Add glfwSetWindowIcon

Adds support for setting window icons programmatically on platforms
where this makes sense.

Fixes #453.
Closes #467.

README.md

@@ -84,6 +84,7 @@ does not find Doxygen, the documentation will not be generated.
  - Added `glfwGetKeyName` for querying the layout-specific name of printable
    keys
  - Added `glfwWaitEventsTimeout` for waiting for events for a set amount of time
+ - Added `glfwSetWindowIcon` for setting the icon of a window
  - Added `glfwGetTimerValue` and `glfwGetTimerFrequency` for raw timer access
  - Added `GLFWuint64` for platform-independent 64-bit unsigned values
  - Added `GLFW_NO_API` for creating window without contexts
@@ -221,6 +222,7 @@ skills.
  - Peoro
  - Braden Pellett
  - Arturo J. Pérez
+ - Orson Peters
  - Emmanuel Gil Peyrot
  - Cyril Pichard
  - Pieroman
@@ -246,6 +248,7 @@ skills.
  - TTK-Bandit
  - Sergey Tikhomirov
  - A. Tombs
+ - Ioannis Tsakpinis
  - Samuli Tuomola
  - urraka
  - Jari Vetoniemi

docs/news.dox

@@ -32,6 +32,11 @@ GLFW now supports window maximization with @ref glfwMaximizeWindow and the
 [GLFW_MAXIMIZED](@ref window_attribs_wnd) window hint and attribute.
 
 
+@subsection news_32_icon Window icon support
+
+GLFW now supports setting the icon of windows with @ref glfwSetWindowIcon.
+
+
 @subsection news_32_focus Window input focus control
 
 GLFW now supports giving windows input focus with @ref glfwFocusWindow.

docs/window.dox

@@ -617,6 +617,26 @@ glfwSetWindowTitle(window, u8"This is always a UTF-8 string");
 @endcode
 
 
+@subsection window_icon Window icon
+
+Decorated windows have icons on some platforms.  You can set this icon by
+specifying a list of candidate images with @ref glfwSetWindowIcon.
+
+@code
+GLFWimage images[2];
+images[0] = load_icon("my_icon.png");
+images[1] = load_icon("my_icon_small.png");
+
+glfwSetWindowIcon(window, 2, images);
+@endcode
+
+To revert to the default window icon, pass in an empty image array.
+
+@code
+glfwSetWindowIcon(window, 0, NULL);
+@endcode
+
+
 @subsection window_monitor Window monitor
 
 Full screen windows are associated with a specific monitor.  You can get the

include/GLFW/glfw3.h

@@ -1913,6 +1913,45 @@ GLFWAPI void glfwSetWindowShouldClose(GLFWwindow* window, int value);
  */
 GLFWAPI void glfwSetWindowTitle(GLFWwindow* window, const char* title);
 
+/*! @brief Sets the icon for the specified window.
+ *
+ *  This function sets the icon of the specified window.  If passed an array of
+ *  candidate images, those of or closest to the sizes desired by the system are
+ *  selected.  If no images are specified, the window reverts to its default
+ *  icon.
+ *
+ *  The desired image sizes varies depending on platform and system settings.
+ *  The selected images will be rescaled as needed.  Good sizes include 16x16,
+ *  32x32 and 48x48.
+ *
+ *  @param[in] window The window whose icon to set.
+ *  @param[in] count The number of images in the specified array, or zero to
+ *  revert to the default window icon.
+ *  @param[in] images The images to create the icon from.  This is ignored if
+ *  count is zero.
+ *
+ *  @errors Possible errors include @ref GLFW_NOT_INITIALIZED and @ref
+ *  GLFW_PLATFORM_ERROR.
+ *
+ *  @pointer_lifetime The specified image data is copied before this function
+ *  returns.
+ *
+ *  @remark @osx The GLFW window has no icon, as it is not a document
+ *  window, but the dock icon will be the same as the application bundle's icon.
+ *  For more information on bundles, see the
+ *  [Bundle Programming Guide](https://developer.apple.com/library/mac/documentation/CoreFoundation/Conceptual/CFBundles/)
+ *  in the Mac Developer Library.
+ *
+ *  @thread_safety This function must only be called from the main thread.
+ *
+ *  @sa @ref window_icon
+ *
+ *  @since Added in version 3.2.
+ *
+ *  @ingroup window
+ */
+GLFWAPI void glfwSetWindowIcon(GLFWwindow* window, int count, const GLFWimage* images);
+
 /*! @brief Retrieves the position of the client area of the specified window.
  *
  *  This function retrieves the position, in screen coordinates, of the

