Yalantis/uCrop · error · CImgDisplayException

CImgDisplay::screenshot(): Failed to take screenshot with…

Error message

CImgDisplay::screenshot(): Failed to take screenshot with coordinates (%d,%d)-(%d,%d).

What it means

Thrown by CImgDisplay::screenshot() when XGetImage fails to read the requested screen rectangle, i.e. the coordinates (x0,y0)-(x1,y1) lie (fully or partly) outside the screen geometry or the root-window image could not be retrieved.

Solutions

1. Clamp the capture rectangle to the actual screen dimensions (e.g. via screen_width()/screen_height()) before calling screenshot()
2. Verify that x1>=x0 and y1>=y0 and that all four coordinates are non-negative and within the display bounds

When it happens

Trigger: Thrown at ucrop/src/main/jni/CImg.h:11308 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of Yalantis/uCrop@f788b534b4 (2026-09-08). Data as JSON: /api/errors/5d73f0a5e31afcea. Report an issue: GitHub.

Appendix: source

Thrown at ucrop/src/main/jni/CImg.h:11308

          const unsigned long
            red_mask = image->red_mask,
            green_mask = image->green_mask,
            blue_mask = image->blue_mask;
          img.assign(image->width,image->height,1,3);
          T *pR = img.data(0,0,0,0), *pG = img.data(0,0,0,1), *pB = img.data(0,0,0,2);
          cimg_forXY(img,x,y) {
            const unsigned long pixel = XGetPixel(image,x,y);
            *(pR++) = (T)((pixel & red_mask)>>16);
            *(pG++) = (T)((pixel & green_mask)>>8);
            *(pB++) = (T)(pixel & blue_mask);
          }
          XDestroyImage(image);
        }
      }
      if (!X11_attr.display) XCloseDisplay(dpy);
      X11_attr.unlock();
      if (img.is_empty())
        throw CImgDisplayException("CImgDisplay::screenshot(): Failed to take screenshot "
                                   "with coordinates (%d,%d)-(%d,%d).",
                                   x0,y0,x1,y1);
    }

    template<typename T>
    const CImgDisplay& snapshot(CImg<T>& img) const {
      if (is_empty()) { img.assign(); return *this; }
      const unsigned char *ptrs = (unsigned char*)_data;
      img.assign(_width,_height,1,3);
      T
        *data1 = img.data(0,0,0,0),
        *data2 = img.data(0,0,0,1),
        *data3 = img.data(0,0,0,2);

      cimg::X11_attr &X11_attr = cimg::X11_attr::ref();
      if (X11_attr.is_blue_first) cimg::swap(data1,data3);
      switch (X11_attr.nb_bits) {
      case 8 : {

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