I am trying to create graphics with GDI+ that include transparency. However,
the transparency never seems to show up, even though my colors have an alpha
value of 0. How can I generate a graphic that is completely transparent in
certain areas (so that the web page background shows through)? I save my
graphics as gif files. I would appreciate, if possible, a simple example so
that I can see the code. Thanks.
--
Nathan Sokalski nj********@hotm ail.com http://www.nathansokalski.com/ 20  4524 
The only graphics formats that have transparency in HTML are GIF and PNG.
What format are you using?
--
HTH,
Kevin Spencer
Microsoft MVP
..Net Developer
Everybody picks their nose,
But some people are better at hiding it.
"Nathan Sokalski" <nj********@hot mail.com> wrote in message
news:Ot******** ******@TK2MSFTN GP10.phx.gbl... I am trying to create graphics with GDI+ that include transparency.
However, the transparency never seems to show up, even though my colors
have an alpha value of 0. How can I generate a graphic that is completely
transparent in certain areas (so that the web page background shows
through)? I save my graphics as gif files. I would appreciate, if possible,
a simple example so that I can see the code. Thanks.
--
Nathan Sokalski
nj********@hotm ail.com
http://www.nathansokalski.com/
Like I said in my original message, I am using GIF. The line that I use to
save my image is as follows (testbitmap is the name of my
System.Drawing. Bitmap object):
testbitmap.Save (Server.MapPath ("GDItest.gif") , Imaging.ImageFo rmat.Gif)
--
Nathan Sokalski nj********@hotm ail.com http://www.nathansokalski.com/
"Kevin Spencer" <ke***@DIESPAMM ERSDIEtakempis. com> wrote in message
news:eq******** ******@TK2MSFTN GP10.phx.gbl... The only graphics formats that have transparency in HTML are GIF and PNG.
What format are you using?
--
HTH,
Kevin Spencer
Microsoft MVP
.Net Developer
Everybody picks their nose,
But some people are better at hiding it.
"Nathan Sokalski" <nj********@hot mail.com> wrote in message
news:Ot******** ******@TK2MSFTN GP10.phx.gbl...I am trying to create graphics with GDI+ that include transparency.
However, the transparency never seems to show up, even though my colors
have an alpha value of 0. How can I generate a graphic that is completely
transparent in certain areas (so that the web page background shows
through)? I save my graphics as gif files. I would appreciate, if
possible, a simple example so that I can see the code. Thanks.
--
Nathan Sokalski
nj********@hotm ail.com
http://www.nathansokalski.com/
I think IE don't support transparency.
At least I can say for sure it doesn't support PNG transparency.
It is an issue that should be fixed with IE 7 or could be fixd with Firefox!
"Nathan Sokalski" <nj********@hot mail.com> wrote in message
news:On******** ******@TK2MSFTN GP14.phx.gbl... Like I said in my original message, I am using GIF. The line that I use to
save my image is as follows (testbitmap is the name of my
System.Drawing. Bitmap object):
testbitmap.Save (Server.MapPath ("GDItest.gif") , Imaging.ImageFo rmat.Gif)
--
Nathan Sokalski
nj********@hotm ail.com
http://www.nathansokalski.com/
"Kevin Spencer" <ke***@DIESPAMM ERSDIEtakempis. com> wrote in message
news:eq******** ******@TK2MSFTN GP10.phx.gbl... The only graphics formats that have transparency in HTML are GIF and PNG.
What format are you using?
--
HTH,
Kevin Spencer
Microsoft MVP
.Net Developer
Everybody picks their nose,
But some people are better at hiding it.
"Nathan Sokalski" <nj********@hot mail.com> wrote in message
news:Ot******** ******@TK2MSFTN GP10.phx.gbl...I am trying to create graphics with GDI+ that include transparency.
However, the transparency never seems to show up, even though my colors
have an alpha value of 0. How can I generate a graphic that is completely
transparen t in certain areas (so that the web page background shows
through)? I save my graphics as gif files. I would appreciate, if
possible, a simple example so that I can see the code. Thanks.
--
Nathan Sokalski
nj********@hotm ail.com
http://www.nathansokalski.com/
I know for sure that IE correctly supports transparency in GIF files because
I have made transparent GIF files using Adobe Photoshop in the past that
worked correctly in IE. What the problem appears to be to me, although I
could be wrong, is that when a new System.Drawing. Bitmap is created in
ASP.NET it automatically gives it a background with an Alpha value of 255
(completely opaque). Because of this, whenever anything is drawn on the
bitmap, it is drawn on top of the opaque background. This means that
anything with an Alpha value of 0 (completely transparent) is not visible.
If this is the case, I think the only solution would be to "erase"
previously drawn pixels (which I do not know of a way to do), including the
background or to have the initial background color have an Alpha value of 0.
This is only a theory, so I could be wrong. A workaround that I have come up
with (but it requires the developer to create an extra file) is to use an
existing image file that is completely transparent in the
System.Drawing. Bitmap constructor. Let me know if you come up with any
ideas. Thanks.
