MATLAB: Changing the pixel value of a region defined by its contour points

contour pointsfill imageImage Processing Toolboxregion

Hi everybody how can i change the pixel of an object to white given that i have only positions of contour's point of the object?

binaryMask = poly2mask(x, y, rows, columns); % Make solid binaryMask.
grayImage(binaryMask) = 255; % Fill inside the mask with white.

If you have the Image Processing Toolbox, you can use the poly2mask() function to do that

[rows, columns, numberOfColorChannels] = size(yourImage);
binaryMask = poly2mask(x, y, rows, columns);