cjmchale@cs.tcd.ie (Ciaran McHale) (03/17/91)
In <1991Mar15.100902.16094@abblund.se> erik@abblund.se (Erik Sparre) writes: >When you develop a direct manipulation graphical user interface you >will sooner or later need the ability to detect whether the user pointed >at a certain graphical object (line, ect, circle). >[...] >Is there any good way to detect picking in X or any X-based library >without having to do the calculations yourself ? This is one of the limitations of raw Xlib. It *is* possible to write the appropriate routines, but it's a major pain to do so. It's best to have such commonly used functionality provided in a graphical toolkit to prevent application developers having to reinvent the wheel each time. Choices: o Do the calculations yourself. o Use Display Popstscript. o Use Interviews, a C++ windowing/graphics library. o Write your own OO graphics library in which each graphical object has a method does_contain_point(short x, short y). This last approach is possible but its a pain to do yourself. Ciaran. -- Ciaran McHale "Verbosity says it all" ____ Department of Computer Science, Trinity College, Dublin 2, Ireland. \ / Telephone: +353-1-772941 ext 1538 FAX: +353-1-772204 \/ Telex: 93782 TCD EI email: cjmchale@cs.tcd.ie