colorcvt.c

linux下的一款播放器

/*
 * Convert a value in the range of [-1,1],
 * to a new range [l,h]; with a middle value equal to m.
 */
static double chrange (double x, double l, double m, double h)
{
    if (x >= 0.) {
        if (x > 1.) x = 1.;
        x = m + (h - m) * x;
    } else {
        if (x < -1.) x = -1.;
        x = m + (m - l) * x;
    }
    return x;
}

/*
 * Checks if variable is signicantly different from zero.
 */
static int is (double val)
{
    return fabs(val) > 0.01;    /* < 1% is not considered a change */
}


/*
 * Returns current state of "from/to I420" converters.
 * Use:
 *  void GetSrcI420Colors (float *brightness, float *contrast, float *saturation, float *hue);
 * Output:
 *  brightness - brightness adjustment [-1,1], 0 - default;
 *  contrast   - contrast adjustment   [-1,1], 0 - default;
 *  saturation - saturation adjustment [-1,1], 0 - default;
 *  hue        - hue adjustment        [-1,1], 0 - default;
 * Returns:
 *  none.
 */
void GetSrcI420Colors (float *brightness, float *contrast, float *saturation, float *hue)
{
    if (brightness && contrast && saturation && hue)
    {
	*brightness = cur_brightness;
	*contrast   = cur_contrast;
	*saturation = cur_saturation;
	*hue	    = cur_hue;
    }
}

/*
 * Initializes "from/to I420" converters.
 * Use:
 *  void SetSrcI420Colors (float brightness, float contrast, float saturation, float hue);
 *  void SetDestI420Colors (float brightness, float contrast, float saturation, float hue);
 * Input:
 *  brightness - brightness adjustment [-1,1], 0 - default;
 *  contrast   - contrast adjustment   [-1,1], 0 - default;
 *  saturation - saturation adjustment [-1,1], 0 - default;
 *  hue        - hue adjustment        [-1,1], 0 - default;
 * Returns:
 *  none.
 */
void SetSrcI420Colors (float brightness, float contrast, float saturation, float hue)
{
    /* check if we need to generate new color conversion tables: */
    if (!color_conversion_tables_inited  ||
        is (cur_brightness - brightness) ||
        is (cur_contrast - contrast)     ||
        is (cur_saturation - saturation) ||
        is (cur_hue - hue)) {

        double alpha, beta, gamma, kappa, lambda;
        double cos_alpha, xi_sin_alpha, minus_zeta_sin_alpha;
        register int i;

        /* hue: */
        alpha = chrange (hue, ALPHA_MIN, ALPHA_MED, ALPHA_MAX);
        cos_alpha = cos (alpha);
        xi_sin_alpha = XI * sin (alpha);
        minus_zeta_sin_alpha = -ZETA * sin (alpha);
        is_alpha = is (cur_hue = hue);

        /* saturation: */
        beta = chrange (saturation, BETA_MIN, BETA_MED, BETA_MAX);
        is_beta = is (cur_saturation = saturation);

        /* brightness: */
        gamma = chrange (brightness, GAMMA_MIN, GAMMA_MED, GAMMA_MAX);
        is_gamma = is (cur_brightness = brightness);

        /* contrast: */
        kappa = chrange (contrast, KAPPA_MIN, KAPPA_MED, KAPPA_MAX);
        lambda = LAMBDA (kappa);
        is_kappa = is (cur_contrast = contrast);

        /*
         * Check if we need to generate clip tables & default palette:
         */
        if (!color_conversion_tables_inited) {

            /* Init clip tables. CLIP4/5/6 includes chop to 3/5/6 bits */
            for (i = -CLIPNEG; i < CLIPRNG + CLIPPOS; i++) {

                if (i < 0) {
                    CLIP4[i] = 0;
                    CLIP5[i] = 0;
                    CLIP6[i] = 0;           /* clip */
                    CLIP8[i] = 0;
                } else if (i > 255) {

                    CLIP4[i] = 255 >> 4;
                    CLIP5[i] = 255 >> 3;
                    CLIP6[i] = 255 >> 2;    /* clip */
                    CLIP8[i] = 255;
                } else {
                    CLIP4[i] = i >> 4;      /* chop to 4 bits */
                    CLIP5[i] = i >> 3;      /* chop to 5 bits */
                    CLIP6[i] = i >> 2;      /* chop to 6 bits */
                    CLIP8[i] = i;           /* leave at 8 bits */
                }
            }

            /* square values: */
            for (i = -RGB_MAX; i <= RGB_MAX; i ++)
                SQ[i] = i * i;

            /* set default palette: */
            SetDestRGB8Palette (256, default_palette, default_palette_idx);

            /* set indicator: */
            color_conversion_tables_inited ++;
        }

        /*
         * Initialize color conversion tables.
         */
        for (i = 0; i < 256; i++) {

