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https://github.com/ricmoo/QRCode
QR code generation library in C, optimized for low-power devices, such as Arduino.
https://github.com/ricmoo/QRCode
arduino arduino-library qr-code qr-generator qrcode
Last synced: about 1 month ago
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QR code generation library in C, optimized for low-power devices, such as Arduino.
- Host: GitHub
- URL: https://github.com/ricmoo/QRCode
- Owner: ricmoo
- License: other
- Created: 2017-04-09T04:01:03.000Z (over 7 years ago)
- Default Branch: master
- Last Pushed: 2023-09-24T00:01:34.000Z (about 1 year ago)
- Last Synced: 2024-10-30T06:58:23.310Z (about 2 months ago)
- Topics: arduino, arduino-library, qr-code, qr-generator, qrcode
- Language: C++
- Homepage:
- Size: 40 KB
- Stars: 650
- Watchers: 36
- Forks: 204
- Open Issues: 35
-
Metadata Files:
- Readme: README.md
- License: LICENSE.txt
Awesome Lists containing this project
README
QRCode
======
A simple library for generating [QR codes](https://en.wikipedia.org/wiki/QR_code) in C,
optimized for processing and memory constrained systems.
**Features:**
- Stack-based (no heap necessary; but you can use heap if you want)
- Low-memory foot print (relatively)
- Compile-time stripping of unecessary logic and constants
- MIT License; do with this as you please
Installing
----------
To install this library, download and save it to your Arduino libraries directory.
Rename the directory to QRCode (if downloaded from GitHub, the filename may be
qrcode-master; library names may not contain the hyphen, so it must be renamed)
API
---
**Generate a QR Code**
```c
// The structure to manage the QR code
QRCode qrcode;
// Allocate a chunk of memory to store the QR code
uint8_t qrcodeBytes[qrcode_getBufferSize()];
qrcode_initText(&qrcode, qrcodeBytes, 3, ECC_LOW, "HELLO WORLD");
```
**Draw a QR Code**
How a QR code is used will vary greatly from project to project. For example:
- Display on an OLED screen (128x64 nicely supports 2 side-by-side version 3 QR codes)
- Print as a bitmap on a thermal printer
- Store as a BMP (or with a some extra work, possibly a PNG) on an SD card
The following example prints a QR code to the Serial Monitor (it likely will
not be scannable, but is just for demonstration purposes).
```c
for (uint8 y = 0; y < qrcode.size; y++) {
for (uint8 x = 0; x < qrcode.size; x++) {
if (qrcode_getModule(&qrcode, x, y) {
Serial.print("**");
} else {
Serial.print(" ");
}
}
Serial.print("\n");
}
```
What is Version, Error Correction and Mode?
-------------------------------------------
A QR code is composed of many little squares, called **modules**, which represent
encoded data, with additional error correction (allowing partially damaged QR
codes to still be read).
The **version** of a QR code is a number between 1 and 40 (inclusive), which indicates
the size of the QR code. The width and height of a QR code are always equal (it is
square) and are equal to `4 * version + 17`.
The level of **error correction** is a number between 0 and 3 (inclusive), or can be
one of the symbolic names ECC_LOW, ECC_MEDIUM, ECC_QUARTILE and ECC_HIGH. Higher
levels of error correction sacrifice data capacity, but allow a larger portion of
the QR code to be damaged or unreadable.
The **mode** of a QR code is determined by the data being encoded. Each mode is encoded
internally using a compact representation, so lower modes can contain more data.
- **NUMERIC:** numbers (`0-9`)
- **ALPHANUMERIC:** uppercase letters (`A-Z`), numbers (`0-9`), the space (` `), dollar sign (`$`), percent sign (`%`), asterisk (`*`), plus (`+`), minus (`-`), decimal point (`.`), slash (`/`) and colon (`:`).
