Unable to lock an image and draggable point

Questions
1

Hello, I have a screen to help struggling students by allowing them to “drag steps” around a graph to walk them through multiplying 2 binomials. Activity
However, I’m struggling with a couple very basic issues. The first is that I can’t prevent students from selecting and resizing images (I want the images themselves to remain locked and only allow students to move them). The second is that I’m unable to lock the draggable points once the student has moved them to the correct spot. I’ve reviewed another discussion but can’t seem to translate into my screen:
Lock image: I’ve locked the image in the graph (edit graph, edit list “gear” and hit lock icon) and minimized the folder it is in, but still no luck. Looking at the CL on the graph in the activity from the above mentioned discussion, not finding anything about locking there, so not sure where to go.

Lock draggable point: Looking at the solution from the discussion of having a second point, I’m getting stuck when I make a point conditional on another variable (conditional point is supposed to be draggable, but when I add the condition (either inside or outside the parentheses) I lose the “dragability.”)

Surely locking an image while still leaving it draggable is dead simple, and there are sooo many old school manipulatives normally done on card stock cut-outs that could be so well done in Desmos. So I’d truly appreciate any advice there, and locking the point would be a nice bonus. Apologies for a third round on a similar topic.

2

Sorry all, just stumbled into realizing that to “lock” an image (prevent students from selecting and resizing), I had to hit the edit list “gear” then click the circle at the left of the entry and “disable graph interactions” (not sure what the big lock emblem on the right side of the entry does, but it captured my attention for quite a while… oops). Still curious on the second part of the question (draggable point with conditions).

3

Here is an example: locking moveable point • Activity Builder by Desmos Classroom

There are a couple of things to know here.

  • You can put all graphics into folders, and click “Hide this folder from students”. That will not hide the graphics but will prevent them from interacting with them. This is handy if you have multiple graphic elements.
  • You can have a draggable point disappear on a condition, without disabling draggability, as long as you put the condition just on one coordinate. So for example, define x1 and y1, have the condition be s_how = 1, and make the point P = (x1, y1 {s_how = 1}) instead of P = (x1, y1){s_how = 1}
  • But, if you make that the center of the image to move, you will have a problem, because when it disappears, so will the image. So you need to define a separate point, in terms of the same variables, that you will assign to the image. So if P is defined as above, I would make another point C = (x1, y1) and have that be the center of the image. When you move point P, it will update x1 and y1, so C will move to the same location, but when P becomes undefined, C will still be defined.
4

Also, if you want to play with manipulatives, have you checked out Polypad? It is now a component in Desmos Classroom. You can find/make just about any manipulative you need, and if you learn about the authoring tools, you can hook up CL exports to drop zones and such. Here’s an example of an open middle using polypad tiles.

5

Thanks, that’s perfect! Hiding the folder is much easier than disabling graph interactions on each and every image and the second point worked also. I guess since I was using a variable from the CL in the condition for the draggable point it showed an error when editing the graph (and I assumed it wouldn’t work), but everything works fine. Thanks so much for the help.

And good point on the polypad (since it’s made specifically for manipulatives). It will take some time to learn to be able to make even the most minor of tweaks to existing screens, but looks worth it. For now I’ll look for screens to use as is. Thanks again.

6

No problem. In case you didn’t know, CL overwrites values of variables with the same name. So you can define a variable in the graph and use it as you want, knowing that it will get the CL value when in an activity. Then you don’t have to worry about errors in the graph like that.

7

For what it’s worth, I don’t think this area of Demos/Amplify is developed well enough for most people to know about it or understand implementation.

Improved documentation here might be helpful for others.

8

Ah, I didn’t realize the CL values would take precedence, and yes, that would be helpful to see things when editing rather than having to be “in” the activity.

And good point @Mike_Gleeson . Don’t want to be guilty of what I sometimes get frustrated with my students for (questions without using the resources they have), but it does seem a little harder to find answers. Guess I just need to put in the time with the videos… just not sure when :slight_smile: