How to make rectangle rotatable

function drag_drop

dragging = [];

orPos = [];

f = figure('WindowButtonUpFcn',@dropObject,'units','normalized','WindowButtonMotionFcn',@moveObject);

tmp = text(0.35,0.35,'Room','VerticalAlignment','bottom');

a = rectangle('position',[0.35, 0.35, 0.35, 0.35],'FaceColor','w','ButtonDownFcn',@dragObject,'UserData',tmp);

tmp = text(0.1,0.1,'StudyTable','VerticalAlignment','bottom');

b = rectangle('position',[0.1, 0.1, 0.1, 0.1],'FaceColor','y','ButtonDownFcn',@dragObject,'UserData',tmp);

tmp = text(0.1,0.1,'CoffeeTable','VerticalAlignment','bottom');

c = rectangle('position',[0.1, 0.1, 0.1, 0.1],'FaceColor','y','ButtonDownFcn',@dragObject,'UserData',tmp);

set(gca,'XLim',[0,1],'YLim',[0,1])

function dragObject(hObject,eventdata)

dragging = hObject;

orPos = get(gcf,'CurrentPoint');

end

function dropObject(hObject,eventdata)

if ~isempty(dragging)

newPos = get(gcf,'CurrentPoint');

posDiff = newPos - orPos;

rectpos = get(dragging,'Position') + [posDiff(1:2) 0 0];

set(dragging,'Position',rectpos);

set(dragging.UserData,'Position',rectpos(1:3));

dragging = [];

end

end

function moveObject(hObject,eventdata)

if ~isempty(dragging)

newPos = get(gcf,'CurrentPoint');

posDiff = newPos - orPos;

orPos = newPos;

rectpos = get(dragging,'Position') + [posDiff(1:2) 0 0];

set(dragging,'Position',rectpos);

set(dragging.UserData,'Position',rectpos(1:3));

end

end

end

I am making a drag and drop function for a floor planner. So far ive been able to drag and drop successfully (code above), but how do i make the rectangles (Studytable, coffeetable, room) to be rotatable??

Answer 1

[Anudeep Kumar]

Hey Axel,

I understand you want to rotate rectangles you plotted on your interactive figure for a floor planner you were trying to develop. As far as my knowledge 'rectangle' function does not support rotation. But the workaround is to use 'patch' or 'hgtransform'.

To achieve this using 'patches' in the following approach we can make the following changes:

• Replaced 'rectangle' with 'patch'
• Added rotation with 'r' key using rotation matrices

Below is the code with the changes.

function drag_drop
    dragging = [];
    orPos = [];
    selected = [];
    f = figure('WindowButtonUpFcn', @dropObject, ...
               'WindowButtonMotionFcn', @moveObject, ...
               'KeyPressFcn', @rotateObject, ...
               'units', 'normalized');

    axis([0 1 0 1]);
    axis manual;

    % Create three draggable & rotatable patches
    createObject([0.35, 0.35], [0.35, 0.35], 'Room', 'w');
    createObject([0.1, 0.1], [0.1, 0.1], 'StudyTable', 'y');
    createObject([0.25, 0.1], [0.1, 0.1], 'CoffeeTable', 'y');

    function createObject(pos, size, label, color)
        x = pos(1); y = pos(2); w = size(1); h = size(2);
        verts = [x y;
                 x+w y;
                 x+w y+h;
                 x y+h];
        p = patch('XData', verts(:,1), 'YData', verts(:,2), ...
                  'FaceColor', color, 'ButtonDownFcn', @dragObject);
        txt = text(x + w/2, y + h/2, label, ...
                   'HorizontalAlignment', 'center', ...
                   'VerticalAlignment', 'middle');
        % Store original data
        p.UserData = struct('Text', txt, ...
                            'Rotation', 0, ...
                            'Center', [x + w/2, y + h/2]);
    end

    function dragObject(hObject, ~)
        dragging = hObject;
        selected = hObject;
        orPos = get(gca, 'CurrentPoint');
    end

    function dropObject(~, ~)
        dragging = [];
    end

    function moveObject(~, ~)
        if isempty(dragging), return; end
        newPos = get(gca, 'CurrentPoint');
        diff = newPos(1,1:2) - orPos(1,1:2);
        orPos = newPos;

        % Move vertices
        x = get(dragging, 'XData') + diff(1);
        y = get(dragging, 'YData') + diff(2);
        set(dragging, 'XData', x, 'YData', y);

        % Move text
        userData = dragging.UserData;
        newCenter = userData.Center + diff;
        userData.Center = newCenter;
        set(userData.Text, 'Position', newCenter);

        dragging.UserData = userData;
    end

    function rotateObject(~, event)
        if isempty(selected), return; end
        if strcmp(event.Key, 'r')
            % Rotate 15 degrees
            rotatePatch(selected, 15);
        end
    end

    function rotatePatch(patchObj, angle)
        userData = patchObj.UserData;
        theta = deg2rad(angle);
        R = [cos(theta), -sin(theta); sin(theta), cos(theta)];

        % Rotate around center
        x = get(patchObj, 'XData')'; x = x(:);
        y = get(patchObj, 'YData')'; y = y(:);
        vertices = [x y];
        center = userData.Center;

        centered = vertices - center;
        rotated = (R * centered')';
        newVerts = rotated + center;

        % Apply new vertices
        set(patchObj, 'XData', newVerts(:,1), 'YData', newVerts(:,2));
        set(userData.Text, 'Position', mean(newVerts,1));
        userData.Rotation = mod(userData.Rotation + angle, 360);
        patchObj.UserData = userData;
    end
end

Here are some MATLAB Answer link discussing rotation of rectangle:

https://www.mathworks.com/matlabcentral/answers/506239-how-to-rotate-a-rectangle

https://www.mathworks.com/matlabcentral/answers/1687249-how-to-rotate-rectangle

Here is the documentation of 'patches' and 'hgtransform' for your reference:

https://www.mathworks.com/help/releases/R2024b/matlab/ref/patch.html

https://www.mathworks.com/help/releases/R2024b/matlab/ref/hgtransform.html