* Add cucul_manage_canvas() and cucul_unmanage_canvas(). Display

drivers no longer need to access the cv->refcount private member
    and __cucul_set_canvas_size() is no longer needed.

caca/caca.c

@@ -42,6 +42,7 @@
 #   define x11_install(p) caca_plugin_install("x11", p)
 #endif
 
+static int caca_can_resize(caca_display_t *);
 static int caca_select_driver(caca_display_t *);
 #if defined(USE_PLUGINS)
 static int caca_plugin_install(char const *, caca_display_t *);
@@ -61,7 +62,7 @@ static int caca_plugin_install(char const *, caca_display_t *);
  *  \param cv The cucul cavas.
  *  \return The caca graphical context or NULL if an error occurred.
  */
-caca_display_t * caca_create_display(cucul_canvas_t * cv)
+caca_display_t * caca_create_display(cucul_canvas_t *cv)
 {
     caca_display_t *dp = malloc(sizeof(caca_display_t));
 
@@ -71,6 +72,13 @@ caca_display_t * caca_create_display(cucul_canvas_t * cv)
         return NULL;
     }
 
+    if(cucul_manage_canvas(cv, (int (*)(void *))caca_can_resize, (void *)dp))
+    {
+        free(dp);
+        seterrno(EBUSY);
+        return NULL;
+    }
+
     dp->cv = cv;
 #if defined(USE_PLUGINS)
     dp->plugin = NULL;
@@ -82,6 +90,7 @@ caca_display_t * caca_create_display(cucul_canvas_t * cv)
         if(dp->plugin)
             dlclose(dp->plugin);
 #endif
+        cucul_unmanage_canvas(cv, (int (*)(void *))caca_can_resize, (void *)dp);
         free(dp);
         seterrno(ENODEV);
         return NULL;
@@ -93,14 +102,12 @@ caca_display_t * caca_create_display(cucul_canvas_t * cv)
         if(dp->plugin)
             dlclose(dp->plugin);
 #endif
+        cucul_unmanage_canvas(cv, (int (*)(void *))caca_can_resize, (void *)dp);
         free(dp);
         seterrno(ENODEV);
         return NULL;
     }
 
-    /* Attached! */
-    dp->cv->refcount++;
-
     /* Graphics stuff */
     dp->delay = 0;
     dp->rendertime = 0;
@@ -127,6 +134,7 @@ caca_display_t * caca_create_display(cucul_canvas_t * cv)
 
     /* Resize events */
     dp->resize.resized = 0;
+    dp->resize.allow = 0;
 
     return dp;
 }
@@ -149,7 +157,7 @@ int caca_free_display(caca_display_t *dp)
     if(dp->plugin)
         dlclose(dp->plugin);
 #endif
-    dp->cv->refcount--;
+    cucul_unmanage_canvas(dp->cv, (int (*)(void *))caca_can_resize, (void *)dp);
     free(dp);
 
     return 0;
@@ -159,6 +167,11 @@ int caca_free_display(caca_display_t *dp)
  * XXX: The following functions are local.
  */
 
+static int caca_can_resize(caca_display_t *dp)
+{
+    return dp->resize.allow;
+}
+
 static int caca_select_driver(caca_display_t *dp)
 {
 #if defined(HAVE_GETENV) && defined(HAVE_STRCASECMP)

caca/caca_internals.h

@@ -141,6 +141,7 @@ struct caca_display
     struct resize
     {
         int resized;   /* A resize event was requested */
+        int allow;     /* The display driver allows resizing */
         unsigned w, h; /* Requested width and height */
     } resize;
 

caca/driver_cocoa.m

@@ -834,7 +834,9 @@ static int cocoa_init_graphics(caca_display_t *dp)
         return -1;
 
     unsigned int width = dp->cv->width, height = dp->cv->height;
-    __cucul_set_canvas_size(dp->cv, width ? width : 80, height ? height : 32);
+    dp->resize.allow = 1;
+    cucul_set_canvas_size(dp->cv, width ? width : 80, height ? height : 32);
+    dp->resize.allow = 0;
 
