From c0974ca09cb87184a41c37f4c6d12a2b8f56e398 Mon Sep 17 00:00:00 2001
From: Ioannis Tsakpinis <iotsakp@gmail.com>
Date: Mon, 7 Sep 2015 16:21:27 +0300
Subject: [PATCH] Implement glfwSetWindowIcons on Linux

---
 src/x11_init.c     |  2 ++
 src/x11_platform.h |  1 +
 src/x11_window.c   | 34 +++++++++++++++++++++++++++++++++-
 3 files changed, 36 insertions(+), 1 deletion(-)

diff --git a/src/x11_init.c b/src/x11_init.c
index 033a06987..4af5f352c 100644
--- a/src/x11_init.c
+++ b/src/x11_init.c
@@ -443,6 +443,8 @@ static void detectEWMH(void)
         getSupportedAtom(supportedAtoms, atomCount, "_NET_WM_FULLSCREEN_MONITORS");
     _glfw.x11.NET_WM_NAME =
         getSupportedAtom(supportedAtoms, atomCount, "_NET_WM_NAME");
+    _glfw.x11.NET_WM_ICON =
+        getSupportedAtom(supportedAtoms, atomCount, "_NET_WM_ICON");
     _glfw.x11.NET_WM_ICON_NAME =
         getSupportedAtom(supportedAtoms, atomCount, "_NET_WM_ICON_NAME");
     _glfw.x11.NET_WM_PID =
diff --git a/src/x11_platform.h b/src/x11_platform.h
index b17478f83..240728a67 100644
--- a/src/x11_platform.h
+++ b/src/x11_platform.h
@@ -129,6 +129,7 @@ typedef struct _GLFWlibraryX11
     Atom            WM_STATE;
     Atom            WM_DELETE_WINDOW;
     Atom            NET_WM_NAME;
+    Atom            NET_WM_ICON;
     Atom            NET_WM_ICON_NAME;
     Atom            NET_WM_PID;
     Atom            NET_WM_PING;
diff --git a/src/x11_window.c b/src/x11_window.c
index 0f78fdae2..ad6a7d1b0 100644
--- a/src/x11_window.c
+++ b/src/x11_window.c
@@ -1647,7 +1647,39 @@ void _glfwPlatformGetWindowFrameSize(_GLFWwindow* window,
 
 void _glfwPlatformSetWindowIcons(_GLFWwindow* window, GLFWimage* icons, int count)
 {
-    // TODO: Implement this
+    int i, d, p;
+    long* data;
+
+    // calculate number of elements
+    int nelements = count * 2; // width & height per icon
+    for (i = 0, nelements = 0;  i < count;  i++)
+        nelements += icons[i].width * icons[i].height; // pixel data
+
+    data = (long*)malloc(sizeof(long), nelements);
+
+    // build property data
+    for (i = 0, d = 0;  i < count;  i++)
+    {
+        data[d++] = icons[i].width;
+        data[d++] = icons[i].height;
+
+        for (p = 0;  p < icons[i].width * icons[i].height;  p++)
+        {
+            unsigned char* pixel = icons[i].pixels + p * 4;
+            data[d++] = // pack to ARGB integer
+                (pixel[3] << 24) |
+                (pixel[0] << 16) |
+                (pixel[1] <<  8) |
+                (pixel[2] <<  0) ;
+        }
+    }
+
+    XChangeProperty(_glfw.x11.display, window->x11.handle,
+                    _glfw.x11.NET_WM_ICON,
+                    XA_CARDINAL,
+                    32, PropModeReplace, (unsigned char*)data, nelements);
+
+    free(data);
 }
 
 void _glfwPlatformIconifyWindow(_GLFWwindow* window)