RectLabel is an image-annotation tool to label images for bounding-box object detection.
Create a label dialog from JSON settings
Layer order for overlapped boxes
Zoom in on a point
Quick zoom to existing boxes
Draw a box including outside the image
Smart guides for creating and transforming boxes
Support the PASCAL VOC format
Note: While the software is classified as free, it offers in-App Purchases.
What’s new in version 2.91
Updated on Aug 28 2019
Added "Draw extra points to reduce glitching when high zoom" on the settings dialog.
It looks that the problem happens when the long line is angled and high zoom.
For boxes and cubic bezier, it does not happen.
To prevent the glitching, you can add points between polygon points.
Because adding points reduces the line length.