Function kernelDisplayInPix

deps/leptonica/src/kernel.c:925–1021

----------------------------------------------------------------------* * Display a kernel in a pix * *----------------------------------------------------------------------*/ ! * \brief kernelDisplayInPix() * * \param[in] kel kernel * \param[in] size of grid interiors; odd; either 1 or a minimum size * of 17 is enforced

 * </pre>
 */
PIX *
kernelDisplayInPix(L_KERNEL     *kel,
                   l_int32       size,
                   l_int32       gthick)
{
l_int32    i, j, w, h, sx, sy, cx, cy, width, x0, y0;
l_int32    normval;
l_float32  minval, maxval, max, val, norm;
PIX       *pixd, *pixt0, *pixt1;

    PROCNAME("kernelDisplayInPix");

    if (!kel)
        return (PIX *)ERROR_PTR("kernel not defined", procName, NULL);

        /* Normalize the max value to be 255 for display */
    kernelGetParameters(kel, &sy, &sx, &cy, &cx);
    kernelGetMinMax(kel, &minval, &maxval);
    max = L_MAX(maxval, -minval);
    if (max == 0.0)
        return (PIX *)ERROR_PTR("kernel elements all 0.0", procName, NULL);
    norm = 255. / (l_float32)max;

        /* Handle the 1 element/pixel case; typically with large kernels */
    if (size == 1 && gthick == 0) {
        pixd = pixCreate(sx, sy, 8);
        for (i = 0; i < sy; i++) {
            for (j = 0; j < sx; j++) {
                kernelGetElement(kel, i, j, &val);
                normval = (l_int32)(norm * L_ABS(val));
                pixSetPixel(pixd, j, i, normval);
            }
        }
        return pixd;
    }

        /* Enforce the constraints for the grid line version */
    if (size < 17) {
        L_WARNING("size < 17; setting to 17\n", procName);
        size = 17;
    }
    if (size % 2 == 0)
        size++;
    if (gthick < 2) {
        L_WARNING("grid thickness < 2; setting to 2\n", procName);
        gthick = 2;
    }

    w = size * sx + gthick * (sx + 1);
    h = size * sy + gthick * (sy + 1);
    pixd = pixCreate(w, h, 8);

        /* Generate grid lines */
    for (i = 0; i <= sy; i++)
        pixRenderLine(pixd, 0, gthick / 2 + i * (size + gthick),
                      w - 1, gthick / 2 + i * (size + gthick),
                      gthick, L_SET_PIXELS);
    for (j = 0; j <= sx; j++)