This is part of a work in progress for a user on the MIT App Inventor forum.
But it is develped enough to demonstrate that a Canvas can be dragged.
Also shown is how the Canvas can be both wider than and taller than the device screen.
The nesting of the Canvas inside a set of screen arrangements as follows allows the Canvas to be positioned exactly:
A vertical screen arrangement is a container for...
A vertical screen arrangment that acts as a spacer to move the Horizontal Arrangement below it up and down by adjusting the arrangment's Height
A horizontal screen arrangment that contains:
A horizontal Arrangement spacer that pushes the Canvas to it's right left and right by adjusting the arrangement's Width
A Canvas
When the user drags a finger on the Canvas, the Canvas Dragged event block uses the prevX, prevY and currentX, currentY values to adjust the screen arrangement width and height spacers and move the Canvas.
![](https://lh3.googleusercontent.com/-E8fwup5HCf8/ViF73lTLuzI/AAAAAAAAN8U/sE_jkPFEN0M/s320/india2.png)
To test the dragging feature, touch the (+)-- magnifying glass on the main screen to zoom in, then drag the canvas.
Responsive sizing is used in this project as well.
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sf