Image Annotation & Markup Tools (RC6/Cairo Based)

[jpbro]

Want to give users the ability to annotate images with lines, shapes, highlights, and text? This project provides flexible drawing tools and customization options for a variety of use-cases.

Screenshot



The above example shows a base image that has been marked up with a text box, polygon (that also happens to be "selected"), line with arrowhead endpoint, and a highlighted date/time.

Features

• Open BMP, PNG, and JPEG images.
  
  
• Draw Lines with optional endpoints (Arrowhead, Ball, Bar).
  
  
• Create rectangles and polygons with customizable fill and stroke.
  
  
• Multiple polygon edge styles (Flat/Straight, Smooth/Bezier Curved, Ratcheted, Zig Zag, and Cloud/Bubbly).
  
  
• Draw multi-line Text Boxes with definable font face, size, colour, and style (Bold, Italic, Underline, and Strikethrough).
  
  
• Adjust stroke thickness, color, and style (Solid, Dashed, Dotted) for supported objects.
  
  
• Improved Dotted stroke drawing (using Round line cap).
  
  
• Set Background Fill Colour and Translucency for fillable shapes (Rectangles, Polygons, and Text Boxes).
  
  
• Highlight rectangular areas for emphasis.
  
  
• Move drawn objects around the image by mouse-click and drag, or using the arrow keys for precise positioning (hold Shift for larger movement).
  
  
• Resize/Reshape drawn objects.
  
  
• Undo/Redo actions.
  
  
• Bring objects forward or backward in the Z-order with SendToFront, SendToBack, SendForward, and SendBackward methods.
  
  
• Right-click to finalize drawing objects (Polygons, Highlighter rectangles, etc.), allowing full mouse-only interaction.
  
  
• Select all objects via Ctrl+A or SelectAllObjects method.
  
  
• Delete selected objects via DeleteSelectedObjects method.
  
  
• Programmatic movement of selected objects via MoveSelectedObjects method.
  
  
• Alternate yellow/blue dashed outline for selected objects, ensuring visibility on light and dark backgrounds.
  
  
• Save Composite image (Base image + Drawn Objects in JPG or PNG format).
  
  
• Export overlay images (annotations on a transparent background) as PNG.
  
  
• Save and restore all drawn object data in JSON format.
  
  
• Ability to set text horizontal and vertical alignment.
  
  
• Custom text input handling via RequestText event (bypassing default InputBox).
  
  
• Double-click text boxes to trigger the TextRequested event for editing.
  
  
• UI refresh handling for tool mode changes via ToolModeChanged event.
  
  
• Option to disable all built-in keyboard shortcuts via EnableKeyboardShortcuts property.
  
  
• Optional global drop shadow rendering via EnableGlobalDropShadow property (thanks for the idea @SearchingDataOnly).
  
  
• Zoom/Fit to Viewport
  

SOURCE CODE

RC6ImageMarkupTools19.zip

NOTES

• Requires Olaf Schmidt's RC6 library available at https://www.vbrichclient.com/ - so make sure to have it installed and registered on your dev machine.
• This is a first-pass and the project has only been lightly tested so far. There are likely to be bugs, so please report any issues you discover and I will try to fix them ASAP.

Enjoy!