# Image distortion App_Inventor vs Cell phone screen

The X and Y values…(and the Radius for size), you organise the coordinates (X,Y) in relation to the canvas size

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Dear @TIMAI2
The coordinates move automatically when I position the ball.
I prefer to send the link QR to see if you can check it

I can’t use that qrcode, this is for use locally on your computer/device.

@TIMAI2
Thanks in advance for the support, … actually I have done all this in Excel, but not everyone has immediate access to use it, it is more useful directly from the cell phone.
This is for people to make good decisions regarding COVID-19 symptoms and to go to the hospital depending on the situation they are in.
I suggest seeing my excel file first.

Excel
My Excel file

AppInvetor
FFCOVID19.aia (107.8 KB)

(Never mind, I found the hidden sheet tabla)

An interesting app.

I did not know arithmetic constant blocks (blue) could be empty.
Have you run your sum procedure successfully against empty text values?

the truth, I don’t know much about this but, you are right the observations that you give me

in case the summation of blank input gives you trouble, here are two revised procedures to handle that …

They are draggable, directly from this post into your Blocks Editor window.

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It is probably easier if I provide an example, you will have to do some maths, and apply it to your project.

Wow!!
I did not know it...!!
that good...
But from my block editor windows to this answer page I don't see what can be done, .. however you have done it ..

On the other hand, in the NZ procedure, why should you ask if it is a number when we know that a number is going to be put ...
Not that we should say yes, it is a number .. "value"

This is an example of bulletproofing, where you want to gracefully handle something unexpected.
The ‘+’ blocks are fragile, and will choke on blank input.
I assume the worst when handling user input.

To start off with, we use a canvas of fixed size, to get out reference points
In this image,

• the canvas is set to 300x300 pixels
• the ball has a radius of 10 - (10x10 pixels)
• the balls coordinates are X = 50, Y = 127
• the ball is set to “origin at center”
• we must assume that the canvas always maintains its aspect ratio

the radius is therefore 1/30th of the canvas size (0.033)
we only have one dimension for the radius, therefore
use the width

Whatever the canvas width, we can define the radius of the ball

the balls X coordinate, in relation to the canvas is
50 / 300 (width) = 0.167
therefore the X coordinate is always 16.7% of the canvas width

Whatever the canvas width is, we can define the X coordinate of the ball

the balls Y coordinate, in relation to the canvas is
127 / 300 (height) = 0.423
therefore the Y coordinate is always 42.3% of the canvas height

Whatever the canvas height is, we can define the Y coordinate of the ball

In this way, you can set the relative / proportional positions for your ball sprites based upon the canvas size. As I previously mentioned, you may need to use a clock timer to set all the positions, as it can take a few milliseconds for the canvas to work out what its width and height is.

Dear
@TIMAI2 a and @ABG and SteveJG
Thanks for the support, he tried to continue understanding the thing about the fixed coordinates for the balls … but I think that the dimensions of the horizontal and vertical designs have not adjusted as I have explained. all right …
Until then I have advanced in the design and I have selected buttons to increase or decrease the varlor when you select a text box to avoid using the keyboard … even so the keyboard continues to appear …
I upload the file to see the progress

Thank you for helping me complete this application, then I will send people from my town

FFCOVID19.aia (122.3 KB)

I could not stop the keyboards from popping up, so I disabled all textboxes and used the balls as textbox selectors, with a clock to blink the appropriate ball.

I introduced global variables to hold the current textbox component and ball component.

I also change Label1.Text to name the text box currently selected, from its Hint.
(I leave it to you to set the Hints for the 10 textboxes in the Designer, it’s tedious.)
The + and - buttons are now the only way to change the text box contents.

Generics, lists, and value procedures shrink the app considerably.

FFCOVID19V2.aia (112.1 KB)

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Greetings, I have been reviewing and making adjustments. Sounds great to me, just as you designed it. For this reason, I have realized that it would be better to use Labels instead of Textbox.
But I have a problem, I can’t find the Labels blocks that have the word “of component” in their structure
I would like you to help me making that block for me to replace it in all the places that are the Textbox.
Sorry for the inconvenience

You need to have at least one component of the desired type in the Designer.
There are two ways to get a generic component block …

• Look in the Blocks Pallette, under the component blocks, for a separate branch of Any blocks.
• Pull out a specific block for the component type you want, and right click on it. Select the Make Generic option.
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Greetings dear @ABG , I am sorry to say that because it is more useful in this case, the use of labels to avoid the keyboard … I have changed all labels for Textboxes. But I don’t understand why it doesn’t increase the values ​​with the + - buttons
there it gives me error …
Please hope this is the last thing that can bother you …
Could you take a look at the file?

FFCOVID19 V3.aia (112.7 KB)

It turns out that setting a background color to a deactivated color block crashes the Companion.
Here’s how far I got it running …
Your screen does not fit into the stock AI2 emulator, which I used.
FFCOVID19V4.aia (109.7 KB)

I had to make the balls big and green to see them.

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Dear friend @ABG
I want to express my sincere thanks. I send you the final application as I am going to send it to the people of my town.
So far I have not been able to attach an icon to Ai2 applications, but with this I am satisfied.

Thanks once again

Aquí está la aplicación:

FFCOVID19V4

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