Enhancements to overlayWith method

[lovell]

The main aim here is to add support for Buffer input and allow for differing dimensions with an optional gravity. The API should look something like:

withOverlay(image, options)

where:

• image is a String filepath or Buffer image data
• optional options is an Object containing gravity e.g. sharp.gravity.southeast, defaults to sharp.gravity.centre

sharp('under.jpg')
  .overlayWith('over.png', {
    gravity: sharp.gravity.northwest
  })
  .toBuffer()
  .then( function(data) {
      ...
  });

Resizing of the image to overlay can be carried out beforehand using the existing resize method.

Applying a padding to the image to overlay will be possible with #128. This too can be carried out beforehand.

(See #97 for the original work on the overlayWith feature.)

[fentas]

I am wondering if there is any progress on this?
Especially of using an Buffer (text as watermark).

[lovell]

@fentas I expect these enhancements to be much easier/faster to implement after #299.

[lovell]

Commit d92ea31 on the needle/v0.14.0 branch enhances the existing overlayWith method by adding support for Buffer-based input, allowing differing formats (8-bit, 16-bit), allowing differing image sizes and therefore accepting a gravity option.

This can be tested via:

npm install lovell/sharp#needle

Many thanks to @chrisriley for his original PR #335 on which I based this work.

[lovell]

v0.14.0 now available via npm, thanks again for all the help with this.

[lemnisk8]

@lovell Please expose the replicate feature from Vips
replicate( int across , int down )
It would be really useful to tile watermark images for overlay

[lovell]

@lemnisk8 Please can you create a new issue for this suggestion along with some examples of how you think the API might look, so we can invite others to discuss and/or submit a PR.