GSoC/2019/StatusReports/hellozee

Porting Magnetic Lasso to Krita

Summary

• Project Name: Porting Magnetic Lasso to Krita
• Proposal: View Proposal
• Abstract: The Magnetic Lasso was lost during the port from Qt3 to Qt4, this project tries to continue the working to port the tool to the current version of Krita

Project Goals

• Add the Magnetic Lasso Selection Tool in Krita.
• The tool when used should stick to the edges found in the picture.
• Starts after user left clicks and makes an anchor, edges are scanned from the anchor point.
• After the mouse moves a fixed amount of distance the tool automatically places another anchor point and uses it as a reference.
• The user can also manually set an anchor point, him/herself.
• The search radius which is used to determine, upto what area the tool would search for an edge as well as the frequency of anchors can be adjusted by the user.
• The above-mentioned parameters as well as the threshold for determining edges can be adjusted using the tool options widget.

Project related links

• Phabricator Task
• Personal Blog

Implementations Status

Status report on each goal implementation.

KisMagneticWorker

Goal: Implement the worker for the algorithm and the corresponding unit test.

Current Status Done

Related blog posts

• Initial Post
• Understanding boost::astar_search
• Another week with boost
• Done with boost
• Deliverable 1 : [✓]

Commits and Differentials

• Adding an initial framework for the test
• Applying Laplacian of Gaussian on KisPaintDevice
• Added the heuristic function for the boost::astar_search
• Implemented boost::graph interface for KisPaintDevice
• an intesity function to the graph for reading threshold
• Implemented boost::astar_search using the KisMagneticGraph wrapper
• heuristic function takes threshold into account now
• Fixed the intensity function
• Finished the Algorithm
• Added docs and completed the test

KisToolSelectMagnetic

Goal: Implement the frontend required for the tool

Current Status Done

Related blog posts

• Topsy-turvy 5th Week
• It is coming alive
• A few more steps
• Somewhat Usable

Commits and Differentials

• Initial take on the UI
• Reduced the number of calls KisPaintDevice::exactBounds() is called
• Creates a bouding rectangle before searching
• LoG now runs on tool activation
• Optimized the algorithm, implemented checkpoints
• Selection can be done with the Magnetic Lasso
• Anchor points are saved now
• Selection works as expected
• Checkpoints are drawn now, :)
• Implemented dual checkpoint procedure, somewhat like PS
• Selection can be canceled on the fly now
• Fixed crashing while completing the selection, can finish selection
• Reimplemented the frequency-based checkpoint procedure
• Updated the cursor and adjusted the checkpoint procedure

KisToolSelectMagneticOptionsWidget

Goal: Implement Options Widget required for adjusting the factors

Current Status Kind of done, :3

Related blog posts

• Sprint ahoy
• Krita Sprint 2019
• Magnetic Lasso for Krita is here

Commits and Differentials

• Overriden the createOptionWidget method
• Added the radius and threshold options to Options Widget
• Fixed crash on paint, suppressed warnings
• Fixed the checkpoint procedure
• Frequency is now based on-screen distance
• Frequency controls the bounding box, radius the kernel size
• Changed handle style for drawing anchorpoints
• Takes relative distance into account instead of absolute distance
• Updated the Tool Options widget to reflect the quantities better
• Can discover multiple anchors in a single event
• Fixed the length calculation algorithm
• Minimum radius increased
• Added some documentation about the checkpoint procedure
• Added tool tips to the options widget
• Added Shift+Z to undo points
• Changed the cursors for the magnetic lasso
• First anchor is highlighted when the loop can be completed