uint8_t etc as color variable

Question

I am very new to coding and I am attempting to teach myself the best I can. I have no prior knowledge of coding and am filling in the blanks via YouTube and forums alike. One place I keep getting hung up on is what seems to be an unsigned integer.

I have tried to figure out how these work (assignment and such) to no avail. I was wondering if anyone could offer some insight for me or at the least a link that gets specific for the Arduino.

I see them used as uint8_t, uint16_t, and uint_32 in various places. Am I correct that it is an unsigned integer? Meaning it is a whole positive number only.

The code I have attached is from Adafruit's article on multi-tasking. I am trying to adapt my sketch for millis() over delay().

 uint32_t Color1, Color2; // What colors are in use
 uint16_t TotalSteps; // total number of steps in the pattern
 uint16_t Index; // current step within the pattern

For instance: on the variable declarations they use these for the color. I will need to change the colors, but have only seen them expressed in RGB. They are in every sketch I see, but I am struggling to answer this question on my own. Thanks in advance for any help.

Answer 1

If you search for information about C types on the internet, there will be much help to find, but effectively you are correct. One format of integer types in C take the form:

uint / int: Signed or unsigned integer. Unsigned integers are stored in simple binary representation, and signed integers are stored in two's complement form.

8 / 16 / 32 / 64: The number of bits to store the value. This means the number of possible values is 2^x where x is the number of bits.

_t: Simply a suffix to indicate that it is a type name, not a variable.

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Colour storage

Colours are generally stored as three components: red, green and blue (or sometimes four, adding alpha, the degree of transparency).

If each component is given an unsigned byte to be stored (so it has a value from 0–255), then the total colour size is 24 bits. However, 24 bit integers are not a standard size, so the next bigger size is selected, 32-bit. This also allows room for an alpha component if necessary, but otherwise the spare 8 bits are unused.

For example:

| 00000000 | 00000000 | 00000000 | 00000000 | = 32 bits
| red | green | blue |alpha/empty|

• Gixxerfool: Thank you so much for this. The breakdown helps to simplify it for me.

Answer 2

Everything about standard integer types is in <stdint.h>