how to draw an outline for a given image

[acpaps]

Can anyone suggest me how to draw outline for an image in C#, image is of any shape.
Thanks.

[fmw42]

Please always provide your IM version and platform. What do you mean by outline? edges in an image? or just the outside borders?

Please show an example of what you want.

Please read the top-most post in this forum at viewtopic.php?f=1&t=9620.

I have moved this topic to the User's forum.

[acpaps]

Thanks for the reply, for now i am not using any IM version, would like to know if by using IM is it possible to draw border by removing extra white spaces around image. I am trying to detect actual image and draw border/outline around that image (shape can be varied based on input).
For example, for a flower image. I would like to draw outline around that flower.
Sorry I didn't find any tool to attach images here that shows an example of what I need.

[fmw42]

Can you provide an example image? You can post to some free hosting service such as dropbox.com and put the URL here. Is the background of your flower image outside the flower a constant color or near-constant color. If not, background removal is rather hard with a cluttered background. Imagemagick does not have any direct function for the latter or the following.

See
http://clippingmagic.com/
https://www.microsoft.com/en-us/researc ... rabCut.pdf
http://docs.opencv.org/3.1.0/d8/d83/tut ... #gsc.tab=0

[acpaps]

Thank you for the reply, yes background color is constant color.
For example, take your profile pic as input. I need to draw outline only around hat and magic wand, and remove extra white space around that.

[snibgo]

Trimming off a constant-colour border is trivial: "-trim" does the job.

Drawing an edge around something is easy: "-edge 1".

There are many variations on these basic techniques.

For many example of simple usage of ImageMagick, see the usage pages: http://www.imagemagick.org/Usage/ .

[fmw42]

Here is a simple example in command line. I do not know C#

input:

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convert A_image.gif -colorspace gray -edge 1 -fuzz 1% -trim +repage A_image_edge.gif

The -fuzz 1% is not needed here since the background is exactly constant. But if you started with JPG, then the background would not be a perfectly flat colored. So you can use -fuzz XX% to allow some percent difference in the background color.

[acpaps]

Thank you so much for the reply.
I need to remove edge exactly to shape 'A' leaving inside triangle as it is. need to have border around 'A' shape.
Thank you, will do more research on how to use.

[fmw42]

Fill the hole with blue:

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convert A_image.gif -fuzz 85% -fill "rgb(0,0,128)" -draw "color 75,75 floodfill" -alpha off -colorspace gray -edge 1 -fuzz 1% -trim +repage A_image_edge2.gif

Or add a 1 pixel border of background white, floodfill the outside of the letter A with red from the top left corner, shave off the 1 pixel border, change non-red to white and red to black, extract edge, trim off the excess region around the outside of the A.

Unix syntax:

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convert A_image.gif -bordercolor white -border 1 \
-fuzz 5% -fill "red" -draw "color 0,0 floodfill" -alpha off \
-shave 1x1 \
-fill white +opaque red -fill black -opaque red \
-edge 1 \
-fuzz 1% -trim +repage \
A_image_edge3.gif

I used unix syntax, since you did not reply to my request to provide your IM version and platform! Syntax differs

[fmw42]

Please supply your image. You can upload to some place such as dropbox.com and put the URL here. Then we can better understand what you are trying to do.

[acpaps]

Please check the images
I have this


and I need this


cropped image is in image shape not regular rectangle or square

[fmw42]

I have asked for you IM version and platform, but you have not provided it. Please always provide that. Please read the top-most post in this forum at viewtopic.php?f=1&t=9620.


If on IM 6, then

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convert 781c0085d6.jpg -bordercolor white -border 1 -fuzz 20% -fill none -draw "matte 0,0 floodfill" -shave 1x1 result.png

If on IM 7, then

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magick 781c0085d6.jpg -bordercolor white -border 1 -fuzz 20% -fill none -draw "alpha 0,0 floodfill" -shave 1x1 result.png

[acpaps]

Thanks for the reply I will try the code...
About IM version, I am not using any IM version for now. I wanted to know if it possible with IM.
I would like to use C# version if possible.

[acpaps]

Is it possible to get rid of the black color part that is outside of the image
here is the result i got (I am using IM7 for this result)

[fmw42]

What was your exact code? What is your IM version and platform? Why do you not answer this question?

Please read the top-most post in this forum at viewtopic.php?f=1&t=9620.


What do you get from

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convert -version

Your output should be transparent. If you tried to save as JPG, then that is the issue. JPG does not support transparency. Use PNG or TIFF.