src/cocoa_window.m

@@ -1032,6 +1032,12 @@ void _glfwPlatformSetWindowTitle(_GLFWwindow* window, const char *title)
     [window->ns.object setTitle:[NSString stringWithUTF8String:title]];
 }
 
+void _glfwPlatformSetWindowIcon(_GLFWwindow* window,
+                                int count, const GLFWimage* images)
+{
+    // Regular windows do not have icons
+}
+
 void _glfwPlatformGetWindowPos(_GLFWwindow* window, int* xpos, int* ypos)
 {
     const NSRect contentRect =

src/internal.h

@@ -617,6 +617,11 @@ void _glfwPlatformDestroyWindow(_GLFWwindow* window);
  */
 void _glfwPlatformSetWindowTitle(_GLFWwindow* window, const char* title);
 
+/*! @copydoc glfwSetWindowIcon
+ *  @ingroup platform
+ */
+void _glfwPlatformSetWindowIcon(_GLFWwindow* window, int count, const GLFWimage* images);
+
 /*! @copydoc glfwGetWindowPos
  *  @ingroup platform
  */

src/mir_window.c

@@ -403,6 +403,13 @@ void _glfwPlatformSetWindowTitle(_GLFWwindow* window, const char* title)
     mir_surface_spec_release(spec);
 }
 
+void _glfwPlatformSetWindowIcon(_GLFWwindow* window,
+                                int count, const GLFWimage* images)
+{
+    _glfwInputError(GLFW_PLATFORM_ERROR,
+                    "Mir: Unsupported function %s", __PRETTY_FUNCTION__);
+}
+
 void _glfwPlatformSetWindowSize(_GLFWwindow* window, int width, int height)
 {
     MirSurfaceSpec* spec;

src/win32_platform.h

@@ -191,6 +191,8 @@ typedef VkBool32 (APIENTRY *PFN_vkGetPhysicalDeviceWin32PresentationSupportKHR)(
 typedef struct _GLFWwindowWin32
 {
     HWND                handle;
+    HICON               bigIcon;
+    HICON               smallIcon;
 
     GLFWbool            cursorTracked;
     GLFWbool            iconified;

src/win32_window.c

@@ -27,6 +27,7 @@
 
 #include "internal.h"
 
+#include <limits.h>
 #include <stdlib.h>
 #include <malloc.h>
 #include <string.h>
@@ -66,6 +67,112 @@ static DWORD getWindowExStyle(const _GLFWwindow* window)
     return style;
 }
 
