# Node-red-contrib-image-tools - combining images

**URL:** <https://discourse.nodered.org/t/node-red-contrib-image-tools-combining-images/50081>\
**Category:** General\
**Created:** [23 August 2021 19:52 UTC](https://discourse.nodered.org/t/node-red-contrib-image-tools-combining-images/50081 "2021-08-23T19:52:27Z")\
**Posts on this page:** 1\
**Showing post:** 2

<div class="post-metadata">

**Author:** ![Steve-Mcl](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/steve-mcl/32/4826_2.png) [@Steve-Mcl](https://discourse.nodered.org/u/Steve-Mcl)\
**Post date:** [23 August 2021 21:47 UTC](https://discourse.nodered.org/t/node-red-contrib-image-tools-combining-images/50081/2 "2021-08-23T21:47:44Z")

</div>

![image](https://us1.discourse-cdn.com/flex026/uploads/nodered/original/3X/6/b/6b943f5e9a9b5025def73c4c67565816ad7539d5.png)

```auto
[{"id":"1778f6d3.186309","type":"image viewer","z":"af952aeaa20f4f97","name":"","width":160,"data":"merged","dataType":"msg","active":true,"x":1370,"y":1500,"wires":[[]]},{"id":"9d9012a6.2a615","type":"Barcode Generator","z":"af952aeaa20f4f97","name":"QR Code","data":"serial","dataType":"msg","barcode":"qrcode","barcodeType":"barcode","options":"","optionsType":"ui","sendProperty":"qrBuffer","props":[],"x":680,"y":1420,"wires":[["d9581a7e1b3a7366"]]},{"id":"f1bcfcf6.b6fea","type":"inject","z":"af952aeaa20f4f97","name":"Serial","props":[{"p":"serial","v":"00001066","vt":"str"}],"repeat":"","crontab":"","once":false,"onceDelay":0.1,"topic":"","x":510,"y":1420,"wires":[["9d9012a6.2a615"]]},{"id":"dfe6eb84.8d2a88","type":"jimp-image","z":"af952aeaa20f4f97","name":"QR Merge","data":"template","dataType":"msg","ret":"img","parameter1":"qr","parameter1Type":"msg","parameter2":"qrx","parameter2Type":"msg","parameter3":"qry","parameter3Type":"msg","parameter4":"0","parameter4Type":"num","parameter5":"0","parameter5Type":"num","parameter6":"qrw","parameter6Type":"msg","parameter7":"qrh","parameter7Type":"msg","parameter8":"","parameter8Type":"msg","sendProperty":"merged","sendPropertyType":"msg","parameterCount":7,"jimpFunction":"blit","selectedJimpFunction":{"name":"blit","fn":"blit","description":"blit the image with another Jimp image at x, y, optionally cropped","parameters":[{"name":"src","type":"","required":true,"hint":"the source image (a Jimp instance)","defaultType":"msg","defaultValue":"payload"},{"name":"x","type":"num","required":true,"hint":"the x position to blit the image"},{"name":"y","type":"num","required":true,"hint":"the y position to blit the image"},{"name":"srcx","type":"num","required":false,"hint":"the x position from which to crop the source image"},{"name":"srcy","type":"num","required":false,"hint":"the y position from which to crop the source image"},{"name":"srcw","type":"num","required":false,"hint":"the width to which to crop the source image"},{"name":"srch","type":"num","required":false,"hint":"the height to which to crop the source image"}]},"x":1210,"y":1500,"wires":[["1778f6d3.186309"]]},{"id":"d1aad62a.7addc8","type":"image viewer","z":"af952aeaa20f4f97","name":"","width":160,"data":"qr","dataType":"msg","active":true,"x":510,"y":1500,"wires":[["274df8a7b5fe670f"]]},{"id":"98f87b98.c5a4b8","type":"image viewer","z":"af952aeaa20f4f97","name":"","width":160,"data":"template","dataType":"msg","active":true,"x":1030,"y":1500,"wires":[["dfe6eb84.8d2a88"]]},{"id":"274df8a7b5fe670f","type":"jimp-image","z":"af952aeaa20f4f97","name":"open template","data":"c:/temp/label_template_1.png","dataType":"str","ret":"img","parameter1":"","parameter1Type":"msg","parameter2":"","parameter2Type":"msg","parameter3":"","parameter3Type":"msg","parameter4":"","parameter4Type":"msg","parameter5":"","parameter5Type":"msg","parameter6":"","parameter6Type":"msg","parameter7":"","parameter7Type":"msg","parameter8":"","parameter8Type":"msg","sendProperty":"template","sendPropertyType":"msg","parameterCount":0,"jimpFunction":"none","selectedJimpFunction":{"name":"none","fn":"none","description":"Just loads the image.","parameters":[]},"x":700,"y":1500,"wires":[["05aaba7fe1e31eb1"]]},{"id":"d9581a7e1b3a7366","type":"jimp-image","z":"af952aeaa20f4f97","name":"","data":"qrBuffer","dataType":"msg","ret":"img","parameter1":"","parameter1Type":"msg","parameter2":"","parameter2Type":"msg","parameter3":"","parameter3Type":"msg","parameter4":"","parameter4Type":"msg","parameter5":"","parameter5Type":"msg","parameter6":"","parameter6Type":"msg","parameter7":"","parameter7Type":"msg","parameter8":"","parameter8Type":"msg","sendProperty":"qr","sendPropertyType":"msg","parameterCount":0,"jimpFunction":"none","selectedJimpFunction":{"name":"none","fn":"none","description":"Just loads the image.","parameters":[]},"x":850,"y":1420,"wires":[["d1aad62a.7addc8"]]},{"id":"05aaba7fe1e31eb1","type":"function","z":"af952aeaa20f4f97","name":"calc center","func":"\nmsg.qrh = msg.qr.bitmap.height;\nmsg.qrw = msg.qr.bitmap.width;\n\nmsg.qrx = (msg.template.bitmap.height / 2) - (msg.qrh / 2);\nmsg.qry = (msg.template.bitmap.width / 2) - (msg.qrw / 2);\n\nreturn msg;","outputs":1,"noerr":0,"initialize":"","finalize":"","libs":[],"x":870,"y":1500,"wires":[["98f87b98.c5a4b8"]]}]

```

* * *

Why it didnt work for you...

The blit src requires the incoming image to be a `jimp` image object.

- The QR code is generated as a buffer - so an image node is required to convert the QR to a jimp image
- The file node loads a buffer - so an image node is required to convert the template to a jimp image - OR - like i did, use an image node to load the template

* * *

PS, avoid flow context where possible as you can get into issues with concurrency when the flow runs faster that the images can be processed. Instead of flow, use `msg` props to carry the loaded image through the flow. (check the output property names I used)

PS 2 - avoid branching as much as possible when working with images - try to keep image msgs serial. This avoids unnecessary msg cloning (images are large when decoded into bitmaps in memory)

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_[View the full topic](https://discourse.nodered.org/t/node-red-contrib-image-tools-combining-images/50081)._