QOI-Format-Codec/qoi.h at main · ACMClassCourse-2022/QOI-Format-Codec · GitHub

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#ifndef QOI_FORMAT_CODEC_QOI_H_
#define QOI_FORMAT_CODEC_QOI_H_

#include "utils.h"

constexpr uint8_t QOI_OP_INDEX_TAG = 0x00;
constexpr uint8_t QOI_OP_DIFF_TAG  = 0x40;
constexpr uint8_t QOI_OP_LUMA_TAG  = 0x80;
constexpr uint8_t QOI_OP_RUN_TAG   = 0xc0;
constexpr uint8_t QOI_OP_RGB_TAG   = 0xfe;
constexpr uint8_t QOI_OP_RGBA_TAG  = 0xff;
constexpr uint8_t QOI_PADDING[8] = {0u, 0u, 0u, 0u, 0u, 0u, 0u, 1u};
constexpr uint8_t QOI_MASK_2 = 0xc0;

/**
 * @brief encode the raw pixel data of an image to qoi format.
 *
 * @param[in] width image width in pixels
 * @param[in] height image height in pixels
 * @param[in] channels number of color channels, 3 = RGB, 4 = RGBA
 * @param[in] colorspace image color space, 0 = sRGB with linear alpha, 1 = all channels linear
 *
 * @return bool true if it is a valid qoi format image, false otherwise
 */
bool QoiEncode(uint32_t width, uint32_t height, uint8_t channels, uint8_t colorspace = 0);

/**
 * @brief decode the qoi format of an image to raw pixel data
 *
 * @param[out] width image width in pixels
 * @param[out] height image height in pixels
 * @param[out] channels number of color channels, 3 = RGB, 4 = RGBA
 * @param[out] colorspace image color space, 0 = sRGB with linear alpha, 1 = all channels linear
 *
 * @return bool true if it is a valid qoi format image, false otherwise
 */
bool QoiDecode(uint32_t &width, uint32_t &height, uint8_t &channels, uint8_t &colorspace);


bool QoiEncode(uint32_t width, uint32_t height, uint8_t channels, uint8_t colorspace) {

    // qoi-header part

    // write magic bytes "qoif"
    QoiWriteChar('q');
    QoiWriteChar('o');
    QoiWriteChar('i');
    QoiWriteChar('f');
    // write image width
    QoiWriteU32(width);
    // write image height
    QoiWriteU32(height);
    // write channel number
    QoiWriteU8(channels);
    // write color space specifier
    QoiWriteU8(colorspace);

    /* qoi-data part */
    int run = 0;
    int px_num = width * height;

    uint8_t history[64][4];
    memset(history, 0, sizeof(history));

    uint8_t r, g, b, a;
    a = 255u;
    uint8_t pre_r, pre_g, pre_b, pre_a;
    pre_r = 0u;
    pre_g = 0u;
    pre_b = 0u;
    pre_a = 255u;

    for (int i = 0; i < px_num; ++i) {
        r = QoiReadU8();
        g = QoiReadU8();
        b = QoiReadU8();
        if (channels == 4) a = QoiReadU8();

        // TODO

        pre_r = r;
        pre_g = g;
        pre_b = b;
        pre_a = a;
    }

    // qoi-padding part
    for (int i = 0; i < sizeof(QOI_PADDING) / sizeof(QOI_PADDING[0]); ++i) {
        QoiWriteU8(QOI_PADDING[i]);
    }

    return true;
}

bool QoiDecode(uint32_t &width, uint32_t &height, uint8_t &channels, uint8_t &colorspace) {

    char c1 = QoiReadChar();
    char c2 = QoiReadChar();
    char c3 = QoiReadChar();
    char c4 = QoiReadChar();
    if (c1 != 'q' || c2 != 'o' || c3 != 'i' || c4 != 'f') {
        return false;
    }

    // read image width
    width = QoiReadU32();
    // read image height
    height = QoiReadU32();
    // read channel number
    channels = QoiReadU8();
    // read color space specifier
    colorspace = QoiReadU8();

    int run = 0;
    int px_num = width * height;

    uint8_t history[64][4];
    memset(history, 0, sizeof(history));

    uint8_t r, g, b, a;
    a = 255u;

    for (int i = 0; i < px_num; ++i) {

        // TODO

        QoiWriteU8(r);
        QoiWriteU8(g);
        QoiWriteU8(b);
        if (channels == 4) QoiWriteU8(a);
    }

    bool valid = true;
    for (int i = 0; i < sizeof(QOI_PADDING) / sizeof(QOI_PADDING[0]); ++i) {
        if (QoiReadU8() != QOI_PADDING[i]) valid = false;
    }

    return valid;
}

#endif // QOI_FORMAT_CODEC_QOI_H_