Graphics algorithms
Various graphics algorithms I learned. Python program using either Tkinter or Python Imaging Library (PIL), or Javascript embedded in SVG files.
There are following library modules used by demo applications:
utils2D.py--- different procedures work with segments, polygons etc.;aabb2D.py--- axis-aligned bounding boxes;isconvex.py--- procedures work with convex polygons;cbezier2D.py--- procedures work with cubic Bezier curves;- convex hull algorithms:
jarvis.py,graham.pyandquickhull.py.
Contents
- Tkinter events serializer
- BSP tree demo (tkinter)
- Approximation of a Bezier curve (tkinter)
- Intersection of Bezier curves (tkinter)
- Find a convex hull using Graham algorithm (tkinter)
- Sutherland-Hodgman --- clip a polygon against a convex polygon (tkinter)
- Exact bounding box of Tkinter "smooth curve" (tkinter)
- Clipping segment using Cohen-Sutherland algorithm (JavaScript + SVG)
- Bounding box of an elliptical arc (JavaScript + SVG)
- Segment-circle intersection (JavaScript + SVG)
- Graph layout using force-based approach (Tkinter)
Tkinter events serializer
Most Tkinter-based scripts relie on tkes.py, it's my attempt to express
interactive tasks in an imperative way. File tkes-demo.py is a simple
drawing program which use this approach.
BSP tree demo (tkinter)
BSP-tree-tkdemo.py allows to edit a polygon and represents it as a BSP tree. Then a user may check if a point lies inside or outside the drawn polygon using the tree.
Approximation of a Bezier curve (tkinter)
cbezier-as-tkdemo.py use different metrics to approximate a Bezier curve with polyline.
Intersection of Bezier curves (tkinter)
cbezier-cc-tkdemo.py approximates curves with polylines, then check intersection of polylines.
Find a convex hull using Graham algorithm (tkinter)
graham-tkdemo.py calculates convex hull of point using Graham algorithm.
Sutherland-Hodgman --- clip a polygon against a convex polygon (tkinter)
polyintersect-tkdemo.py allows to define two or more polygons and clip them using Sutherland-Hodgman algorithm.
Exact bounding box of Tkinter "smooth curve" (tkinter)
tk_ebbox-demo.py --- Tkinter uses Bezier splines to represent "smoothed curves", however its method bbox returns the bounding box of control points. This demo shows how to calculate an exact bounding box.
Clipping segment using Cohen-Sutherland algorithm (JavaScript + SVG)
Cohen_Sutherland-demo.svg demonstrates the algorithm.
Bounding box of an elliptical arc (JavaScript + SVG)
elarc_aabb-demo.svg shows how to find the bounding-box of a rotated elliptical arc using basic math properties.
There's an article in Polish which describes the algorithm.
Segment-circle intersection (JavaScript + SVG)
segment-circle-intersection-test.svg show an algorithm to check whether a segment crosses a circle or not.
Graph layout using force-based approach (Tkinter)
fba.py allows to select a few graphs and adjust algorithm's settings.
