svg2png-many

NodeJS module and CLI to convert many svg files to png rapidly.

Inspired by svg2png and phantomjs-node. Many thanks to them.

The main difference from svg2png that it works much faster convering many files.
Because of it uses one PhantomJS instenct for many files and opens many web-pages simultaniously.

Using as NodeJS module

NOTE! All functions below return a promise.

Convert all svg from certain folder to the other folder.
``javascript
const svg2png = require('svg2png-many');
var srcDir = 'dir/with/source/svgs';
var dstDir = 'dir/with/result/pngs';
svg2png(srcDir, dstDir).then(
() => console.log('Done'),
// rejected with the list of all happened errors
// even if error happens while processing one file it will not stop conversion other files
// first all files are processed, only then the result promise is rejected or resolved
errors => errors.forEach(error => {
arrors = Array.isArray(errors) ? errors : [errors];
console.error(error.stack || error);
})
);

// same function can be run as alias
svg2png.svg2PngDir(srcDir, dstDir);
`
Convert only certain files to defined destination.

All possible arguments described below are also accepted by this function.
`javascript
var fileMap = {
'one/file/to/convert.svg': 'first/file/result/image.png',
'second/file/to/process.svg': 'other/place/to/save/result.png'
};
svg2png.svg2PngFiles(fileMap);
`

Define sizes of result png.

Height or/and width can be skipped. Aspect ration is preserved.
`javascript
var sizes = {
height: 300,
width: 500
};
svg2png(srcDir, dstDir, sizes);
`

Define how many web-pages can be opened in PhantomJS simultaneously.

This argument manages performance aspects. The higher this argument is the faster conversion, but more memory is consumed.

Default value is 20.
`javascript
var parallelPages = 10;
svg2png(srcDir, dstDir, null, parallelPages);
`

Using as CLI


To convert all svg files from one folter and put png to the other
`bash
$ ./node_modules/.bin/svg2png-many -i dir/with/source/svgs/ -o dir/with/result/pngs/
3 files have been converted successfully
`
To see all possible argument, run with help option
`bash
$ ./node_modules/.bin/svg2png-many --help
Options:
-i, --input Path to dir with svg files [string] [required]
-o, --output Path to dir with results, it not defined, input will be used
[string]
-w, --width With of result png [number]
-h, --height Height of result png [number]
-t, --threads Number of threads [number]
--phantom Path to alternative phantom [string]
--help Show help [boolean]
`

Benchmark

I compared speed on 500 files.

svg2png vs svg2png-many

11min vs 27sec

`bash
$ time ./node_modules/.bin/svg2png-many -i src res
500 files have been converted successfully
real 0m27.489s
user 0m11.483s
sys 0m7.330s

$ time for f in src/*.svg; do ./node_modules/.bin/svg2png $f; done
real 11m40.203s
user 5m47.640s
sys 1m45.301s
``