| data | ||
| pybind11 | ||
| .gitattributes | ||
| .gitignore | ||
| CMakeLists.txt | ||
| contours_and_segments.hh | ||
| dash.py | ||
| dashing.cc | ||
| dashing.hh | ||
| dashing_F.hh | ||
| LICENSE.md | ||
| main.cc | ||
| Makefile | ||
| parse_numbers.hh | ||
| pydashing.cc | ||
| pyproject.toml | ||
| README.md | ||
| setup.py | ||
| splitall.py | ||
dashing - a library for autocad-style hatch patterns
License: permissive (zlib); see source files for additional details.
On a i5-1235U in multithreaded benchmark mode, it runs at over 3.3 billion dashes per second:
$ time ./dashing.omp -b -s .002 data/HWOOD6E1.pat data/sf.seg
2822685873
real 0m0.851s
Development status
The author (@jepler) is not actively using or developing this project. Issues and pull requests are not likely to be acted on. I would be interested in passing this project to a new maintainer.
Usage
API
xyhatch(const HatchPattern&, It start, It end, Cb cb, Wr wr):
Iterators start..end define a range of segments, which must define a set of closed contours.
The winding rule wr defines which regions are in the interior of the contours.
For each dash or dot in the resulting hatch, cb is called with the output segment.
xyhatch(const HatchPattern&, const C &segments, Cb cb, Wr wr):
The container C holds segments which must define a set of closed
contours.
The winding rule wr defines which regions are in the interior of the contours.
For each dash or dot in the resulting hatch, cb is called with the output segment.
xyhatch(const HatchPattern&, const C &segments, Cb cb, const char *wr):
The container C holds segments which must define a set of closed
contours.
The winding rule wr defines which regions are in the interior of the contours.
For each dash or dot in the resulting hatch, cb is called with the output segment.
HatchPattern::FromFile: Read a hatch pattern from a file.
parse_numbers(std::string line): Read a comma and/or space-separated
sequence of numbers into a vector
SegmentsFromFile, ContoursFromFile, ContourToSegments, ContoursToSegments: Read and convert segments and contours
Useful winding rules include:
[](int i) { return i % 2 != 0; }, the even-odd winding rule[](int i) { return i != 0;}, the non-zero winding rule[](int i) { return i > 0;}, the greater-than-zero winding rule
but any predicate of a single integer may be used.
Parallel API
These APIs are available if built with -fopenmp -DDASHING_OMP
xyhatch_omp(const HatchPattern&, It start, It end, Cb cb, Wr wr):
Iterators start..end define a range of segments, which must define a set of closed contours.
The winding rule wr defines which regions are in the interior of the contours.
For each dash or dot in the resulting hatch, cb is called with the output segment and the thread ID.
xyhatch_omp(const HatchPattern&, const C &segments, Cb cb, Wr wr):
The container C holds segments which must define a set of closed
contours.
The winding rule wr defines which regions are in the interior of the contours.
For each dash or dot in the resulting hatch, cb is called with the output segment and the thread ID.
Other APIs
Other items in the header files are implementation details.
Demo program
The demo program, which compiles to dashing with make, reads a dash
pattern file and a segment list file and produces a svg file on the output
which visualizes the result of the hatch operation.
A segment list file consists of a closed contour on each line specified as a series of x,y coordinates. For instance, this segment list is a simple box:
-100 -100 100 -100 100 100 -100 100
The first point is -100 -100.
It accepts several commandline parameters:
-b: Benchmark mode: print only the number of dashes that would have been
generated
-j: Apply a jitter to all coordinates in the segment list file
-s: scale the dash pattern file by a given factor
-r rulename: select the given rulename, one of the following: odd nonzero positive negative abs_geq_two
Hatch pattern files
The syntax of hatch pattern files is based on public documentation of Autocad.
A file consists of:
- A line with a star followed by arbitrary, ignored text (the pattern name)
- A series of lines which specify individual dash patterns
The dash-pattern lines consist of comma-separated values. The first five values have a set meaning:
- The dash angle in degrees
- The X dash origin
- The Y dash origin
- The X dash repeat distance
- The Y dash repeat distance
The remaining values are alternating positive and negative nonzero values, giving the length of marked (positive) and skipped (negative) portions of the dash. In dashing, the number of values must be even, the first value must be positive, and the signs must strictly alternate.
If there are no dash/space lengths specified, the entire line is stroked.