+// Returns the image whose area most closely matches the desired one
+//
+static const GLFWimage* chooseImage(int count, const GLFWimage* images,
+                                    int width, int height)
+{
+    int i, leastDiff = INT_MAX;
+    const GLFWimage* closest = NULL;
+
+    for (i = 0;  i < count;  i++)
+    {
+        const int currDiff = abs(images[i].width * images[i].height -
+                                 width * height);
+        if (currDiff < leastDiff)
+        {
+            closest = images + i;
+            leastDiff = currDiff;
+        }
+    }
+
+    return closest;
+}
+
+// Creates an RGBA icon or cursor
+//
+static HICON createIcon(const GLFWimage* image,
+                        int xhot, int yhot, GLFWbool icon)
+{
+    int i;
+    HDC dc;
+    HICON handle;
+    HBITMAP color, mask;
+    BITMAPV5HEADER bi;
+    ICONINFO ii;
+    unsigned char* target = NULL;
+    unsigned char* source = image->pixels;
+
+    ZeroMemory(&bi, sizeof(bi));
+    bi.bV5Size        = sizeof(BITMAPV5HEADER);
+    bi.bV5Width       = image->width;
+    bi.bV5Height      = -image->height;
+    bi.bV5Planes      = 1;
+    bi.bV5BitCount    = 32;
+    bi.bV5Compression = BI_BITFIELDS;
+    bi.bV5RedMask     = 0x00ff0000;
+    bi.bV5GreenMask   = 0x0000ff00;
+    bi.bV5BlueMask    = 0x000000ff;
+    bi.bV5AlphaMask   = 0xff000000;
+
+    dc = GetDC(NULL);
+    color = CreateDIBSection(dc,
+                             (BITMAPINFO*) &bi,
+                             DIB_RGB_COLORS,
+                             (void**) &target,
+                             NULL,
+                             (DWORD) 0);
+    ReleaseDC(NULL, dc);
+
+    if (!color)
+    {
+        _glfwInputError(GLFW_PLATFORM_ERROR,
+                        "Win32: Failed to create RGBA bitmap");
+        return NULL;
+    }
+
+    mask = CreateBitmap(image->width, image->height, 1, 1, NULL);
+    if (!mask)
+    {
+        _glfwInputError(GLFW_PLATFORM_ERROR,
+                        "Win32: Failed to create mask bitmap");
+        DeleteObject(color);
+        return NULL;
+    }
+
+    for (i = 0;  i < image->width * image->height;  i++)
+    {
+        target[0] = source[2];
+        target[1] = source[1];
+        target[2] = source[0];
+        target[3] = source[3];
+        target += 4;
+        source += 4;
+    }
+
+    ZeroMemory(&ii, sizeof(ii));
+    ii.fIcon    = icon;
+    ii.xHotspot = xhot;
+    ii.yHotspot = yhot;
+    ii.hbmMask  = mask;
+    ii.hbmColor = color;
+
+    handle = CreateIconIndirect(&ii);
+
+    DeleteObject(color);
+    DeleteObject(mask);
+
+    if (!handle)
+    {
+        if (icon)
+            _glfwInputError(GLFW_PLATFORM_ERROR, "Win32: Failed to create icon");
+        else
+            _glfwInputError(GLFW_PLATFORM_ERROR, "Win32: Failed to create cursor");
+    }
+
+    return handle;
+}
+
 // Translate client window size to full window size according to styles
 //
 static void getFullWindowSize(DWORD style, DWORD exStyle,
@@ -886,6 +993,12 @@ void _glfwPlatformDestroyWindow(_GLFWwindow* window)
     }
 
     destroyWindow(window);
+
+    if (window->win32.bigIcon)
+        DestroyIcon(window->win32.bigIcon);
+
+    if (window->win32.smallIcon)
+        DestroyIcon(window->win32.smallIcon);
 }
 
 void _glfwPlatformSetWindowTitle(_GLFWwindow* window, const char* title)
@@ -902,6 +1015,37 @@ void _glfwPlatformSetWindowTitle(_GLFWwindow* window, const char* title)
     free(wideTitle);
 }
 
