Support for drag and resize operations

README.md

@@ -141,6 +141,10 @@ information on what to include when reporting a bug.
   (#235,#439,#677,#845,#898)
 - Added `glfwRequestWindowAttention` function for requesting attention from the
   user (#732,#988)
+- Added `glfwDragWindow` function for starting a drag operation on a window
+  (#987)
+- Added `glfwResizeWindow` function for starting a resize operation on a window
+  (#923)
 - Added `glfwGetKeyScancode` function that allows retrieving platform dependent
   scancodes for keys (#830)
 - Added `glfwSetWindowMaximizeCallback` and `GLFWwindowmaximizefun` for

include/GLFW/glfw3.h

@@ -1015,6 +1015,15 @@ extern "C" {
 #define GLFW_EGL_CONTEXT_API        0x00036002
 #define GLFW_OSMESA_CONTEXT_API     0x00036003
 
+#define GLFW_WINDOW_LEFT 0
+#define GLFW_WINDOW_TOP 1
+#define GLFW_WINDOW_RIGHT 2
+#define GLFW_WINDOW_BOTTOM 3
+#define GLFW_WINDOW_TOPLEFT 4
+#define GLFW_WINDOW_TOPRIGHT 5
+#define GLFW_WINDOW_BOTTOMLEFT 6
+#define GLFW_WINDOW_BOTTOMRIGHT 7
+
 /*! @defgroup shapes Standard cursor shapes
  *  @brief Standard system cursor shapes.
  *
@@ -3192,6 +3201,54 @@ GLFWAPI void glfwHideWindow(GLFWwindow* window);
  */
 GLFWAPI void glfwFocusWindow(GLFWwindow* window);
 
+/*! @brief Starts drag operation to the specified window.
+ *
+ *  This function starts the drag operation of the specified window.
+ *
+ *  @param[in] window The window to start the dragging operation.
+ *  @thread_safety This function must only be called from the main thread.
+ *
+ *  @sa @ref window_drag
+ *
+ *  @since Added in version 3.3.
+ *
+ *  @ingroup window
+ */
+GLFWAPI void glfwDragWindow(GLFWwindow* handle);
+
+/*! @brief Starts a resize operation with the specified window.
+ *
+ *  This function starts a resize operation on one of the borders of the
+ *  specified window.
+ *  
+ *  this function must be called from a pointer or touch event callback,
+ *  otherwise it risks reacting to a different event.
+ *
+ *  The borders are [GLFW_WINDOW_LEFT](@ref GLFW_GLFW_WINDOW_LEFT),
+ *  [GLFW_WINDOW_TOP](@ref GLFW_WINDOW_TOP),
+ *  [GLFW_WINDOW_RIGHT](@ref GLFW_WINDOW_RIGHT),
+ *  [GLFW_WINDOW_BOTTOM](@ref GLFW_WINDOW_BOTTOM),
+ *  [GLFW_WINDOW_TOPLEFT](@ref GLFW_WINDOW_TOPLEFT),
+ *  [GLFW_WINDOW_TOPRIGHT](@ref GLFW_WINDOW_TOPRIGHT),
+ *  [GLFW_WINDOW_BOTTOMLEFT](@ref GLFW_WINDOW_BOTTOMLEFT) and
+ *  [GLFW_WINDOW_BOTTOMRIGHT](@ref GLFW_WINDOW_BOTTOMRIGHT).
+ *
+ *  @param[in] window The window to start the resize operation.
+ *  @param[in] border One of the window borders.
+ *
+ *  @errors Possible errors include @ref GLFW_NOT_INITIALIZED and @ref
+ *  GLFW_PLATFORM_ERROR.
+ *
+ *  @thread_safety This function must only be called from the main thread.
+ *
+ *  @sa @ref window_resize
+ *
+ *  @since Added in version 3.3.
+ *
+ *  @ingroup window
+ */
+GLFWAPI void glfwResizeWindow(GLFWwindow* window, int border);
+
 /*! @brief Requests user attention to the specified window.
  *
  *  This function requests user attention to the specified window.  On

src/cocoa_window.m

@@ -1146,6 +1146,15 @@ void _glfwPlatformFocusWindow(_GLFWwindow* window)
     [window->ns.object makeKeyAndOrderFront:nil];
 }
 
+void _glfwPlatformDragWindow(_GLFWwindow* window)
+{
+    [window->ns.object performWindowDragWithEvent:[NSApp currentEvent]];
+}
+
+void _glfwPlatformResizeWindow(_GLFWwindow* window, int border)
+{
+}
+
 void _glfwPlatformSetWindowMonitor(_GLFWwindow* window,
                                    _GLFWmonitor* monitor,
                                    int xpos, int ypos,

src/internal.h

@@ -655,6 +655,8 @@ void _glfwPlatformFocusWindow(_GLFWwindow* window);
 void _glfwPlatformSetWindowMonitor(_GLFWwindow* window, _GLFWmonitor* monitor,
                                    int xpos, int ypos, int width, int height,
                                    int refreshRate);
+void _glfwPlatformDragWindow(_GLFWwindow* window);
+void _glfwPlatformResizeWindow(_GLFWwindow* window, int border);
 int _glfwPlatformWindowFocused(_GLFWwindow* window);
 int _glfwPlatformWindowIconified(_GLFWwindow* window);
 int _glfwPlatformWindowVisible(_GLFWwindow* window);

src/null_window.c

@@ -217,6 +217,14 @@ void _glfwPlatformFocusWindow(_GLFWwindow* window)
 {
 }
 
+void _glfwPlatformDragWindow(_GLFWwindow* window)
+{
+}
+
+void _glfwPlatformResizeWindow(_GLFWwindow* window, int border)
+{
+}
+
 int _glfwPlatformWindowFocused(_GLFWwindow* window)
 {
     return GLFW_FALSE;

src/win32_window.c

@@ -33,6 +33,7 @@
 #include <string.h>
 #include <windowsx.h>
 #include <shellapi.h>
+#include <assert.h>
 
 #define _GLFW_KEY_INVALID -2
 
@@ -1656,6 +1657,48 @@ void _glfwPlatformFocusWindow(_GLFWwindow* window)
     SetFocus(window->win32.handle);
 }
 
+void _glfwPlatformDragWindow(_GLFWwindow* window)
+{
+    ReleaseCapture();
+    SendMessage(window->win32.handle, WM_NCLBUTTONDOWN, HTCAPTION, 0);
+}
+
+void _glfwPlatformResizeWindow(_GLFWwindow* window, int border)
+{
+    WPARAM wBorder;
+    switch (border)
+    {
+        case GLFW_WINDOW_LEFT:
+            wBorder = HTLEFT;
+            break;
+        case GLFW_WINDOW_TOP:
+            wBorder = HTTOP;
+            break;
+        case GLFW_WINDOW_RIGHT:
+            wBorder = HTRIGHT;
+            break;
+        case GLFW_WINDOW_BOTTOM:
+            wBorder = HTBOTTOM;
+            break;
+        case GLFW_WINDOW_TOPLEFT:
+            wBorder = HTTOPLEFT;
+            break;
+        case GLFW_WINDOW_TOPRIGHT:
+            wBorder = HTTOPRIGHT;
+            break;
+        case GLFW_WINDOW_BOTTOMLEFT:
+            wBorder = HTBOTTOMLEFT;
+            break;
+        case GLFW_WINDOW_BOTTOMRIGHT:
+            wBorder = HTBOTTOMRIGHT;
+			break;
+		default:
+			assert(GLFW_FALSE);
+    }
+    ReleaseCapture();
+    SendMessage(window->win32.handle, WM_NCLBUTTONDOWN, wBorder, 0);
+}
+
 void _glfwPlatformSetWindowMonitor(_GLFWwindow* window,
                                    _GLFWmonitor* monitor,
                                    int xpos, int ypos,

src/window.c

@@ -801,6 +801,29 @@ GLFWAPI void glfwFocusWindow(GLFWwindow* handle)
     _glfwPlatformFocusWindow(window);
 }
 
+GLFWAPI void glfwDragWindow(GLFWwindow* handle)
+{
+    _GLFWwindow* window = (_GLFWwindow*) handle;
+    assert(window != NULL);
+
+    _GLFW_REQUIRE_INIT();
+
+    _glfwPlatformDragWindow(window);
+}
+
+GLFWAPI void glfwResizeWindow(GLFWwindow* handle, int border)
+{
+	_GLFWwindow* window = (_GLFWwindow*)handle;
+	assert(window != NULL);
+
+	_GLFW_REQUIRE_INIT();
+
+	if (border < GLFW_WINDOW_LEFT || border > GLFW_WINDOW_BOTTOMRIGHT)
+		return;
+
+	_glfwPlatformResizeWindow(window, border);
+}
+
 GLFWAPI int glfwGetWindowAttrib(GLFWwindow* handle, int attrib)
 {
     _GLFWwindow* window = (_GLFWwindow*) handle;

src/wl_window.c

@@ -1215,6 +1215,49 @@ void _glfwPlatformFocusWindow(_GLFWwindow* window)
                     "Wayland: Focusing a window requires user interaction");
 }
 
+void _glfwPlatformDragWindow(_GLFWwindow* window)
+{
+    wl_shell_surface_move(window->wl.shellSurface, _glfw.wl.seat, _glfw.wl.pointerSerial);
+}
+
+void _glfwPlatformResizeWindow(_GLFWwindow* window, int border)
+{
+    int wlBorder;
+    switch (border)
+    {
+        case GLFW_WINDOW_LEFT:
+            wlBorder = WL_SHELL_SURFACE_RESIZE_LEFT;
+            break;
+        case GLFW_WINDOW_TOP:
+            wlBorder = WL_SHELL_SURFACE_RESIZE_TOP;
+            break;
+        case GLFW_WINDOW_RIGHT:
+            wlBorder = WL_SHELL_SURFACE_RESIZE_RIGHT;
+            break;
+        case GLFW_WINDOW_BOTTOM:
+            wlBorder = WL_SHELL_SURFACE_RESIZE_BOTTOM;
+            break;
+        case GLFW_WINDOW_TOPLEFT:
+            wlBorder = WL_SHELL_SURFACE_RESIZE_TOP_LEFT;
+            break;
+        case GLFW_WINDOW_TOPRIGHT:
+            wlBorder = WL_SHELL_SURFACE_RESIZE_TOP_RIGHT;
+            break;
+        case GLFW_WINDOW_BOTTOMLEFT:
+            wlBorder = WL_SHELL_SURFACE_RESIZE_BOTTOM_LEFT;
+            break;
+        case GLFW_WINDOW_BOTTOMRIGHT:
+            wlBorder = WL_SHELL_SURFACE_RESIZE_BOTTOM_RIGHT;
+			break;
+		default:
+			assert(GLFW_FALSE);
+    }
+    wl_shell_surface_resize(window->wl.shellSurface,
+                            _glfw.wl.seat,
+                            _glfw.wl.pointerSerial,
+                            wlBorder);
+}
+
 void _glfwPlatformSetWindowMonitor(_GLFWwindow* window,
                                    _GLFWmonitor* monitor,
                                    int xpos, int ypos,

src/x11_window.c

@@ -43,6 +43,15 @@
 #define _NET_WM_STATE_REMOVE        0
 #define _NET_WM_STATE_ADD           1
 #define _NET_WM_STATE_TOGGLE        2
+#define _NET_WM_MOVERESIZE_SIZE_TOPLEFT      0
+#define _NET_WM_MOVERESIZE_SIZE_TOP          1
+#define _NET_WM_MOVERESIZE_SIZE_TOPRIGHT     2
+#define _NET_WM_MOVERESIZE_SIZE_RIGHT        3
+#define _NET_WM_MOVERESIZE_SIZE_BOTTOMRIGHT  4
+#define _NET_WM_MOVERESIZE_SIZE_BOTTOM       5
+#define _NET_WM_MOVERESIZE_SIZE_BOTTOMLEFT   6
+#define _NET_WM_MOVERESIZE_SIZE_LEFT         7
+#define _NET_WM_MOVERESIZE_MOVE              8
 
 // Additional mouse button names for XButtonEvent
 #define Button6            6
@@ -2388,6 +2397,78 @@ void _glfwPlatformFocusWindow(_GLFWwindow* window)
     XFlush(_glfw.x11.display);
 }
 
+void _glfwPlatformDragWindow(_GLFWwindow* window)
+{
+    int winXpos, winYpos;
+    double curXpos, curYpos;
+    XClientMessageEvent xclient;
+    memset(&xclient, 0, sizeof(XClientMessageEvent));
+    XUngrabPointer(_glfw.x11.display, 0);
+    XFlush(_glfw.x11.display);
+    _glfwPlatformGetCursorPos(window, &curXpos, &curYpos);
+    _glfwPlatformGetWindowPos(window, &winXpos, &winYpos);
+    xclient.type = ClientMessage;
+    xclient.window = window->x11.handle;
+    xclient.message_type = XInternAtom(_glfw.x11.display, "_NET_WM_MOVERESIZE", False);
+    xclient.format = 32;
+    xclient.data.l[0] = winXpos + curXpos;
+    xclient.data.l[1] = winYpos + curYpos;
+    xclient.data.l[2] = _NET_WM_MOVERESIZE_MOVE;
+    xclient.data.l[3] = 0;
+    xclient.data.l[4] = 0;
+    XSendEvent(_glfw.x11.display, _glfw.x11.root, False, SubstructureRedirectMask | SubstructureNotifyMask, (XEvent *)&xclient);
+}
+
+void _glfwPlatformResizeWindow(_GLFWwindow* window, int border)
+{
+    int winXpos, winYpos;
+    double curXpos, curYpos;
+    XClientMessageEvent xclient;
+    memset(&xclient, 0, sizeof(XClientMessageEvent));
+    XUngrabPointer(_glfw.x11.display, 0);
+    XFlush(_glfw.x11.display);
+    _glfwPlatformGetCursorPos(window, &curXpos, &curYpos);
+    _glfwPlatformGetWindowPos(window, &winXpos, &winYpos);
+    xclient.type = ClientMessage;
+    xclient.window = window->x11.handle;
+    xclient.message_type = XInternAtom(_glfw.x11.display, "_NET_WM_MOVERESIZE", False);
+    xclient.format = 32;
+    xclient.data.l[0] = winXpos + curXpos;
+    xclient.data.l[1] = winYpos + curYpos;
+    switch (border)
+    {
+        case GLFW_WINDOW_LEFT:
+            xclient.data.l[2] = _NET_WM_MOVERESIZE_SIZE_LEFT;
+            break;
+        case GLFW_WINDOW_TOP:
+            xclient.data.l[2] = _NET_WM_MOVERESIZE_SIZE_TOP;
+            break;
+        case GLFW_WINDOW_RIGHT:
+            xclient.data.l[2] = _NET_WM_MOVERESIZE_SIZE_RIGHT;
+            break;
+        case GLFW_WINDOW_BOTTOM:
+            xclient.data.l[2] = _NET_WM_MOVERESIZE_SIZE_BOTTOM;
+            break;
+        case GLFW_WINDOW_TOPLEFT:
+            xclient.data.l[2] = _NET_WM_MOVERESIZE_SIZE_TOPLEFT;
+            break;
+        case GLFW_WINDOW_TOPRIGHT:
+            xclient.data.l[2] = _NET_WM_MOVERESIZE_SIZE_TOPRIGHT;
+            break;
+        case GLFW_WINDOW_BOTTOMLEFT:
+            xclient.data.l[2] = _NET_WM_MOVERESIZE_SIZE_BOTTOMLEFT;
+            break;
+        case GLFW_WINDOW_BOTTOMRIGHT:
+            xclient.data.l[2] = _NET_WM_MOVERESIZE_SIZE_BOTTOMRIGHT;
+			break;
+		default:
+			assert(GLFW_FALSE);
+    }
+    xclient.data.l[3] = 0;
+    xclient.data.l[4] = 0;
+    XSendEvent(_glfw.x11.display, _glfw.x11.root, False, SubstructureRedirectMask | SubstructureNotifyMask, (XEvent *)&xclient);
+}
+
 void _glfwPlatformSetWindowMonitor(_GLFWwindow* window,
                                    _GLFWmonitor* monitor,
                                    int xpos, int ypos,

tests/windows.c

@@ -89,6 +89,12 @@ static void key_callback(GLFWwindow* window, int key, int scancode, int action,
     }
 }
 
+void mouse_button_callback(GLFWwindow* window, int button, int action, int mods)
+{
+    if (button == GLFW_MOUSE_BUTTON_LEFT && action == GLFW_PRESS)
+        glfwDragWindow(window);
+}
+
 int main(int argc, char** argv)
 {
     int i, ch;
@@ -138,6 +144,7 @@ int main(int argc, char** argv)
         }
 
         glfwSetKeyCallback(windows[i], key_callback);
+        glfwSetMouseButtonCallback(windows[i], mouse_button_callback);
 
         glfwMakeContextCurrent(windows[i]);
         gladLoadGLLoader((GLADloadproc) glfwGetProcAddress);