            /* Y'Cr'Cb'->R'G'B' conversion tables: */
            double y = lambda + (i - CCIR601_YOFFSET) * kappa; /* adjust contrast */
            if (y < 0) y = 0; else if (y > CCIR601_YMAX) y = CCIR601_YMAX;
            ytab  [i] = INT(y * YCOEF * gamma);
            rvtab [i] = INT((i-CCIR601_VOFFSET) * cos_alpha * RVCOEF * beta * gamma);
            gvtab [i] = INT((i-CCIR601_VOFFSET) * GVCOEF * beta * gamma);
            bvtab [i] = INT((i-CCIR601_VOFFSET) * xi_sin_alpha * BUCOEF * beta * gamma);
            rutab [i] = INT((i-CCIR601_UOFFSET) * minus_zeta_sin_alpha * RVCOEF * beta * gamma);
            gutab [i] = INT((i-CCIR601_UOFFSET) * GUCOEF * beta * gamma);
            butab [i] = INT((i-CCIR601_UOFFSET) * cos_alpha * BUCOEF * beta * gamma);

            /* Y'Cr'Cb'->Y'Cr'Cb' conversion tables: */
            y = lambda + (i - CCIR601_YOFFSET) * kappa;
            _yytab [i] = CLIP8 [CCIR601_YOFFSET + INT(y * gamma)];
            _vvtab [i] = CCIR601_VOFFSET + INT((i-CCIR601_VOFFSET) * cos_alpha * beta * gamma);
            _uutab [i] = CCIR601_UOFFSET + INT((i-CCIR601_UOFFSET) * cos_alpha * beta * gamma);
            _vutab [i] = INT((i-CCIR601_UOFFSET) * minus_zeta_sin_alpha * beta * gamma);
            _uvtab [i] = INT((i-CCIR601_VOFFSET) * xi_sin_alpha * beta * gamma);
            if (!is_alpha) {
                _vvtab [i] = CLIP8 [_vvtab [i]];
                _uutab [i] = CLIP8 [_uutab [i]];
            }
        }
    }
}

void SetDestI420Colors (float brightness, float contrast, float saturation, float hue)
{
    /* Currently, all color adjustment parameters are ignored,
     * and tables will always be initialized for CCIR 601-2 - compliant
     * color conversion. */

    register int i, j;

    /* initialize y*tab[] tables: */
    for (i = 0; i <= RGB_MAX; i++) {
        yrtab [i] = INT((double)i * CCIR601_YRCOEF);
        ygtab [i] = INT((double)i * CCIR601_YGCOEF);
        ybtab [i] = INT((double)i * CCIR601_YBCOEF);
    }

    /* initialize yytab[]: */
    for (i = 0; i <= YMAX; i++) {
        j = INT((double)i * YSCALE);
        if (j > CCIR601_YMAX) j = CCIR601_YMAX;
        yytab [i] = j + CCIR601_YOFFSET;
    }

    /* initialize vrytab[]: */
    for (i = -VMIN; i <= VMAX; i++) {
        j = INT((double)i * VSCALE);
        if (j < -CCIR601_VMAX/2) j = -CCIR601_VMAX/2;
        if (j >  CCIR601_VMAX/2) j =  CCIR601_VMAX/2;
        vrytab [VMIN+i] = j + CCIR601_VOFFSET;
    }

    /* initialize ubytab[]: */
    for (i = -UMIN; i <= UMAX; i++) {
        j = INT((double)i * USCALE);
        if (j < -CCIR601_UMAX/2) j = -CCIR601_UMAX/2;
        if (j >  CCIR601_UMAX/2) j =  CCIR601_UMAX/2;
        ubytab [UMIN+i] = j + CCIR601_UOFFSET;
    }
}

/*
 * Suggest palettes to use for 8-bit RGB formats.
 * Use:
 *  int SuggestSrcRGB8Palette (int nColors, unsigned int *lpRGBVals);
 *  int SuggestDestRGB8Palette (int nColors, unsigned int *lpRGBVals);
 * Input:
 *  nColors - the number of existing colors in palette
 *  lpRGBVals - RGB values for each palette entry
 *  lpIndices - pixel values (palette indices)
 * Returns:
 *  >0, the total number of colors to be used, if success
 *  -1, if error
 */
int SuggestSrcRGB8Palette (int nColors, unsigned int *lpRGBVals)
{
    return -1;    /* not implemented yet... */
}

int SuggestDestRGB8Palette (int nColors, unsigned int *lpRGBVals)
{
    unsigned int rgb;
    int r, g, b, i, j, delta;

    /* determine the quanization step size: */
    if      (256 - nColors >= 6*6*6)    delta = 0x33;   /* 6x6x6 = 216 */
    else if (256 - nColors >= 5*5*5)    delta = 0x40;   /* 5x5x5 = 125 */
    else if (256 - nColors >= 4*4*4)    delta = 0x55;   /* 4x4x4 = 64  */
    else return nColors;

    /* complement the set of palette entries with ours: */
    i = nColors;
    for (r = 0; r <= 256; r += delta) { if (r == 256) r = 255;
    for (g = 0; g <= 256; g += delta) { if (g == 256) g = 255;
    for (b = 0; b <= 256; b += delta) { if (b == 256) b = 255;

        /* form palette entry: */
        rgb = b | (g << 8) | (r << 16);