+void _glfwPlatformSetWindowIcon(_GLFWwindow* window,
+                                int count, const GLFWimage* images)
+{
+    HICON bigIcon = NULL, smallIcon = NULL;
+
+    if (count)
+    {
+        const GLFWimage* bigImage = chooseImage(count, images,
+                                                GetSystemMetrics(SM_CXICON),
+                                                GetSystemMetrics(SM_CYICON));
+        const GLFWimage* smallImage = chooseImage(count, images,
+                                                  GetSystemMetrics(SM_CXSMICON),
+                                                  GetSystemMetrics(SM_CYSMICON));
+
+        bigIcon = createIcon(bigImage, 0, 0, GLFW_TRUE);
+        smallIcon = createIcon(smallImage, 0, 0, GLFW_TRUE);
+    }
+
+    SendMessage(window->win32.handle, WM_SETICON, ICON_BIG, (LPARAM) bigIcon);
+    SendMessage(window->win32.handle, WM_SETICON, ICON_SMALL, (LPARAM) smallIcon);
+
+    if (window->win32.bigIcon)
+        DestroyIcon(window->win32.bigIcon);
+
+    if (window->win32.smallIcon)
+        DestroyIcon(window->win32.smallIcon);
+
+    window->win32.bigIcon = bigIcon;
+    window->win32.smallIcon = smallIcon;
+}
+
 void _glfwPlatformGetWindowPos(_GLFWwindow* window, int* xpos, int* ypos)
 {
     POINT pos = { 0, 0 };
@@ -1236,61 +1380,7 @@ int _glfwPlatformCreateCursor(_GLFWcursor* cursor,
                               const GLFWimage* image,
                               int xhot, int yhot)
 {
-    HDC dc;
-    HBITMAP bitmap, mask;
-    BITMAPV5HEADER bi;
-    ICONINFO ii;
-    DWORD* target = 0;
-    BYTE* source = (BYTE*) image->pixels;
-    int i;
-
-    ZeroMemory(&bi, sizeof(bi));
-    bi.bV5Size        = sizeof(BITMAPV5HEADER);
-    bi.bV5Width       = image->width;
-    bi.bV5Height      = -image->height;
-    bi.bV5Planes      = 1;
-    bi.bV5BitCount    = 32;
-    bi.bV5Compression = BI_BITFIELDS;
-    bi.bV5RedMask     = 0x00ff0000;
-    bi.bV5GreenMask   = 0x0000ff00;
-    bi.bV5BlueMask    = 0x000000ff;
-    bi.bV5AlphaMask   = 0xff000000;
-
-    dc = GetDC(NULL);
-    bitmap = CreateDIBSection(dc, (BITMAPINFO*) &bi, DIB_RGB_COLORS,
-                              (void**) &target, NULL, (DWORD) 0);
-    ReleaseDC(NULL, dc);
-
-    if (!bitmap)
-        return GLFW_FALSE;
-
-    mask = CreateBitmap(image->width, image->height, 1, 1, NULL);
-    if (!mask)
-    {
-        DeleteObject(bitmap);
-        return GLFW_FALSE;
-    }
-
-    for (i = 0;  i < image->width * image->height;  i++, target++, source += 4)
-    {
-        *target = (source[3] << 24) |
-                  (source[0] << 16) |
-                  (source[1] <<  8) |
-                   source[2];
-    }
-
-    ZeroMemory(&ii, sizeof(ii));
-    ii.fIcon    = FALSE;
-    ii.xHotspot = xhot;
-    ii.yHotspot = yhot;
-    ii.hbmMask  = mask;
-    ii.hbmColor = bitmap;
-
-    cursor->win32.handle = (HCURSOR) CreateIconIndirect(&ii);
-
-    DeleteObject(bitmap);
-    DeleteObject(mask);
-
+    cursor->win32.handle = (HCURSOR) createIcon(image, xhot, yhot, GLFW_FALSE);
     if (!cursor->win32.handle)
         return GLFW_FALSE;
 

src/window.c

@@ -447,6 +447,18 @@ GLFWAPI void glfwSetWindowTitle(GLFWwindow* handle, const char* title)
     _glfwPlatformSetWindowTitle(window, title);
 }
 
