Add glfwGetWindowTitle

This adds a function for querying the current title of a window.  This
currently returns a copy of the last title set via GLFW.

Fixes #1448
Closes #1909
Closes #2482

CONTRIBUTORS.md

@@ -15,6 +15,7 @@ video tutorials.
  - Keith Bauer
  - John Bartholomew
  - Coşku Baş
+ - Bayemite
  - Niklas Behrens
  - Andrew Belt
  - Nevyn Bengtsson

README.md

@@ -167,6 +167,7 @@ information on what to include when reporting a bug.
  - Added support for `XDG_SESSION_TYPE` environment variable
  - Added `GLFW_PKG_CONFIG_REQUIRES_PRIVATE` and `GLFW_PKG_CONFIG_LIBS_PRIVATE` CMake
    variables exposing pkg-config dependencies (#1307)
+ - Added `glfwGetWindowTitle` function for GLFWwindow for querying window titles (#1448,#1909)
  - Made joystick subsystem initialize at first use (#1284,#1646)
  - Made `GLFW_DOUBLEBUFFER` a read-only window attribute
  - Updated the minimum required CMake version to 3.1

docs/news.md

@@ -41,6 +41,12 @@ to whatever window is behind it.  This can also be changed after window
 creation with the matching [window attribute](@ref GLFW_MOUSE_PASSTHROUGH_attrib).
 
 
+#### Ability to get a window's title {#features_34_get_window_title}
+
+GLFW now supports retrieving a window's title with the @ref glfwGetWindowTitle
+function.
+
+
 #### Wayland libdecor decorations {#wayland_libdecor_34}
 
 GLFW now supports improved fallback window decorations via
@@ -253,6 +259,7 @@ then GLFW will fail to initialize.
  - @ref glfwGetPlatform
  - @ref glfwPlatformSupported
  - @ref glfwInitVulkanLoader
+ - @ref glfwGetWindowTitle
 
