initial version

README.md

@@ -1,2 +1,90 @@
 # flipperzero-qrcode
-Display qrcodes on the Flipper Zero
+Display qrcodes on the [Flipper Zero]
+
+## Building
+First, clone the [flipperzero-firmware] repo and then clone this repo in the
+`applications_user` directory:
+
+```bash
+git clone git@github.com:flipperdevices/flipperzero-firmware.git
+cd flipperzero-firmware/applications_user
+git clone git@github.com:bmatcuk/flipperzero-qrcode.git
+```
+
+Next, in the base of the [flipperzero-firmware] directory, run fbt:
+
+```bash
+cd ..
+./fbt fap_qrcode
+```
+
+This will automatically install dependencies and build the application. When it
+has finished building, the .fap will be in
+`build/f7-firmware-D/.extapps/qrcode.fap` (fbt output will tell you where to
+find the .fap, should it change in the future).
+
+## Installation
+Copy the `qrcode.fap` file onto your [Flipper Zero] sd card in the `apps/Tools`
+directory. Then create a top level directory called `qrcodes` to store your
+qrcode files.
+
+## Creating QR Codes
+qrcode files are simple text files with the extension .qrcode. This app will
+expect them to live in a top-level directory on your sd card called `qrcodes`.
+They should have the following content:
+
+```
+Filetype: QRCode
+Version: 0
+Message: your content here
+```
+
+### Message Format
+qrcodes support 4 formats called "modes": numeric, alpha-numeric, binary, and
+kanji. Because of the limited screen real-estate on the [Flipper Zero], you'll
+want to pick the best mode for the data you are trying to display.
+
+The app will automatically detect the best mode to use, so the only thing you
+need to do is make sure the message in your file is formatted to use the best
+mode. For example, if your message is entirely numeric, make sure you don't
+include any extraneous punctuation in your file. If you're only encoding a
+domain name, make sure it's uppercase to take advantage of alpha-numeric mode,
+etc.
+
+#### Numeric Mode
+Consists of only numbers, nothing else. This mode can encode the most data.
+
+#### Alpha-Numeric Mode
+This mode can encode numbers, uppercase letters *only*, spaces, and the
+following symbols: `$%*+-./:`. This format _may_ be appropriate for urls, as
+long as you're only encoding the domain name and you remember to use uppercase
+letters (ex: `HTTP://EXAMPLE.COM`). If your url includes some path after the
+domain, you'll likely need to use binary mode because the paths are usually
+case-sensitive.
+
+A qrcode in alpha-numeric mode can encode ~40% less data than numeric mode.
+
+#### Binary Mode
+This mode is a little bit of a misnomer: binary mode simply means that the
+message will be encoded as 8-bit bytes. The qrcode standard stipulates that
+text will use ISO-8859-1 (also known as Latin-1) encoding, _not_ utf8 as would
+be the standard these days. However, _some_ readers _may_ automatically detect
+utf8. To be standard-compliant, that basically means you can only use Latin
+letters, numbers, and symbols.
+
+A qrcode in binary mode can encode ~60% less data than numeric mode, and ~30%
+less than alpha-numeric.
+
+#### Kanji Mode
+This mode is unsupported, so I won't go into detail.
+
+## qrcode library
+This application uses the [QRCode] library by ricmoo. This is the same library
+that is in the lib directory of the flipper-firmware repo (which was originally
+included for a [now-removed demo app]), but modified slightly to fix some
+compiler errors.
+
+[now-removed demo app]: https://github.com/flipperdevices/flipperzero-firmware/pull/160/files
+[flipperzero-firmware]: https://github.com/flipperdevices/flipperzero-firmware
+[Flipper Zero]: https://flipperzero.one/
+[QRCode]: https://github.com/ricmoo/QRCode

application.fam

@@ -0,0 +1,18 @@
+App(
+    appid="qrcode",
+    name="qrcode",
+    fap_description="Display qrcodes",
+    fap_author="Bob Matcuk",
+    fap_weburl="https://github.com/bmatcuk/flipperzero-qrcode",
+    apptype=FlipperAppType.EXTERNAL,
+    entry_point="qrcode_app",
+    stack_size=1024,
+    cdefines=["APP_QRCODE"],
+    requires=[
+        "gui",
+        "dialogs",
+    ],
+    fap_category="Tools",
+    fap_icon="icons/qrcode_10px.png",
+    fap_icon_assets="icons",
+)

qrcode.c

@@ -0,0 +1,858 @@
+/**
+ * The MIT License (MIT)
+ *
+ * This library is written and maintained by Richard Moore.
+ * Major parts were derived from Project Nayuki's library.
+ *
+ * Copyright (c) 2017 Richard Moore     (https://github.com/ricmoo/QRCode)
+ * Copyright (c) 2017 Project Nayuki    (https://www.nayuki.io/page/qr-code-generator-library)
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+/**
+ *  Special thanks to Nayuki (https://www.nayuki.io/) from which this library was
+ *  heavily inspired and compared against.
+ *
+ *  See: https://github.com/nayuki/QR-Code-generator/tree/master/cpp
+ */
+
+#include "qrcode.h"
+
+#include <stdlib.h>
+#include <string.h>
+
+#if LOCK_VERSION == 0
+
+static const uint16_t NUM_ERROR_CORRECTION_CODEWORDS[4][40] = {
+    // 1,  2,  3,  4,  5,   6,   7,   8,   9,  10,  11,  12,  13,  14,  15,  16,  17,  18,  19,  20,  21,  22,  23,  24,   25,   26,   27,   28,   29,   30,   31,   32,   33,   34,   35,   36,   37,   38,   39,   40    Error correction level
+    { 10, 16, 26, 36, 48,  64,  72,  88, 110, 130, 150, 176, 198, 216, 240, 280, 308, 338, 364, 416, 442, 476, 504, 560,  588,  644,  700,  728,  784,  812,  868,  924,  980, 1036, 1064, 1120, 1204, 1260, 1316, 1372},  // Medium
+    {  7, 10, 15, 20, 26,  36,  40,  48,  60,  72,  80,  96, 104, 120, 132, 144, 168, 180, 196, 224, 224, 252, 270, 300,  312,  336,  360,  390,  420,  450,  480,  510,  540,  570,  570,  600,  630,  660,  720,  750},  // Low
+    { 17, 28, 44, 64, 88, 112, 130, 156, 192, 224, 264, 308, 352, 384, 432, 480, 532, 588, 650, 700, 750, 816, 900, 960, 1050, 1110, 1200, 1260, 1350, 1440, 1530, 1620, 1710, 1800, 1890, 1980, 2100, 2220, 2310, 2430},  // High
+    { 13, 22, 36, 52, 72,  96, 108, 132, 160, 192, 224, 260, 288, 320, 360, 408, 448, 504, 546, 600, 644, 690, 750, 810,  870,  952, 1020, 1050, 1140, 1200, 1290, 1350, 1440, 1530, 1590, 1680, 1770, 1860, 1950, 2040},  // Quartile
+};
+
+static const uint8_t NUM_ERROR_CORRECTION_BLOCKS[4][40] = {
+    // Version: (note that index 0 is for padding, and is set to an illegal value)
+    // 1, 2, 3, 4, 5, 6, 7, 8, 9,10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40    Error correction level
