--- Ravi Mehrotra <ravi@csnpl.ren.nic.in> wrote:
> # To subscribers of the xforms list from Ravi Mehrotra
> <ravi@csnpl.ren.nic.in> :
>
> Hi,
>
> I am using XForms version 0.89 on a Linux 2.2.6 Pentium II machine.
> I have a True color image with depth 16. I use the following code to
> display the image in a canvas.
>
> void load_cb(FL_OBJECT *ob, long data)
> {
> FL_IMAGE *pic;
>
> pic=flimage_alloc();
lose the above statement. Call flimage_alloc() only if
you're creating image with raw data.
> pic=flimage_load("picture.ppm");
> pic->display(pic, FL_ObjWin(canvas));
> XFlush(fl_display);
> sleep(1);
> fl_set_object_position(canvas,canvas->x+50,canvas->y+50);
> pic->display(pic, FL_ObjWin(canvas));
> XFlush(fl_display);
> }
This is basically a programming error. When you call set_position,
it'll generate an Expose event on the canvas, which may or may
not get delivered or handled by the time you call pic->display again.
If you can't see the image after second pic->display() call,
it's most likely that it gets wiped by the default canvas Expose
handler, which just refreshes the canvas. To correctly handle this
kind of situation,
always install a canvas expose handler, and lose the second display
call.
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