An image viewer

Read an image, scale it and show it; load a library; choose a file; add a filter.

So far we used the Standard library, whose nodes are small utilities. Let's make a small application: an image viewer. Start from start here again (or File > New network if you already have the tutorial data in a folder you know).

Load the Imaging library

  1. Press Libraries… at the top and load Imaging. It appears in the list on the left, in its own color.
  2. Type read in Find a node and drag Read Image onto the network. Type show and drag Show Image to its right.
  3. Connect Read Image's image output to Show Image's image input.

Choose a file

Read Image's filename input has a file widget. Its … button opens a file browser on the server, in the network's folder; its ⇧ button uploads a file from your own computer into that folder.

The file browser in the network folder's cartoonMovie folder
The file browser, in the network's cartoonMovie folder. A file in the network's folder is given relative to it (cartoonMovie/crnCartoon0000.png), so the network keeps working when its folder moves.

Open cartoonMovie and choose crnCartoon0000.png. The network runs, and the image appears in a Show Image panel in the row under the network.

Scale it

  1. Add Scale (Imaging > Mapper) between the two nodes. Show Image's input takes one connection: right-click the connection from Read Image and choose Delete connection. Then connect Read Image to Scale's image, and Scale's scaledImage to Show Image.
  2. Click Scale. Its widgets are in the parameter column on the right (and on its rows in the node): change Scale and watch the image.
Read Image, Scale and Show Image connected; the image of a protein cartoon in a panel; Scale's parameters on the right
The image viewer. The image panel's header gives the image's size and mode, a 💾 button that saves it, and the buttons that size the row.
Checkpoint cartoon0: an image viewer

run on change is Vision's immediate mode: when it is checked, every change of a widget runs the network. Uncheck it to change several things, then press Run.

Exercise: the contour

Find a way to extract the contour of the image with a node of the Imaging library, and show the image and its contour side by side.

Scale's output also goes to a Filter Image node set to CONTOUR, shown by a second Show Image
One solution. Filter Image (Imaging > Filter) with its filter set to CONTOUR, and a second Show Image. Each Show Image node has its own panel, side by side in the row.
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