     // first create a full cocoa app if the host has no bundle
     if(![[NSBundle mainBundle] bundleIdentifier])

caca/driver_conio.c

@@ -58,8 +58,11 @@ static int conio_init_graphics(caca_display_t *dp)
 #   else
     /* FIXME */
 #   endif
-    __cucul_set_canvas_size(dp->cv, dp->drv.p->ti.screenwidth,
-                                    dp->drv.p->ti.screenheight);
+    dp->resize.allow = 1;
+    cucul_set_canvas_size(dp->cv, dp->drv.p->ti.screenwidth,
+                                  dp->drv.p->ti.screenheight);
+    dp->resize.allow = 0;
+
     return 0;
 }
 

caca/driver_gl.c

@@ -102,7 +102,9 @@ static int gl_init_graphics(caca_display_t *dp)
         sscanf(geometry, "%ux%u", &width, &height);
 #endif
 
-    __cucul_set_canvas_size(dp->cv, width ? width : 80, height ? height : 32);
+    dp->resize.allow = 1;
+    cucul_set_canvas_size(dp->cv, width ? width : 80, height ? height : 32);
+    dp->resize.allow = 0;
 
     /* Load a libcucul internal font */
     fonts = cucul_get_font_list();

caca/driver_ncurses.c

@@ -301,7 +301,9 @@ static int ncurses_init_graphics(caca_display_t *dp)
             }
         }
 
-    __cucul_set_canvas_size(dp->cv, COLS, LINES);
+    dp->resize.allow = 1;
+    cucul_set_canvas_size(dp->cv, COLS, LINES);
+    dp->resize.allow = 0;
 
     return 0;
 }

caca/driver_raw.c

@@ -40,7 +40,9 @@ static int raw_init_graphics(caca_display_t *dp)
         sscanf(geometry, "%ux%u", &width, &height);
 #endif
 
-    __cucul_set_canvas_size(dp->cv, width ? width : 80, height ? height : 24);
+    dp->resize.allow = 1;
+    cucul_set_canvas_size(dp->cv, width ? width : 80, height ? height : 24);
+    dp->resize.allow = 0;
 
     return 0;
 }

caca/driver_slang.c

@@ -170,7 +170,9 @@ static int slang_init_graphics(caca_display_t *dp)
     SLtt_utf8_enable(1);
 #endif
 
-    __cucul_set_canvas_size(dp->cv, SLtt_Screen_Cols, SLtt_Screen_Rows);
+    dp->resize.allow = 1;
+    cucul_set_canvas_size(dp->cv, SLtt_Screen_Cols, SLtt_Screen_Rows);
+    dp->resize.allow = 0;
 
     return 0;
 }

caca/driver_vga.c

@@ -76,7 +76,9 @@ static int vga_init_graphics(caca_display_t *dp)
     outb(tmp, 0x3d5);
 
     /* We don't have much choice */
-    __cucul_set_canvas_size(dp->cv, 80, 25);
+    dp->resize.allow = 1;
+    cucul_set_canvas_size(dp->cv, 80, 25);
+    dp->resize.allow = 0;
 
     return 0;
 }

caca/driver_win32.c

@@ -126,9 +126,11 @@ static int win32_init_graphics(caca_display_t *dp)
     if(!GetConsoleScreenBufferInfo(dp->drv.p->screen, &csbi))
         return -1;
 
-    __cucul_set_canvas_size(dp->cv,
-                            csbi.srWindow.Right - csbi.srWindow.Left + 1,
-                            csbi.srWindow.Bottom - csbi.srWindow.Top + 1);
+    dp->resize.allow = 1;
+    cucul_set_canvas_size(dp->cv,
+                          csbi.srWindow.Right - csbi.srWindow.Left + 1,
+                          csbi.srWindow.Bottom - csbi.srWindow.Top + 1);
+    dp->resize.allow = 0;
 
     SetConsoleMode(dp->drv.p->screen, 0);
 

caca/driver_x11.c

@@ -88,7 +88,9 @@ static int x11_init_graphics(caca_display_t *dp)
         sscanf(geometry, "%ux%u", &width, &height);
 #endif
 
-    __cucul_set_canvas_size(dp->cv, width ? width : 80, height ? height : 32);
+    dp->resize.allow = 1;
+    cucul_set_canvas_size(dp->cv, width ? width : 80, height ? height : 32);
+    dp->resize.allow = 0;
 
     dp->drv.p->dpy = XOpenDisplay(NULL);
     if(dp->drv.p->dpy == NULL)

caca/graphics.c

@@ -238,7 +238,11 @@ void _caca_handle_resize(caca_display_t *dp)
 
