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2.2 Quick interface tour

Start up nip. You should see something like Figure 1.1 (the exact look and feel might be different since nip is skinnable).

Use the tabs along the bottom to flip between workspaces. The things down the right are the available image processing toolkits. The green thing is the current column (the thing that new stuff will get added to). Click on the 2 GB free text and it toggles between showing space free on your disc and space free for calculations.

Click on Insert=>Image from file to get a file dialog and load up one of your images. nip can load most image formats, try it and see. You can drag with the left mouse button to select many files to load. Check the Pin up box to have the dialog remain after you press OK. Click on Show thumbnails and nip will try to display thumbnail images for all the files in the directory. You can tab-complete in the directory line at the top. See §4.3 for full details.

After you've loaded an image, nip should look like Figure 2.1. Double click on the thumbnail to open an image view window. Alternatively, select Edit from the right-button menu on the thumbnail. See Figure 2.2.

Figure 2.1: After loading an image
\includegraphics[width=3in]{figs/snap2.PS}

Figure 2.2: Image view window
\includegraphics[width=3in]{figs/snap3.PS}

nip has lots of shortcuts for navigating images, see Table 2.1. Use the View menu to turn on other features. You can have a status bar (shows image properties, mouse position and pixel value), a display control bar (lets you change scale and offset for display pixels, click on the arrow on the left for a useful extra menu), and some rulers.


Table 2.1: nip shortcuts for the image view window
Keys in image display widget Action
i Zoom in on mouse pointer
o Zoom out
Cursor up/down/left/right Scroll a small amount in direction
Shift plus cursor up/down/left/right Scroll a screenful in direction
Ctrl plus cursor up/down/left/right Scroll to edge of image
Middle mouse drag Pan image
Mouse wheel Scroll up/down. Combine with Shift and Ctrl to scroll faster

Accelerator Action
0 (zero key) Zoom out to fit image to window
1, 2, 4, 8 (number keys) Set magnification to 1, 2, 4 or 8
Ctrl plus 2, 4, 8 Set zoom out factor to 2, 4 or 8


You can mark things on an image. Hold down Ctrl and drag down and right with the left mouse button to mark a region. Ctrl-left-click to mark a point. Drag up and left to mark an arrow (two points connected by a line). Drag from the rulers to mark guides. Right-click on a label to get a menu which you can use to remove or edit one of these things. Left drag on a label to move the things around, left-drag on the edges or corners to resize. Figure 2.3 shows the same image with stuff marked on it.

Figure 2.3: Image view window with marked regions
\includegraphics[width=3in]{figs/snap4.PS}

Clean up any messing about and leave two regions on your image. The main window should now look something like Figure 2.4.

Figure 2.4: Main window, two regions marked
\includegraphics[width=3in]{figs/snap5.PS}

There are three rows visible here, A1, A4 and A7. Each row has (from left to right) a pair of up/down arrows (these indicate that the row is a class instance: click on the down arrow several times to open the row up and see inside), the name button (left-click to select, Shift-left-click to extend-select, Ctrl-left-click to toggle select, click on the workspace background to unselect everything, left-drag on the name button to reorder items within the column) and the thumbnail image.

Left-click on the name button of one of these images to select it, and then click on Rotate=>Rotate_free (alternatively, if nothing is selected when you click on one of the menus down the right, nip will apply the operation to the bottom object in the current column). A new row will appear representing the rotation operation. Left-click twice on the down button to the left of the name button and a slider will appear. Drag the slider to rotate the image (or type an angle in degrees into the box to the left of the slider and press Return). See Figure 2.5.

Figure 2.5: Using Rotate_free
\includegraphics[width=3in]{figs/snap6.PS}

The same thing works for image processing operations that take two arguments. Left-click on one of your original regions, Ctrl-left-click on the rotated image (the bottom right of the window says what's selected and in what order), and click on Image=>Join=>Left_right. A new row appears representing the join operation. Click on the down arrow twice to open it up and you'll see a bunch of controls.

Click on the 0 to the right of background_colour, type in 128 and press Return. Drag the shim slider to 50 (or type 50 into the box just to the left of the slider and press Return). See Figure 2.6.

Figure: Using Join=>Left_right
\includegraphics[width=3in]{figs/snap7.PS}

The box at the bottom of the column is for entering new expressions. You can type stuff here, and nip will make a new row for each item you enter. Try typing 2 + 2 and pressing Return. The syntax is (almost, with a few small differences) the same as the C programming language. Try multiplying the joined images by a small amount (eg. type something like A9 * 1.2 and press Return).

This will make a floating point image, which will not save as TIFF, JPEG, PNG or PPM. To save to one of these formats, your image must have 1 or 3 bands and must be unsigned 8 bit. To convert back to an 8 bit image, click on Format=>Convert_format_to=>unsigned_8bit. To save an image, right click on the thumbnail and select Save. To break an image into separate bands, click on Format=>Decompose, and then on Edit=>Ungroup. To make several single band images into a multi-band image, group them and click on Format=>Compose.

Click the down button once on your brightened image and left-click on the area just below the thumbnail. You should see the stuff you typed to make that row. You can edit it to be anything else, press Return and nip will recalculate. Try going back to your original image (the one you loaded from a file), open an image view window, and try dragging one of the regions. You can change any of the sliders in the rotate or the join rows as well.

Right-click on a workspace tab to get a useful context menu. Right click on a column title bar to get another useful menu. Click on Insert=>New column to make another column (handy for organising a workspace). If nip falls over (I do hope it doesn't), you can often get your workspace back by restarting nip and clicking on File=>Recover after crash. The Preferences workspace has hundreds of stupid things you can change, it might be worth glancing through (see Appendix A). You can use the mousewheel to scroll up and down through workspaces.

There is a lot of stuff in the menus down the right, but they do almost all have tooltips. If you let your mouse hover over a menu item for a moment you should get some helpful text. Most operations can work on groups as well as on single images, so you can batch things up. You can use Edit=>Clone to make copies of objects. If you select lots of objects and press clone, nip will (fairly intelligently) rename everything for you so it all still works.


next up previous contents
Next: 2.3 nip for reflectogram Up: 2. Tutorial Previous: 2.1 Introduction   Contents
John Cupitt 2003-07-21