Method: Magick::Image#deskew

Defined in:

ext/RMagick/rmimage.cpp

#deskew(threshold = 0.40, auto_crop_width = nil) ⇒ Magick::Image

Straightens an image. A threshold of 40% works for most images.

Returns a new image.

Parameters:

• threshold (Numeric, String) (defaults to: 0.40) —

  A percentage of QuantumRange. Either a Float between 0 and 1.0, inclusive, or a string in the form “NN%” where NN is between 0 and 100.

• auto_crop_width (Numeric) (defaults to: nil) —

  Specify a value for this argument to cause the deskewed image to be auto-cropped. The argument is the pixel width of the image background (e.g. 40).

Returns:

• (Magick::Image) —

  a new image

# File 'ext/RMagick/rmimage.cpp', line 5429

VALUE
Image_deskew(int argc, VALUE *argv, VALUE self)
{
    Image *image, *new_image;
    double threshold = 40.0 * QuantumRange / 100.0;
    unsigned long width;
    char auto_crop_width[20];
    ExceptionInfo *exception;

    image = rm_check_destroyed(self);

    switch (argc)
    {
        case 2:
            width = NUM2ULONG(argv[1]);
            memset(auto_crop_width, 0, sizeof(auto_crop_width));
            snprintf(auto_crop_width, sizeof(auto_crop_width), "%lu", width);
            SetImageArtifact(image, "deskew:auto-crop", auto_crop_width);
        case 1:
            threshold = rm_percentage(argv[0], 1.0) * QuantumRange;
        case 0:
            break;
        default:
            rb_raise(rb_eArgError, "wrong number of arguments (%d for 0 to 2)", argc);
            break;
    }

    exception = AcquireExceptionInfo();
    GVL_STRUCT_TYPE(DeskewImage) args = { image, threshold, exception };
    new_image = (Image *)CALL_FUNC_WITHOUT_GVL(GVL_FUNC(DeskewImage), &args);
    CHECK_EXCEPTION();
    DestroyExceptionInfo(exception);

    return rm_image_new(new_image);
}