Matlab: Click mouse points on an image

	classdef GuiImagePointClicker < handle
	%GuiImagePointClicker Point selection on an image with the ability
	% to delete points using backspace.
	%
	%
	% EXAMPLE
	% I = load('gatlin');
	% mygui = GuiImagePointClicker(I.X./max(I.X(:)));
	% mygui.x
	% mygui.y
	%
	properties(SetAccess = private)
	x = [];
	y = [];
	I = [];
	imh = 0;
	fh = 0;
	ptHandles = [];
	end
	methods
	function obj = GuiImagePointClicker(I)
	obj.init();
	obj.I = I;
	obj.getPoints();
	end
	function init(obj)
	obj.I = [];
	obj.x = [];
	obj.y = [];
	obj.imh = 0;
	obj.fh = 0;
	obj.ptHandles = [];
	end
	function getPoints(obj)
	% show image
	obj.fh = figure();
	obj.imh = imshow(obj.I);
	hold on;
	fprintf(1, ['\n\nPress mouse to put points.\n', ...
	'Enter on the figure to finish and backspace to ', ...
	'remove last point.\n\n']);
	% set callback function for keyboard press
	set(obj.fh, 'KeyPressFcn', ...
	@(s,e) obj.callback_keyPressFcn(s,e) );
	% set callback function for mouse press
	set(obj.imh, 'ButtonDownFcn', ...
	@(s,e) obj.callback_mousePressFcn(s,e) );
	end
	function callback_mousePressFcn(obj, hObject, ~)
	% get position of mouse click
	imaxis = get(hObject,'parent');
	point = get(imaxis,'currentpoint');
	x = point(1,1);
	y = point(1,2);
	% save it
	obj.x(end + 1) = x;
	obj.y(end + 1) = y;
	% show the click points
	obj.showPoints();
	end
	function callback_keyPressFcn(obj, hObject, evnt)
	pressedKey = evnt.Key;
	switch pressedKey
	case 'backspace'
	obj.deleteOnePoint();
	case 'return'
	obj.closeFigure();
	end
	end
	function deleteOnePoint(obj)
	numPoints = numel(obj.x);
	if numPoints < 1
	disp('No points to delete');
	return;
	end
	% remove last point
	obj.x(end) = [];
	obj.y(end) = [];
	% redraw points
	obj.showPoints();
	end
	function closeFigure(obj)
	disp('finished.');
	close(obj.fh);
	end
	function showPoints(obj)
	%first delete all points and than redraw them
	arrayfun(@delete, obj.ptHandles);
	obj.ptHandles = [];
	% redraw points
	for pi = 1:numel(obj.x)
	x = obj.x(pi);
	y = obj.y(pi);
	ph = plot(x, y, 'or', ...
	'MarkerFaceColor', 'red', ...
	'MarkerSize', 6);
	obj.ptHandles(end+1) = ph;
	end
	end
	end
	end

view raw GuiImagePointClicker.m hosted with ❤ by GitHub