 
 #### New types in version 3.4 {#types_34}

docs/window.md

@@ -919,6 +919,15 @@ If you are using C++11 or C11, you can use a UTF-8 string literal.
 glfwSetWindowTitle(window, u8"This is always a UTF-8 string");
 ```
 
+The window title can be retrieved with @ref glfwGetWindowTitle.
+
+```c
+const char* title = glfwGetWindowTitle(window);
+```
+
+The title returned is an internally managed copy of the title set
+by @ref glfwCreateWindow or @ref glfwSetWindowTitle. It does not
+include any additional text which may be appended by the platform.
 
 ### Window icon {#window_icon}
 

include/GLFW/glfw3.h

@@ -3305,6 +3305,30 @@ GLFWAPI int glfwWindowShouldClose(GLFWwindow* window);
  */
 GLFWAPI void glfwSetWindowShouldClose(GLFWwindow* window, int value);
 
+/*! @brief Retrieves the title of the specified window.
+ *
+ *  This function gets the window title, encoded as UTF-8, of the specified
+ *  window.
+ *
+ *  @param[in] window The window to query.
+ *  @return A copy of the UTF-8 encoded window title, as set by glfwCreateWindow
+ *  or glfwSetWindowTitle, or NULL if there is an error.
+ *
+ *  @errors Possible errors include @ref GLFW_NOT_INITIALIZED
+ *
+ *  @pointer_lifetime The returned string is allocated and freed by GLFW.  You
+ *  should not free it yourself.  It is valid until the next call to @ref
+ *  glfwSetWindowTitle, or until the library is terminated.
+ *
+ *  @thread_safety This function must only be called from the main thread.
+ *
+ *  @sa @ref window_title
+ *  @sa @ref glfwSetWindowTitle
+ *
+ *  @ingroup window
+ */
+GLFWAPI const char* glfwGetWindowTitle(GLFWwindow* window);
+
 /*! @brief Sets the title of the specified window.
  *
  *  This function sets the window title, encoded as UTF-8, of the specified

src/internal.h

@@ -532,6 +532,7 @@ struct _GLFWwindow
     GLFWvidmode         videoMode;
     _GLFWmonitor*       monitor;
     _GLFWcursor*        cursor;
+    char*               title;
 
     int                 minwidth, minheight;
     int                 maxwidth, maxheight;

src/window.c

@@ -242,6 +242,7 @@ GLFWAPI GLFWwindow* glfwCreateWindow(int width, int height,
     window->maxheight   = GLFW_DONT_CARE;
     window->numer       = GLFW_DONT_CARE;
     window->denom       = GLFW_DONT_CARE;
+    window->title       = _glfw_strdup(title);
 
     if (!_glfw.platform.createWindow(window, &wndconfig, &ctxconfig, &fbconfig))
     {
@@ -493,7 +494,7 @@ GLFWAPI void glfwDestroyWindow(GLFWwindow* handle)
 
         *prev = window->next;
     }
-
+    _glfw_free(window->title);
     _glfw_free(window);
 }
 
@@ -515,6 +516,16 @@ GLFWAPI void glfwSetWindowShouldClose(GLFWwindow* handle, int value)
     window->shouldClose = value;
 }
 
+GLFWAPI const char* glfwGetWindowTitle(GLFWwindow* handle)
+{
+    _GLFWwindow* window = (_GLFWwindow*) handle;
+    assert(window != NULL);
+
+    _GLFW_REQUIRE_INIT_OR_RETURN(NULL);
+
+    return window->title;
+}
+
 GLFWAPI void glfwSetWindowTitle(GLFWwindow* handle, const char* title)
 {
     _GLFWwindow* window = (_GLFWwindow*) handle;
@@ -522,7 +533,12 @@ GLFWAPI void glfwSetWindowTitle(GLFWwindow* handle, const char* title)
     assert(title != NULL);
 
     _GLFW_REQUIRE_INIT();
+
+    char* prev = window->title;
+    window->title = _glfw_strdup(title);
+
     _glfw.platform.setWindowTitle(window, title);
+    _glfw_free(prev);
 }
 
 GLFWAPI void glfwSetWindowIcon(GLFWwindow* handle,

tests/window.c

@@ -62,6 +62,7 @@ int main(int argc, char** argv)
     char min_width_buffer[12] = "", min_height_buffer[12] = "";
     char max_width_buffer[12] = "", max_height_buffer[12] = "";
     int may_close = true;
+    char window_title[64] = "";
 
     if (!glfwInit())
         exit(EXIT_FAILURE);
@@ -71,7 +72,7 @@ int main(int argc, char** argv)
     glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 2);
     glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 1);
 
-    GLFWwindow* window = glfwCreateWindow(600, 630, "Window Features", NULL, NULL);
+    GLFWwindow* window = glfwCreateWindow(600, 660, "Window Features", NULL, NULL);
     if (!window)
     {
         glfwTerminate();
@@ -109,6 +110,11 @@ int main(int argc, char** argv)
     nk_glfw3_font_stash_begin(&atlas);
     nk_glfw3_font_stash_end();
 
+    // test setting title with result from glfwGetWindowTitle
+    glfwSetWindowTitle(window, glfwGetWindowTitle(window));
+
+    strncpy( window_title, glfwGetWindowTitle(window), sizeof(window_title));
+
     while (!(may_close && glfwWindowShouldClose(window)))
     {
         int width, height;
@@ -188,11 +194,25 @@ int main(int argc, char** argv)
 
             nk_label(nk, "Press Enter in a text field to set value", NK_TEXT_CENTERED);
 
+
+
             nk_flags events;
             const nk_flags flags = NK_EDIT_FIELD |
                                    NK_EDIT_SIG_ENTER |
                                    NK_EDIT_GOTO_END_ON_ACTIVATE;
 
+            nk_layout_row_dynamic(nk, 30, 2);
+            nk_label(nk, "Window Title:", NK_TEXT_LEFT);
+
+            events = nk_edit_string_zero_terminated( nk, flags, window_title, sizeof(window_title), NULL );
+
+            if (events & NK_EDIT_COMMITED)
+            {
+                glfwSetWindowTitle(window, window_title);
+                // we do not need to call glfwGetWindowTitle as we already store the title, but using it here for testing purposes
+                strncpy( window_title, glfwGetWindowTitle(window), sizeof(window_title));
+            }
+
             if (position_supported)
             {
                 int xpos, ypos;