Pass Mouse Click to Group Parent
This example shows how a group of objects can pass a mouse click to a parent, which operates on all objects in the group.
Objective and Design
Suppose you want a single mouse click on any member of a group of objects to execute a single button down callback affecting all objects in the group.
Define the graphics objects to be added to the group.
hggroupobject as the parent of the graphics objects.
Define a function to execute when any of the objects are clicked. Assign its function handle to the
HitTestproperty of every object in the group to
offso that the mouse click is passed to the object’s parent.
Object Hierarchy and Key Properties
This example uses the following object hierarchy.
Create a file with two functions:
pickPatch— The main function that creates the graphics objects.
groupCB— The local function for the
pickPatch function creates three patch objects and parents
them to an
hggroup object. Setting the
HitTest property of each
patch to off directs mouse clicks to the parent.
function pickPatch figure x = [0 1 2]; y = [0 1 0]; hGroup = hggroup('ButtonDownFcn',@groupCB); patch(x,y,'b',... 'Parent',hGroup,... 'HitTest','off') patch(x+2,y,'b',... 'Parent',hGroup,... 'HitTest','off') patch(x+3,y,'b',... 'Parent',hGroup,... 'HitTest','off') end
groupCB callback operates on all objects contained in the
groupCB function uses the
callback source argument passed to the callback (
src) to obtain the
handles of the patch objects.
Using the callback source argument (which is the handle to
hggroup object) eliminates the need to create global data or
pass additional arguments to the callback.
A left-click on any patch changes the face color of all three patches to a random RGB color value.
function groupCB(src,~) s = src.Children; set(s,'FaceColor',rand(1,3)) end
For more information on callback functions, see Create Callbacks for Graphics Objects