Very Computer

by **Sturla Mold** » Fri, 01 Jun 2001 21:23:28

Is there any way of doing this? Can I e.g. specify the
RGB values of the image pixels individually?

S.M.

by **Jordan Rosentha** » Fri, 01 Jun 2001 23:08:48

Sturla,

You can set the transparency using the 'AlphaData' property:

%---------
[n1,n2] = meshgrid(-5:5);
x = rand(size(n1));
hImage = imagesc(x)
idx_Invisible = abs(n1+n2)<3;
set(hImage,'AlphaData', idx_Invisible);
%---------

It seems to take significantly longer to display though.

Yes, you can use RGB values. Just feed the IMAGE command a MxNx3 matrix.

imagesc(rand(5,5,3));

Jordan

Quote:
> Is there any way of doing this? Can I e.g. specify the
> RGB values of the image pixels individually?

> S.M.

by **Brett Shoelso** » Sat, 02 Jun 2001 02:04:55

Hi Sturla,
Not sure what this has to do with your subject, but here's a little function
that you can use to specify individually the RGB colors of pixels.
(Actually, it specifies the RGB colors of patches over the pixels, and
doesn't alter your image.):

function colorpixel(xpos,ypos,coloropt)
for i=1:length(xpos)
patch([xpos(i)-0.5 xpos(i)+0.5 xpos(i)+0.5 xpos(i)-0.5],...
[ypos(i)-0.5 ypos(i)-0.5 ypos(i)+0.5 ypos(i)+0.5],...
coloropt,'edgecolor','none','tag','colorpixel');
end

Note that I included tags on the patches. That allows you to easily toggle
the patches on and off.

HTH,
Brett

Quote:
> Is there any way of doing this? Can I e.g. specify the
> RGB values of the image pixels individually?

> S.M.

Very Computer

Plotting NaNs white or transperent

Plotting NaNs white or transperent

Plotting NaNs white or transperent

Plotting NaNs white or transperent