+    {  1, 1, 1, 2, 2, 4, 4, 4, 5, 5,  5,  8,  9,  9, 10, 10, 11, 13, 14, 16, 17, 17, 18, 20, 21, 23, 25, 26, 28, 29, 31, 33, 35, 37, 38, 40, 43, 45, 47, 49},  // Medium
+    {  1, 1, 1, 1, 1, 2, 2, 2, 2, 4,  4,  4,  4,  4,  6,  6,  6,  6,  7,  8,  8,  9,  9, 10, 12, 12, 12, 13, 14, 15, 16, 17, 18, 19, 19, 20, 21, 22, 24, 25},  // Low
+    {  1, 1, 2, 4, 4, 4, 5, 6, 8, 8, 11, 11, 16, 16, 18, 16, 19, 21, 25, 25, 25, 34, 30, 32, 35, 37, 40, 42, 45, 48, 51, 54, 57, 60, 63, 66, 70, 74, 77, 81},  // High
+    {  1, 1, 2, 2, 4, 4, 6, 6, 8, 8,  8, 10, 12, 16, 12, 17, 16, 18, 21, 20, 23, 23, 25, 27, 29, 34, 34, 35, 38, 40, 43, 45, 48, 51, 53, 56, 59, 62, 65, 68},  // Quartile
+};
+
+static const uint16_t NUM_RAW_DATA_MODULES[40] = {
+    //  1,   2,   3,   4,    5,    6,    7,    8,    9,   10,   11,   12,   13,   14,   15,   16,   17,
+      208, 359, 567, 807, 1079, 1383, 1568, 1936, 2336, 2768, 3232, 3728, 4256, 4651, 5243, 5867, 6523,
+    //   18,   19,   20,   21,    22,    23,    24,    25,   26,    27,     28,    29,    30,    31,
+       7211, 7931, 8683, 9252, 10068, 10916, 11796, 12708, 13652, 14628, 15371, 16411, 17483, 18587,
+    //    32,    33,    34,    35,    36,    37,    38,    39,    40
+       19723, 20891, 22091, 23008, 24272, 25568, 26896, 28256, 29648
+};
+
+// @TODO: Put other LOCK_VERSIONS here
+#elif LOCK_VERSION == 3
+
+static const int16_t NUM_ERROR_CORRECTION_CODEWORDS[4] = {
+    26, 15, 44, 36
+};
+
+static const int8_t NUM_ERROR_CORRECTION_BLOCKS[4] = {
+    1, 1, 2, 2
+};
+
+static const uint16_t NUM_RAW_DATA_MODULES = 567;
+
+#else
+
+#error Unsupported LOCK_VERSION (add it...)
+
+#endif
+
+
+static int max(int a, int b) {
+    if (a > b) { return a; }
+    return b;
+}
+
+/*
+static int abs(int value) {
+    if (value < 0) { return -value; }
+    return value;
+}
+*/
+
+
+static int8_t getAlphanumeric(char c) {
+    
+    if (c >= '0' && c <= '9') { return (c - '0'); }
+    if (c >= 'A' && c <= 'Z') { return (c - 'A' + 10); }
+    
+    switch (c) {
+        case ' ': return 36;
+        case '$': return 37;
+        case '%': return 38;
+        case '*': return 39;
+        case '+': return 40;
+        case '-': return 41;
+        case '.': return 42;
+        case '/': return 43;
+        case ':': return 44;
+    }
+    
+    return -1;
+}
+
+static bool isAlphanumeric(const char *text, uint16_t length) {
+    while (length != 0) {
+        if (getAlphanumeric(text[--length]) == -1) { return false; }
+    }
+    return true;
+}
+
+
+static bool isNumeric(const char *text, uint16_t length) {
+    while (length != 0) {
+        char c = text[--length];
+        if (c < '0' || c > '9') { return false; }
+    }
+    return true;
+}
+
+
+// We store the following tightly packed (less 8) in modeInfo
+//               <=9  <=26  <= 40
+// NUMERIC      ( 10,   12,    14);
+// ALPHANUMERIC (  9,   11,    13);
+// BYTE         (  8,   16,    16);
+static char getModeBits(uint8_t version, uint8_t mode) {
+    // Note: We use 15 instead of 16; since 15 doesn't exist and we cannot store 16 (8 + 8) in 3 bits
+    // hex(int("".join(reversed([('00' + bin(x - 8)[2:])[-3:] for x in [10, 9, 8, 12, 11, 15, 14, 13, 15]])), 2))
+    unsigned int modeInfo = 0x7bbb80a;
+    
+#if LOCK_VERSION == 0 || LOCK_VERSION > 9
+    if (version > 9) { modeInfo >>= 9; }
+#endif
+    
+#if LOCK_VERSION == 0 || LOCK_VERSION > 26
+    if (version > 26) { modeInfo >>= 9; }
+#endif
+    
+    char result = 8 + ((modeInfo >> (3 * mode)) & 0x07);
+    if (result == 15) { result = 16; }
+    
+    return result;
+}
+
+
+typedef struct BitBucket {
+    uint32_t bitOffsetOrWidth;
+    uint16_t capacityBytes;
+    uint8_t *data;
+} BitBucket;
+
+/*
+void bb_dump(BitBucket *bitBuffer) {
+    printf("Buffer: ");
+    for (uint32_t i = 0; i < bitBuffer->capacityBytes; i++) {
+        printf("%02x", bitBuffer->data[i]);
+        if ((i % 4) == 3) { printf(" "); }
+    }
+    printf("\n");
+}
+*/
+
+static uint16_t bb_getGridSizeBytes(uint8_t size) {
+    return (((size * size) + 7) / 8);
+}
+
+static uint16_t bb_getBufferSizeBytes(uint32_t bits) {
+    return ((bits + 7) / 8);
+}
+
+static void bb_initBuffer(BitBucket *bitBuffer, uint8_t *data, int32_t capacityBytes) {
+    bitBuffer->bitOffsetOrWidth = 0;
+    bitBuffer->capacityBytes = capacityBytes;
+    bitBuffer->data = data;
+    
+    memset(data, 0, bitBuffer->capacityBytes);
+}
+
+static void bb_initGrid(BitBucket *bitGrid, uint8_t *data, uint8_t size) {
+    bitGrid->bitOffsetOrWidth = size;
+    bitGrid->capacityBytes = bb_getGridSizeBytes(size);
+    bitGrid->data = data;
+
+    memset(data, 0, bitGrid->capacityBytes);
+}
+
+static void bb_appendBits(BitBucket *bitBuffer, uint32_t val, uint8_t length) {
+    uint32_t offset = bitBuffer->bitOffsetOrWidth;
+    for (int8_t i = length - 1; i >= 0; i--, offset++) {
+        bitBuffer->data[offset >> 3] |= ((val >> i) & 1) << (7 - (offset & 7));
+    }
+    bitBuffer->bitOffsetOrWidth = offset;
+}
+/*
+void bb_setBits(BitBucket *bitBuffer, uint32_t val, int offset, uint8_t length) {
+    for (int8_t i = length - 1; i >= 0; i--, offset++) {
+        bitBuffer->data[offset >> 3] |= ((val >> i) & 1) << (7 - (offset & 7));
+    }
+}
+*/
+static void bb_setBit(BitBucket *bitGrid, uint8_t x, uint8_t y, bool on) {
+    uint32_t offset = y * bitGrid->bitOffsetOrWidth + x;
+    uint8_t mask = 1 << (7 - (offset & 0x07));
+    if (on) {
+        bitGrid->data[offset >> 3] |= mask;
+    } else {
+        bitGrid->data[offset >> 3] &= ~mask;
+    }
+}
+
+static void bb_invertBit(BitBucket *bitGrid, uint8_t x, uint8_t y, bool invert) {
+    uint32_t offset = y * bitGrid->bitOffsetOrWidth + x;
+    uint8_t mask = 1 << (7 - (offset & 0x07));
+    bool on = ((bitGrid->data[offset >> 3] & (1 << (7 - (offset & 0x07)))) != 0);
+    if (on ^ invert) {
+        bitGrid->data[offset >> 3] |= mask;
+    } else {
+        bitGrid->data[offset >> 3] &= ~mask;
+    }
+}
+
+static bool bb_getBit(BitBucket *bitGrid, uint8_t x, uint8_t y) {
+    uint32_t offset = y * bitGrid->bitOffsetOrWidth + x;
+    return (bitGrid->data[offset >> 3] & (1 << (7 - (offset & 0x07)))) != 0;
+}
+
+
+// XORs the data modules in this QR Code with the given mask pattern. Due to XOR's mathematical
+// properties, calling applyMask(m) twice with the same value is equivalent to no change at all.
+// This means it is possible to apply a mask, undo it, and try another mask. Note that a final
+// well-formed QR Code symbol needs exactly one mask applied (not zero, not two, etc.).
+static void applyMask(BitBucket *modules, BitBucket *isFunction, uint8_t mask) {
+    uint8_t size = modules->bitOffsetOrWidth;
+    
+    for (uint8_t y = 0; y < size; y++) {
+        for (uint8_t x = 0; x < size; x++) {
+            if (bb_getBit(isFunction, x, y)) { continue; }
+            
+            bool invert = 0;
+            switch (mask) {
+                case 0:  invert = (x + y) % 2 == 0;                    break;
+                case 1:  invert = y % 2 == 0;                          break;
+                case 2:  invert = x % 3 == 0;                          break;
+                case 3:  invert = (x + y) % 3 == 0;                    break;
+                case 4:  invert = (x / 3 + y / 2) % 2 == 0;            break;
+                case 5:  invert = x * y % 2 + x * y % 3 == 0;          break;
+                case 6:  invert = (x * y % 2 + x * y % 3) % 2 == 0;    break;
+                case 7:  invert = ((x + y) % 2 + x * y % 3) % 2 == 0;  break;
+            }
+            bb_invertBit(modules, x, y, invert);
+        }
+    }
+}
+
+static void setFunctionModule(BitBucket *modules, BitBucket *isFunction, uint8_t x, uint8_t y, bool on) {
+    bb_setBit(modules, x, y, on);
+    bb_setBit(isFunction, x, y, true);
+}
+
+// Draws a 9*9 finder pattern including the border separator, with the center module at (x, y).
+static void drawFinderPattern(BitBucket *modules, BitBucket *isFunction, uint8_t x, uint8_t y) {
+    uint8_t size = modules->bitOffsetOrWidth;
+
+    for (int8_t i = -4; i <= 4; i++) {
+        for (int8_t j = -4; j <= 4; j++) {
+            uint8_t dist = max(abs(i), abs(j));  // Chebyshev/infinity norm
+            int16_t xx = x + j, yy = y + i;
+            if (0 <= xx && xx < size && 0 <= yy && yy < size) {
+                setFunctionModule(modules, isFunction, xx, yy, dist != 2 && dist != 4);
+            }
+        }
+    }
+}
+
+// Draws a 5*5 alignment pattern, with the center module at (x, y).
+static void drawAlignmentPattern(BitBucket *modules, BitBucket *isFunction, uint8_t x, uint8_t y) {
+    for (int8_t i = -2; i <= 2; i++) {
+        for (int8_t j = -2; j <= 2; j++) {
+            setFunctionModule(modules, isFunction, x + j, y + i, max(abs(i), abs(j)) != 1);
+        }
+    }
+}
+
+// Draws two copies of the format bits (with its own error correction code)
+// based on the given mask and this object's error correction level field.
+static void drawFormatBits(BitBucket *modules, BitBucket *isFunction, uint8_t ecc, uint8_t mask) {
+    
+    uint8_t size = modules->bitOffsetOrWidth;
+
+    // Calculate error correction code and pack bits
+    uint32_t data = ecc << 3 | mask;  // errCorrLvl is uint2, mask is uint3
+    uint32_t rem = data;
+    for (int i = 0; i < 10; i++) {
+        rem = (rem << 1) ^ ((rem >> 9) * 0x537);
+    }
+    
+    data = data << 10 | rem;
+    data ^= 0x5412;  // uint15
+    
+    // Draw first copy
+    for (uint8_t i = 0; i <= 5; i++) {
+        setFunctionModule(modules, isFunction, 8, i, ((data >> i) & 1) != 0);
+    }
+    
+    setFunctionModule(modules, isFunction, 8, 7, ((data >> 6) & 1) != 0);
+    setFunctionModule(modules, isFunction, 8, 8, ((data >> 7) & 1) != 0);
+    setFunctionModule(modules, isFunction, 7, 8, ((data >> 8) & 1) != 0);
+    
+    for (int8_t i = 9; i < 15; i++) {
+        setFunctionModule(modules, isFunction, 14 - i, 8, ((data >> i) & 1) != 0);
+    }
+    
+    // Draw second copy
+    for (int8_t i = 0; i <= 7; i++) {
+        setFunctionModule(modules, isFunction, size - 1 - i, 8, ((data >> i) & 1) != 0);
+    }
+    
+    for (int8_t i = 8; i < 15; i++) {
+        setFunctionModule(modules, isFunction, 8, size - 15 + i, ((data >> i) & 1) != 0);
+    }
+    
+    setFunctionModule(modules, isFunction, 8, size - 8, true);
+}
+
+
+// Draws two copies of the version bits (with its own error correction code),
+// based on this object's version field (which only has an effect for 7 <= version <= 40).
+static void drawVersion(BitBucket *modules, BitBucket *isFunction, uint8_t version) {
+    
+    int8_t size = modules->bitOffsetOrWidth;
+
+#if LOCK_VERSION != 0 && LOCK_VERSION < 7
+    return;
+    
+#else
+    if (version < 7) { return; }
+    
+    // Calculate error correction code and pack bits
+    uint32_t rem = version;  // version is uint6, in the range [7, 40]
+    for (uint8_t i = 0; i < 12; i++) {
+        rem = (rem << 1) ^ ((rem >> 11) * 0x1F25);
+    }
+    
+    uint32_t data = version << 12 | rem;  // uint18
+    
+    // Draw two copies
+    for (uint8_t i = 0; i < 18; i++) {
+        bool bit = ((data >> i) & 1) != 0;
+        uint8_t a = size - 11 + i % 3, b = i / 3;
+        setFunctionModule(modules, isFunction, a, b, bit);
+        setFunctionModule(modules, isFunction, b, a, bit);
+    }
+    
+#endif
+}
+
+static void drawFunctionPatterns(BitBucket *modules, BitBucket *isFunction, uint8_t version, uint8_t ecc) {
+    
+    uint8_t size = modules->bitOffsetOrWidth;
+
+    // Draw the horizontal and vertical timing patterns
+    for (uint8_t i = 0; i < size; i++) {
+        setFunctionModule(modules, isFunction, 6, i, i % 2 == 0);
+        setFunctionModule(modules, isFunction, i, 6, i % 2 == 0);
+    }
+    
+    // Draw 3 finder patterns (all corners except bottom right; overwrites some timing modules)
+    drawFinderPattern(modules, isFunction, 3, 3);
+    drawFinderPattern(modules, isFunction, size - 4, 3);
+    drawFinderPattern(modules, isFunction, 3, size - 4);
+    
+#if LOCK_VERSION == 0 || LOCK_VERSION > 1
+
+    if (version > 1) {
+
+        // Draw the numerous alignment patterns
+        
+        uint8_t alignCount = version / 7 + 2;
+        uint8_t step;
+        if (version != 32) {
+            step = (version * 4 + alignCount * 2 + 1) / (2 * alignCount - 2) * 2;  // ceil((size - 13) / (2*numAlign - 2)) * 2
+        } else { // C-C-C-Combo breaker!