     /* Tell libcucul we changed size */
     if(dp->resize.w != dp->cv->width || dp->resize.h != dp->cv->height)
-        __cucul_set_canvas_size(dp->cv, dp->resize.w, dp->resize.h);
+    {
+        dp->resize.allow = 1;
+        cucul_set_canvas_size(dp->cv, dp->resize.w, dp->resize.h);
+        dp->resize.allow = 0;
+    }
 }
 
 void _caca_set_term_title(char const *str)

cucul/cucul.c

@@ -34,6 +34,8 @@
 #include "cucul.h"
 #include "cucul_internals.h"
 
+static int cucul_resize(cucul_canvas_t *, unsigned int, unsigned int);
+
 /** \brief Initialise a \e libcucul canvas.
  *
  *  Initialise internal \e libcucul structures and the backend that will
@@ -60,6 +62,8 @@ cucul_canvas_t * cucul_create_canvas(unsigned int width, unsigned int height)
 
     cv->refcount = 0;
     cv->autoinc = 0;
+    cv->resize_callback = NULL;
+    cv->resize_data = NULL;
 
     cv->frame = 0;
     cv->framecount = 1;
@@ -81,7 +85,7 @@ cucul_canvas_t * cucul_create_canvas(unsigned int width, unsigned int height)
     _cucul_load_frame_info(cv);
     cucul_set_color_ansi(cv, CUCUL_DEFAULT, CUCUL_TRANSPARENT);
 
-    if(__cucul_set_canvas_size(cv, width, height) < 0)
+    if(cucul_resize(cv, width, height) < 0)
     {
         int saved_errno = geterrno();
         free(cv->frames[0].name);
@@ -98,6 +102,70 @@ nomem:
     return NULL;
 }
 
+/** \brief Manage a canvas.
+ *
+ *  Lock a canvas to prevent it from being resized. If non-NULL,
+ *  the \e callback function pointer will be called upon each
+ *  \e cucul_set_canvas_size call and if the returned value is zero, the
+ *  canvas resize request will be denied.
+ *
+ *  This function is only useful for display drivers such as the \e libcaca
+ *  library.
+ *
+ *  If an error occurs, -1 is returned and \b errno is set accordingly:
+ *  - \c EBUSY The canvas is already being managed.
+ *
+ *  \param cv A libcucul canvas.
+ *  \param callback An optional callback function pointer.
+ *  \param p The argument to be passed to \e callback.
+ *  \return 0 in case of success, -1 if an error occurred.
+ */
+int cucul_manage_canvas(cucul_canvas_t *cv, int (*callback)(void *), void *p)
+{
+    if(cv->refcount)
+    {
+        seterrno(EBUSY);
+        return -1;
+    }
+
+    cv->refcount = 1;
+
+    return 0;
+}
+
+/** \brief Unmanage a canvas.
+ *
+ *  Unlock a canvas previously locked by cucul_manage_canvas(). For safety
+ *  reasons, the callback and callback data arguments must be the same as for
+ *  the cucul_manage_canvas() call.
+ *
+ *  This function is only useful for display drivers such as the \e libcaca
+ *  library.
+ *
+ *  If an error occurs, -1 is returned and \b errno is set accordingly:
+ *  - \c EINVAL The canvas is not managed, or the callback arguments do
+ *              not match.
+ *
+ *  \param cv A libcucul canvas.
+ *  \param callback The \e callback argument previously passed to
+                    cucul_manage_canvas().
+ *  \param p The \e p argument previously passed to cucul_manage_canvas().
+ *  \return 0 in case of success, -1 if an error occurred.
+ */
+int cucul_unmanage_canvas(cucul_canvas_t *cv, int (*callback)(void *), void *p)
+{
+    if(!cv->refcount
+        || cv->resize_callback != callback || cv->resize_data != p)
+    {
+        seterrno(EINVAL);
+        return -1;
+    }
+
+    cv->refcount = 0;
+
+    return 0;
+}
+
 /** \brief Resize a canvas.
  *
  *  Set the canvas' width and height, in character cells.
@@ -123,21 +191,22 @@ nomem:
  *  - \c ENOMEM Not enough memory for the requested canvas size. If this
  *    happens, the canvas handle becomes invalid and should not be used.
  *
- *  \param cv A libcucul canvas
- *  \param width The desired canvas width
- *  \param height The desired canvas height
+ *  \param cv A libcucul canvas.
+ *  \param width The desired canvas width.
+ *  \param height The desired canvas height.
  *  \return 0 in case of success, -1 if an error occurred.
  */
 int cucul_set_canvas_size(cucul_canvas_t *cv, unsigned int width,
                                               unsigned int height)
 {
-    if(cv->refcount)
+    if(cv->refcount && cv->resize_callback
+        && !cv->resize_callback(cv->resize_data))
     {
         seterrno(EBUSY);
         return -1;
     }
 
