1. display_image()
- Posted by pwcroft at home.com
Aug 05, 2001
This is a multi-part message in MIME format.
------=_NextPart_000_0024_01C11D49.48578D40
charset="iso-8859-1"
2. Re: display_image()
- Posted by euman at bellsouth.net
Aug 05, 2001
This is a multi-part message in MIME format.
------=_NextPart_000_000E_01C11D06.FCC0FD40
charset="iso-8859-1"
you need to look into manipulating the palette in DOS.
'palutil' on the user contrib page should give you some
insight.
Euman
euman at bellsouth.net
----- Original Message -----
From: pwcroft at home.com
To: EUforum
Sent: Sunday, August 05, 2001 02:55
Subject: display_image()
I'm using display_image() and I'm having the following problem. I use it
once, to display the picture of a map, then again, to put a picture of a
compass in the corner of the screen. But when I display the compass, the map
vanishes, and I have a black screen, with the compass in the corner. Why is
that? How do I fix it?
Thanks for your time, all.
-Phil
------=_NextPart_000_000E_01C11D06.FCC0FD40
Content-Type: text/html;
charset="iso-8859-1"
Content-Transfer-Encoding: 8bit
3. Re: display_image()
- Posted by pwcroft at home.com
Aug 05, 2001
This is a multi-part message in MIME format.
------=_NextPart_000_0374_01C11D59.A1077580
charset="iso-8859-1"
4. Re: display_image()
On Sunday 05 August 2001 05:52, pwcroft at home.com wrote:
> I'm using display_image() and I'm having the following problem. I use
> it once, to display the picture of a map, then again, to put a picture of a
> compass in the corner of the screen. But when I display the compass, the
> map vanishes, and I have a black screen, with the compass in the corner.
> Why is that? How do I fix it?
Are you trying to overlap the images? That won't work (without some extra
effort) because bitmaps don't support transparency.
If the images are NOT overlapping, you still have to arrive at a common
"palette" of colors. If you are using, for example, 256 colors, DOS keeps
an array of [0...255], and in each element of that array, stores the color
value for that color. If color[12] = 0, then color[12] would be black.
Your bitmaps have a similar array attached (the palette) which may
have some other value altogether stored in color[12]. Loading a new
bitmap can change all the colors of the bitmap which is already on display.
It's quite possible that your compass bitmap has only a few colors, with
zero stored in the rest of the color array. Therefor, most or all of the
colors in your map get changed to black when the compass is loaded.
The way to avoid this is to convert all your bitmaps to use the same,
common set of colors. Most good photo editing programs can do that,
programs like PaintShop Pro.
Regards,
Irv
5. Re: display_image()
- Posted by pwcroft at home.com
Aug 05, 2001
I'm still a little lost. What is the easiest ways to use transparency? Best
example?
----- Original Message -----
From: "Irv Mullins" <irvm at ellijay.com>
To: "EUforum" <EUforum at topica.com>
Subject: Re: display_image()
>
> On Sunday 05 August 2001 05:52, pwcroft at home.com wrote:
>
> > I'm using display_image() and I'm having the following problem. I
use
> > it once, to display the picture of a map, then again, to put a picture
of a
> > compass in the corner of the screen. But when I display the compass, the
> > map vanishes, and I have a black screen, with the compass in the corner.
> > Why is that? How do I fix it?
>
> Are you trying to overlap the images? That won't work (without some extra
> effort) because bitmaps don't support transparency.
>
> If the images are NOT overlapping, you still have to arrive at a common
> "palette" of colors. If you are using, for example, 256 colors, DOS keeps
> an array of [0...255], and in each element of that array, stores the color
> value for that color. If color[12] = 0, then color[12] would be black.
> Your bitmaps have a similar array attached (the palette) which may
> have some other value altogether stored in color[12]. Loading a new
> bitmap can change all the colors of the bitmap which is already on
display.
>
> It's quite possible that your compass bitmap has only a few colors, with
> zero stored in the rest of the color array. Therefor, most or all of the
> colors in your map get changed to black when the compass is loaded.
>
> The way to avoid this is to convert all your bitmaps to use the same,
> common set of colors. Most good photo editing programs can do that,
> programs like PaintShop Pro.
>
> Regards,
> Irv
>
>
>
>
>
6. Re: display_image()
On Sunday 05 August 2001 10:12, pwcroft at home.com wrote:
>
> I'm still a little lost. What is the easiest ways to use transparency? Best
> example?
Well, since bitmaps don't support transparency, it's pretty much a matter
of choosing a color value to be "transparent", and then writing a routine
to put your image on the screen pixel-by-pixel, skipping those pixels which
are colored "transparent".
Search the RDS archives on the word "transparent" - you'll see several
contributions which will help.
Regards,
Irv
7. Re: display_image()
- Posted by euman at bellsouth.net
Aug 05, 2001
try a search for Colin Taylor or Palette
Palette Management Utilities Colin Taylor 1/24/99
(pal_util.e)
His code will show you how to get around the
palette problem....sortof
I personaly use this prefered way.
Irv mentioned useing the same palette for multiple
images... Jasc PaintShop Pro is probably the best
Ive seen to handle images.
I first create the main image or convert an existing image to 16million
colors then, convert the same image useing JASC back to 256 colors then I use:
Optimized Median Cut
Error Diffusion
and Reduce Color Bleeding
I then save that palette to a file from the initial image and apply this saved
palette to any image I create after this for the same project.
Euman
euman at bellsouth.net
----- Original Message -----
From: "Irv Mullins" <irvm at ellijay.com>
To: "EUforum" <EUforum at topica.com>
Sent: Sunday, August 05, 2001 21:25
Subject: Re: display_image()
>
> On Sunday 05 August 2001 10:12, pwcroft at home.com wrote:
> >
> > I'm still a little lost. What is the easiest ways to use transparency? Best
> > example?
>
> Well, since bitmaps don't support transparency, it's pretty much a matter
> of choosing a color value to be "transparent", and then writing a routine
> to put your image on the screen pixel-by-pixel, skipping those pixels which
> are colored "transparent".
>
> Search the RDS archives on the word "transparent" - you'll see several
> contributions which will help.
>
> Regards,
> Irv
>
>
>
>
>
8. Re: display_image()
Phil wrote:
> I'm still a little lost. What is the easiest ways to use
transparency? Best
> example?
The attached routine is definitely *not* the best example, but it's
usually fast enough for me.
jiri
global procedure merge_image(
integer x, -- top left corner, horizontal coordinate
integer y, -- top left corner, vertical coordinates
sequence image, -- 2-d image sequence
integer c -- transparent cell color index
)
-- display 2-d sequence im at point x,y
-- image cells of color c are considered transparent
-- with 'on-the-fly' run-length-encoding
sequence row
integer f,k,w
x -= 1
for i=1 to length(image) do
row=image[i]
w = length(row)
f=0 -- not in run
for j=1 to w do
if row[j]=c then
if f then
pixel(row[k..j-1],{x+k,y})
f=0
end if
else
if not f then
k=j
f=1
end if
end if
end for
if f then
pixel(row[k..w],{x+k,y})
end if
y+=1
end for
end procedure -- merge_image
