将BLOB读入图像时出现Magick ++错误

Question

I'm trying to export an image from raw pixel data into a RGBA PNG using the Magick++ library.

However, I'm getting a strange error when I'm attempting to run it:

terminate called after throwing an instance of 'Magick::ErrorCorruptImage'
  what():  test: unexpected end-of-file `': No such file or directory @ error/rgb.c/ReadRGBImage/229
Aborted

This is the relevant code part (I omitted filling the pixel vector, but that doesn't change anything):

#include <iostream>
#include <vector>
#include <ImageMagick/Magick++.h>

using namespace std;

int main(int argc, char *argv[]) {
    Magick::InitializeMagick(*argv);
    int rres, ires;
    cin >> rres >> ires;
    //RGBA
    //rres: horiz. resolution, ires: vert. resolution
    vector<unsigned char> image(rres * ires * 4);
    Magick::Blob blob(&image[0], rres*ires*4);
    Magick::Image img;
    img.size(to_string(rres) + "x" + to_string(ires));
    img.magick("RGBA");
    img.read(blob);
    img.write("out.png");
}

Compilation with:

g++ --std=c++11 -O0 -g3 -ggdb3 -D_GLIBCXX_DEBUG -Wall test.cpp -o test `Magick++-config --cppflags --cxxflags --ldflags --libs`

Answer 1

Your example works if you are using the Q8 version of ImageMagick. But it seems that you are using the Q16 version of ImageMagick. That latter uses 16 bits per pixel channel. You are using a vector<unsigned char> which is only 8 bits. I would advise you to switch to a vector<unsigned short> or use an vector<unsigned char> that is twice the current size. You could also switch to the Q8 version of ImageMagick if you don't need 16 bits per pixel channel.