Implement getcellpixels() for MacVim

Don't use `gui.char_width` / `char_height` unlike the other GVim
implementations. Those are used for deriving screen pixel sizes and
MacVim has been hard-coding them to 1 for simplicity since the actual
GUI functionality is handled out of the Vim process anyway. Changing
those values would require some refactoring. Instead, just use a new
variable to store them.

Related: vim/vim#16004

Author: ychin

src/MacVim/MMBackend.h

@@ -57,6 +57,8 @@
 #endif
 }
 
+@property (nonatomic, readonly) NSSize cellSize;
+
 + (MMBackend *)sharedInstance;
 
 - (void)setBackgroundColor:(int)color;

src/MacVim/MMBackend.m

@@ -2253,6 +2253,8 @@ - (void)handleInputEvent:(int)msgid data:(NSData *)data
         [self handleScrollbarEvent:data];
     } else if (SetFontMsgID == msgid) {
         [self handleSetFont:data];
+    } else if (UpdateCellSizeMsgID == msgid) {
+        [self handleCellSize:data];
     } else if (VimShouldCloseMsgID == msgid) {
         gui_shell_closed();
     } else if (DropFilesMsgID == msgid) {
@@ -2705,6 +2707,18 @@ - (void)handleSetFont:(NSData *)data
     CONVERT_FROM_UTF8_FREE(s);
 }
 
+- (void)handleCellSize:(NSData *)data
+{
+    if (!data) return;
+
+    const void *bytes = [data bytes];
+
+    // Don't use gui.char_width/height because for simplicity we set those to
+    // 1. We store the cell size separately (it's only used for
+    // getcellpixels()).
+    memcpy(&_cellSize, bytes, sizeof(NSSize));
+}
+
 - (void)handleDropFiles:(NSData *)data
 {
     // TODO: Get rid of this method; instead use Vim script directly.  At the

src/MacVim/MMVimController.m

@@ -1012,6 +1012,10 @@ - (void)handleMessage:(int)msgid data:(NSData *)data
             }
 
             [windowController setFont:font];
+
+            NSSize cellsize = windowController.vimView.textView.cellSize;
+            [self sendMessage:UpdateCellSizeMsgID
+                         data:[NSData dataWithBytes:&cellsize length:sizeof(cellsize)]];
             [name release];
         }
         break;

src/MacVim/MacVim.h

@@ -300,6 +300,7 @@ extern const char * const MMVimMsgIDStrings[];
     MSG(ScrollbarEventMsgID) \
     MSG(SetFontMsgID) \
     MSG(SetWideFontMsgID) \
+    MSG(UpdateCellSizeMsgID) \
     MSG(VimShouldCloseMsgID) \
     MSG(SetDefaultColorsMsgID) \
     MSG(SetTablineColorsMsgID) \

src/MacVim/gui_macvim.m

@@ -247,6 +247,9 @@
     // correspondence (assuming all characters have the same dimensions).
     gui.scrollbar_width = gui.scrollbar_height = 0;
 
+    // For simplicity we just set char width/height to 1 as the GUI is
+    // decoupled from Vim anyway so Vim doesn't need to know the accurate
+    // pixel sizes.
     gui.char_height = 1;
     gui.char_width = 1;
     gui.char_ascent = 0;
@@ -1664,6 +1667,18 @@
     return OK;
 }
 
+    int
+gui_mch_get_cell_width(void)
+{
+    return [MMBackend sharedInstance].cellSize.width;
+}
+
+    int
+gui_mch_get_cell_height(void)
+{
+    return [MMBackend sharedInstance].cellSize.height;
+}
+
 
     void
 gui_mch_beep(void)

src/evalfunc.c

@@ -5407,8 +5407,13 @@ f_getcellpixels(typval_T *argvars UNUSED, typval_T *rettv)
     if (gui.in_use)
     {
         // success pixel size and no gui.
+#ifdef FEAT_GUI_MACVIM
+        list_append_number(rettv->vval.v_list, (varnumber_T)gui_mch_get_cell_width());
+        list_append_number(rettv->vval.v_list, (varnumber_T)gui_mch_get_cell_height());
+#else
         list_append_number(rettv->vval.v_list, (varnumber_T)gui.char_width);
         list_append_number(rettv->vval.v_list, (varnumber_T)gui.char_height);
+#endif
     }
     else
 #endif

src/os_unix.c

@@ -4442,7 +4442,17 @@ mch_report_winsize(int fd, int rows, int cols)
 
     // calcurate and set tty pixel size
     struct cellsize cs;
-    mch_calc_cell_size(&cs);
+#if defined(FEAT_GUI) && defined(FEAT_GUI_MACVIM)
+    if (gui.in_use)
+    {
+	cs.cs_xpixel = gui_mch_get_cell_width();
+	cs.cs_ypixel = gui_mch_get_cell_height();
+    }
+    else
+#endif
+    {
+	mch_calc_cell_size(&cs);
+    }
 
     if (cs.cs_xpixel == -1)
     {

src/proto/gui_macvim.pro

@@ -43,6 +43,8 @@ void gui_mch_set_font(GuiFont font);
 void gui_mch_expand_font(optexpand_T *args, void *param, int (*add_match)(char_u *val));
 int gui_mch_adjust_charheight(void);
 int gui_mch_adjust_charwidth(void);
+int gui_mch_get_cell_width(void);
+int gui_mch_get_cell_height(void);
 void gui_mch_beep(void);
 char_u *gui_mch_browse(int saving, char_u *title, char_u *dflt, char_u *ext, char_u *initdir, char_u *filter);
 char_u *gui_mch_browsedir(char_u *title, char_u *initdir);

src/terminal.c

@@ -4831,8 +4831,13 @@ parse_csi(
 #ifdef FEAT_GUI
 	if (gui.in_use)
 	{
+#ifdef FEAT_GUI_MACVIM
+	    x += wp->w_wincol * gui_mch_get_cell_width();
+	    y += W_WINROW(wp) * gui_mch_get_cell_height();
+#else
 	    x += wp->w_wincol * gui.char_width;
 	    y += W_WINROW(wp) * gui.char_height;
+#endif
 	}
 	else
 #endif