Vindaloo comes with basical functionality for a PDF viewer. You can zoom in and zoom out, fit page, width or height, and jump pages. The performance of going through pages are reasonablly good. Although you cannot select text for copy-and-paste, you can search text and the found ones will be rendered with light yellow background. That's pretty much all it does for now.
Another application to preview PDF is Yap. It is more like a previewer before you print the documents. It uses a2ps to generate PostScript, therefore, you can use it on many formats as long as a2ps supports, including most source codes, html, even LaTeX. You can also view images, but the only way to scale is to use menu 'Resolution' to do limited scaling. An interesting function is that if you select an area of image, that part of image will be automatically copied into pasteboard. Then you can paste it into other applications. You can also use menu 'File > Save pasteboard as TIFF' to save it directly.
For formats other than images, it uses GhostScript for rendering. For the first time, you should use menu 'Info > Preferences' to set the external tools. Click button Defaults should work for most of people. Use Set to save the preferences. Once you open a PDF document, it shows a row of radio buttons on the top as pages. You can use menu 'Resolution' to adjust scale for viewing. If you have any problem with Yap, it is mostly caused by wrong parameters in a2ps. You can look at your terminal emulator and find the command like this
/usr/bin/a2ps ("--portrait", "--rows=2", "--columns=2", "-o", "-", "source_code.m")
These paramters, like portrait, rows, are the same as menu 'Options > Display'. You can either use menu 'Options > Reset' or go through each option to make sure none of them are enabled.
Previous articles in this series: