Add a glfwSetWindowIcon function.

As for the implementations, there is one for X11, the Wayland protocol doesn’t
support that feature so I added a comment, and the rest is stubbed.

Fixes #453.

include/GLFW/glfw3.h

@@ -1844,6 +1844,26 @@ GLFWAPI void glfwGetWindowSize(GLFWwindow* window, int* width, int* height);
  */
 GLFWAPI void glfwSetWindowSize(GLFWwindow* window, int width, int height);
 
+/*! @brief Sets the icons representing the specified window.
+ *
+ *  This function sets the icons, as an array of GLFWimage, of the specified
+ *  window.
+ *
+ *  If count is 0, it removes any icon previously set that way.
+ *
+ *  @param[in] window The window whose icons to change.
+ *  @param[in] images Array with the icons to set.
+ *  @param[in] count Number of images in the array.
+ *
+ *  @par Thread Safety
+ *  TODO
+ *
+ *  @since Added in GLFW TODO.
+ *
+ *  @ingroup window
+ */
+GLFWAPI void glfwSetWindowIcons(GLFWwindow* window, const GLFWimage* images, int count);
+
 /*! @brief Retrieves the size of the framebuffer of the specified window.
  *
  *  This function retrieves the size, in pixels, of the framebuffer of the

src/cocoa_window.m

@@ -996,6 +996,13 @@ void _glfwPlatformSetWindowSize(_GLFWwindow* window, int width, int height)
         [window->ns.object setContentSize:NSMakeSize(width, height)];
 }
 
+void _glfwPlatformSetWindowIcons(_GLFWwindow* window, const GLFWimage* images, int count)
+{
+    // TODO
+    _glfwInputError(GLFW_PLATFORM_ERROR,
+                    "Cocoa: Set window icons not implemented yet");
+}
+
 void _glfwPlatformGetFramebufferSize(_GLFWwindow* window, int* width, int* height)
 {
     const NSRect contentRect = [window->ns.view frame];

src/internal.h

@@ -544,6 +544,11 @@ void _glfwPlatformGetWindowSize(_GLFWwindow* window, int* width, int* height);
  */
 void _glfwPlatformSetWindowSize(_GLFWwindow* window, int width, int height);
 
+/*! @copydoc glfwSetWindowIcons
+ *  @ingroup platform
+ */
+void _glfwPlatformSetWindowIcons(_GLFWwindow* window, const GLFWimage* images, int count);
+
 /*! @copydoc glfwGetFramebufferSize
  *  @ingroup platform
  */

src/mir_window.c

@@ -531,6 +531,12 @@ void _glfwPlatformSetWindowSize(_GLFWwindow* window, int width, int height)
                     "Mir: Unsupported function %s", __PRETTY_FUNCTION__);
 }
 
+void _glfwPlatformSetWindowIcons(_GLFWwindow* window, const GLFWimage* images, int count)
+{
+    _glfwInputError(GLFW_PLATFORM_ERROR,
+                    "Mir: Unsupported function %s", __PRETTY_FUNCTION__);
+}
+
 void _glfwPlatformGetWindowSize(_GLFWwindow* window, int* width, int* height)
 {
     if (width)

src/win32_window.c

@@ -916,6 +916,13 @@ void _glfwPlatformSetWindowSize(_GLFWwindow* window, int width, int height)
     }
 }
 
+void _glfwPlatformSetWindowIcons(_GLFWwindow* window, const GLFWimage* images, int count)
+{
+    // TODO
+    _glfwInputError(GLFW_PLATFORM_ERROR,
+                    "Win32: Set window icons not implemented yet");
+}
+
 void _glfwPlatformGetFramebufferSize(_GLFWwindow* window, int* width, int* height)
 {
     _glfwPlatformGetWindowSize(window, width, height);

src/window.c

@@ -514,6 +514,15 @@ GLFWAPI void glfwSetWindowSize(GLFWwindow* handle, int width, int height)
     _glfwPlatformSetWindowSize(window, width, height);
 }
 
+GLFWAPI void glfwSetWindowIcons(GLFWwindow* handle, const GLFWimage* images, int count)
+{
+    _GLFWwindow* window = (_GLFWwindow*) handle;
+
+    _GLFW_REQUIRE_INIT();
+
+    _glfwPlatformSetWindowIcons(window, images, count);
+}
+
 GLFWAPI void glfwGetFramebufferSize(GLFWwindow* handle, int* width, int* height)
 {
     _GLFWwindow* window = (_GLFWwindow*) handle;

src/wl_window.c

@@ -265,6 +265,16 @@ void _glfwPlatformSetWindowSize(_GLFWwindow* window, int width, int height)
     window->wl.height = height;
 }
 
+void _glfwPlatformSetWindowIcons(_GLFWwindow* window, const GLFWimage* images, int count)
+{
+    // There is currently no standard way to set the icon at runtime on
+    // Wayland, the closest thing is xdg_surface.set_app_id combined with a
+    // .desktop file containing the icon.
+
+    _glfwInputError(GLFW_PLATFORM_ERROR,
+                    "Wayland: Set window icons not supported");
+}
+
 void _glfwPlatformGetFramebufferSize(_GLFWwindow* window, int* width, int* height)
 {
     _glfwPlatformGetWindowSize(window, width, height);

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 =

src/x11_platform.h

@@ -130,6 +130,7 @@ 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;

src/x11_window.c

@@ -1572,6 +1572,42 @@ void _glfwPlatformSetWindowSize(_GLFWwindow* window, int width, int height)
     XFlush(_glfw.x11.display);
 }
 
+void _glfwPlatformSetWindowIcons(_GLFWwindow* window, const GLFWimage* images, int count)
+{
+    if (count > 0)
+    {
+        int propsize = 2 * count;
+        int i;
+        for (i = 0; i < count; ++i)
+            propsize += images[i].width * images[i].height * 4;
+
+        long* propdata = calloc(propsize, sizeof(long));
+        long index = 0;
+        for (i = 0; i < count; ++i)
+        {
+            int width = images[i].width;
+            int height = images[i].height;
+            propdata[index++] = width;
+            propdata[index++] = height;
+
+            // As Xlib specifies its properties in terms of long, we can’t blindly
+            // memcpy the provided data, since sizeof(long) can be different from 4.
+            const uint32_t* pixels = (const uint32_t*) images[i].pixels;
+            int j;
+            for (j = 0; j < width * height; ++j)
+                propdata[index++] = *pixels++;
+        }
+
+        XChangeProperty(_glfw.x11.display, window->x11.handle,
+                        _glfw.x11.NET_WM_ICON, XA_CARDINAL, 32,
+                        PropModeReplace, (unsigned char*) propdata, propsize);
+        free(propdata);
+    }
+    else
+        XDeleteProperty(_glfw.x11.display, window->x11.handle,
+                        _glfw.x11.NET_WM_ICON);
+}
+
 void _glfwPlatformGetFramebufferSize(_GLFWwindow* window, int* width, int* height)
 {
     _glfwPlatformGetWindowSize(window, width, height);