how to plot rectangles on characters of an image in gui?

Question

malek el pikho 2014-4-20

回答： Image Analyst 2014-4-20

in the calback i wrote img=imread(..... axes(handles.axes1) imshow(img) hold on; X=mat{j}.X;%coordines of the rectangle Y=mat{j}.Y;

plot(X,Y,'r+'); hold on; plot(X,Y,'r'); plot([X(length(X)) X(1)],[Y(length(Y)) Y(1)],'r');

but i had no rectangle

Answer 1

Image Analyst 2014-4-20

Assuming that X and Y are the coordinates of the 5 corners, try

plot(X,Y,'r+-');

instead of all those other plots. If X and Y are just 2 elements long like the left/right or top/bottom, do

xBox = [X(1), X(2), X(2), X(1), X(1)]; % 5 corners of the box.
yBox = [Y(1), Y(1), Y(2), Y(2), Y(1)]; % 5 Corners of the box.
plot(X,Y,'r+-');