Drop support for Composite < 0.2

Rational: current workaround for Composite < 0.2 doesn't work with the
GLX backend, it also doesn't handle window border properly. Plus,
Composite 0.2 came out more than a decade ago, it's safe to assume
everyone has it.

Signed-off-by: Yuxuan Shui <yshuiv7@gmail.com>

src/backend/gl/glx.c

@@ -389,12 +389,8 @@ void *glx_prepare_win(void *backend_data, session_t *ps, win *w) {
 	}
 
 	auto wd = ccalloc(1, struct _glx_win_data);
-	if (ps->has_name_pixmap) {
 	wd->pixmap = xcb_generate_id(ps->c);
 	xcb_composite_name_window_pixmap(ps->c, w->id, wd->pixmap);
-	} else {
-		wd->pixmap = w->id;
-	}
 	if (!wd->pixmap) {
 		log_error("Failed to get pixmap for window %#010x", w->id);
 		goto err;

src/common.h

@@ -457,9 +457,6 @@ typedef struct session {
   int composite_error;
   /// Major opcode for X Composite extension.
   int composite_opcode;
-  /// Whether X Composite NameWindowPixmap is available. Aka if X
-  /// Composite version >= 0.2.
-  bool has_name_pixmap;
   /// Whether X Shape extension exists.
   bool shape_exists;
   /// Event base number for X Shape extension.

src/compton.c

@@ -2426,7 +2426,6 @@ session_init(int argc, char **argv, Display *dpy, const char *config_file,
     .composite_event = 0,
     .composite_error = 0,
     .composite_opcode = 0,
-    .has_name_pixmap = false,
     .shape_exists = false,
     .shape_event = 0,
     .shape_error = 0,
@@ -2541,8 +2540,9 @@ session_init(int argc, char **argv, Display *dpy, const char *config_file,
           xcb_composite_query_version(ps->c, XCB_COMPOSITE_MAJOR_VERSION, XCB_COMPOSITE_MINOR_VERSION),
           NULL);
 
-    if (reply && (reply->major_version > 0 || reply->minor_version >= 2)) {
+    if (!reply || (reply->major_version == 0 && reply->minor_version < 2)) {
-      ps->has_name_pixmap = true;
+      log_fatal("Your X server doesn't have Composite >= 0.2 support, compton cannot run.");
+      exit(1);
     }
     free(reply);
   }

src/diagnostic.c

@@ -12,7 +12,6 @@ void print_diagnostics(session_t *ps, const char *config_file) {
 	printf("**Version:** " COMPTON_VERSION "\n");
 	//printf("**CFLAGS:** %s\n", "??");
 	printf("\n### Extensions:\n\n");
-	printf("* Name Pixmap: %s\n", ps->has_name_pixmap ? "Yes" : "No");
 	printf("* Shape: %s\n", ps->shape_exists ? "Yes" : "No");
 	printf("* XRandR: %s\n", ps->randr_exists ? "Yes" : "No");
 	printf("* Present: %s\n", ps->present_exists ? "Present" : "Not Present");

src/render.c

@@ -234,15 +234,19 @@ static inline bool paint_isvalid(session_t *ps, const paint_t *ppaint) {
  */
 void paint_one(session_t *ps, win *w, const region_t *reg_paint) {
 	// Fetch Pixmap
-	if (!w->paint.pixmap && ps->has_name_pixmap) {
+	if (!w->paint.pixmap) {
 		w->paint.pixmap = xcb_generate_id(ps->c);
 		set_ignore_cookie(
 		    ps, xcb_composite_name_window_pixmap(ps->c, w->id, w->paint.pixmap));
 	}
 
 	xcb_drawable_t draw = w->paint.pixmap;
-	if (!draw)
+	if (!draw) {
-		draw = w->id;
+		log_error("Failed to get pixmap from window %#010x (%s), window won't be "
+		          "visible",
+		          w->id, w->name);
+		return;
+	}
 
 	// XRender: Build picture
 	if (bkend_use_xrender(ps) && !w->paint.pict) {