Jack Jack - 1 year ago 78
Linux Question

Missing XGetPixel() in X11/Xlib.h?

I am writing a program that uses the XGetPixel() method. However, upon using it I get an error saying "Error: XGetPixel was not declared in this scope"

My code is the following:

#include <X11/Xlib.h>
#include <X11/X.h>
#include <unistd.h>
#include <iostream>
using namespace std;

int main()
// Open a display.
Display *d = XOpenDisplay(NULL);

// Get the root of the display
Window root = DefaultRootWindow(d);

// Map the root window
XMapWindow(d, root);

// Get width and height of the display
int windowHeight = XDisplayHeight (d, 0);
int windowWidth = XDisplayWidth(d, 0);

// Get dump of screen
XImage *image = XGetImage(d, root, 0, 0, windowWidth, windowHeight, AllPlanes, ZPixmap);


return 0;

Strangely, when I check in the X11/Xlib.h it dosn't appear to even have a XGetPixel() method or structure. Is it possible this is a bug? I am currently using Ubuntu 16 and installed it using apt-get libx11-dev and I cannot find any reported issues about this problem.

Answer Source

Image manipulation functions are defined at #include <X11/Xutil.h>.