Wayland: Add support for xdg-decoration

This allows compositors which prefer to draw the decorations around
clients to do so, rather than letting GLFW draw its own decorations.
The appearance is thus entirely subject to the compositor used, but
should generally be better than the current solid colour decorations we
have, which we continue to use when the compositor doesn’t support this
protocol or tells us to draw the decorations ourselves.

This new protocol has been tested against wlroots’s rootston compositor.

Fixes #1257.

.travis.yml

@@ -65,7 +65,7 @@ script:
           sudo dpkg -i extra-cmake-modules_5.38.0a-0ubuntu1_amd64.deb;
           git clone git://anongit.freedesktop.org/wayland/wayland-protocols;
           pushd wayland-protocols;
-          git checkout 1.12 && ./autogen.sh --prefix=/usr && make && sudo make install;
+          git checkout 1.15 && ./autogen.sh --prefix=/usr && make && sudo make install;
           popd;
       fi
     - cmake -DCMAKE_VERBOSE_MAKEFILE=ON -DBUILD_SHARED_LIBS=${BUILD_SHARED_LIBS} -DGLFW_USE_WAYLAND=${USE_WAYLAND} ..

CMakeLists.txt

@@ -262,7 +262,7 @@ if (_GLFW_WAYLAND)
 
     find_package(Wayland REQUIRED Client Cursor Egl)
     find_package(WaylandScanner REQUIRED)
-    find_package(WaylandProtocols 1.12 REQUIRED)
+    find_package(WaylandProtocols 1.15 REQUIRED)
 
     list(APPEND glfw_PKG_DEPS "wayland-egl")
 

src/CMakeLists.txt

@@ -35,6 +35,10 @@ elseif (_GLFW_WAYLAND)
         PROTOCOL
         "${WAYLAND_PROTOCOLS_PKGDATADIR}/stable/xdg-shell/xdg-shell.xml"
         BASENAME xdg-shell)
+    ecm_add_wayland_client_protocol(glfw_SOURCES
+        PROTOCOL
+        "${WAYLAND_PROTOCOLS_PKGDATADIR}/unstable/xdg-decoration/xdg-decoration-unstable-v1.xml"
+        BASENAME xdg-decoration)
     ecm_add_wayland_client_protocol(glfw_SOURCES
         PROTOCOL
         "${WAYLAND_PROTOCOLS_PKGDATADIR}/stable/viewporter/viewporter.xml"

src/wl_init.c

@@ -758,6 +758,13 @@ static void registryHandleGlobal(void* data,
             wl_registry_bind(registry, name, &xdg_wm_base_interface, 1);
         xdg_wm_base_add_listener(_glfw.wl.wmBase, &wmBaseListener, NULL);
     }
+    else if (strcmp(interface, "zxdg_decoration_manager_v1") == 0)
+    {
+        _glfw.wl.decorationManager =
+            wl_registry_bind(registry, name,
+                             &zxdg_decoration_manager_v1_interface,
+                             1);
+    }
     else if (strcmp(interface, "wp_viewporter") == 0)
     {
         _glfw.wl.viewporter =
@@ -1138,6 +1145,8 @@ void _glfwPlatformTerminate(void)
         wl_shell_destroy(_glfw.wl.shell);
     if (_glfw.wl.viewporter)
         wp_viewporter_destroy(_glfw.wl.viewporter);
+    if (_glfw.wl.decorationManager)
+        zxdg_decoration_manager_v1_destroy(_glfw.wl.decorationManager);
     if (_glfw.wl.wmBase)
         xdg_wm_base_destroy(_glfw.wl.wmBase);
     if (_glfw.wl.pointer)

src/wl_platform.h

@@ -57,6 +57,7 @@ typedef VkBool32 (APIENTRY *PFN_vkGetPhysicalDeviceWaylandPresentationSupportKHR
 #include "osmesa_context.h"
 
 #include "wayland-xdg-shell-client-protocol.h"
+#include "wayland-xdg-decoration-client-protocol.h"
 #include "wayland-viewporter-client-protocol.h"
 #include "wayland-relative-pointer-unstable-v1-client-protocol.h"
 #include "wayland-pointer-constraints-unstable-v1-client-protocol.h"
@@ -185,6 +186,7 @@ typedef struct _GLFWwindowWayland
     struct {
         struct xdg_surface*     surface;
         struct xdg_toplevel*    toplevel;
+        struct zxdg_toplevel_decoration_v1* decoration;
     } xdg;
 
     _GLFWcursor*                currentCursor;
@@ -210,6 +212,7 @@ typedef struct _GLFWwindowWayland
     GLFWbool                    justCreated;
 
     struct {
+        GLFWbool                           serverSide;
         struct wl_buffer*                  buffer;
         _GLFWdecorationWayland             top, left, right, bottom;
         int                                focus;
@@ -231,6 +234,7 @@ typedef struct _GLFWlibraryWayland
     struct wl_pointer*          pointer;
     struct wl_keyboard*         keyboard;
     struct xdg_wm_base*         wmBase;
+    struct zxdg_decoration_manager_v1*      decorationManager;
     struct wp_viewporter*       viewporter;
     struct zwp_relative_pointer_manager_v1* relativePointerManager;
     struct zwp_pointer_constraints_v1*      pointerConstraints;

src/wl_window.c

@@ -274,7 +274,7 @@ static void createDecorations(_GLFWwindow* window)
     const GLFWimage image = { 1, 1, data };
     GLFWbool opaque = (data[3] == 255);
 
