Yalantis/uCrop · error · CImgArgumentException

deriche(): Invalid specified order

Error message

deriche(): Invalid specified order '%d' ('order' can be { 0=smoothing | 1=1st-derivative | 2=2nd-derivative }).

What it means

CImg's Deriche filter (deriche()) only supports order 0 (smoothing), 1 (first derivative) or 2 (second derivative). Any order value greater than 2 throws this argument-validation exception; order is checked at the top of the routine before any processing.

Solutions

  1. Pass order as 0, 1 or 2
  2. For higher derivatives, chain multiple 1st-derivative calls (deriche twice approximates 2nd order already) or use a different method
  3. Clamp or validate the order variable before calling

Example fix

// before
img.deriche(2.0f, 3, 'x');
// after
img.deriche(2.0f, 2, 'x'); // max supported derivative order
Defensive patterns

Strategy: validation

Validate before calling

if (order > 2) order = 2; // clamp before deriche()

Type guard

bool validDerivativeOrder(unsigned order) { return order <= 2; }

Try / catch

try {
  img.deriche(sigma, order, axis);
} catch (cimg_library::CImgArgumentException& e) {
  img.deriche(sigma, 0, axis); // fall back to smoothing
}

Prevention

When it happens

Trigger: Calling img.deriche(sigma, order, axis) with order >= 3, e.g. passing a derivative order taken from a loop variable that overruns, or confusing 'order' with a filter size or iteration count.

Common situations: Mapping an arbitrary nth-derivative request onto Deriche (which only implements up to 2nd order); copy-pasting a vanvliet/Haar call pattern with wrong semantics; unsigned underflow is not possible here (order>2 fails, not negative).

Understand the failure class

Background: "Must be a positive integer", "Invalid value", "Unsupported": the invalid-argument-value error family, when a library rejects the value you pass — this error's family across 35 libraries.

Related errors

AI-assisted analysis of Yalantis/uCrop@f788b534b4 (2026-09-08). Data as JSON: /api/errors/77537ae5262e9392. Report an issue: GitHub.

Appendix: source

Thrown at ucrop/src/main/jni/CImg.h:43755

  T xp = (T)0; \
  if (boundary_conditions) { xp = *ptrX; yb = yp = (double)(coefp*xp); } \
  for (int m = 0; m<N; ++m) { \
    const T xc = *ptrX; ptrX+=off; \
    const double yc = *(ptrY++) = (double)(a0*xc + a1*xp - b1*yp - b2*yb); \
    xp = xc; yb = yp; yp = yc; \
  } \
  T xn = (T)0, xa = (T)0; \
  double yn = 0, ya = 0; \
  if (boundary_conditions) { xn = xa = *(ptrX - off); yn = ya = (double)coefn*xn; } \
  for (int n = N - 1; n>=0; --n) { \
    const T xc = *(ptrX-=off); \
    const double yc = (double)(a2*xn + a3*xa - b1*yn - b2*ya); \
    xa = xn; xn = xc; ya = yn; yn = yc; \
    *ptrX = (T)(*(--ptrY)+yc); \
  }

      if (order>2)
        throw CImgArgumentException(_cimg_instance
                                    "deriche(): Invalid specified order '%d' "
                                    "('order' can be { 0=smoothing | 1=1st-derivative | 2=2nd-derivative }).",
                                    cimg_instance,
                                    order);

      const char naxis = cimg::lowercase(axis);
      if (naxis!='x' && naxis!='y' && naxis!='z' && naxis!='c')
        throw CImgArgumentException(_cimg_instance
                                    "deriche(): Invalid specified axis '%c'.",
                                    cimg_instance,
                                    axis);
      const double
        nsigma = sigma>=0?sigma:-sigma*(naxis=='x'?_width:
                                        naxis=='y'?_height:
                                        naxis=='z'?_depth:_spectrum)/100,
        nnsigma = nsigma<0.1f?0.1f:nsigma;

      if (is_empty() || (nsigma<0.1f && !order)) return *this;

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