Fix macOS mouse position reporting

Under SDL2, with HighDPI enabled, we end up with two coordinate
systems for our window... there's the pixel coordinates which we
draw in, and are available via SDL_GetWindowSizeInPixels(), and
there's the "screen" coordinates, which is an underlying source
size that is scaled from, and is available via SDL_GetWindowSize().

Mouse events are in the screen coordinates, drawing is in pixel
coordinates.  This commit converts mouse event positions to pixel
coordinates before converting further to text coordinates. :(

A specual thanks to u/ten-oh-four for working to track this down
with me, they ran multiple experimental builds and collected logs
which allowed to to be tracked down.

Fixes issue 155

src/conio/sdl_con.c

@@ -83,6 +83,14 @@ static pthread_mutex_t sdl_headlock;
 static struct rectlist *update_list = NULL;
 static struct rectlist *update_list_tail = NULL;
 
+#ifdef __DARWIN__
+static int mac_width;
+static int mac_height;
+#define UPDATE_WINDOW_SIZE sdl.GetWindowSize(win, &mac_width, &mac_height)
+#else
+#define UPDATE_WINDOW_SIZE
+#endif
+
 enum {
 	 SDL_USEREVENT_FLUSH
 	,SDL_USEREVENT_SETTITLE
@@ -459,6 +467,7 @@ static void internal_setwinsize(struct video_stats *vs, bool force)
 	else {
 		pthread_mutex_lock(&win_mutex);
 		sdl.GetWindowSizeInPixels(win, &w, &h);
+		UPDATE_WINDOW_SIZE;
 		pthread_mutex_unlock(&win_mutex);
 		if (w != vs->winwidth || h != vs->winheight) {
 			vs->winwidth = w;
@@ -637,6 +646,7 @@ static void setup_surfaces(struct video_stats *vs)
 		new_win = true;
 		if (sdl.CreateWindowAndRenderer(vs->winwidth, vs->winheight, flags, &win, &renderer) == 0) {
 			sdl.GetWindowSizeInPixels(win, &idealw, &idealh);
+			UPDATE_WINDOW_SIZE;
 			vs->winwidth = idealw;
 			vs->winheight = idealh;
 			sdl.RenderClear(renderer);
@@ -663,6 +673,7 @@ static void setup_surfaces(struct video_stats *vs)
 			sdl.SetWindowSize(win, idealw, idealh);
 		}
 		sdl.GetWindowSizeInPixels(win, &idealw, &idealh);
+		UPDATE_WINDOW_SIZE;
 		vs->winwidth = idealw;
 		vs->winheight = idealh;
 		if (internal_scaling) {
@@ -713,6 +724,7 @@ static void sdl_add_key(unsigned int keyval, struct video_stats *vs)
 
 		// Get current window size
 		sdl.GetWindowSizeInPixels(win, &w, &h);
+		UPDATE_WINDOW_SIZE;
 		// Limit to max window size if available
 		if (!fullscreen) {
 			SDL_Rect r;
@@ -861,6 +873,9 @@ static int win_to_res_xpos(int winpos, struct video_stats *vs)
 	int w, h;
 
 	bitmap_get_scaled_win_size(vs->scaling, &w, &h, 0, 0);
+#ifdef __DARWIN__
+	winpos = winpos * vs->winwidth / mac_width;
+#endif
 	int xoff = (vs->winwidth - w) / 2;
 	if (xoff < 0)
 		xoff = 0;
@@ -880,6 +895,9 @@ static int win_to_res_ypos(int winpos, struct video_stats *vs)
 	int w, h;
 
 	bitmap_get_scaled_win_size(vs->scaling, &w, &h, 0, 0);
+#ifdef __DARWIN__
+	winpos = winpos * vs->winheight / mac_height;
+#endif
 	int yoff = (vs->winheight - h) / 2;
 	if (yoff < 0)
 		yoff = 0;

src/syncterm/CHANGES

@@ -6,6 +6,7 @@ Create dirs on macOS when needed - fixes adding first BBS
 Fix cache subdirectories on Windows
 Make File Locations window wider
 Ensure window can be resized if started in fullscreen mode
+Fix macOS mouse position reporting
 
 Version 1.2rc2
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