An adjuster and response handler element that lets the subject adjust properties of other elements by clicking and dragging the mouse cursor on screen like a slider. Or you can use property move to adjust the position of another element by clicking and dragging the element. One mouse button adjusts and the other says "done adjusting". Note mouseAdjuster elements may not work with trackpad taps.

Response values generated are adjusted property value(s).

"Ends on its own" means ends automatically at that point. If an element can end on its own, you don't need to set end conditions for it in property end (unless you want it to maybe end earlier).

drag_x
drag_y
drag_xy

No defaults

Properties = <cd>true<cd>/<cd>false<cd> setting adjustment mode. Set ONE of these = <cd>true<cd>:

drag_x = <cd>true<cd>: Subject adjusts by dragging the mouse cursor horizontally. Adjustment value is a number per distance dragged—see deltaRate below.

drag_y = <cd>true<cd>: Same but vertically.

drag_xy = <cd>true<cd>: Subject adjusts by dragging the mouse cursor in both dimensions. Adjustment value is a 1×2 vector per distance dragged (so typically the target you set in adjust.target must be a 1×2 vector).

deltaRate

No default

A number that is adjustment to apply per distance dragged on screen. By default distance on screen is in deg, as usual. Magnitude of adjustment is magnitude of deltaRate × distance dragged. Positive deltaRate = positive adjustment when dragging right/up, negative adjustment when dragging left/down. And negative deltaRate means the opposite. (Note since this is for the subject, it follows the general convention up = +, not standard screen coordinate convention down = +.)

e.g.
drag_x = <cd>true<cd>
deltaRate = +0.5
→ +0.5/deg dragging right, −0.5/deg dragging left

If drag_xy = <cd>true<cd> then deltaRate can also be a 1×2 vector for different rates for [x y].

Use adjust to set where and how adjustments are applied.

deltaIncrement

Default: apply adjustments of any magnitude

By default drag applies adjustments of any magnitude. However, some element properties can only receive adjustments that are multiples of some increment. e.g. a property that must be an integer can only receive adjustments that are integers (multiples of 1). If so, you can set increment here (a number > 0). The adjuster will apply adjustments in multiples of that. If drag_xy = <cd>true<cd> then deltaIncrement can also be a 1×2 vector for different increments for [x y]. 0 = apply adjustments of any magnitude.

clickAreaSize

‍Default: click anywhere to drag

Size of the area on screen that the subject can click in to start a drag. This is a number that is side length for a square, or a vector [width height] for a rectangle (deg). Or the number <cd>inf<cd> = click anywhere. Click area is centered at element position, which you can set in property position (default relative to screen center).

move

Default: <cd>false<cd>

<cd>true<cd>/<cd>false<cd>: special mode to adjust target element position on screen by clicking & dragging the element. If = <cd>true<cd>:

• ‍adjust.target must point to property position (e.g. <cds>"<element>.position"<cds>, or <cds>"<element>.position{1}"<cds> if you use a distance unit other than deg), or at least part of position.
• drag_x/drag_y/drag_xy above apply as usual. drag_x and drag_y send adjustments that are single numbers, so if using one of them, typically set target to the corresponding position dimension (e.g. drag_y = <cd>true<cd> → target = <cds>"<element>.position(2)"<cds>). drag_xy sends adjustments that are 1×2 vectors, so if using it, typically set target to the whole position, i.e. move in both dimensions.
• deltaRate, deltaIncrement, clickAreaSize above are ignored.

n_dragButton

Default: button 1 drags; all other buttons input done adjusting

A number or vector that is mouse button number(s) to click to drag. For all other buttons a click means the subject is done adjusting (i.e. the response).

cursorShape

Default: hand

A string or number setting mouse cursor shape. This goes to the type input of Psychtoolbox ShowCursor—see there for more information. Standard options are:

<cds>"Arrow"<cds>
<cds>"CrossHair"<cds>
<cds>"Hand"<cds>
<cds>"SandClock"<cds>
<cds>"TextCursor"<cds>

(None)