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Motion · 17 Drag Coordinates and Bounds
Series contents · Technology map
Stage: Gestures and Equivalent Interaction · Editable example · Storage ID: motion-step-17
Goals and learning outcomes
- Learning outcome: Explain the role of Drag. Input case: Moving beyond the left and right bounds.
- Deliverable: A table of final x values and container widths. Connect your rationale for handling Constraints to the code.
Prerequisites
Prepare the results of the Pressed state and Functional events exercises from Unit 16, “Tap Feedback”.
Key concepts and explanations
Drag
drag connects pointer movement to coordinate changes. Restricting movement to the x axis is distinct from movement along y.
Constraints
Bounds define the draggable range. A ref-based range is useful in a responsive container.
Practice setup
First check the execution scope guidance on the example screen. The following describes the environment needed to extend the assignment in a separate project. The existing motion-01·02·03 examples are limited examples based on Motion JS animate. For React layout, AnimatePresence, and hooks exercises, install motion in a separate local React project and import from motion/react. Do not assume JSX runs directly in the editor; preserve CSP and isolation.
The linked example is a starting point. It does not implement every task below. Complete work beyond its supported scope in a separate project.
Practice tasks
- In src/day-17.tsx of a separate exercise project, set drag=x and a dragConstraints ref. Use the existing Unit 1·14·28 examples only as starting points.
- Input condition: Moving beyond the left and right bounds. Baseline: 500px. Run under the baseline condition, then record observations and errors in notes/day-17.md.
- Variable to change: Container width; new value: 280px. Run again with the same input path. Deliverable to save: A table of final x values and container widths. Hypothesis to test: The card stays within the new bounds. Compare it with the actual results and record whether they agree and the causes of any differences.
Variables to observe
| Variable | Baseline | Change | Expected change / hypothesis |
|---|---|---|---|
| Container width | 500px | 280px | The card stays within the new bounds. |
Predictions in this table are not measured results. Change one condition at a time and record why the actual result differs.
Completion criteria
- Required deliverable: A table of final x values and container widths. You have results for both the baseline and changed conditions, allowing a comparison of 2 conditions, and have recorded the input values and execution environment.
- Your explanation of the differences between the two conditions connects both concepts: Drag and Constraints. For unexpected items, give at least 1 cause or reason they remain unresolved.
Self-check
- Which processing stage does Drag affect in this exercise? Input case: Moving beyond the left and right bounds.
- Variable to change: Container width. Hypothesis to test: The card stays within the new bounds. Did the actual results agree with the hypothesis? Explain your evidence in terms of Constraints.
Official references
Linked example and execution scope
Example source · Runtime environments and limits
Interactive Drag Coordinates and Bounds experiment with cleanup of the resources used.
Source code and records are not overwritten automatically. Resetting an existing example also preserves your notes.