--
Nathan Sokalski nj********@hotm ail.com http://www.nathansokalski.com/
"Lloyd Dupont" <net.galador@ld > wrote in message
news:ey******** ******@TK2MSFTN GP09.phx.gbl... I think IE don't support transparency.
At least I can say for sure it doesn't support PNG transparency.
It is an issue that should be fixed with IE 7 or could be fixd with
Firefox!
"Nathan Sokalski" <nj********@hot mail.com> wrote in message
news:On******** ******@TK2MSFTN GP14.phx.gbl... Like I said in my original message, I am using GIF. The line that I use
to save my image is as follows (testbitmap is the name of my
System.Drawing. Bitmap object):
testbitmap.Save (Server.MapPath ("GDItest.gif") , Imaging.ImageFo rmat.Gif)
--
Nathan Sokalski
nj********@hotm ail.com
http://www.nathansokalski.com/
"Kevin Spencer" <ke***@DIESPAMM ERSDIEtakempis. com> wrote in message
news:eq******** ******@TK2MSFTN GP10.phx.gbl... The only graphics formats that have transparency in HTML are GIF and
PNG. What format are you using?
--
HTH,
Kevin Spencer
Microsoft MVP
.Net Developer
Everybody picks their nose,
But some people are better at hiding it.
"Nathan Sokalski" <nj********@hot mail.com> wrote in message
news:Ot******** ******@TK2MSFTN GP10.phx.gbl...
I am trying to create graphics with GDI+ that include transparency.
However, the transparency never seems to show up, even though my colors
have an alpha value of 0. How can I generate a graphic that is
completel y transparent in certain areas (so that the web page background
shows through)? I save my graphics as gif files. I would appreciate, if
possible, a simple example so that I can see the code. Thanks.
--
Nathan Sokalski
nj********@hotm ail.com
http://www.nathansokalski.com/
mmhh...
never really investigate this matter, but I would have guess that maybe you
could do:
Bitmap bmp = new Bitmap(width, height);
bmp.MakeTranspa rent();
or with
bmp.LockBit() you could directly access the bitmap's color pointer
as explained here: http://msdn.microsoft.com/library/de...rp11152001.asp
Not correct. While IE doesn't support PNG transparency, it has lawys
supported GIF transparency.
--
HTH,
Kevin Spencer
Microsoft MVP
..Net Developer
Everybody picks their nose,
But some people are better at hiding it.
"Lloyd Dupont" <net.galador@ld > wrote in message
news:ey******** ******@TK2MSFTN GP09.phx.gbl... I think IE don't support transparency.
At least I can say for sure it doesn't support PNG transparency.
It is an issue that should be fixed with IE 7 or could be fixd with
Firefox!
"Nathan Sokalski" <nj********@hot mail.com> wrote in message
news:On******** ******@TK2MSFTN GP14.phx.gbl... Like I said in my original message, I am using GIF. The line that I use
to save my image is as follows (testbitmap is the name of my
System.Drawing. Bitmap object):
testbitmap.Save (Server.MapPath ("GDItest.gif") , Imaging.ImageFo rmat.Gif)
--
Nathan Sokalski
nj********@hotm ail.com
http://www.nathansokalski.com/
"Kevin Spencer" <ke***@DIESPAMM ERSDIEtakempis. com> wrote in message
news:eq******** ******@TK2MSFTN GP10.phx.gbl... The only graphics formats that have transparency in HTML are GIF and
PNG. What format are you using?
--
HTH,
Kevin Spencer
Microsoft MVP
.Net Developer
Everybody picks their nose,
But some people are better at hiding it.
"Nathan Sokalski" <nj********@hot mail.com> wrote in message
news:Ot******** ******@TK2MSFTN GP10.phx.gbl...
I am trying to create graphics with GDI+ that include transparency.
However, the transparency never seems to show up, even though my colors
have an alpha value of 0. How can I generate a graphic that is
completel y transparent in certain areas (so that the web page background
shows through)? I save my graphics as gif files. I would appreciate, if
possible, a simple example so that I can see the code. Thanks.
--
Nathan Sokalski
nj********@hotm ail.com
http://www.nathansokalski.com/
Hi Nathan,
Sorry, I missed the "gif" reference in your OP.
A GIF image palette can define one color as transparent. I'm not sure how
you're defining the transparent color in your palette, but the following
Microsoft KB article explains how to do it. Note that the article is not
specifically about making a transparent gif, but it covers creating a
palette with a single transparent color, which is encoded as the transparent
color for the GIF: http://support.microsoft.com/default...;EN-US;Q319061
--
HTH,
Kevin Spencer
Microsoft MVP
..Net Developer
Everybody picks their nose,
But some people are better at hiding it.
