Just a few extra notes to round out Albrecht's suggestions... On 12 Oct 2008, at 8:52, Albrecht Schlosser wrote: > Decide, how to implement your piano widget. I can see two rather > different approaches: > (1) use 128 Fl_Buttons, and put then into a Fl_Group > (2) use one widget, probably derived from Fl_Box, and draw the layout > yourself. > > I assume (2), because (1) seems easier at the first glance, but (2) > looks more flexible in the way you can do the setup (see below).
Yes - agree strongly. > Now, derive your own widget from Fl_Box, and write a draw() method to > draw the keys. This should be rather simple, if you first draw the > white > keys and draw the black keys on top of them (maybe you need only > fl_rect() and fl_rectf() ). Yes - I did something similar for a keyboard simulator way back. Simple rectangles is pretty much all I needed. > The active ranges could be drawn below the keys, as in your picture > (fl_polygon() or similar). > > Next, write your handle() method to get the user input (key > clicks). You > would need to calculate the position of a key from the x/y mouse > coordinates, but that should be rather straight forward (test the > black > keys first, then the white keys, and this can be done with simple x/y > range comparisons). Based on your box widget's x(), y(), w(), h() and the Fl::event_x(), event_y() values returned for the mouse click in your handle method. Also check out Fl::event_inside(int,int,int,int) which may be a better option for you. > For setting up the ranges, I would suggest to add a radio button group > somewhere else, to let the user select normal display, or start > setting > up range 1-4. > > After switching to setup mode for a certain range, you could let the > user click four keys, and the callbacks from your handle() would > fire to > let your application know what s/he clicked. If you are handling the clicks yourself in the handle method, you can do all sorts of clever stuff to set your ranges etc... > If you want to let the user drag a range of keys, then IMHO approach 2 > would be much easier to implement, because your handle() method > could do > this. Left click, right click, double click, and the combination could > also help to decide which of the 4 points of a range the user wants to > set. Clicking on a previously defined range point and dragging it > elsewhere would also be nice (left click for normal range, right click > for fade in/out) ? FL_PUSH, FL_RELESE, FL_DRAG. Fl::event_buttons(), ::event_button1() etc... Fl::event_is_click() might also be handy. _______________________________________________ fltk mailing list [email protected] http://lists.easysw.com/mailman/listinfo/fltk
