Legacy ImageMagick Discussions Archive

Hi.
I want to remove background color from my images. The sample of images is as follow


I tried following command: and this is the result that I got.


How to make all of black color become transparent instead of just an area of black.

Regards.

Your image has gray pixels around the edge and at 0,0. Perhaps it has been mangled by the image hosting site.

Your second image shows correct working of floodfill. It has stopped at non-black pixels. You could add a black border first, floodfill from 0,0, and finally shave off the border.

The easier way of making all black pixels transparent is:

try

convert Tree.png.jpeg -fuzz 10% -transparent black result.png

This looks for any pixel within 10% of pure black and makes it transparent.

see
http://www.imagemagick.org/Usage/color_basics/#opaque

P.S. In windows syntax you need to use %% rather than %

see
http://www.imagemagick.org/Usage/windows/

snibgo wrote:Your image has gray pixels around the edge and at 0,0. Perhaps it has been mangled by the image hosting site.

Do you mean the thumbnail? I clicked the image to link to actual image and it seems okay.
Even I suggested the usage of the hosting for this forum.

Sorry if I cannot give good explanation, but what I want to achieve is for using ImageMagick to remove all background by using top-left pixel as sample. Something like

convert tree.png -alpha set -transparent #000000 TransparentTree.png

, but using top-left pixel as sample instead of #000000.
Because I have a lot of images which have non black background colors. So, whatever it is black, purple, blue, or etc, ImageMagick just look for top-left pixel as sample.

Thanks.

"-transparent" needs an actual colour. It would be nice if it accepted syntax like ... ... but it doesn't. So you have to extract the colour with a separate command. This depends on your scripting language. For example, in Windows BAT:

snibgo wrote:"-transparent" needs an actual colour. It would be nice if it accepted syntax like ...

I am very agree to you. Is it possible for me to suggest such feature to ImageMagick Developers? How could I do that?

You can write a post in the developers forum: viewforum.php?f=2

I believe that this is what you want to do using replace rather than floodfill:

convert Tree.png.jpeg -fuzz 10% -fill none -draw "matte 0,0 replace" result.png

see section on matte x,y method
http://www.imagemagick.org/script/magic ... aphics.php


In Windows syntax, you may need to use %% rather than %.

snibgo wrote:

Code: Select all

FOR /F "usebackq" %%C ^
IN (`convert tree.png -format "%%[pixel:p{0,0}]" info:`) ^
DO convert tree.png -transparent %%C out.png

fmw42 wrote:

Code: Select all

convert Tree.png.jpeg -fuzz 10% -fill none -draw "matte 0,0 replace" result.png

Result:


Both worked. Thanks for all.