Image Decoder

static bool hasExtension(const char *name, const char *extension)

1. Executeconst size_t name_length = strlen(name);
2. Executeconst size_t extension_length = strlen(extension);
3. Decisionname_length < extension_length
   True

   1. Exit this functionreturn false;

   False

   Continue after this decision.

4. Executename += name_length - extension_length;
5. FOR loopsize_t index = 0; index < extension_length; ++index

   Repeat body while the loop condition permits; then continue below.

   1. 1. Decisiontolower((unsigned char)name[index]) != extension[index]
         True

         1. Exit this functionreturn false;

         False

         Continue after this decision.

6. Exit this functionreturn true;

static bool hasExtension(const char *name, const char *extension)
{
    const size_t name_length = strlen(name);
    const size_t extension_length = strlen(extension);
    if (name_length < extension_length) return false;
    name += name_length - extension_length;
    for (size_t index = 0; index < extension_length; ++index) {
        if (tolower((unsigned char)name[index]) != extension[index]) return false;
    }
    return true;
}

bool imageIsSupportedName(const char *name)

Calls into this documentation:

1. Exit this functionreturn name != NULL && (hasExtension(name, ".jpg") || hasExtension(name, ".jpeg") || hasExtension(name, ".png"));

bool imageIsSupportedName(const char *name)
{
    return name != NULL && (hasExtension(name, ".jpg") || hasExtension(name, ".jpeg") || hasExtension(name, ".png"));
}

static UINT jpegInput(JDEC *decoder, BYTE *buffer, UINT bytes)

1. ExecuteFILE *file = (FILE *)decoder->device;
2. Decisionbuffer != NULL
   True

   1. Exit this functionreturn (UINT)fread(buffer, 1, bytes, file);

   False

   Continue after this decision.

3. Exit this functionreturn fseek(file, (long)bytes, SEEK_CUR) == 0 ? bytes : 0;

static UINT jpegInput(JDEC *decoder, BYTE *buffer, UINT bytes)
{
    FILE *file = (FILE *)decoder->device;
    if (buffer != NULL) return (UINT)fread(buffer, 1, bytes, file);
    return fseek(file, (long)bytes, SEEK_CUR) == 0 ? bytes : 0;
}

static UINT jpegOutput(JDEC *decoder, void *bitmap, JRECT *rect)

1. Execute(void)decoder;
2. Decisionjpeg_target == NULL || rect->right + jpeg_offset_x >= LCD_WIDTH || rect->bottom + jpeg_offset_y >= LCD_HEIGHT
   True

   1. Exit this functionreturn 0;

   False

   Continue after this decision.

3. Executeconst BYTE *source = bitmap;
4. Executeconst unsigned width = rect->right - rect->left + 1U;
5. Executeconst unsigned height = rect->bottom - rect->top + 1U;
6. FOR loopunsigned row = 0; row < height; ++row

   Repeat body while the loop condition permits; then continue below.

   1. FOR loopunsigned column = 0; column < width; ++column

      Repeat body while the loop condition permits; then continue below.

      1. 1. Executeconst unsigned pixel = row * width + column;
         2. Executejpeg_target[(rect->top + row + jpeg_offset_y) * LCD_WIDTH + rect->left + column + jpeg_offset_x] = RGB565(source[pixel * 3U], source[pixel * 3U + 1U], source[pixel * 3U + 2U]);
7. Exit this functionreturn 1;

static UINT jpegOutput(JDEC *decoder, void *bitmap, JRECT *rect)
{
    (void)decoder;
    if (jpeg_target == NULL || rect->right + jpeg_offset_x >= LCD_WIDTH || rect->bottom + jpeg_offset_y >= LCD_HEIGHT) return 0;
    const BYTE *source = bitmap;
    const unsigned width = rect->right - rect->left + 1U;
    const unsigned height = rect->bottom - rect->top + 1U;
    for (unsigned row = 0; row < height; ++row) for (unsigned column = 0; column < width; ++column) {
        const unsigned pixel = row * width + column;
        jpeg_target[(rect->top + row + jpeg_offset_y) * LCD_WIDTH + rect->left + column + jpeg_offset_x] =
            RGB565(source[pixel * 3U], source[pixel * 3U + 1U], source[pixel * 3U + 2U]);
    }
    return 1;
}

static bool decodeJpegFile(const char *path, uint16_t *frame, unsigned offset_x, unsigned offset_y, bool clear_target,
                           unsigned requested_scale)

Calls into this documentation:

1. ExecuteFILE *file = fopen(path, "rb");
2. Decisionfile == NULL
   True

   1. Exit this functionreturn false;

   False

   Continue after this decision.

3. ExecuteJDEC decoder;
4. ExecuteJRESULT result = jd_prepare(&decoder, jpegInput, jpeg_work, sizeof(jpeg_work), file);
5. Decisionresult != JDR_OK
   True

   1. 1. Executefclose(file);
      2. Exit this functionreturn false;

   False

   Continue after this decision.

6. Executeunsigned scale = requested_scale;
7. Decisionclear_target
   True

   1. 1. Executescale = 0;
      2. WHILE loopscale < 3U && (((decoder.width + ((1U << scale) - 1U)) >> scale) > LCD_WIDTH || ((decoder.height + ((1U << scale) - 1U)) >> scale) > LCD_HEIGHT)

         Repeat body while the loop condition permits; then continue below.

         1. Execute++scale;

   False

   Continue after this decision.

8. Decisionscale > 3U
   True

   1. 1. Executefclose(file);
      2. Exit this functionreturn false;

   False

   Continue after this decision.

9. Executeconst unsigned width = (decoder.width + ((1U << scale) - 1U)) >> scale;
10. Executeconst unsigned height = (decoder.height + ((1U << scale) - 1U)) >> scale;
11. Decisionwidth > LCD_WIDTH || height > LCD_HEIGHT || offset_x > LCD_WIDTH - width || offset_y > LCD_HEIGHT - height
    True

    1. 1. Executefclose(file);
       2. Exit this functionreturn false;

    False

    Continue after this decision.

12. Decisionclear_target
    True

    1. Executeclear(frame, COLOR_BLACK);

    False

    Continue after this decision.

13. Executejpeg_offset_x = clear_target ? (LCD_WIDTH - width) / 2U : offset_x;
14. Executejpeg_offset_y = clear_target ? (LCD_HEIGHT - height) / 2U : offset_y;
15. Executejpeg_target = frame;
16. Executeresult = jd_decomp(&decoder, jpegOutput, scale);
17. Executejpeg_target = NULL;
18. Executefclose(file);
19. Exit this functionreturn result == JDR_OK;

static bool decodeJpegFile(const char *path, uint16_t *frame, unsigned offset_x, unsigned offset_y, bool clear_target,
                           unsigned requested_scale)
{
    FILE *file = fopen(path, "rb");
    if (file == NULL) return false;
    JDEC decoder;
    JRESULT result = jd_prepare(&decoder, jpegInput, jpeg_work, sizeof(jpeg_work), file);
    if (result != JDR_OK) {
        fclose(file);
        return false;
    }
    unsigned scale = requested_scale;
    if (clear_target) {
        scale = 0;
        while (scale < 3U && (((decoder.width + ((1U << scale) - 1U)) >> scale) > LCD_WIDTH ||
                              ((decoder.height + ((1U << scale) - 1U)) >> scale) > LCD_HEIGHT)) ++scale;
    }
    if (scale > 3U) { fclose(file); return false; }
    const unsigned width = (decoder.width + ((1U << scale) - 1U)) >> scale;
    const unsigned height = (decoder.height + ((1U << scale) - 1U)) >> scale;
    if (width > LCD_WIDTH || height > LCD_HEIGHT || offset_x > LCD_WIDTH - width || offset_y > LCD_HEIGHT - height) {
        fclose(file);
        return false;
    }
    if (clear_target) clear(frame, COLOR_BLACK);
    jpeg_offset_x = clear_target ? (LCD_WIDTH - width) / 2U : offset_x;
    jpeg_offset_y = clear_target ? (LCD_HEIGHT - height) / 2U : offset_y;
    jpeg_target = frame;
    result = jd_decomp(&decoder, jpegOutput, scale);
    jpeg_target = NULL;
    fclose(file);
    return result == JDR_OK;
}

static uint32_t readBigEndian(const uint8_t *bytes)

1. Exit this functionreturn ((uint32_t)bytes[0] << 24) | ((uint32_t)bytes[1] << 16) | ((uint32_t)bytes[2] << 8) | bytes[3];

static uint32_t readBigEndian(const uint8_t *bytes)
{
    return ((uint32_t)bytes[0] << 24) | ((uint32_t)bytes[1] << 16) | ((uint32_t)bytes[2] << 8) | bytes[3];
}

static uint8_t paeth(uint8_t left, uint8_t above, uint8_t upper_left)

1. Executeconst int prediction = (int)left + above - upper_left;
2. Executeconst int left_distance = prediction > left ? prediction - left : left - prediction;
3. Executeconst int above_distance = prediction > above ? prediction - above : above - prediction;
4. Executeconst int upper_left_distance = prediction > upper_left ? prediction - upper_left : upper_left - prediction;
5. Decisionleft_distance <= above_distance && left_distance <= upper_left_distance
   True

   1. Exit this functionreturn left;

   False

   Continue after this decision.

6. Exit this functionreturn above_distance <= upper_left_distance ? above : upper_left;

static uint8_t paeth(uint8_t left, uint8_t above, uint8_t upper_left)
{
    const int prediction = (int)left + above - upper_left;
    const int left_distance = prediction > left ? prediction - left : left - prediction;
    const int above_distance = prediction > above ? prediction - above : above - prediction;
    const int upper_left_distance = prediction > upper_left ? prediction - upper_left : upper_left - prediction;
    if (left_distance <= above_distance && left_distance <= upper_left_distance) return left;
    return above_distance <= upper_left_distance ? above : upper_left;
}

static bool decodePngFile(const char *path, uint16_t *frame)

Calls into this documentation:

1. Executestatic const uint8_t png_signature[PNG_SIGNATURE_BYTES] = { 137, 80, 78, 71, 13, 10, 26, 10 };
2. ExecuteFILE *file = fopen(path, "rb");
3. Executeuint8_t signature[PNG_SIGNATURE_BYTES], header[8], ihdr[PNG_IHDR_BYTES];
4. Executeuint8_t *compressed = NULL;
5. Executeuint8_t *pixels = NULL;
6. Executetinfl_decompressor *decompressor = NULL;
7. Executesize_t compressed_bytes = 0;
8. Executebool result = false;
9. Executeunsigned channels = 0;
10. Decisionfile == NULL || fread(signature, 1, sizeof(signature), file) != sizeof(signature) || memcmp(signature, png_signature, sizeof(signature)) != 0
    True

    1. Jump to labelgoto done;

    False

    Continue after this decision.

11. FOR loop;;

    Repeat body while the loop condition permits; then continue below.

    1. 1. Decisionfread(header, 1, sizeof(header), file) != sizeof(header)
          True

          1. Jump to labelgoto done;

          False

          Continue after this decision.

       2. Executeconst uint32_t length = readBigEndian(header);
       3. Decisionlength > PNG_MAX_COMPRESSED_BYTES
          True

          1. Jump to labelgoto done;

          False

          Continue after this decision.

       4. Decisionmemcmp(header + 4, "IHDR", 4) == 0
          True

          1. 1. Decisionlength != PNG_IHDR_BYTES || fread(ihdr, 1, sizeof(ihdr), file) != sizeof(ihdr)
                True

                1. Jump to labelgoto done;

                False

                Continue after this decision.

             2. DecisionreadBigEndian(ihdr) != LCD_WIDTH || readBigEndian(ihdr + 4) != LCD_HEIGHT || ihdr[8] != 8U || ihdr[10] != 0U || ihdr[11] != 0U || ihdr[12] != 0U
                True

                1. Jump to labelgoto done;

                False

                Continue after this decision.

             3. Decisionihdr[9] == 2U
                True

                1. Executechannels = 3U;

                False

                1. Decisionihdr[9] == 6U
                   True

                   1. Executechannels = 4U;

                   False

                   1. Jump to labelgoto done;

          False

          1. Decisionmemcmp(header + 4, "IDAT", 4) == 0
             True

             1. 1. Decisionlength > PNG_MAX_COMPRESSED_BYTES - compressed_bytes
                   True

                   1. Jump to labelgoto done;

                   False

                   Continue after this decision.

                2. Executeuint8_t *expanded = heap_caps_realloc(compressed, compressed_bytes + length, MALLOC_CAP_SPIRAM | MALLOC_CAP_8BIT);
                3. Decisionexpanded == NULL
                   True

                   1. Jump to labelgoto done;

                   False

                   Continue after this decision.

                4. Executecompressed = expanded;
                5. Decisionfread(compressed + compressed_bytes, 1, length, file) != length
                   True

                   1. Jump to labelgoto done;

                   False

                   Continue after this decision.

                6. Executecompressed_bytes += length;

             False

             1. Decisionfseek(file, (long)length, SEEK_CUR) != 0
                True

                1. Jump to labelgoto done;

                False

                Continue after this decision.

       5. Decisionfseek(file, 4L, SEEK_CUR) != 0
          True

          1. Jump to labelgoto done;

          False

          Continue after this decision.

       6. Decisionmemcmp(header + 4, "IEND", 4) == 0
          True

          1. Exit enclosing loop or switchbreak;

          False

          Continue after this decision.

12. Decisionchannels == 0U || compressed_bytes == 0U
    True

    1. Jump to labelgoto done;

    False

    Continue after this decision.

13. Executeconst size_t row_bytes = LCD_WIDTH * channels;
14. Executeconst size_t decoded_bytes = LCD_HEIGHT * (row_bytes + 1U);
15. Executepixels = heap_caps_malloc(decoded_bytes, MALLOC_CAP_SPIRAM | MALLOC_CAP_8BIT);
16. Executedecompressor = calloc(1, sizeof(*decompressor));
17. Decisionpixels == NULL || decompressor == NULL
    True

    1. Jump to labelgoto done;

    False

    Continue after this decision.

18. Executetinfl_init(decompressor);
19. Executesize_t input_position = 0, output_position = 0;
20. FOR loop;;

    Repeat body while the loop condition permits; then continue below.

    1. 1. Executesize_t input_bytes = compressed_bytes - input_position;
       2. Executesize_t output_bytes = decoded_bytes - output_position;
       3. Executeconst tinfl_status status = tinfl_decompress(decompressor, compressed + input_position, &input_bytes, pixels, pixels + output_position, &output_bytes, TINFL_FLAG_PARSE_ZLIB_HEADER | TINFL_FLAG_USING_NON_WRAPPING_OUTPUT_BUF);
       4. Executeinput_position += input_bytes;
       5. Executeoutput_position += output_bytes;
       6. Decisionstatus == TINFL_STATUS_DONE
          True

          1. Exit enclosing loop or switchbreak;

          False

          Continue after this decision.

       7. Decisionstatus < TINFL_STATUS_DONE || (input_bytes == 0U && output_bytes == 0U)
          True

          1. Jump to labelgoto done;

          False

          Continue after this decision.

21. Decisionoutput_position != decoded_bytes
    True

    1. Jump to labelgoto done;

    False

    Continue after this decision.

22. FOR loopunsigned row = 0; row < LCD_HEIGHT; ++row

    Repeat body while the loop condition permits; then continue below.

    1. 1. Executeuint8_t *current = pixels + row * (row_bytes + 1U) + 1U;
       2. Executeconst uint8_t *previous = row == 0U ? NULL : current - (row_bytes + 1U);
       3. Executeconst uint8_t filter = current[-1];
       4. Decisionfilter > 4U
          True

          1. Jump to labelgoto done;

          False

          Continue after this decision.

       5. FOR loopsize_t column = 0; column < row_bytes; ++column

          Repeat body while the loop condition permits; then continue below.

          1. 1. Executeconst uint8_t left = column < channels ? 0U : current[column - channels];
             2. Executeconst uint8_t above = previous == NULL ? 0U : previous[column];
             3. Executeconst uint8_t upper_left = previous == NULL || column < channels ? 0U : previous[column - channels];
             4. Decisionfilter == 1U
                True

                1. Executecurrent[column] = (uint8_t)(current[column] + left);

                False

                1. Decisionfilter == 2U
                   True

                   1. Executecurrent[column] = (uint8_t)(current[column] + above);

                   False

                   1. Decisionfilter == 3U
                      True

                      1. Executecurrent[column] = (uint8_t)(current[column] + ((left + above) >> 1));

                      False

                      1. Decisionfilter == 4U
                         True

                         1. Executecurrent[column] = (uint8_t)(current[column] + paeth(left, above, upper_left));

                         False

                         Continue after this decision.

23. FOR loopunsigned y = 0; y < LCD_HEIGHT; ++y

    Repeat body while the loop condition permits; then continue below.

    1. FOR loopunsigned x = 0; x < LCD_WIDTH; ++x

       Repeat body while the loop condition permits; then continue below.

