Saving Canvas to a file causes the screen layout to change

Bugs and Other Issues
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1

Hi,
I am a computer sciences teacher.
One of my students developed the attached app based on PaintPot.
After clicking btnDownload ("Download the image" - below the Wipe button) the first 2 rows of buttons (horizontal arrangements) disappeared.
I tested on 2 Android Phones - Galaxy S20FE and Galaxy A12) and the issue persisted in both.
Here is a link to the AIA file: https://drive.google.com/file/d/1U9gmFO43dBHXLIzldxDD5l91ef-kRam7/view?usp=sharing
Thank you

2

Confirmed on my BlueStacks emulator:
canvas save as

I looked for event blocks to blame, and found none.

blocks
blocks645Ɨ2896 173 KB

image
image1345Ɨ755 183 KB

3

I looked closely at the project in the Designer, and remembered a flash of a red error message when it first loaded.

The Table Arrangement looks fishy.

image
image471Ɨ530 64.2 KB

It's got 2 rows and 2 columns, but has 5 components hanging under it in the Components Tree pane. (2*2= 4, right, so how is that possible?)

I recommend nesting Horizontal and Vertical Arrangements as an alternative to using Table Arrangements, because they are internally complex and bug-prone.

Take backups (.aia exports) of this project before trying to replace that Table Arrangement. They get internally tangled under cut and paste operations.

Also, don't mix pixel counts with proportions with automatic sizes. The AI2 component sizing algorithm is a free for all fight for space on the Screen at run time. Pixel counts are unpredictable if the screen is set responsive, because you won't know how many pixels fit on the screen.

Canvas sizes take a moment to calculate, and are unreliable in Screen1.Initialize.

4

I did a little surgery on Screen1.scm, changing TableArrangement2 to a VerticalArrangement in 7zip. That got all 5 Arrangement subcomponents showing (after setting Screen1 scrollable), but it did not eliminate the error of the top 2 Horizontal Arrangements disappearing.
canvas save as

5

Setting the top 2 Horizontal Arrangements to 10% Height did not save them from disappearing after the Canvas Save.
canvas save as

6

Caging the lion (Canvas) in a Vertical Arrangement saved the upper Horizontal Arrangements from being eaten after a Canvas Save.

image
image269Ɨ537 33.3 KB

canvas save as caged the lion
PaintPot2.aia (44.2 KB)

Good fences make good neighbors in AI2 Screen Design.

I did not look in the other Screens for the transitory red loading warning.

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