Scanner GUI with NodeRed

In a former post I installed CUPS printer software for a Cannon printer. The scanning functionality is supported by the package SANE. But there is no nice GUI for the scanning function so I made one, with NodeRed(NR), which I really think is "wife" enabled.

If you are new to NodeRed here is a post to start with.

The first thing you have to check, with CUPS installed(including SANE), are which options the scanner accepts. It's done with the command 

$ sudo scanimage --help

Among others, one respons was regarding resolution

--resolution auto||75|150|300|600|1200dpi [75]

another was mode

--mode auto|Color|Gray|Lineart [Color]

which values I want to be able to change via the scanner GUI.

Lineart was a new scan function to me and very nice for drawings, since there is no greyscale, just black/white.

The NR flow starts with setting my defaults, via the function node "Default scan settings", as flow context data

• Resolution     300 Dpi
• Mode             Auto

The function node "Issue scan command" builds the command for the "Exec" node. To get unique file names I'm using the time but substitute the colons, ":", to a dash, "-", due too that in the Apple world colons are not allowed in filenames.

During the scan process the scan button goes red with a wait message and if somethings goes wrong with the scan command you will get an popup message.

The flow is found here.

The template node, the actual scan button, took some Googling to create....

<style>

.button {

height: 100%;

border-radius: 35px;

font-size: 28px;

font-weight: bold;

border-color: white;

border-style: solid;

border-width:10px;

}

</style>

<md-button

class="button"

style="{{'background-color:'+ msg.background}}"

ng-click="send({payload: 'scan'})">

<div ng-bind-html= "msg.topic"></div>

</md-button>