Fix render backend crashes: resolve view IDs in all drawing functions

All WINGs render backend functions (draw_line, draw_rect, fill_rect,
pixmap_copy, composite_pixmap) now use resolve_drawable() to handle
WINGs view IDs (0x20000000+) by looking up the backing pixman image.

Also fixes:
- wfont_wl.c: resolve view IDs in draw_string/draw_image_string
- wtextfield.c paintCursor: use render backend draw_line (not XDrawLine)
- dialog.c wShowInfoPanel: guard scr->w_visual for Wayland mode

WINGs/wfont_wl.c

@@ -20,6 +20,14 @@
 #include <pixman.h>
 #include <string.h>
 
+extern void *W_GetViewBacking(unsigned long id);
+static inline pixman_image_t *wl_font_resolve_drawable(WMDrawable d)
+{
+    if ((unsigned long)d >= 0x20000000 && (unsigned long)d < 0x30000000)
+        return (pixman_image_t *)W_GetViewBacking((unsigned long)d);
+    return (pixman_image_t *)(uintptr_t)d;
+}
+
 /* ------------------------------------------------------------------ */
 
 typedef struct {
@@ -139,7 +147,7 @@ wl_draw_string(void *sctx, void *handle, WMDrawable d,
                const char *text, int len)
 {
     FontHandleWL   *h   = handle;
-    pixman_image_t *dst = (pixman_image_t *)(uintptr_t)d;
+    pixman_image_t *dst = wl_font_resolve_drawable(d); if (!dst) return;
     (void)sctx; (void)pixel;
 
     const char *prev = pango_layout_get_text(h->layout);
@@ -178,7 +186,7 @@ wl_draw_image_string(void *sctx, void *handle, WMDrawable d,
                      int bg_w, int bg_h,
                      const char *text, int len)
 {
-    pixman_image_t *dst = (pixman_image_t *)(uintptr_t)d;
+    pixman_image_t *dst = wl_font_resolve_drawable(d); if (!dst) return;
     (void)tpix; (void)bpix;
 
     /* Fill background. */

WINGs/wrender_wl.c

@@ -22,6 +22,17 @@ render_wl_screen_fini(void *rctx)
     wfree(rctx);
 }
 
+/* Resolve a WMDrawable to a pixman_image_t*.
+ * If it's a WINGs view ID (0x20000000..0x2FFFFFFF), look up backing image. */
+extern void *W_GetViewBacking(unsigned long id);
+static inline pixman_image_t *
+resolve_drawable(WMDrawable d)
+{
+    if ((unsigned long)d >= 0x20000000 && (unsigned long)d < 0x30000000)
+        return (pixman_image_t *)W_GetViewBacking((unsigned long)d);
+    return (pixman_image_t *)d;
+}
+
 static WMDrawable
 render_wl_pixmap_create(void *rctx, unsigned int width, unsigned int height, int depth)
 {
@@ -45,16 +56,8 @@ render_wl_pixmap_copy(void *rctx, WMDrawable src, WMDrawable dst,
 {
     (void)rctx;
     pixman_image_t *s = (pixman_image_t *)src;
-    pixman_image_t *d;
-
-    /* If dst is a WINGs view ID, look up its backing image */
-    if ((unsigned long)dst >= 0x20000000 && (unsigned long)dst < 0x30000000) {
-        extern void *W_GetViewBacking(unsigned long id);
-        d = (pixman_image_t *)W_GetViewBacking((unsigned long)dst);
-        if (!d) return;  /* no backing store yet */
-    } else {
-        d = (pixman_image_t *)dst;
-    }
+    pixman_image_t *d = resolve_drawable(dst);
+    if (!d) return;
     pixman_image_composite32(PIXMAN_OP_SRC, s, NULL, d,
                              sx, sy, 0, 0, dx, dy, w, h);
 }
@@ -75,7 +78,7 @@ render_wl_draw_line(void *rctx, WMDrawable d, WMColor *color,
                     int x1, int y1, int x2, int y2)
 {
     (void)rctx;
-    pixman_image_t *dst = (pixman_image_t *)d;
+    pixman_image_t *dst = resolve_drawable(d); if (!dst) return;
     pixman_color_t pc = wm_color_to_pixman(color);
     pixman_image_t *fill = pixman_image_create_solid_fill(&pc);
 
