Scrollbars

Thursday February 25th, 2010

Scrolling content on a limited screen estate space is one of the most basic things in modern software - whether that being a computer or mobile phone. Scrolling has evolved over time. Nowadays we have multitouch and gesture based scrolling. But it started with the scrollbar.

I remember that when I wrote my Master Thesis back in 1994 the scrolling algorithm of the otherwise quite basic Windows application was quite complicated, especially if the content to scroll is large and dynamic in nature.

Managing scrollbars is not hard in principle. The basic idea is not that difficult, but there are a lot of small details that need to be ironed out. If you don't get the details just right, your program will feel odd in a strange way that you often can't pinpoint, much like a subtle background hum that makes you feel uneasy without realizing it. Getting the details right is important to making your program feel crisp and clean.

The above quote is from the blog The Old New Thing by Raymond Chen which in July-September 2003 ran a series of posts which makes an excellent introduction in the scrollbar fundamentals in Windows. For reference I've listed the complete series of posts here:

• Part 1 - The scratch program, 2003-07-23
• Part 2 - Continuing to lay the groundwork for scrollbar discussion, 2003-07-25
• Part 3 - Optimizing the paint cycle , 2003-07-29
  • Answer to yesterday's exercise, 2003-07-30
• Part 4 - Adding a proportional scrollbar, 2003-07-31
• Part 5 - Keyboard accessibility for scrollbars, 2003-08-05
  • Answers to previous exercise, 2003-08-05
• Part 6 - The wheel, 2003-08-07
  • Answers to excercises, 2003-08-11
• Part 7 - Integrality, 2003-08-11
• Part 8 - Integral interactive resizing, 2003-08-13
  • Answer to exercise, 2003-08-15
• Part 9 - Maintaining the metaphor, 2003-09-09
• Part 10 - Towards a deeper understanding of the WM_NCCALCSIZE message, 2003-09-11
  • Answers to exercises, 2003-09-13
• Part 11 - Towards an even deeper understanding of the WM_NCCALCSIZE message, 2003-09-15
  • Answers to excercises,, 2003-09-17
• Part 12 - Applying WM_NCCALCSIZE to our scrollbar sample. 2003-09-17
• The end of the scrollbar series, 2003-09-17
• Scrollbars redux: Display a word-style scroll tip,, 2003-10-16