- **BYTE:** any character
Data Capacities
---------------
Version
Size
Error Correction
Mode
Numeric
Alphanumeric
Byte
1
21 x 21
LOW412517
MEDIUM342014
QUARTILE271611
HIGH17107
2
25 x 25
LOW774732
MEDIUM633826
QUARTILE482920
HIGH342014
3
29 x 29
LOW1277753
MEDIUM1016142
QUARTILE774732
HIGH583524
4
33 x 33
LOW18711478
MEDIUM1499062
QUARTILE1116746
HIGH825034
5
37 x 37
LOW255154106
MEDIUM20212284
QUARTILE1448760
HIGH1066444
6
41 x 41
LOW322195134
MEDIUM255154106
QUARTILE17810874
HIGH1398458
7
45 x 45
LOW370224154
MEDIUM293178122
QUARTILE20712586
HIGH1549364
8
49 x 49
LOW461279192
MEDIUM365221152
QUARTILE259157108
HIGH20212284
9
53 x 53
LOW552335230
MEDIUM432262180
QUARTILE312189130
HIGH23514398
10
57 x 57
LOW652395271
MEDIUM513311213
QUARTILE364221151
HIGH288174119
11
61 x 61
LOW772468321
MEDIUM604366251
QUARTILE427259177
HIGH331200137
12
65 x 65
LOW883535367
MEDIUM691419287
QUARTILE489296203
HIGH374227155
13
69 x 69
LOW1022619425
MEDIUM796483331
QUARTILE580352241
HIGH427259177
14
73 x 73
LOW1101667458
MEDIUM871528362
QUARTILE621376258
HIGH468283194
15
77 x 77
LOW1250758520
MEDIUM991600412
QUARTILE703426292
HIGH530321220
16
81 x 81
LOW1408854586
MEDIUM1082656450
QUARTILE775470322
HIGH602365250
17
85 x 85
LOW1548938644
MEDIUM1212734504
QUARTILE876531364
HIGH674408280
18
89 x 89
LOW17251046718
MEDIUM1346816560
QUARTILE948574394
HIGH746452310
19
93 x 93
LOW19031153792
MEDIUM1500909624
QUARTILE1063644442
HIGH813493338
20
97 x 97
LOW20611249858
MEDIUM1600970666
QUARTILE1159702482
HIGH919557382
21
101 x 101
LOW22321352929
MEDIUM17081035711
QUARTILE1224742509
HIGH969587403
22
105 x 105
LOW240914601003
MEDIUM18721134779
QUARTILE1358823565
HIGH1056640439
23
109 x 109
LOW262015881091
MEDIUM20591248857
QUARTILE1468890611
HIGH1108672461
24
113 x 113
LOW281217041171
MEDIUM21881326911
QUARTILE1588963661
HIGH1228744511
25
117 x 117
LOW305718531273
MEDIUM23951451997
QUARTILE17181041715
HIGH1286779535
26
121 x 121
LOW328319901367
MEDIUM254415421059
QUARTILE18041094751
HIGH1425864593
27
125 x 125
LOW351721321465
MEDIUM270116371125
QUARTILE19331172805
HIGH1501910625
28
129 x 129
LOW366922231528
MEDIUM285717321190
QUARTILE20851263868
HIGH1581958658
29
133 x 133
LOW390923691628
MEDIUM303518391264
QUARTILE21811322908
HIGH16771016698
30
137 x 137
LOW415825201732
MEDIUM328919941370
QUARTILE23581429982
HIGH17821080742
31
141 x 141
LOW441726771840
MEDIUM348621131452
QUARTILE247314991030
HIGH18971150790
32
145 x 145
LOW468628401952
MEDIUM369322381538
QUARTILE267016181112
HIGH20221226842
33
149 x 149
LOW496530092068
MEDIUM390923691628
QUARTILE280517001168
HIGH21571307898
34
153 x 153
LOW525331832188
MEDIUM413425061722
QUARTILE294917871228
HIGH23011394958
35
157 x 157
LOW552933512303
MEDIUM434326321809
QUARTILE308118671283
HIGH23611431983
36
161 x 161
LOW583635372431
MEDIUM458827801911
QUARTILE324419661351
HIGH252415301051
37
165 x 165
LOW615337292563
MEDIUM477528941989
QUARTILE341720711423
HIGH262515911093
38
169 x 169
LOW647939272699
MEDIUM503930542099
QUARTILE359921811499
HIGH273516581139
39
173 x 173
LOW674340872809
MEDIUM531332202213
QUARTILE379122981579
HIGH292717741219
40
177 x 177
LOW708942962953
MEDIUM559633912331
QUARTILE399324201663
HIGH305718521273
Special Thanks
--------------
A HUGE thank you to [Project Nayuki](https://www.nayuki.io/) for the
[QR code C++ library](https://github.com/nayuki/QR-Code-generator/tree/master/cpp)
which was critical in development of this library.
License
-------
MIT License.