The automated python2 -> python3 converter creates some suboptimal
code patterns in some cases, notably in its handling of dicts.
This commit handles the following cases:
* "if x in list(y.keys()):" => "if x in y:"
The original code is neuters the O(1) lookup effeciency of a dict
by turning it into a list. This occurs a O(n) in converting it to
a list and then another O(n) for the lookup. When done in a loop,
this becomes O(n * m) rather than the optimal O(m).
* "for x in list(y.keys()):" => "for x in y:" OR "for x in list(y):"
A dict (y in these cases) operates as an iterator over keys in the
dict by default. This makes the entire "list(y.keys())" dance
redundant _in most cases_. In a some cases, scour modifies the
dict while iterating over it and in those cases, we need a
"list(y)" (but not a "y.keys()").
The benefit of this differs between python2 and python3. In
python3, we basically "only" avoid function call. In python2,
y.keys() generates a list, so here we avoid generating a
"throw-away list".
The test suite succeed both with "python testscour.py" and "python3
testscour.py" (used 2.7.14+ and 3.6.4 from Debian testing).
On a 341kB flame-graph generated by "nytprof" (a perl profiler), this
commit changes the runtimes of scour from the range 3.39s - 3.45s to
3.27s - 3.35s making it roughly 3% faster in this case (YMMV,
particularly with different input). The timings were recorded using
the following command line:
time PYTHONPATH=. python3 -m scour.scour --enable-id-stripping \
--shorten-ids --indent=none --enable-comment-stripping
-i input.svg -o output.svg
This was used 5 times with and 5 times without the patch picking the
worst and best time to define the range. The runtime test was only
preformed on python3.
All changed lines where found with:
grep -rE ' in list[(].*[.]keys[(][)][)]:'
Signed-off-by: Niels Thykier <niels@thykier.net>
There has been a minor rearrangement of the code that handles the children
of the element being serialized: The relevant `if' statement has had its
condition effectively negated and thus has also had its consequent and
alternative swapped; now, there is a very short consequent, followed by a
very long alternative, rather than a very long consequent followed by a
very short alternative.
* Do not collapse straight path segments in paths that have intermediate markers (see #145). The intermediate nodes might be unnecessary for the shape of the path, but their markers would be lost.
* Collapse subpaths of moveto `m` and lineto `l` commands if they have the same direction (before we only collapsed horizontal/vertical `h`/`v` lineto commands)
* Attempt to collapse lineto `l` commands into a preceding moveto `m` command (these are then called "implicit lineto commands")
* Preserve empty path segments if they have `stroke-linecap` set to `round` or `square`. They render no visible line but a tiny dot or square.
Third-party applications obviously can not handle additional output on stdout nor can they be expected to do any weird stdout/sterr redirection as we do via `options.stdout`
We probably shouldn't print anything in `scourString()` to start with unless we offer an option to disable all non-SVG output for third-party libraries to use.
- prevent '--set-precision=0' by requiring >=1
- warn user if '--set-c-precision' > '--set-precision' instead of silently ignoring the value
- some code cleanup
Also omit short option strings of advanced options for now (if we offer them again in future, they should be chosen very carefully as should the options for which we offer them)
Add a separate precision option for curve control points (--set-c-precision)
This can considerably reduce file size with marginal effect on visual appearance.
