Werner ha scritto: > Tomas Eroles i Forner wrote: > >> commands in a Draw.Begin(DrawingArea)...Draw.End group of code. >> >> It seems to work, but, I see that you can start drawing if you put a >> command button, or a menu or something like this, but it does not work >> in a Form_Open event. >> >> Is it like this? >> > However, it is much more practical to use the drawing area's draw event > http://gambasdoc.org/help/comp/gb.qt/drawingarea/.draw > > because it will also deal with needs to redraw that come from outside the > application i.e.other applications' windows that were partially overlapping. > Have a look at the "Analog Watch" example. > Werner is right but, perhaps, you can still get what you want if you set the "Cached" property of the DrawingArea. By setting that property, the DrawingArea repaints automatically itself when needed; whether to go this way or the other depends on several factors: dimension of the drawing, complexity of the drawing, complexity of the code needed to remember what to draw...
I suppose that the main difference between the two methods is this. If you use the Cached property, your code can update the drawing when it wants; the result is a cached bitmap that can consume a lot of memory, but still is a simple bitmap. This is the easiest way. If you don't use the Cached property, your code to update the drawing is called every time the DrawingArea "unveals". If this code is fast, then this method is better. However, this second method is a little more complicated to understand: when the program, asynchronously, wants to change the appearance, it can Draw() directly, but it must also remember the sequence of operations needed to refresh the entire drawing, so a double job is needed. And this is the harder way... Cheers, Doriano Blengino ------------------------------------------------------------------------- This SF.Net email is sponsored by the Moblin Your Move Developer's challenge Build the coolest Linux based applications with Moblin SDK & win great prizes Grand prize is a trip for two to an Open Source event anywhere in the world http://moblin-contest.org/redirect.php?banner_id=100&url=/ _______________________________________________ Gambas-user mailing list Gambas-user@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/gambas-user