Thanks to Kostka. I see, the problem is I didn't return true. Now I can see the image.
On Wed, 26 Jan 2005 21:38:12 -0500, Tim Kostka <[EMAIL PROTECTED]> wrote: > I haven't looked at Cobalt, but I imagine the procedure is the same: > > 1) In your frmOpenEvent, draw the form via FrmDrawForm, then draw your > bitmap, and return true. > > 2) In your frmUpdateEvent, do the exact same thing. > > If you do not return true, the system will call FrmDrawForm and any custom > drawing you have done will be erased. > --- > Tim Kostka > > "ye vicky" <[EMAIL PROTECTED]> wrote in message > news:[EMAIL PROTECTED] > > Hi, > > > > It's really a naive questions, but why I just cannot manage it. > > > > I'm using develop suit, writing codes for Palm Cobalt system. > > I want to draw a bitmap whenever the form is drawn. How do I approach > > it? So far I know from creating a form bitmap element resource can > > draw a bitmap when the form is drawn. But I don't want that way. > > Because the bitmap being displayed will be a dynamic image. So, must > > there some other ways can do it. > > > > By now, I made a drawing method which is used to draw a bitmap. The > > method is functionable. It can be called and draw bitmap in other > > forms. I don't know what is the problem, I guess maybe I did not > > handle the correct event. > > I don't know how many event will be generated after FrmGotoForm() > > function. > > But it seems quite a lot of them. So far I know after FrmGotoForm(), > > will at least generate, frmLoadEvent, frmOpenEvent, frmUpdateEvent, > > winUpdateEvent, winResizedEvent. Because I tried to call the drawing > > method under each of them, I can see the program did run the method > > but nothing is drawn. Only when I responsed to winResizedEvent, I saw > > the bitmap flashed once and soon disappeared. And Palm OS Reporter > > tool gives a debug message: > > [Form] PrvDrawFormTab: Drawing list outside an update!\n > > > > The form I created to draw the bitmap is a traditional form. And the > > form is empty(no elements created in the form). > > I know for this kinds of form there is a gc created and stored in the > > back buffer. So, I also guess, is it because I did not draw the bitmap > > to back buffer, so once the form is redrawn, the bitmap is overwrited? > > If it is the point, then how do I write to back buffer? > > > > And also I don't understand, why there are so many event generated > > after FrmGotoForm(), and why the form was drawn several times since no > > action to the form at all after the form is fist time opened? > > > > I'm very new to Palm, and this is the only place I found can get some > > help, so pls forgive my so many naive questions. > > > > Thanks > > > > > -- > For information on using the Palm Developer Forums, or to unsubscribe, please > see http://www.palmos.com/dev/support/forums/ > -- For information on using the Palm Developer Forums, or to unsubscribe, please see http://www.palmos.com/dev/support/forums/