+            step = 26;
+        }
+        
+        uint8_t alignPositionIndex = alignCount - 1;
+        uint8_t alignPosition[alignCount];
+        
+        alignPosition[0] = 6;
+        
+        uint8_t size = version * 4 + 17;
+        for (uint8_t i = 0, pos = size - 7; i < alignCount - 1; i++, pos -= step) {
+            alignPosition[alignPositionIndex--] = pos;
+        }
+        
+        for (uint8_t i = 0; i < alignCount; i++) {
+            for (uint8_t j = 0; j < alignCount; j++) {
+                if ((i == 0 && j == 0) || (i == 0 && j == alignCount - 1) || (i == alignCount - 1 && j == 0)) {
+                    continue;  // Skip the three finder corners
+                } else {
+                    drawAlignmentPattern(modules, isFunction, alignPosition[i], alignPosition[j]);
+                }
+            }
+        }
+    }
+    
+#endif
+    
+    // Draw configuration data
+    drawFormatBits(modules, isFunction, ecc, 0);  // Dummy mask value; overwritten later in the constructor
+    drawVersion(modules, isFunction, version);
+}
+
+
+// Draws the given sequence of 8-bit codewords (data and error correction) onto the entire
+// data area of this QR Code symbol. Function modules need to be marked off before this is called.
+static void drawCodewords(BitBucket *modules, BitBucket *isFunction, BitBucket *codewords) {
+    
+    uint32_t bitLength = codewords->bitOffsetOrWidth;
+    uint8_t *data = codewords->data;
+    
+    uint8_t size = modules->bitOffsetOrWidth;
+    
+    // Bit index into the data
+    uint32_t i = 0;
+    
+    // Do the funny zigzag scan
+    for (int16_t right = size - 1; right >= 1; right -= 2) {  // Index of right column in each column pair
+        if (right == 6) { right = 5; }
+        
+        for (uint8_t vert = 0; vert < size; vert++) {  // Vertical counter
+            for (int j = 0; j < 2; j++) {
+                uint8_t x = right - j;  // Actual x coordinate
+                bool upwards = ((right & 2) == 0) ^ (x < 6);
+                uint8_t y = upwards ? size - 1 - vert : vert;  // Actual y coordinate
+                if (!bb_getBit(isFunction, x, y) && i < bitLength) {
+                    bb_setBit(modules, x, y, ((data[i >> 3] >> (7 - (i & 7))) & 1) != 0);
+                    i++;
+                }
+                // If there are any remainder bits (0 to 7), they are already
+                // set to 0/false/white when the grid of modules was initialized
+            }
+        }
+    }
+}
+
+
+
+#define PENALTY_N1      3
+#define PENALTY_N2      3
+#define PENALTY_N3     40
+#define PENALTY_N4     10
+
+// Calculates and returns the penalty score based on state of this QR Code's current modules.
+// This is used by the automatic mask choice algorithm to find the mask pattern that yields the lowest score.
+// @TODO: This can be optimized by working with the bytes instead of bits.
+static uint32_t getPenaltyScore(BitBucket *modules) {
+    uint32_t result = 0;
+    
+    uint8_t size = modules->bitOffsetOrWidth;
+    
+    // Adjacent modules in row having same color
+    for (uint8_t y = 0; y < size; y++) {
+        
+        bool colorX = bb_getBit(modules, 0, y);
+        for (uint8_t x = 1, runX = 1; x < size; x++) {
+            bool cx = bb_getBit(modules, x, y);
+            if (cx != colorX) {
+                colorX = cx;
+                runX = 1;
+                
+            } else {
+                runX++;
+                if (runX == 5) {
+                    result += PENALTY_N1;
+                } else if (runX > 5) {
+                    result++;
+                }
+            }
+        }
+    }
+    
+    // Adjacent modules in column having same color
+    for (uint8_t x = 0; x < size; x++) {
+        bool colorY = bb_getBit(modules, x, 0);
+        for (uint8_t y = 1, runY = 1; y < size; y++) {
+            bool cy = bb_getBit(modules, x, y);
+            if (cy != colorY) {
+                colorY = cy;
+                runY = 1;
+            } else {
+                runY++;
+                if (runY == 5) {
+                    result += PENALTY_N1;
+                } else if (runY > 5) {
+                    result++;
+                }
+            }
+        }
+    }
+    
+    uint16_t black = 0;
+    for (uint8_t y = 0; y < size; y++) {
+        uint16_t bitsRow = 0, bitsCol = 0;
+        for (uint8_t x = 0; x < size; x++) {
+            bool color = bb_getBit(modules, x, y);
+
+            // 2*2 blocks of modules having same color
+            if (x > 0 && y > 0) {
+                bool colorUL = bb_getBit(modules, x - 1, y - 1);
+                bool colorUR = bb_getBit(modules, x, y - 1);
+                bool colorL = bb_getBit(modules, x - 1, y);
+                if (color == colorUL && color == colorUR && color == colorL) {
+                    result += PENALTY_N2;
+                }
+            }
+
+            // Finder-like pattern in rows and columns
+            bitsRow = ((bitsRow << 1) & 0x7FF) | color;
+            bitsCol = ((bitsCol << 1) & 0x7FF) | bb_getBit(modules, y, x);
+
+            // Needs 11 bits accumulated
+            if (x >= 10) {
+                if (bitsRow == 0x05D || bitsRow == 0x5D0) {
+                    result += PENALTY_N3;
+                }
+                if (bitsCol == 0x05D || bitsCol == 0x5D0) {
+                    result += PENALTY_N3;
+                }
+            }
+
+            // Balance of black and white modules
+            if (color) { black++; }
+        }
+    }
+
+    // Find smallest k such that (45-5k)% <= dark/total <= (55+5k)%
+    uint16_t total = size * size;
+    for (uint16_t k = 0; black * 20 < (9 - k) * total || black * 20 > (11 + k) * total; k++) {
+        result += PENALTY_N4;
+    }
+    
+    return result;
+}
+
+
+static uint8_t rs_multiply(uint8_t x, uint8_t y) {
+    // Russian peasant multiplication
+    // See: https://en.wikipedia.org/wiki/Ancient_Egyptian_multiplication
+    uint16_t z = 0;
+    for (int8_t i = 7; i >= 0; i--) {
+        z = (z << 1) ^ ((z >> 7) * 0x11D);
+        z ^= ((y >> i) & 1) * x;
+    }
+    return z;
+}
+
+static void rs_init(uint8_t degree, uint8_t *coeff) {
+    memset(coeff, 0, degree);
+    coeff[degree - 1] = 1;
+    
+    // Compute the product polynomial (x - r^0) * (x - r^1) * (x - r^2) * ... * (x - r^{degree-1}),
+    // drop the highest term, and store the rest of the coefficients in order of descending powers.