       1. 1. Executeconst uint8_t *pixel = pixels + y * (row_bytes + 1U) + 1U + x * channels;
          2. Executeconst uint8_t alpha = channels == 4U ? pixel[3] : 255U;
          3. Executeframe[y * LCD_WIDTH + x] = RGB565((uint8_t)((pixel[0] * alpha) / 255U), (uint8_t)((pixel[1] * alpha) / 255U), (uint8_t)((pixel[2] * alpha) / 255U));
24. Executeresult = true;
25. Executedone: free(pixels);
26. Executefree(compressed);
27. Executefree(decompressor);
28. Decisionfile != NULL
    True

    1. Executefclose(file);

    False

    Continue after this decision.

29. Exit this functionreturn result;

static bool decodePngFile(const char *path, uint16_t *frame)
{
    static const uint8_t png_signature[PNG_SIGNATURE_BYTES] = { 137, 80, 78, 71, 13, 10, 26, 10 };
    FILE *file = fopen(path, "rb");
    uint8_t signature[PNG_SIGNATURE_BYTES], header[8], ihdr[PNG_IHDR_BYTES];
    uint8_t *compressed = NULL;
    uint8_t *pixels = NULL;
    tinfl_decompressor *decompressor = NULL;
    size_t compressed_bytes = 0;
    bool result = false;
    unsigned channels = 0;

    if (file == NULL || fread(signature, 1, sizeof(signature), file) != sizeof(signature) ||
        memcmp(signature, png_signature, sizeof(signature)) != 0) goto done;
    for (;;) {
        if (fread(header, 1, sizeof(header), file) != sizeof(header)) goto done;
        const uint32_t length = readBigEndian(header);
        if (length > PNG_MAX_COMPRESSED_BYTES) goto done;
        if (memcmp(header + 4, "IHDR", 4) == 0) {
            if (length != PNG_IHDR_BYTES || fread(ihdr, 1, sizeof(ihdr), file) != sizeof(ihdr)) goto done;
            if (readBigEndian(ihdr) != LCD_WIDTH || readBigEndian(ihdr + 4) != LCD_HEIGHT ||
                ihdr[8] != 8U || ihdr[10] != 0U || ihdr[11] != 0U || ihdr[12] != 0U) goto done;
            if (ihdr[9] == 2U) channels = 3U;
            else if (ihdr[9] == 6U) channels = 4U;
            else goto done;
        } else if (memcmp(header + 4, "IDAT", 4) == 0) {
            if (length > PNG_MAX_COMPRESSED_BYTES - compressed_bytes) goto done;
            uint8_t *expanded = heap_caps_realloc(compressed, compressed_bytes + length,
                                                  MALLOC_CAP_SPIRAM | MALLOC_CAP_8BIT);
            if (expanded == NULL) goto done;
            compressed = expanded;
            if (fread(compressed + compressed_bytes, 1, length, file) != length) goto done;
            compressed_bytes += length;
        } else if (fseek(file, (long)length, SEEK_CUR) != 0) goto done;
        if (fseek(file, 4L, SEEK_CUR) != 0) goto done;
        if (memcmp(header + 4, "IEND", 4) == 0) break;
    }
    if (channels == 0U || compressed_bytes == 0U) goto done;
    const size_t row_bytes = LCD_WIDTH * channels;
    const size_t decoded_bytes = LCD_HEIGHT * (row_bytes + 1U);
    pixels = heap_caps_malloc(decoded_bytes, MALLOC_CAP_SPIRAM | MALLOC_CAP_8BIT);
    decompressor = calloc(1, sizeof(*decompressor));
    if (pixels == NULL || decompressor == NULL) goto done;
    tinfl_init(decompressor);
    size_t input_position = 0, output_position = 0;
    for (;;) {
        size_t input_bytes = compressed_bytes - input_position;
        size_t output_bytes = decoded_bytes - output_position;
        const tinfl_status status = tinfl_decompress(decompressor, compressed + input_position, &input_bytes,
                                                     pixels, pixels + output_position, &output_bytes,
                                                     TINFL_FLAG_PARSE_ZLIB_HEADER | TINFL_FLAG_USING_NON_WRAPPING_OUTPUT_BUF);
        input_position += input_bytes;
        output_position += output_bytes;
        if (status == TINFL_STATUS_DONE) break;
        if (status < TINFL_STATUS_DONE || (input_bytes == 0U && output_bytes == 0U)) goto done;
    }
    if (output_position != decoded_bytes) goto done;
    for (unsigned row = 0; row < LCD_HEIGHT; ++row) {
        uint8_t *current = pixels + row * (row_bytes + 1U) + 1U;
        const uint8_t *previous = row == 0U ? NULL : current - (row_bytes + 1U);
        const uint8_t filter = current[-1];
        if (filter > 4U) goto done;
        for (size_t column = 0; column < row_bytes; ++column) {
            const uint8_t left = column < channels ? 0U : current[column - channels];
            const uint8_t above = previous == NULL ? 0U : previous[column];
            const uint8_t upper_left = previous == NULL || column < channels ? 0U : previous[column - channels];
            if (filter == 1U) current[column] = (uint8_t)(current[column] + left);
            else if (filter == 2U) current[column] = (uint8_t)(current[column] + above);
            else if (filter == 3U) current[column] = (uint8_t)(current[column] + ((left + above) >> 1));
            else if (filter == 4U) current[column] = (uint8_t)(current[column] + paeth(left, above, upper_left));
        }
    }
    for (unsigned y = 0; y < LCD_HEIGHT; ++y) for (unsigned x = 0; x < LCD_WIDTH; ++x) {
        const uint8_t *pixel = pixels + y * (row_bytes + 1U) + 1U + x * channels;
        const uint8_t alpha = channels == 4U ? pixel[3] : 255U;
        frame[y * LCD_WIDTH + x] = RGB565((uint8_t)((pixel[0] * alpha) / 255U),
                                          (uint8_t)((pixel[1] * alpha) / 255U),
                                          (uint8_t)((pixel[2] * alpha) / 255U));
    }
    result = true;