-    return __cucul_set_canvas_size(cv, width, height);
+    return cucul_resize(cv, width, height);
 }
 
 /** \brief Get the canvas width.
@@ -146,7 +215,7 @@ int cucul_set_canvas_size(cucul_canvas_t *cv, unsigned int width,
  *
  *  This function never fails.
  *
- *  \param cv A libcucul canvas
+ *  \param cv A libcucul canvas.
  *  \return The canvas width.
  */
 unsigned int cucul_get_canvas_width(cucul_canvas_t const *cv)
@@ -160,7 +229,7 @@ unsigned int cucul_get_canvas_width(cucul_canvas_t const *cv)
  *
  *  This function never fails.
  *
- *  \param cv A libcucul canvas
+ *  \param cv A libcucul canvas.
  *  \return The canvas height.
  */
 unsigned int cucul_get_canvas_height(cucul_canvas_t const *cv)
@@ -177,7 +246,7 @@ unsigned int cucul_get_canvas_height(cucul_canvas_t const *cv)
  *  If an error occurs, -1 is returned and \b errno is set accordingly:
  *  - \c EBUSY The canvas is in use by a display driver and cannot be freed.
  *
- *  \param cv A libcucul canvas
+ *  \param cv A libcucul canvas.
  *  \return 0 in case of success, -1 if an error occurred.
  */
 int cucul_free_canvas(cucul_canvas_t *cv)
@@ -231,8 +300,7 @@ int cucul_rand(int min, int max)
  * XXX: The following functions are local.
  */
 
-int __cucul_set_canvas_size(cucul_canvas_t *cv, unsigned int width,
-                                                unsigned int height)
+int cucul_resize(cucul_canvas_t *cv, unsigned int width, unsigned int height)
 {
     unsigned int x, y, f, old_width, old_height, new_size, old_size;
 

cucul/cucul.h

@@ -84,6 +84,8 @@ typedef struct cucul_font cucul_font_t;
  *
  *  @{ */
 __extern cucul_canvas_t * cucul_create_canvas(unsigned int, unsigned int);
+__extern int cucul_manage_canvas(cucul_canvas_t *, int (*)(void *), void *);
+__extern int cucul_unmanage_canvas(cucul_canvas_t *, int (*)(void *), void *);
 __extern int cucul_set_canvas_size(cucul_canvas_t *, unsigned int,
                                    unsigned int);
 __extern unsigned int cucul_get_canvas_width(cucul_canvas_t const *);

cucul/cucul_internals.h

@@ -43,8 +43,11 @@ struct cucul_canvas
     unsigned int frame, framecount;
     struct cucul_frame *frames;
 
+    /* Canvas management */
     unsigned int refcount;
     unsigned int autoinc;
+    int (*resize_callback)(void *);
+    void *resize_data;
 
     /* Shortcut to the active frame information */
     unsigned int width, height;
@@ -60,10 +63,6 @@ struct cucul_buffer
     int user_data;
 };
 
-/* Canvas functions */
-extern int __cucul_set_canvas_size(cucul_canvas_t *,
-                                   unsigned int, unsigned int);
-
 /* Colour functions */
 extern uint16_t _cucul_attr_to_rgb12fg(uint32_t);
 extern uint16_t _cucul_attr_to_rgb12bg(uint32_t);

msvc/libcucul.def

@@ -1,4 +0,0 @@
-LIBRARY "libcucul"
-
-EXPORTS
-    __cucul_set_canvas_size ; Private symbol used by libcaca