@@ -101,7 +104,7 @@ render_wl_draw_rect(void *rctx, WMDrawable d, WMColor *color,
                     int x, int y, unsigned int w, unsigned int h)
 {
     (void)rctx;
-    pixman_image_t *dst = (pixman_image_t *)d;
+    pixman_image_t *dst = resolve_drawable(d); if (!dst) return;
     pixman_color_t pc = wm_color_to_pixman(color);
 
     /* top */
@@ -123,7 +126,7 @@ render_wl_fill_rect(void *rctx, WMDrawable d, WMColor *color,
                     int x, int y, unsigned int w, unsigned int h)
 {
     (void)rctx;
-    pixman_image_t *dst = (pixman_image_t *)d;
+    pixman_image_t *dst = resolve_drawable(d); if (!dst) return;
     pixman_color_t pc = wm_color_to_pixman(color);
     pixman_image_fill_rectangles(PIXMAN_OP_OVER, dst, &pc, 1,
         &(pixman_rectangle16_t){x, y, w, h});
@@ -134,7 +137,7 @@ render_wl_fill_stippled(void *rctx, WMDrawable d, WMColor *color,
                         int x, int y, unsigned int w, unsigned int h)
 {
     (void)rctx;
-    pixman_image_t *dst = (pixman_image_t *)d;
+    pixman_image_t *dst = resolve_drawable(d); if (!dst) return;
     pixman_color_t pc = wm_color_to_pixman(color);
     pixman_image_t *fill = pixman_image_create_solid_fill(&pc);
 
@@ -154,7 +157,7 @@ render_wl_composite_pixmap(void *rctx, WMDrawable dst, W_Pixmap *src,
                            int dx, int dy)
 {
     (void)rctx;
-    pixman_image_t *d = (pixman_image_t *)dst;
+    pixman_image_t *d = resolve_drawable(dst); if (!d) return;
     pixman_image_t *s = (pixman_image_t *)(uintptr_t)src->pixmap;
     pixman_image_t *m = src->mask ? (pixman_image_t *)(uintptr_t)src->mask : NULL;
 
@@ -168,7 +171,7 @@ render_wl_fill_polygon(void *rctx, WMDrawable d, WMColor *color,
 {
     (void)rctx;
     if (npoints < 3) return;
-    pixman_image_t *dst = (pixman_image_t *)d;
+    pixman_image_t *dst = resolve_drawable(d); if (!dst) return;
     pixman_color_t pc = wm_color_to_pixman(color);
 
     /* Find bounding box */
@@ -204,7 +207,7 @@ render_wl_fill_arc(void *rctx, WMDrawable d, WMColor *color,
                    int angle1, int angle2)
 {
     (void)rctx;
-    pixman_image_t *dst = (pixman_image_t *)d;
+    pixman_image_t *dst = resolve_drawable(d); if (!dst) return;
     pixman_color_t pc = wm_color_to_pixman(color);
 
     /* X11 angles are in 64ths of a degree */

src/dialog.c

@@ -1353,9 +1353,14 @@ void wShowInfoPanel(WScreen *scr)
 		strbuf = wstrappend(strbuf, buffer);
 	}
 
-	snprintf(buffer, sizeof(buffer), _("Using visual 0x%x: %s %ibpp "),
-		 (unsigned)scr->w_visual->visualid, visuals[scr->w_visual->class], scr->w_depth);
-	strbuf = wstrappend(strbuf, buffer);
+	if (scr->w_visual) {
+		snprintf(buffer, sizeof(buffer), _("Using visual 0x%x: %s %ibpp "),
+			 (unsigned)scr->w_visual->visualid, visuals[scr->w_visual->class], scr->w_depth);
+		strbuf = wstrappend(strbuf, buffer);
+	} else {
+		snprintf(buffer, sizeof(buffer), _("Using Wayland compositor %ibpp "), scr->w_depth ? scr->w_depth : 32);
+		strbuf = wstrappend(strbuf, buffer);
+	}
 
 	switch (scr->w_depth) {
 	case 15: