Fixed bug 1842 - [patch] SDL_SetWindowPosition sets bad position values when given SDL_WINDOWPOS_CENTERED args
authorSam Lantinga <slouken@libsdl.org>
Sun, 19 May 2013 22:36:54 -0700
changeset 7195 d206c3a59b2e
parent 7194 987fb567bba9
child 7196 fe0848afab9f
Fixed bug 1842 - [patch] SDL_SetWindowPosition sets bad position values when given SDL_WINDOWPOS_CENTERED args Alex Szpakowski When calling SDL_SetWindowPosition(window, SDL_WINDOWPOS_CENTERED, SDL_WINDOWPOS_CENTERED), the window moves to the correct position but it seems to internally set its x/y position values to the literal value of the SDL_WINDOWPOS_CENTERED define. This causes all sorts of problems when SDL functions which use the window position (e.g. SDL_SetWindowGrab) are called after the aforementioned SDL_SetWindowPosition call. Looking at the SDL_SetWindowPosition code, it seems that SDL_SendWindowEvent with the SDL_WINDOWEVENT_MOVED event is called at the end of the function using the literal value of the SDL_WINDOWPOS_CENTERED define, instead of the newly set window->x and window->y values. SDL_SendWindowEvent then sets the values of window->windowed.x and window->windowed.y to that value (0x2FFF0000, aka 805240832.) I have attached a patch which changes SDL_SetWindowPosition to make sure SDL_SendWindowEvent is called with the correct coordinate values, if SDL_WINDOWPOS_CENTERED is used (fixes the issue for me.) Tested with Mac OS 10.8.3.
src/video/SDL_video.c
--- a/src/video/SDL_video.c	Sun May 19 22:28:10 2013 -0700
+++ b/src/video/SDL_video.c	Sun May 19 22:36:54 2013 -0700
@@ -1497,12 +1497,6 @@
 {
     CHECK_WINDOW_MAGIC(window, );
 
-    if (!SDL_WINDOWPOS_ISUNDEFINED(x)) {
-        window->x = x;
-    }
-    if (!SDL_WINDOWPOS_ISUNDEFINED(y)) {
-        window->y = y;
-    }
     if (SDL_WINDOWPOS_ISCENTERED(x) || SDL_WINDOWPOS_ISCENTERED(y)) {
         SDL_VideoDisplay *display = SDL_GetDisplayForWindow(window);
         int displayIndex;
@@ -1511,12 +1505,20 @@
         displayIndex = SDL_GetIndexOfDisplay(display);
         SDL_GetDisplayBounds(displayIndex, &bounds);
         if (SDL_WINDOWPOS_ISCENTERED(x)) {
-            window->x = bounds.x + (bounds.w - window->w) / 2;
+            x = bounds.x + (bounds.w - window->w) / 2;
         }
         if (SDL_WINDOWPOS_ISCENTERED(y)) {
-            window->y = bounds.y + (bounds.h - window->h) / 2;
+            y = bounds.y + (bounds.h - window->h) / 2;
         }
     }
+
+    if (!SDL_WINDOWPOS_ISUNDEFINED(x)) {
+        window->x = x;
+    }
+    if (!SDL_WINDOWPOS_ISUNDEFINED(y)) {
+        window->y = y;
+    }
+
     if (!(window->flags & SDL_WINDOW_FULLSCREEN)) {
         if (_this->SetWindowPosition) {
             _this->SetWindowPosition(_this, window);