |
Discard shapes when exiting drawing mode | false |
ShowColorHints |
Show hotkey hints on color swatches | true |
SaveLastUsedOnExit |
Remember color, width, opacity on exit | true |
showHelpOnStartup |
Show help window on application start | true |
TextFont |
Font family for text mode | Segoe UI |
TextSize |
Font size for text mode (6–200) | 18 |
TextBold |
Bold text | false |
TextItalic |
Italic text | false |
TextUnderline |
Underline text | false |
| Key | Description | Default |
|---|---|---|
ToggleDrawingMode |
Start/Stop drawing | ^F9 |
ExitApp |
Close application | ^+F12 |
ClearDrawing |
Clear all shapes | Esc |
UndoDrawing |
Undo last action | ^z |
RedoDrawing |
Redo last undone action | ^y |
IncreaseLineWidth |
Line width + | ^NumpadAdd |
DecreaseLineWidth |
Line width - | ^NumpadSub |
OrthoMode |
Toggle ortho mode | F8 |
HotkeysHelp |
Show help window | F1 |
FillModifier |
Modifier key for background fill | + (Shift) |
TextMode |
Enter text mode | t |
ExitTextMode |
Commit text and exit text mode | Esc |
DecreaseTextSize |
Decrease font size in text mode | F2 |
IncreaseTextSize |
Increase font size in text mode | F3 |
CycleTextColor |
Cycle text color through palette | F4 |
Hotkey syntax: ^ = Ctrl, + = Shift, ! = Alt, # = Win. Example: ^+F9 = Ctrl+Shift+F9.
On Screen Drawing.ahk — Main script
AppLib.ahk — Config classes and shared helpers
CommonDialog.ahk — Font and color picker dialog wrappers
Settings.ahk — Settings window
Help.ahk — Help window
DrawText.ahk — Text mode implementation
CtrlToolTip.ahk — Helper for standard Windows tooltips on GUI controls
Gdip.ahk — GDI+ wrapper library
settings.ini — User configuration
app_icon.ico — Tray icon
- Toolbar tooltips: Added standard Windows tooltips to the compact drawing toolbar controls using
CtrlToolTip.ahk. - Better toolbar guidance: Hovering line width, opacity, undo, redo, clear, help, stop drawing, and exit app controls now explains each action and shows assigned hotkeys where relevant.
- Help/About polish: The always-on-top Help window remains the central searchable reference for app actions and hotkeys.
- Text Mode: Press
t(configurable) in drawing mode to enter text mode. Click anywhere on the overlay to place a text cursor and start typing. Enter inserts a new line; Esc commits the text and exits text mode. Committed text is fully undoable/redoable. - Font settings: Font family, size, bold, italic, and underline are configurable in Settings > Text tab via a native font picker dialog with live preview.
- Text mode hotkeys: Decrease/increase font size (F2/F3), cycle through palette colors (F4) — all configurable.
- New file:
DrawText.ahkcontains all text mode logic.CommonDialog.ahkprovides font and color picker dialog wrappers. - Help window search: The hotkeys list in the Help window now has a live search box — type to filter actions or hotkeys instantly.
- Background Fill: Press Shift (configurable) + a color hotkey to fill the screen background with a solid color — useful for whiteboard, blackboard, or colored canvas effects. The fill is fully undoable/redoable. Clear (Esc) preserves the active fill color.
- Configurable fill modifier: The fill modifier key (Shift, Ctrl, Alt, Win) can be changed in Settings > Hotkeys.
- Freehand fix: A very short freehand stroke (2 points) is no longer discarded.
- Settings Window: All application settings (general options, hotkeys, color palette) can now be edited through a built-in GUI. Changes are saved to
settings.iniautomatically; hotkey and color changes take effect after restart. - Help Window: The separate About dialog and hotkeys help message box have been merged into a single always-on-top Help window. Includes app info, author links, full hotkey list, and a startup visibility toggle.
- Ortho Mode: New F8 toggle (configurable) constrains line and arrow drawing to horizontal or vertical axis, similar to CAD ortho mode.
- Undo/Redo overhaul: Clear is now a fully undoable/redoable step in the linear history. No shapes are lost when undoing or redoing across clear operations.
- Standard undo/redo hotkeys: Changed from Backspace/Shift+Backspace to Ctrl+Z / Ctrl+Y.
- Persistent Settings: Automatically saves last used color, line width, and opacity on exit and restores them on next launch.
- Performance Optimization: Major improvements to freehand drawing to avoid memory bottlenecks.
- Code Organization: Restructured configuration classes and grouped global variables.
- UI Enhancement: Added hotkey hints to color swatches in the right-click settings panel.
- New Setting:
ShowColorHintsoption to disable color hotkey hints.
- Enhanced Undo/Redo: Added support for undoing Clear Drawing actions.
- Interaction Fixes: Mouse wheel no longer interferes with numeric edit boxes in the settings panel.
- Code Refactoring: Centralized application state using a unified
Appobject andDrawingColorsclass.
- Redo Support: Added
RedoLastShapefunctionality with a redo stack. - Mouse Shortcuts: Undo/redo via mouse side buttons (XButton1/XButton2).
- Improved Settings GUI: Added Clear and Help buttons; reordered action buttons.
- Added configurable
HotkeysHelpaction (F1 default). - Added pen cursor while drawing mode is active.
- Improved floating settings panel (hide/reopen instead of recreate).
- Updated tray menu labels to show assigned hotkeys.
- Initial public release.
- Overlay drawing tools: freehand, line, rectangle, ellipse, circle, arrow.
- Configurable hotkeys, color shortcuts, tray menu,
settings.inisupport.
Nothing happens when pressing the toggle hotkey
- Check
ToggleDrawingModeinsettings.ini. - Ensure no other application is capturing the same hotkey.
Error about GDI+ on startup
- Verify that
Gdip.ahkexists in the same folder as the script and is compatible with AHK v2.
Wrong position or scale on multi-monitor / mixed-DPI setups
- The script applies per-monitor DPI awareness with multiple fallbacks. Restart after changing monitor layout or DPI settings.
Color hotkeys do not work while drawing
- Confirm all
[Colors]entries use the0xRRGGBBformat. - Make sure the mouse cursor is on the active drawing monitor.
Shapes disappear when re-entering drawing mode
- Check that
ClearOnExitDrawis set tofalseinsettings.ini. - Note: switching to a different monitor always resets the shape history.
Text mode does not accept keyboard input
- Make sure no other window has focus. The overlay must be the active window while in text mode.
- Try clicking on the overlay again to re-place the text cursor.
Issues and pull requests are welcome on GitHub.
When reporting a bug, please include:
- Windows version
- AutoHotkey version (if running from source)
- Your
settings.inicontents - Steps to reproduce
- Gdip_All.ahk by buliasz — GDI+ wrapper library for AutoHotkey v2.
Gdip.ahkincluded in this project contains only the functions required by this project, extracted from the original.
Mesut Akcan
- GitHub: akcansoft
- Blog: mesutakcan.blogspot.com
- YouTube: youtube.com/mesutakcan