cdf5e479a6
In some cases, gnuplot generates a very suboptimal SVG content of the
following pattern:
<g color="black" fill="none" stroke="currentColor">
<path d="m82.5 323.3v-4.1" stroke="#000"/>
</g>
<g color="black" fill="none" stroke="currentColor">
<path d="m116.4 323.3v-4.1" stroke="#000"/>
</g>
... repeated 10+ more times here ...
<g color="black" fill="none" stroke="currentColor">
<path d="m65.4 72.8v250.5h420v-250.5h-420z" stroke="#000"/>
</g>
A more optimal pattern would be:
<g color="black" fill="none" stroke="#000">
<path d="m82.5 323.3v-4.1"/>
<path d="m116.4 323.3v-4.1"/>
... 10+ more paths here ...
<path d="m65.4 72.8v250.5h420v-250.5h-420z"/>
</g>
This patch enables that optimization by handling the merging of two
sibling <g> entries that have identical attributes. In the above
example that does not solve the rewrite from "currentColor" to "#000"
for the stroke attribute. However, the existing code already handles
that automatically after the <g> elements have been merged.
This change provides comparable results to --create-groups as shown by
the following diagram while being a distinct optimization:
+----------------------------+-------+--------+
| Test | Size | in % |
+----------------------------+-------+--------+
| baseline | 17961 | 100% |
| baseline + --create-groups | 17418 | 97.0% |
| patched | 16939 | 94.3% |
| patched + --create-groups | 16855 | 93.8% |
+----------------------------+-------+--------+
The image used in the size table above was generated based on the
instructions from https://bugs.debian.org/858039#10 with gnuplot 5.2
patchlevel 2. Beyond the test-based "--create-groups", the following
scour command-line parameters were used:
--enable-id-stripping --enable-comment-stripping \
--shorten-ids --indent=none
Note that the baseline was scour'ed repeatedly to stablize the image
size.
Signed-off-by: Niels Thykier <niels@thykier.net>
29 lines
1.1 KiB
XML
29 lines
1.1 KiB
XML