+    // Note that r = 0x02, which is a generator element of this field GF(2^8/0x11D).
+    uint16_t root = 1;
+    for (uint8_t i = 0; i < degree; i++) {
+        // Multiply the current product by (x - r^i)
+        for (uint8_t j = 0; j < degree; j++) {
+            coeff[j] = rs_multiply(coeff[j], root);
+            if (j + 1 < degree) {
+                coeff[j] ^= coeff[j + 1];
+            }
+        }
+        root = (root << 1) ^ ((root >> 7) * 0x11D);  // Multiply by 0x02 mod GF(2^8/0x11D)
+    }
+}
+
+static void rs_getRemainder(uint8_t degree, uint8_t *coeff, uint8_t *data, uint8_t length, uint8_t *result, uint8_t stride) {
+    // Compute the remainder by performing polynomial division
+    
+    //for (uint8_t i = 0; i < degree; i++) { result[] = 0; }
+    //memset(result, 0, degree);
+    
+    for (uint8_t i = 0; i < length; i++) {
+        uint8_t factor = data[i] ^ result[0];
+        for (uint8_t j = 1; j < degree; j++) {
+            result[(j - 1) * stride] = result[j * stride];
+        }
+        result[(degree - 1) * stride] = 0;
+        
+        for (uint8_t j = 0; j < degree; j++) {
+            result[j * stride] ^= rs_multiply(coeff[j], factor);
+        }
+    }
+}
+
+
+
+static int8_t encodeDataCodewords(BitBucket *dataCodewords, const uint8_t *text, uint16_t length, uint8_t version) {
+    int8_t mode = MODE_BYTE;
+    
+    if (isNumeric((char*)text, length)) {
+        mode = MODE_NUMERIC;
+        bb_appendBits(dataCodewords, 1 << MODE_NUMERIC, 4);
+        bb_appendBits(dataCodewords, length, getModeBits(version, MODE_NUMERIC));
+
+        uint16_t accumData = 0;
+        uint8_t accumCount = 0;
+        for (uint16_t i = 0; i < length; i++) {
+            accumData = accumData * 10 + ((char)(text[i]) - '0');
+            accumCount++;
+            if (accumCount == 3) {
+                bb_appendBits(dataCodewords, accumData, 10);
+                accumData = 0;
+                accumCount = 0;
+            }
+        }
+        
+        // 1 or 2 digits remaining
+        if (accumCount > 0) {
+            bb_appendBits(dataCodewords, accumData, accumCount * 3 + 1);
+        }
+        
+    } else if (isAlphanumeric((char*)text, length)) {
+        mode = MODE_ALPHANUMERIC;
+        bb_appendBits(dataCodewords, 1 << MODE_ALPHANUMERIC, 4);
+        bb_appendBits(dataCodewords, length, getModeBits(version, MODE_ALPHANUMERIC));
+
+        uint16_t accumData = 0;
+        uint8_t accumCount = 0;
+        for (uint16_t i = 0; i  < length; i++) {
+            accumData = accumData * 45 + getAlphanumeric((char)(text[i]));
+            accumCount++;
+            if (accumCount == 2) {
+                bb_appendBits(dataCodewords, accumData, 11);
+                accumData = 0;
+                accumCount = 0;
+            }
+        }
+        
+        // 1 character remaining
+        if (accumCount > 0) {
+            bb_appendBits(dataCodewords, accumData, 6);
+        }
+        
+    } else {
+        bb_appendBits(dataCodewords, 1 << MODE_BYTE, 4);
+        bb_appendBits(dataCodewords, length, getModeBits(version, MODE_BYTE));
+        for (uint16_t i = 0; i < length; i++) {
+            bb_appendBits(dataCodewords, (char)(text[i]), 8);
+        }
+    }
+    
+    //bb_setBits(dataCodewords, length, 4, getModeBits(version, mode));
+    
+    return mode;
+}
+
+static void performErrorCorrection(uint8_t version, uint8_t ecc, BitBucket *data) {
+    
+    // See: http://www.thonky.com/qr-code-tutorial/structure-final-message
+    
+#if LOCK_VERSION == 0
+    uint8_t numBlocks = NUM_ERROR_CORRECTION_BLOCKS[ecc][version - 1];
+    uint16_t totalEcc = NUM_ERROR_CORRECTION_CODEWORDS[ecc][version - 1];
+    uint16_t moduleCount = NUM_RAW_DATA_MODULES[version - 1];
+#else
+    uint8_t numBlocks = NUM_ERROR_CORRECTION_BLOCKS[ecc];
+    uint16_t totalEcc = NUM_ERROR_CORRECTION_CODEWORDS[ecc];
+    uint16_t moduleCount = NUM_RAW_DATA_MODULES;
+#endif
+    
+    uint8_t blockEccLen = totalEcc / numBlocks;
+    uint8_t numShortBlocks = numBlocks - moduleCount / 8 % numBlocks;
+    uint8_t shortBlockLen = moduleCount / 8 / numBlocks;
+    
+    uint8_t shortDataBlockLen = shortBlockLen - blockEccLen;
+    
+    uint8_t result[data->capacityBytes];
+    memset(result, 0, sizeof(result));
+    
+    uint8_t coeff[blockEccLen];
+    rs_init(blockEccLen, coeff);
+    
+    uint16_t offset = 0;
+    uint8_t *dataBytes = data->data;
+    
+    
+    // Interleave all short blocks
+    for (uint8_t i = 0; i < shortDataBlockLen; i++) {
+        uint16_t index = i;
+        uint8_t stride = shortDataBlockLen;
+        for (uint8_t blockNum = 0; blockNum < numBlocks; blockNum++) {
+            result[offset++] = dataBytes[index];
+            
+#if LOCK_VERSION == 0 || LOCK_VERSION >= 5
+            if (blockNum == numShortBlocks) { stride++; }
+#endif
+            index += stride;
+        }
+    }
+    
+    // Version less than 5 only have short blocks
+#if LOCK_VERSION == 0 || LOCK_VERSION >= 5
+    {
+        // Interleave long blocks
+        uint16_t index = shortDataBlockLen * (numShortBlocks + 1);
+        uint8_t stride = shortDataBlockLen;
+        for (uint8_t blockNum = 0; blockNum < numBlocks - numShortBlocks; blockNum++) {
+            result[offset++] = dataBytes[index];
+            
+            if (blockNum == 0) { stride++; }
+            index += stride;
+        }
+    }
+#endif
+    
+    // Add all ecc blocks, interleaved
+    uint8_t blockSize = shortDataBlockLen;
+    for (uint8_t blockNum = 0; blockNum < numBlocks; blockNum++) {
+        
+#if LOCK_VERSION == 0 || LOCK_VERSION >= 5
+        if (blockNum == numShortBlocks) { blockSize++; }
+#endif
+        rs_getRemainder(blockEccLen, coeff, dataBytes, blockSize, &result[offset + blockNum], numBlocks);
+        dataBytes += blockSize;
+    }
+    
+    memcpy(data->data, result, data->capacityBytes);
+    data->bitOffsetOrWidth = moduleCount;
+}
+
+// We store the Format bits tightly packed into a single byte (each of the 4 modes is 2 bits)
+// The format bits can be determined by ECC_FORMAT_BITS >> (2 * ecc)
+static const uint8_t ECC_FORMAT_BITS = (0x02 << 6) | (0x03 << 4) | (0x00 << 2) | (0x01 << 0);
+
+
+uint16_t qrcode_getBufferSize(uint8_t version) {
+    return bb_getGridSizeBytes(4 * version + 17);
+}
+
+// @TODO: Return error if data is too big.