"Nathan Sokalski" <nj********@hot mail.com> wrote in message
news:On******** ******@TK2MSFTN GP14.phx.gbl... Like I said in my original message, I am using GIF. The line that I use to
save my image is as follows (testbitmap is the name of my
System.Drawing. Bitmap object):
testbitmap.Save (Server.MapPath ("GDItest.gif") , Imaging.ImageFo rmat.Gif)
--
Nathan Sokalski
nj********@hotm ail.com
http://www.nathansokalski.com/
"Kevin Spencer" <ke***@DIESPAMM ERSDIEtakempis. com> wrote in message
news:eq******** ******@TK2MSFTN GP10.phx.gbl... The only graphics formats that have transparency in HTML are GIF and PNG.
What format are you using?
--
HTH,
Kevin Spencer
Microsoft MVP
.Net Developer
Everybody picks their nose,
But some people are better at hiding it.
"Nathan Sokalski" <nj********@hot mail.com> wrote in message
news:Ot******** ******@TK2MSFTN GP10.phx.gbl...I am trying to create graphics with GDI+ that include transparency.
However, the transparency never seems to show up, even though my colors
have an alpha value of 0. How can I generate a graphic that is completely
transparen t in certain areas (so that the web page background shows
through)? I save my graphics as gif files. I would appreciate, if
possible, a simple example so that I can see the code. Thanks.
--
Nathan Sokalski
nj********@hotm ail.com
http://www.nathansokalski.com/
The MakeTransparent () didn't seem to have any affect, and I'm not sure why
(maybe the example wasn't quite clear enough) but the link you gave didn't
seem very clear to me. I think what I really need is a just a basic example
that just draws a simple shape or two and then adds a transparent area.
Thanks.
--
Nathan Sokalski nj********@hotm ail.com http://www.nathansokalski.com/
"Lloyd Dupont" <net.galador@ld > wrote in message
news:OM******** ******@tk2msftn gp13.phx.gbl... mmhh...
never really investigate this matter, but I would have guess that maybe
you could do:
Bitmap bmp = new Bitmap(width, height);
bmp.MakeTranspa rent();
or with
bmp.LockBit() you could directly access the bitmap's color pointer
as explained here:
http://msdn.microsoft.com/library/de...rp11152001.asp
I looked at the article you mentioned, and it definitely cleared up for me
why I was never getting any transparency, but I am still having trouble
figuring out how to fix the problem. I think what I really need is just a
basic example that just draws a simple shape or two and then adds a
transparent area. (Preferably in VB.NET, but I can usually get enough from
C# that it helps enough to solve my problem) Thanks.
--
Nathan Sokalski nj********@hotm ail.com http://www.nathansokalski.com/
"Kevin Spencer" <ke***@DIESPAMM ERSDIEtakempis. com> wrote in message
news:%2******** ********@TK2MSF TNGP12.phx.gbl. .. Hi Nathan,
Sorry, I missed the "gif" reference in your OP.
A GIF image palette can define one color as transparent. I'm not sure how
you're defining the transparent color in your palette, but the following
Microsoft KB article explains how to do it. Note that the article is not
specifically about making a transparent gif, but it covers creating a
palette with a single transparent color, which is encoded as the
transparent color for the GIF:
http://support.microsoft.com/default...;EN-US;Q319061
--
HTH,
Kevin Spencer
Microsoft MVP
.Net Developer
Everybody picks their nose,
But some people are better at hiding it.
"Nathan Sokalski" <nj********@hot mail.com> wrote in message
news:On******** ******@TK2MSFTN GP14.phx.gbl... Like I said in my original message, I am using GIF. The line that I use
to save my image is as follows (testbitmap is the name of my
System.Drawing. Bitmap object):
testbitmap.Save (Server.MapPath ("GDItest.gif") , Imaging.ImageFo rmat.Gif)
--
Nathan Sokalski
nj********@hotm ail.com
http://www.nathansokalski.com/
"Kevin Spencer" <ke***@DIESPAMM ERSDIEtakempis. com> wrote in message
news:eq******** ******@TK2MSFTN GP10.phx.gbl... The only graphics formats that have transparency in HTML are GIF and
PNG. What format are you using?
--
HTH,
Kevin Spencer
Microsoft MVP
.Net Developer
Everybody picks their nose,
But some people are better at hiding it.
"Nathan Sokalski" <nj********@hot mail.com> wrote in message
news:Ot******** ******@TK2MSFTN GP10.phx.gbl...
I am trying to create graphics with GDI+ that include transparency.
However, the transparency never seems to show up, even though my colors
have an alpha value of 0. How can I generate a graphic that is
completel y transparent in certain areas (so that the web page background
shows through)? I save my graphics as gif files. I would appreciate, if
possible, a simple example so that I can see the code. Thanks.
--
Nathan Sokalski
nj********@hotm ail.com
http://www.nathansokalski.com/
This thread has been closed and replies have been disabled. Please start a new discussion. Similar topics | |
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last post by:
I am trying to create graphics with GDI+ that include transparency. However,
the transparency never seems to show up, even though my colors have an alpha
value of 0. How can I generate a graphic that is completely transparent in
certain areas (so that the web page background shows through)? I save my
graphics as gif files. I would appreciate, if possible, a simple example so
that I can see the code. Thanks.
--
Nathan Sokalski...
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