        /* check if we had this color before: */
        for (j = 0; j < nColors; j ++)  if (lpRGBVals[j] == rgb) goto skip;

        /* add color: */
        lpRGBVals[i] = rgb;
        i ++;

skip:   ;
    }}}

    /* return total # of entries used: */
    return i;
}

/*
 * Set palettes to use for 8-bit RGB formats.
 * Use:
 *  int SetSrcRGB8Palette (int nColors, unsigned int *lpRGBVals, int *lpIndices);
 *  int SetDestRGB8Palette (int nColors, unsigned int *lpRGBVals, int *lpIndices);
 * Input:
 *  nColors - the number of colors in palette
 *  lpRGBVals - RGB values for each palette entry
 *  lpIndices - pixel values (palette indices)
 * Returns:
 *  >0, the total number of colors set, if success
 *  -1, if error
 */
int SetSrcRGB8Palette (int nColors, unsigned int *lpRGBVals, int *lpIndices)
{
    return -1;    /* not implemented yet... */
}

int SetDestRGB8Palette (int nColors, unsigned int *lpRGBVals, int *lpIndices)
{
    register unsigned int r, g, b, delta = 1U << 4;

    /* perform the minimum energy mismatch mapping: */
    for (r = 0; r < 256; r += delta) {
    for (g = 0; g < 256; g += delta) {
    for (b = 0; b < 256; b += delta) {

        /* initialize search: */
        int idx, match_idx = 0;
        unsigned int j, diff, match_diff;
        j = lpRGBVals[0];
        match_diff =
            SQ[(int)(r - ((j >> 0)  & 0xFF))] +
            SQ[(int)(g - ((j >> 8)  & 0xFF))] +
            SQ[(int)(b - ((j >> 16) & 0xFF))];

        /* find minimum: */
        for (idx = 1; idx < nColors; idx ++) {
            j = lpRGBVals[idx];
            diff =
                SQ[(int)(r - ((j >> 0)  & 0xFF))] +
                SQ[(int)(g - ((j >> 8)  & 0xFF))] +
                SQ[(int)(b - ((j >> 16) & 0xFF))];

            if (diff < match_diff) {
                match_idx = idx;
                match_diff = diff;
            }
        }

        /* store the result: */
        pmap[(b >> 4) | g | (r << 4)] = lpIndices[match_idx];
    }}}

    return nColors;
}

/*
 * Checks format conversion parameters.
 * Use:
 *  int chk_args (unsigned char *dest_ptr, int dest_width, int dest_height,
 *      int dest_pitch, int dest_x, int dest_y, int dest_dx, int dest_dy,
 *      unsigned char *src_ptr, int src_width, int src_height,
 *      int src_pitch, int src_x, int src_y, int src_dx, int src_dy,
 *      int *p_scale_x, int *p_scale_y);
 * Input:
 *  dest_ptr - pointer to a destination buffer
 *  dest_width, dest_height - width/height of the destination image (pixels)
 *  dest_pitch - pitch of the dest. buffer (in bytes; <0 - if bottom up image)
 *  dest_x, dest_y, dest_dx, dest_dy - destination rectangle (pixels)
 *  src_ptr - pointer to an input image
 *  src_width, src_height - width/height of the input image (pixels)
 *  src_pitch - pitch of the source buffer (in bytes; <0 - if bottom up image)
 *  src_x, src_y, src_dx, src_dy - source rectangle (pixels)
 * Output:
 *  p_scale_x, p_scale_y - scale factors for x,y axes
 *      (currently only 1:1, and 2:1 scale factors are allowed)
 * Returns:
 *  0 - if success; -1 if failure.
 */
static int
chk_args (unsigned char *dest_ptr, int dest_width, int dest_height,
    int dest_pitch, int dest_x, int dest_y, int dest_dx, int dest_dy,
    unsigned char *src_ptr, int src_width, int src_height,
    int src_pitch, int src_x, int src_y, int src_dx, int src_dy,
    int *p_scale_x, int *p_scale_y)
{
    /* alignments: */
    if (((unsigned)dest_ptr & 3) || (dest_pitch & 3) ||
        ((unsigned)src_ptr  & 3) || (src_pitch  & 3) ||
    /* image sizes: */
        dest_width <= 0 || dest_height <= 0 ||
        src_width  <= 0 || src_height  <= 0 ||
    /* rectangles: */
        dest_x < 0 || dest_y < 0 || dest_dx <= 0 || dest_dy <= 0 ||
        src_x  < 0 || src_y  < 0 || src_dx  <= 0 || src_dy  <= 0 ||
    /* overlaps: */
        dest_width < dest_x + dest_dx || dest_height < dest_y + dest_dy ||
        src_width  < src_x  + src_dx  || src_height  < src_y  + src_dy)
        goto fail;

    /* scale factors: */
    if (dest_dx == src_dx)          *p_scale_x = 1;
    else if (dest_dx == 2 * src_dx) *p_scale_x = 2;
    else goto fail;
    if (dest_dy == src_dy)          *p_scale_y = 1;
    else if (dest_dy == 2 * src_dy) *p_scale_y = 2;
    else goto fail;

    /* success: */
    return 1;