+int8_t qrcode_initBytes(QRCode *qrcode, uint8_t *modules, uint8_t version, uint8_t ecc, uint8_t *data, uint16_t length) {
+    uint8_t size = version * 4 + 17;
+    qrcode->version = version;
+    qrcode->size = size;
+    qrcode->ecc = ecc;
+    qrcode->modules = modules;
+    
+    uint8_t eccFormatBits = (ECC_FORMAT_BITS >> (2 * ecc)) & 0x03;
+    
+#if LOCK_VERSION == 0
+    uint16_t moduleCount = NUM_RAW_DATA_MODULES[version - 1];
+    uint16_t dataCapacity = moduleCount / 8 - NUM_ERROR_CORRECTION_CODEWORDS[eccFormatBits][version - 1];
+#else
+    version = LOCK_VERSION;
+    uint16_t moduleCount = NUM_RAW_DATA_MODULES;
+    uint16_t dataCapacity = moduleCount / 8 - NUM_ERROR_CORRECTION_CODEWORDS[eccFormatBits];
+#endif
+    
+    struct BitBucket codewords;
+    uint8_t codewordBytes[bb_getBufferSizeBytes(moduleCount)];
+    bb_initBuffer(&codewords, codewordBytes, (int32_t)sizeof(codewordBytes));
+    
+    // Place the data code words into the buffer
+    int8_t mode = encodeDataCodewords(&codewords, data, length, version);
+    
+    if (mode < 0) { return -1; }
+    qrcode->mode = mode;
+    
+    // Add terminator and pad up to a byte if applicable
+    uint32_t padding = (dataCapacity * 8) - codewords.bitOffsetOrWidth;
+    if (padding > 4) { padding = 4; }
+    bb_appendBits(&codewords, 0, padding);
+    bb_appendBits(&codewords, 0, (8 - codewords.bitOffsetOrWidth % 8) % 8);
+
+    // Pad with alternate bytes until data capacity is reached
+    for (uint8_t padByte = 0xEC; codewords.bitOffsetOrWidth < (dataCapacity * 8); padByte ^= 0xEC ^ 0x11) {
+        bb_appendBits(&codewords, padByte, 8);
+    }
+
+    BitBucket modulesGrid;
+    bb_initGrid(&modulesGrid, modules, size);
+    
+    BitBucket isFunctionGrid;
+    uint8_t isFunctionGridBytes[bb_getGridSizeBytes(size)];
+    bb_initGrid(&isFunctionGrid, isFunctionGridBytes, size);
+    
+    // Draw function patterns, draw all codewords, do masking
+    drawFunctionPatterns(&modulesGrid, &isFunctionGrid, version, eccFormatBits);
+    performErrorCorrection(version, eccFormatBits, &codewords);
+    drawCodewords(&modulesGrid, &isFunctionGrid, &codewords);
+    
+    // Find the best (lowest penalty) mask
+    uint8_t mask = 0;
+    int32_t minPenalty = INT32_MAX;
+    for (uint8_t i = 0; i < 8; i++) {
+        drawFormatBits(&modulesGrid, &isFunctionGrid, eccFormatBits, i);
+        applyMask(&modulesGrid, &isFunctionGrid, i);
+        int penalty = getPenaltyScore(&modulesGrid);
+        if (penalty < minPenalty) {
+            mask = i;
+            minPenalty = penalty;
+        }
+        applyMask(&modulesGrid, &isFunctionGrid, i);  // Undoes the mask due to XOR
+    }
+    
+    qrcode->mask = mask;
+    
+    // Overwrite old format bits
+    drawFormatBits(&modulesGrid, &isFunctionGrid, eccFormatBits, mask);
+    
+    // Apply the final choice of mask
+    applyMask(&modulesGrid, &isFunctionGrid, mask);
+
+    return 0;
+}
+
+int8_t qrcode_initText(QRCode *qrcode, uint8_t *modules, uint8_t version, uint8_t ecc, const char *data) {
+    return qrcode_initBytes(qrcode, modules, version, ecc, (uint8_t*)data, strlen(data));
+}
+
+bool qrcode_getModule(QRCode *qrcode, uint8_t x, uint8_t y) {
+    if (x >= qrcode->size || y >= qrcode->size) {
+        return false;
+    }
+
+    uint32_t offset = y * qrcode->size + x;
+    return (qrcode->modules[offset >> 3] & (1 << (7 - (offset & 0x07)))) != 0;
+}
+
+/*
+uint8_t qrcode_getHexLength(QRCode *qrcode) {
+    return ((qrcode->size * qrcode->size) + 7) / 4;
+}
+
+void qrcode_getHex(QRCode *qrcode, char *result) {
+    
+}
+*/

qrcode.h

@@ -0,0 +1,100 @@
+/**
+ * The MIT License (MIT)
+ *
+ * This library is written and maintained by Richard Moore.
+ * Major parts were derived from Project Nayuki's library.
+ *
+ * Copyright (c) 2017 Richard Moore     (https://github.com/ricmoo/QRCode)
+ * Copyright (c) 2017 Project Nayuki    (https://www.nayuki.io/page/qr-code-generator-library)
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+/**
+ *  Special thanks to Nayuki (https://www.nayuki.io/) from which this library was
+ *  heavily inspired and compared against.
