diff options
Diffstat (limited to 'src/w32fns.c')
| -rw-r--r-- | src/w32fns.c | 16 |
1 files changed, 15 insertions, 1 deletions
diff --git a/src/w32fns.c b/src/w32fns.c index d4e4b2a30bf..fb71fecd95a 100644 --- a/src/w32fns.c +++ b/src/w32fns.c @@ -1802,9 +1802,16 @@ w32_set_tool_bar_lines (struct frame *f, Lisp_Object value, Lisp_Object oldval) w32_change_tool_bar_height (f, nlines * FRAME_LINE_HEIGHT (f)); } +/* Enable or disable double buffering on F. + + When double buffering is enabled, all drawing happens on a back + buffer (a bitmap), which is then displayed as a single operation + after redisplay is complete. This avoids flicker caused by the + results of an incomplete redisplay becoming visible. */ static void w32_set_inhibit_double_buffering (struct frame *f, Lisp_Object new_value, + /* This parameter is unused. */ Lisp_Object old_value) { block_input (); @@ -4114,7 +4121,8 @@ w32_wnd_proc (HWND hwnd, UINT msg, WPARAM wParam, LPARAM lParam) f = w32_window_to_frame (dpyinfo, hwnd); enter_crit (); - if (f && !FRAME_OUTPUT_DATA (f)->paint_buffer) + if (f && (w32_disable_double_buffering + || !FRAME_OUTPUT_DATA (f)->paint_buffer)) { HDC hdc = get_frame_dc (f); GetUpdateRect (hwnd, &wmsg.rect, FALSE); @@ -11236,6 +11244,12 @@ see `w32-ansi-code-page'. */); w32_multibyte_code_page = _getmbcp (); #endif + DEFVAR_BOOL ("w32-disable-double-buffering", w32_disable_double_buffering, + doc: /* Completely disable double buffering. +This variable is used for debugging, and takes precedence over any +value of the `inhibit-double-buffering' frame parameter. */); + w32_disable_double_buffering = false; + if (os_subtype == OS_SUBTYPE_NT) w32_unicode_gui = 1; else |