Line in a matrix and differentiation between matrix indices.

How can I create a line in a matrix. Since I create it, how can I differentiate between the indices from the one side of the line with them of the other. What I am trying to do, is to create a shaped image. The shape can be a square, rhombus, etc. Thus, I want to set the values of the matrix that exist out of the shape to zero (or 255).

[Jan]

Please give us an example. Are you looking for a method to fill a region, which is defined by an edge with a specific value?

[Sotirios]

Yes I would like to fill in a region or more, in order to make visible only a specific part of the image. For instance, lets say I have an image with a matrix mat. Then I draw a line from mat(size(mat,2)/2,1) to mat(1,size(mat,1)/2). What I want to do next, is to fill the indices located on the left of the line with 0. Is this feasible?

Thank you.

Answer 1

[Image Analyst]

I have a number of masking demos and demos to burn things into images. For example, run the attached demos.

[Image Analyst]

Another demo. Evidently there is a 3 file attachment limit.

[Sotirios]

Thank you :) I guess that demo burn_overlay_into_image.m, can solve my problem.