+ *
+ *  See: https://github.com/nayuki/QR-Code-generator/tree/master/cpp
+ */
+
+
+#ifndef __QRCODE_H_
+#define __QRCODE_H_
+
+// #ifndef __cplusplus
+// typedef unsigned char bool;
+// static const bool false = 0;
+// static const bool true = 1;
+// #endif
+
+#include <stdbool.h>
+#include <stdint.h>
+
+
+// QR Code Format Encoding
+#define MODE_NUMERIC        0
+#define MODE_ALPHANUMERIC   1
+#define MODE_BYTE           2
+
+
+// Error Correction Code Levels
+#define ECC_LOW            0
+#define ECC_MEDIUM         1
+#define ECC_QUARTILE       2
+#define ECC_HIGH           3
+
+
+// If set to non-zero, this library can ONLY produce QR codes at that version
+// This saves a lot of dynamic memory, as the codeword tables are skipped
+#ifndef LOCK_VERSION
+#define LOCK_VERSION       0
+#endif
+
+
+typedef struct QRCode {
+    uint8_t version;
+    uint8_t size;
+    uint8_t ecc;
+    uint8_t mode;
+    uint8_t mask;
+    uint8_t *modules;
+} QRCode;
+
+
+#ifdef __cplusplus
+extern "C"{
+#endif  /* __cplusplus */
+
+
+
+uint16_t qrcode_getBufferSize(uint8_t version);
+
+int8_t qrcode_initText(QRCode *qrcode, uint8_t *modules, uint8_t version, uint8_t ecc, const char *data);
+int8_t qrcode_initBytes(QRCode *qrcode, uint8_t *modules, uint8_t version, uint8_t ecc, uint8_t *data, uint16_t length);
+
+bool qrcode_getModule(QRCode *qrcode, uint8_t x, uint8_t y);
+
+
+
+#ifdef __cplusplus
+}
+#endif  /* __cplusplus */
+
+
+#endif  /* __QRCODE_H_ */

qrcode_app.c

@@ -0,0 +1,392 @@
+#include <furi.h>
+
+#include <dialogs/dialogs.h>
+#include <gui/gui.h>
+#include <storage/storage.h>
+
+#include <lib/flipper_format/flipper_format.h>
+
+// this file is generated by the build script
+#include <qrcode_icons.h>
+#include "qrcode.h"
+
+#define TAG "qrcode"
+#define QRCODE_FOLDER ANY_PATH("qrcodes")
+#define QRCODE_EXTENSION ".qrcode"
+#define QRCODE_FILETYPE "QRCode"
+#define QRCODE_FILE_VERSION 0
+
+/**
+ * Maximum version is 11 because the f0 screen is only 64 pixels high and
+ * version 12 is 65x65. Version 11 is 61x61.
+ */
+#define MAX_QRCODE_VERSION 11
+
+/** Maximum length by mode, ecc, and version */
+static const uint16_t MAX_LENGTH[3][4][MAX_QRCODE_VERSION] = {
+    {
+        // Numeric
+        {41, 77, 127, 187, 255, 322, 370, 461, 552, 652, 772}, // Low
+        {34, 63, 101, 149, 202, 255, 293, 365, 432, 513, 604}, // Medium
+        {27, 48, 77, 111, 144, 178, 207, 259, 312, 364, 427},  // Quartile
+        {17, 34, 58, 82, 106, 139, 154, 202, 235, 288, 331},   // High
+    },
+    {
+        // Alphanumeric
+        {25, 47, 77, 114, 154, 195, 224, 279, 335, 395, 468}, // Low
+        {20, 38, 61, 90, 122, 154, 178, 221, 262, 311, 366},  // Medium
+        {16, 29, 47, 67, 87, 108, 125, 157, 189, 221, 259},   // Quartile
+        {10, 20, 35, 50, 64, 84, 93, 122, 143, 174, 200},     // High
+    },
+    {
+        // Binary
+        {17, 32, 53, 78, 106, 134, 154, 192, 230, 271, 321}, // Low
+        {14, 26, 42, 62, 84, 106, 122, 152, 180, 213, 251},  // Medium
+        {11, 20, 32, 46, 60, 74, 86, 108, 130, 151, 177},    // Quartile
+        {7, 14, 24, 34, 44, 58, 64, 84, 98, 119, 137},       // High
+    },
+};
+
+/** Main app instance */
+typedef struct {
+    FuriMessageQueue* input_queue;
+    Gui* gui;
+    ViewPort* view_port;
+
+    FuriMutex** mutex;
+    QRCode* qrcode;
+    bool too_long;
+} QRCodeApp;
+
+/**
+ * Render
+ * @param canvas The canvas to render to
+ * @param ctx Context provided to the callback by view_port_draw_callback_set
+ */
+static void render_callback(Canvas* canvas, void* ctx) {
+    QRCodeApp* instance = ctx;
+    furi_check(furi_mutex_acquire(instance->mutex, FuriWaitForever) == FuriStatusOk);
+
+    canvas_clear(canvas);
+    canvas_set_color(canvas, ColorBlack);
+
+    uint8_t width = canvas_width(canvas);
+    uint8_t height = canvas_height(canvas);
+    if (instance->qrcode) {
+        uint8_t size = instance->qrcode->size;
+        uint8_t pixel_size = height / size;
+        uint8_t top = (height - pixel_size * size) / 2;
+        uint8_t left = (width - pixel_size * size) / 2;
+        for (uint8_t y = 0; y < size; y++) {
+            for (uint8_t x = 0; x < size; x++) {
+                if (qrcode_getModule(instance->qrcode, x, y)) {
+                    if (pixel_size == 1) {
+                        canvas_draw_dot(canvas, left + x * pixel_size, top + y * pixel_size);
+                    } else {
+                        canvas_draw_box(canvas, left + x * pixel_size, top + y * pixel_size, pixel_size, pixel_size);
+                    }
+                }
+            }
+        }
+    } else {
+        canvas_set_font(canvas, FontPrimary);
+
+        uint8_t font_height = canvas_current_font_height(canvas);
+        uint8_t margin = (height - font_height * 2) / 3;
+        canvas_draw_str_aligned(canvas, width / 2, margin, AlignCenter, AlignTop, "Could not load qrcode.");
+        if (instance->too_long) {
+            canvas_set_font(canvas, FontSecondary);
+            canvas_draw_str(canvas, width / 2, margin * 2 + font_height, "Message is too long.");
+        }
+    }
+
+    furi_mutex_release(instance->mutex);
+}
+
+/**
+ * Handle input
+ * @param input_event The received input event
+ * @param ctx Context provided to the callback by view_port_input_callback_set
+ */
+static void input_callback(InputEvent* input_event, void* ctx) {
+    if (input_event->type == InputTypeShort) {
+        QRCodeApp* instance = ctx;
+        furi_message_queue_put(instance->input_queue, input_event, 0);
+    }
+}
+
+/**
+ * Determine if the given string is all numeric
+ * @param str The string to test
+ * @returns true if the string is all numeric
+ */
+static bool is_numeric(const char* str, uint16_t len) {
+    while (len > 0) {
+        char c = str[--len];
+        if (c < '0' || c > '9') return false;
+    }
+    return true;
+}
+
+/**
+ * Determine if the given string is alphanumeric
+ * @param str The string to test
+ * @returns true if the string is alphanumeric
+ */
+static bool is_alphanumeric(const char* str, uint16_t len) {
+    while (len > 0) {
+        char c = str[--len];
+        if (c >= '0' && c <= '9') continue;
+        if (c >= 'A' && c <= 'Z') continue;
+        if (c == ' '
+                || c == '$'
+                || c == '%'
+                || c == '*'
+                || c == '+'
+                || c == '-'
+                || c == '.'