+GLFWAPI void glfwSetWindowIcon(GLFWwindow* handle,
+                               int count, const GLFWimage* images)
+{
+    _GLFWwindow* window = (_GLFWwindow*) handle;
+    assert(window != NULL);
+    assert(count >= 0);
+    assert(count == 0 || images != NULL);
+
+    _GLFW_REQUIRE_INIT();
+    _glfwPlatformSetWindowIcon(window, count, images);
+}
+
 GLFWAPI void glfwGetWindowPos(GLFWwindow* handle, int* xpos, int* ypos)
 {
     _GLFWwindow* window = (_GLFWwindow*) handle;

src/wl_window.c

@@ -383,6 +383,13 @@ void _glfwPlatformSetWindowTitle(_GLFWwindow* window, const char* title)
     wl_shell_surface_set_title(window->wl.shell_surface, title);
 }
 
+void _glfwPlatformSetWindowIcon(_GLFWwindow* window,
+                                int count, const GLFWimage* images)
+{
+    // TODO
+    fprintf(stderr, "_glfwPlatformSetWindowIcon not implemented yet\n");
+}
+
 void _glfwPlatformGetWindowPos(_GLFWwindow* window, int* xpos, int* ypos)
 {
     // A Wayland client is not aware of its position, so just warn and leave it

src/x11_init.c

@@ -454,6 +454,8 @@ static void detectEWMH(void)
         getSupportedAtom(supportedAtoms, atomCount, "_NET_WM_NAME");
     _glfw.x11.NET_WM_ICON_NAME =
         getSupportedAtom(supportedAtoms, atomCount, "_NET_WM_ICON_NAME");
+    _glfw.x11.NET_WM_ICON =
+        getSupportedAtom(supportedAtoms, atomCount, "_NET_WM_ICON");
     _glfw.x11.NET_WM_PID =
         getSupportedAtom(supportedAtoms, atomCount, "_NET_WM_PID");
     _glfw.x11.NET_WM_PING =

src/x11_platform.h

@@ -167,6 +167,7 @@ typedef struct _GLFWlibraryX11
     Atom            WM_DELETE_WINDOW;
     Atom            NET_WM_NAME;
     Atom            NET_WM_ICON_NAME;
+    Atom            NET_WM_ICON;
     Atom            NET_WM_PID;
     Atom            NET_WM_PING;
     Atom            NET_WM_STATE;

src/x11_window.c

@@ -1536,6 +1536,51 @@ void _glfwPlatformSetWindowTitle(_GLFWwindow* window, const char* title)
     XFlush(_glfw.x11.display);
 }
 
+void _glfwPlatformSetWindowIcon(_GLFWwindow* window,
+                                int count, const GLFWimage* images)
+{
+    if (count)
+    {
+        int i, j, longCount = 0;
+
+        for (i = 0;  i < count;  i++)
+            longCount += 2 + images[i].width * images[i].height;
+
+        long* icon = calloc(longCount, sizeof(long));
+        long* target = icon;
+
+        for (i = 0;  i < count;  i++)
+        {
+            *target++ = images[i].width;
+            *target++ = images[i].height;
+
+            for (j = 0;  j < images[i].width * images[i].height;  i++)
+            {
+                *target++ = (images[i].pixels[i * 4 + 0] << 16) |
+                            (images[i].pixels[i * 4 + 1] <<  8) |
+                            (images[i].pixels[i * 4 + 2] <<  0) |
+                            (images[i].pixels[i * 4 + 3] << 24);
+            }
+        }
+
+        XChangeProperty(_glfw.x11.display, window->x11.handle,
+                        _glfw.x11.NET_WM_ICON,
+                        XA_CARDINAL, 32,
+                        PropModeReplace,
+                        (unsigned char*) icon,
+                        longCount);
+
+        free(icon);
+    }
+    else
+    {
+        XDeleteProperty(_glfw.x11.display, window->x11.handle,
+                        _glfw.x11.NET_WM_ICON);
+    }
+
+    XFlush(_glfw.x11.display);
+}
+
 void _glfwPlatformGetWindowPos(_GLFWwindow* window, int* xpos, int* ypos)
 {
     Window child;