Image Size Quality is Bad

## Issue or Feature
- [ ] If this is an issue with installation, I have read the [troubleshooting guide](https://github.com/Automattic/node-canvas/issues/1511).

Can you guys advice me :

my problem #1 - > i am using small image sizes of .svg format images 36x36px generating images from multiple elements but when it generate me image is with bad quality (when i preset w:36 h:36)

my problem #2 - other way i tried is to use w:1000 h:1000 but when i resize to 36px quality is horible and blurry

any chance for advice working with pixel images and not broke their quality ?

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## Your Environment
* Version of node-canvas (output of `npm list canvas` or `yarn list canvas`):
* Environment (e.g. node 4.2.0 on Mac OS X 10.8):