+                || c == '/'
+                || c == ':')
+            continue;
+        return false;
+    }
+    return true;
+}
+
+/**
+ * Allocate a qrcode
+ * @param version qrcode version
+ * @returns an allocated QRCode
+ */
+static QRCode* qrcode_alloc(uint8_t version) {
+    QRCode* qrcode = malloc(sizeof(QRCode));
+    qrcode->modules = malloc(qrcode_getBufferSize(version));
+    return qrcode;
+}
+
+/**
+ * Free a QRCode
+ * @param qrcode The QRCode to free
+ */
+static void qrcode_free(QRCode* qrcode) {
+    free(qrcode->modules);
+    free(qrcode);
+}
+
+/**
+ * Load a qrcode from a string
+ * @param instance The qrcode app instance
+ * @param str The message to encode as a qrcode
+ * @returns true if the string was successfully loaded
+ */
+static bool qrcode_load_string(QRCodeApp* instance, FuriString* str) {
+    furi_check(furi_mutex_acquire(instance->mutex, FuriWaitForever) == FuriStatusOk);
+    if (instance->qrcode) {
+        qrcode_free(instance->qrcode);
+        instance->qrcode = NULL;
+    }
+    instance->too_long = false;
+
+    bool result = false;
+    do {
+        const char* cstr = furi_string_get_cstr(str);
+        uint16_t len = strlen(cstr);
+
+        // figure out the qrcode "mode"
+        uint8_t mode = MODE_BYTE;
+        if      (is_numeric(cstr, len))      mode = MODE_NUMERIC;
+        else if (is_alphanumeric(cstr, len)) mode = MODE_ALPHANUMERIC;
+
+        // Figure out the smallest qrcode version that'll fit all of the data -
+        // we prefer the smallest version to maximize the pixel size of each
+        // module to improve reader performance. Here, version is the 0-based
+        // index. The qrcode_initBytes function will want a 1-based version
+        // number, so we'll add one later.
+        uint8_t ecc = ECC_LOW;
+        uint8_t version = 0;
+        while (version < MAX_QRCODE_VERSION && MAX_LENGTH[mode][ecc][version] < len) {
+            version++;
+        }
+
+        if (version == MAX_QRCODE_VERSION) {
+            instance->too_long = true;
+            break;
+        }
+
+        // Figure out the maximum ECC we can use. I shouldn't need to
+        // bounds-check ecc in this loop because I already know from the loop
+        // above that ECC_LOW (0) works... don't forget to add one to that
+        // version number...
+        ecc = ECC_HIGH;
+        while (MAX_LENGTH[mode][ecc][version] < len) {
+            ecc--;
+        }
+        version++;
+
+        // Build the qrcode
+        instance->qrcode = qrcode_alloc(version);
+        int8_t res = qrcode_initBytes(instance->qrcode, instance->qrcode->modules, version, ecc, (uint8_t*)cstr, len);
+        if (res != 0) {
+            FURI_LOG_E(TAG, "Could not create qrcode");
+
+            qrcode_free(instance->qrcode);
+            instance->qrcode = NULL;
+
+            break;
+        }
+
+        result = true;
+    } while (false);
+
+    furi_mutex_release(instance->mutex);
+
+    return result;
+}
+
+/**
+ * Load a qrcode from a file
+ * @param instance The qrcode app instance
+ * @param file_path Path to the file to read
+ * @returns true if the file was successfully loaded
+ */
+static bool qrcode_load_file(QRCodeApp* instance, const char* file_path) {
+    furi_assert(instance);
+    furi_assert(file_path);
+
+    FuriString* temp_str = furi_string_alloc();
+    bool result = false;
+
+    Storage* storage = furi_record_open(RECORD_STORAGE);
+    FlipperFormat* file = flipper_format_file_alloc(storage);
+
+    do {
+        if (!flipper_format_file_open_existing(file, file_path)) break;
+
+        uint32_t version = 0;
+        if (!flipper_format_read_header(file, temp_str, &version)) break;
+        if (furi_string_cmp_str(temp_str, QRCODE_FILETYPE)
+                || version != QRCODE_FILE_VERSION) {
+            FURI_LOG_E(TAG, "Incorrect file format or version");
+            break;
+        }
+
+        if (!flipper_format_read_string(file, "Message", temp_str)) {
+            FURI_LOG_E(TAG, "Message is missing");
+            break;
+        }
+
+        if (!qrcode_load_string(instance, temp_str)) {
+            break;
+        }
+
+        result = true;
+    } while (false);
+
+    furi_record_close(RECORD_STORAGE);
+    flipper_format_free(file);
+    furi_string_free(temp_str);
+
+    return result;
+}
+
+/**
+ * Allocate the qrcode app
+ * @returns a qrcode app instance
+ */
+static QRCodeApp* qrcode_app_alloc() {
+    QRCodeApp* instance = malloc(sizeof(QRCodeApp));
+
+    instance->input_queue = furi_message_queue_alloc(8, sizeof(InputEvent));
+
+    instance->view_port = view_port_alloc();
+    view_port_draw_callback_set(instance->view_port, render_callback, instance);
+    view_port_input_callback_set(instance->view_port, input_callback, instance);
+
+    instance->gui = furi_record_open(RECORD_GUI);
+    gui_add_view_port(instance->gui, instance->view_port, GuiLayerFullscreen);
+
+    instance->mutex = furi_mutex_alloc(FuriMutexTypeNormal);
+
+    return instance;
+}
+
+/**
+ * Free the qrcode app
+ * @param qrcode_app The app to free
+ */
+static void qrcode_app_free(QRCodeApp* instance) {
+    if (instance->qrcode) qrcode_free(instance->qrcode);
+
+    gui_remove_view_port(instance->gui, instance->view_port);
+    furi_record_close(RECORD_GUI);
+
+    view_port_free(instance->view_port);
+
+    furi_message_queue_free(instance->input_queue);
+
+    furi_mutex_free(instance->mutex);
+
+    free(instance);
+}
+
+/** App entrypoint */
+int32_t qrcode_app(void* p) {
+    QRCodeApp* instance = qrcode_app_alloc();
+
+    FuriString* file_path;
+    file_path = furi_string_alloc();
+
+    do {
+        if (p && strlen(p)) {
+            furi_string_set(file_path, (const char*)p);
+        } else {
+            furi_string_set(file_path, QRCODE_FOLDER);
+
+            DialogsFileBrowserOptions browser_options;
+            dialog_file_browser_set_basic_options(
+                    &browser_options, QRCODE_EXTENSION, &I_qrcode_10px);
+            browser_options.hide_ext = true;
+            browser_options.base_path = QRCODE_FOLDER;
+
+            DialogsApp* dialogs = furi_record_open(RECORD_DIALOGS);
+            bool res = dialog_file_browser_show(dialogs, file_path, file_path, &browser_options);
+
+            furi_record_close(RECORD_DIALOGS);
+            if (!res) {
+                FURI_LOG_E(TAG, "No file selected");
+                break;
+            }
+        }
+
+        if (!qrcode_load_file(instance, furi_string_get_cstr(file_path))) {
+            FURI_LOG_E(TAG, "Unable to load file");
+        }
+
+        InputEvent input;
+        while (furi_message_queue_get(instance->input_queue, &input, FuriWaitForever) == FuriStatusOk) {
+            furi_check(furi_mutex_acquire(instance->mutex, FuriWaitForever) == FuriStatusOk);
+
+            if (input.key == InputKeyBack) {
+                if (instance->qrcode) {
+                    qrcode_free(instance->qrcode);
+                    instance->qrcode = NULL;
+                }
+                furi_mutex_release(instance->mutex);
+                break;
+            }
+
+            furi_mutex_release(instance->mutex);
+            view_port_update(instance->view_port);
+        }
+
+        if (p && strlen(p)) {
+            // if started with an arg, exit instead of going to the browser
+            break;
+        }
+    } while (1);
+
+    furi_string_free(file_path);
+    qrcode_app_free(instance);
+
+    return 0;
+}