Re: XForms: Problem displaying images

Ravi Mehrotra (ravi@csnpl.ren.nic.in)
Wed, 15 Sep 1999 08:49:23 +0530

# To subscribers of the xforms list from Ravi Mehrotra <ravi@csnpl.ren.nic.in> :

Dear Michael,

I also tried the xpm format. On my machine xpm format does not
work at all at any depth. I get a blank image and error messages like
.
.
In LookupColor [rgb_db.c 210] can't handle color #f8f8fafaffff",
In LookupColor [rgb_db.c 210] can't handle color #fafaffffffff",
.
.
for many colors. I did use flimage_enable_xpm().

Regards,

Ravi Mehrotra
National Physical Laboratory
New Delhi, India.

Michael Glickman wrote:
>
> # To subscribers of the xforms list from Michael Glickman <michaelg@linx.com.au> :
>
> Hello, Ravi
>
> You didn't tell, how the canvas moves. Do you make it moving
> programmatically, or it moves as a result of user interaction
> (dragging the form, etc) ?
>
> If canvas moves as the result of your code, I would suggest to
> repeat 'pic->display' and 'XFlush' after move. This may help.
> If the problem appears as the result of user interaction, you can
> trap 'move' event and do 'pic->display' and 'XFlush' in the
> handler.
>
> Actually PPM support is a relatively new feature in XForms,
> therefore
> I prefer good old pixmap (XPM) format. It has a number of
> advantages,
> e.g. direct X server support, no need for extra libraries, and
> ability
> to keep the image as the source code. And, what is more important,
> I don't have any troubles like that. You may argue, that XPM
> requires
> more hard disc space then the compressed PPM. But you can
> compress XPM with gzip and decompress it into a temporary file
> by calling zcat from your program before starting using the image.
>
> Regards, Michael
>
> > -----Original Message-----
> > From: Ravi Mehrotra [SMTP:ravi@csnpl.ren.nic.in]
> > Sent: Tuesday, 14 September 1999 17:05 EST
> > To: xforms@bob.usuhs.mil
> > Subject: XForms: Problem displaying images
> >
> > # 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();
> > 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);
> > }
> >
> > The picture shows up OK. However, after the canvas is moved, the
> > picture appears as a faint ghost without color. This happens if I
> > start my Xserver with depth 16 or 24. The problem disappears if
> > I start up the Xserver with depth 8 but then I am limited in colors.
> >
> > Is there a bug or am I doing something wrong ? I will appreciate any
> > help.
> >
> > Thanks.
> >
> > Ravi Mehrotra
> > National Physical Laboratory
> > New Delhi 110012
> > India
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