Raster line iterator

[pos, count] = cv.LineIterator(img, pt1, pt2)
[...] = cv.LineIterator(..., 'OptionName',optionValue, ...)

Input

• img input image
• pt1 first point [x,y]
• pt2 second point [x,y]

Output

• pos pixel position coordinates [x,y] as a count-by-2 matrix
• count number of pixels along the line

Options

• Connectivity 8-connected or 4-connected. default 8
• LeftToRight default false

The function iterates over the line connecting pt1 and pt2. The line will be clipped on the image boundaries. The line is 8-connected or 4-connected. If LeftToRight=true, then the iteration is always done from the left-most point to the right most, not to depend on the ordering of pt1 and pt2 parameters.

The function is used to iterate over all the pixels on the raster line segment connecting two specified points.

The function cv.LineIterator is used to get each pixel of a raster line. It can be treated as versatile implementation of the Bresenham algorithm where you can stop at each pixel and do some extra processing, for example, grab pixel values along the line or draw a line with an effect (for example, with XOR operation).

The function cv.LineIterator returns the positions in the image, and the number of pixels along the line.

Example

img = imread(fullfile(mexopencv.root(),'test','fruits.jpg'));
pt1 = [10 15];    % 0-based
pt2 = [200 100];  % 0-based

% grabs pixels along the line (pt1, pt2) from 8-bit 3-channel image
[xy,num] = cv.LineIterator(img, pt1, pt2, 'Connectivity',8);
xy = xy + 1;  % 1-based subscripts
c = zeros(num, size(img,3), class(img));
for i=1:num
    c(i,:) = img(xy(i,2), xy(i,1), :);
end