B4R Question Is there a StringBuilder library for B4R?

[Robert Gately]

Where is the StringBuilder library download? I searched but could not find it. Thanks

 

[derez]

Read this https://www.b4x.com/android/forum/threads/strings-and-bytes.66729/

 

[Erel]

What do you need it for?

 

[Robert Gately]

What do you need it for?

I was looking at this example: Utilizzo di StringBuilder ? ...and it looked like they were using a StringBuilder library.

I was looking for a way to convert 256 numbers into RGB colors. Not sure that I need StringBuilder any more, since I decided to make a simple 24 color lookup table.

Also, I was hoping to store the lookup table in ProgMem but couldn't get it to save RGB hex numbers.

 

[Robert Gately]

Read this https://www.b4x.com/android/forum/threads/strings-and-bytes.66729/

I will study this page to see what I can learn from it. Thank you.

 

[Cableguy]

Remember that in B4R it is not a good idea using variable length strings, since they need to have memory allocated

See here
https://www.b4x.com/android/forum/threads/strings-and-bytes.66729/#content

 

[Robert Gately]

Remember that in B4R it is not a good idea using variable length strings, since they need to have memory allocated

See here
https://www.b4x.com/android/forum/threads/strings-and-bytes.66729/#content

Yes. So far, I have not used strings and probably won't ever need to. Thanks

 

[miker2069]

Are you looking to convert a number array to a string (i.e. Array of Int(100,200,300)) to "100,200,300"? What's it need to look like.

 

[Robert Gately]

Are you looking to convert a number array to a string (i.e. Array of Int(100,200,300)) to "100,200,300"? What's it need to look like.

Strings aren't that important to me after all. I was looking at some example string code that looked helpful.

Ideally, I'd like a routine that can convert a byte into 256 RGB values. It can be decimal: 255,255,255 or it can be hex: 0xffffff.

I'm working with a strip of 60 WS2812b LEDs. The LEDs expect the RGB format, like:"setled(ledNum,125,250,0). But the sensor data is in bytes and the 256 values need to be converted to spread evenly across the much larger range of RGB values.

Since I wasn't getting anywhere with conversion, I made a Select/Case routine that maps the 256 byte values to 24 colors in the RGB format. It is probably all the colors I need for my particular color scheme (Red, Magenta, Blue, Cyan, Green, Yellow and 3 colors in between them).

I'd be happy to use hex values (0xffffff) and convert them into RGB format, especially if they could be saved to ProgMem. I couldn't figure out how to do it with those large hex values.

If nothing better comes along, I'm happy with the 24 color look-up table. If you have something that you think might be helpful, please share. Otherwise, I'm happy to proceed with what I've got.

Thanks

 

[Erel]

Avoid using strings if you can.

You can store RGB values in long variables or as arrays of three bytes. Use GlobalStore or Queue or Stack to store those arrays.
[module] GlobalStore - Global objects storage

 

[Robert Gately]

Avoid using strings if you can.

You can store RGB values in long variables or as arrays of three bytes. Use GlobalStore or Queue or Stack to store those arrays.
[module] GlobalStore - Global objects storage

Thanks for the help! When you say "arrays of three bytes", do you mean 3 dimensional array?

I'm also trying to decipher this Arduino code that I used a few years ago...

// Input a value of 0 to 255 to get a color value. The colors are a transition r - g - b - back to r.
uint32_t Wheel(byte WheelPos) {
  //if (debugPrint==1) {Serial.println("Wheel");}
  if(WheelPos < 85) {
   return strip1.Color(WheelPos * 3, 255 - WheelPos * 3, 0);
  } else if(WheelPos < 170) {
   WheelPos -= 85;
   return strip1.Color(255 - WheelPos * 3, 0, WheelPos * 3);
  } else {
   WheelPos -= 170;
   return strip1.Color(0, WheelPos * 3, 255 - WheelPos * 3);
  }
}

Sorry if I'm off topic (strings) now.

 

[Robert Gately]

I was able to rewrite the Arduino code and it works perfectly. 0 - 255 produces a smooth rainbow transition through all of the colors. I don't need a look-up table anymore.

Erel, would you like me to polish this up and post it in the code snippet section?

Private Sub ByteToRGB (Value As Byte) As ULong
      If Value< 85 Then
          Log(Value * 3, 255 - Value* 3, 0)
          Strip1.setColor(10, Value * 3, 255 - Value* 3, 0)
      Else If Value< 170 Then
          Value= Value-85
          Log(255 - Value* 3, 0, Value* 3)
          Strip1.setColor(10, 255 - Value* 3, 0, Value* 3)
      Else
          Value= Value- 170
          Log(0, Value* 3, 255 - Value* 3)
          Strip1.setColor(10, 0, Value* 3, 255 - Value* 3)
      End If
      Strip1.show
End Sub

Also, I'd like to delete this thread regarding StringBuilder, since it turned out to be why I thought I needed StringBuilder. It would just be misleading and annoying for anyone who was looking for information about StringBuilder.

 

[Erel]

Also, I'd like to delete this thread regarding StringBuilder, since it turned out to be why I thought I needed StringBuilder. It would just be misleading and annoying for anyone who was looking for information about StringBuilder.

It is important discussion. I prefer not to delete it.

Erel, would you like me to polish this up and post it in the code snippet section?

Sure. That will be useful.