-    if (!_glfw.wl.viewporter)
+    if (!_glfw.wl.viewporter || !window->decorated || window->wl.decorations.serverSide)
         return;
 
     if (!window->wl.decorations.buffer)
@@ -321,6 +321,22 @@ static void destroyDecorations(_GLFWwindow* window)
     destroyDecoration(&window->wl.decorations.bottom);
 }
 
+static void xdgDecorationHandleConfigure(void* data,
+                                         struct zxdg_toplevel_decoration_v1* decoration,
+                                         uint32_t mode)
+{
+    _GLFWwindow* window = data;
+
+    window->wl.decorations.serverSide = (mode == ZXDG_TOPLEVEL_DECORATION_V1_MODE_SERVER_SIDE);
+
+    if (!window->wl.decorations.serverSide)
+        createDecorations(window);
+}
+
+static const struct zxdg_toplevel_decoration_v1_listener xdgDecorationListener = {
+    xdgDecorationHandleConfigure,
+};
+
 // Makes the surface considered as XRGB instead of ARGB.
 static void setOpaqueRegion(_GLFWwindow* window)
 {
@@ -493,9 +509,6 @@ static GLFWbool createSurface(_GLFWwindow* window,
     if (!window->wl.transparent)
         setOpaqueRegion(window);
 
-    if (window->decorated && !window->monitor)
-        createDecorations(window);
-
     return GLFW_TRUE;
 }
 
@@ -517,6 +530,7 @@ static void setFullscreen(_GLFWwindow* window, _GLFWmonitor* monitor,
             monitor->wl.output);
     }
     setIdleInhibitor(window, GLFW_TRUE);
+    if (!window->wl.decorations.serverSide)
         destroyDecorations(window);
 }
 
@@ -553,11 +567,13 @@ static GLFWbool createShellSurface(_GLFWwindow* window)
     {
         wl_shell_surface_set_maximized(window->wl.shellSurface, NULL);
         setIdleInhibitor(window, GLFW_FALSE);
+        createDecorations(window);
     }
     else
     {
         wl_shell_surface_set_toplevel(window->wl.shellSurface);
         setIdleInhibitor(window, GLFW_FALSE);
+        createDecorations(window);
     }
 
     wl_surface_commit(window->wl.surface);
@@ -646,6 +662,27 @@ static const struct xdg_surface_listener xdgSurfaceListener = {
     xdgSurfaceHandleConfigure
 };
 
+static void setXdgDecorations(_GLFWwindow* window)
+{
+    if (_glfw.wl.decorationManager)
+    {
+        window->wl.xdg.decoration =
+            zxdg_decoration_manager_v1_get_toplevel_decoration(
+                _glfw.wl.decorationManager, window->wl.xdg.toplevel);
+        zxdg_toplevel_decoration_v1_add_listener(window->wl.xdg.decoration,
+                                                 &xdgDecorationListener,
+                                                 window);
+        zxdg_toplevel_decoration_v1_set_mode(
+            window->wl.xdg.decoration,
+            ZXDG_TOPLEVEL_DECORATION_V1_MODE_SERVER_SIDE);
+    }
+    else
+    {
+        window->wl.decorations.serverSide = GLFW_FALSE;
+        createDecorations(window);
+    }
+}
+
 static GLFWbool createXdgSurface(_GLFWwindow* window)
 {
     window->wl.xdg.surface = xdg_wm_base_get_xdg_surface(_glfw.wl.wmBase,
@@ -693,10 +730,12 @@ static GLFWbool createXdgSurface(_GLFWwindow* window)
     {
         xdg_toplevel_set_maximized(window->wl.xdg.toplevel);
         setIdleInhibitor(window, GLFW_FALSE);
+        setXdgDecorations(window);
     }
     else
     {
         setIdleInhibitor(window, GLFW_FALSE);
+        setXdgDecorations(window);
     }
 
     wl_surface_commit(window->wl.surface);
@@ -946,6 +985,9 @@ void _glfwPlatformDestroyWindow(_GLFWwindow* window)
         window->context.destroy(window);
 
     destroyDecorations(window);
+    if (window->wl.xdg.decoration)
+        zxdg_toplevel_decoration_v1_destroy(window->wl.xdg.decoration);
+
     if (window->wl.decorations.buffer)
         wl_buffer_destroy(window->wl.decorations.buffer);
 
@@ -1061,7 +1103,7 @@ void _glfwPlatformGetWindowFrameSize(_GLFWwindow* window,
                                      int* left, int* top,
                                      int* right, int* bottom)
 {
-    if (window->decorated && !window->monitor)
+    if (window->decorated && !window->monitor && !window->wl.decorations.serverSide)
     {
         if (top)
             *top = _GLFW_DECORATION_TOP;
@@ -1190,7 +1232,7 @@ void _glfwPlatformSetWindowMonitor(_GLFWwindow* window,
         else if (window->wl.shellSurface)
             wl_shell_surface_set_toplevel(window->wl.shellSurface);
         setIdleInhibitor(window, GLFW_FALSE);
-        if (window->decorated)
+        if (!_glfw.wl.decorationManager)
             createDecorations(window);
     }
     _glfwInputWindowMonitor(window, monitor);