9 Output from map3d

9.1 Capturing images for animation, printing, or photos/slides

While screen images are lovely to look at, we need to be able to get the output from the screen to some transportable medium like paper, animation movies, video tape, or film. This section describes some of the methods available for this process.

9.1.1 Image capture

There are no standard provisions in OpenGL for generating output from the images generated by map3d. However, map3d uses a collection of the GL windows to create an image and save it to a file. Once preserved, this file can be viewed later, either by itself or as part of a sequence of images in an animation.

To capture an image using map3d simply set the image you want to preserve and hit the ``w''-key. There will be a slight pause and the a line will appear in the control window telling you where the image has been stored. Filenames for image storage are generated automatically, using the filename specified in the Saving dialog, which defaults to the value set with the -if option or it will default to map3d.png (See Section 8.3.2). Appended to this base filename are sets of four digits, denoting the frame number currently in the display, starting with ``0001''. Thus, for example, if the base image file were daltorso.png, the first file produced would be daltorso0001.png. Note the .png file extension, standard for this sort of file, can also be changed to .ppm or .jpg.

The screen area captured in this mode is the smallest rectangle that contains all the windows currently managed by the current invocation of map3d. This often requires with careful placement of the windows or setting the background window for the display to black or something that matches the background of the map3d display.

9.1.2 Animations

Sometimes it is desirable to save a sequence of images in a movie for use in a demonstration. map3d does not (currently) have the ability to save movies directly, but it does have the ability to automatically save a sequence of images based on a set of input events, which can be pieced into a movie from external software. The images are saved into a sequence of files based on the rules in the image capture section, and each time the appended digits increment. See Section 8.3.2 for more information on how to control the animations.

9.1.2.1 Making movies

There are a few commercial programs we have found useful in generating movies directly:

1. Snapz Pro, which is a marvelous program from Ambrosia Software for grabbing frames in real time from the screen.
2. Final Cut Pro, a program from Apple that is as good as most professional tools (so they say).
3. iMovie HD, which comes free on a Mac. It is worth checking the iLife version, which is usually a little ahead the version shipped with Macs, if you are serious about editing video.

Otherwise, while we are working on integrating movie support directly into map3d, there are a few packages to create movies from your frames.

1. QuickTimePro (for Mac OSX), if you want this one in a version that allows editing, you'll have to pay.
2. Snapz Pro (for Mac OSX), also some cost involved but very modest for what this program will do.
3. Discreet Cleaner XL (for Win32).
4. mencoder (for Linux or Windows).
5. ffmpeg is a cross-platform utility you can use to generate movies. However, you would have to download it and compile it yourself. Once you have downloaded and compiled it, you can, for example: ffmpeg -i map3d%04d.jpg map3d.mpg, which will turn map3d0001.jpg, etc. into map3d.mpg.

We are still learning which combinations of settings work best to capture, edit, and save animations. It depends a lot on the context in which you plan to view/show the results. As we learn more, we will share it with you.