done:
    free(pixels);
    free(compressed);
    free(decompressor);
    if (file != NULL) fclose(file);
    return result;
}

bool imageDecodeFile(const char *path, uint16_t *frame)

Calls into this documentation:

1. Decisionpath == NULL || frame == NULL
   True

   1. Exit this functionreturn false;

   False

   Continue after this decision.

2. DecisionhasExtension(path, ".jpg") || hasExtension(path, ".jpeg")
   True

   1. Exit this functionreturn decodeJpegFile(path, frame, 0U, 0U, true, 0U);

   False

   Continue after this decision.

3. DecisionhasExtension(path, ".png")
   True

   1. Exit this functionreturn decodePngFile(path, frame);

   False

   Continue after this decision.

4. Exit this functionreturn false;

bool imageDecodeFile(const char *path, uint16_t *frame)
{
    if (path == NULL || frame == NULL) return false;
    if (hasExtension(path, ".jpg") || hasExtension(path, ".jpeg")) return decodeJpegFile(path, frame, 0U, 0U, true, 0U);
    if (hasExtension(path, ".png")) return decodePngFile(path, frame);
    return false;
}

bool imageDecodeJpegAt(const char *path, uint16_t *frame, unsigned x, unsigned y)

Calls into this documentation:

1. Decisionpath == NULL || frame == NULL || (!hasExtension(path, ".jpg") && !hasExtension(path, ".jpeg"))
   True

   1. Exit this functionreturn false;

   False

   Continue after this decision.

2. Exit this functionreturn decodeJpegFile(path, frame, x, y, false, 0U);

bool imageDecodeJpegAt(const char *path, uint16_t *frame, unsigned x, unsigned y)
{
    if (path == NULL || frame == NULL || (!hasExtension(path, ".jpg") && !hasExtension(path, ".jpeg"))) return false;
    return decodeJpegFile(path, frame, x, y, false, 0U);
}

bool imageDecodeJpegScaledAt(const char *path, uint16_t *frame, unsigned x, unsigned y, unsigned scale)

Calls into this documentation:

1. Decisionpath == NULL || frame == NULL || scale > 3U || (!hasExtension(path, ".jpg") && !hasExtension(path, ".jpeg"))
   True

   1. Exit this functionreturn false;

   False

   Continue after this decision.

2. Exit this functionreturn decodeJpegFile(path, frame, x, y, false, scale);

bool imageDecodeJpegScaledAt(const char *path, uint16_t *frame, unsigned x, unsigned y, unsigned scale)
{
    if (path == NULL || frame == NULL || scale > 3U || (!hasExtension(path, ".jpg") && !hasExtension(path, ".jpeg"))) return false;
    return decodeJpegFile(path, frame, x, y, false, scale);
}