Index: generic/tkCanvText.c
==================================================================
--- generic/tkCanvText.c
+++ generic/tkCanvText.c
@@ -955,23 +955,27 @@
      * it would causes problems with anti-aliased text because the two
      * anti-aliasing colors would blend together.
      */
 
     if ((selFirstChar >= 0) && (textPtr->selTextGC != textPtr->gc)) {
-	TkDrawAngledTextLayout(display, drawable, textPtr->gc,
-		textPtr->textLayout, drawableX, drawableY, textPtr->angle,
-		0, selFirstChar);
+	if (0 < selFirstChar) {
+	    TkDrawAngledTextLayout(display, drawable, textPtr->gc,
+		    textPtr->textLayout, drawableX, drawableY, textPtr->angle,
+		    0, selFirstChar);
+	}
 	TkDrawAngledTextLayout(display, drawable, textPtr->selTextGC,
 		textPtr->textLayout, drawableX, drawableY, textPtr->angle,
 		selFirstChar, selLastChar + 1);
-	TkDrawAngledTextLayout(display, drawable, textPtr->gc,
-		textPtr->textLayout, drawableX, drawableY, textPtr->angle,
-		selLastChar + 1, -1);
+	if (selLastChar + 1 < textPtr->numChars) {
+	    TkDrawAngledTextLayout(display, drawable, textPtr->gc,
+		    textPtr->textLayout, drawableX, drawableY, textPtr->angle,
+		    selLastChar + 1, textPtr->numChars);
+	}
     } else {
 	TkDrawAngledTextLayout(display, drawable, textPtr->gc,
 		textPtr->textLayout, drawableX, drawableY, textPtr->angle,
-		0, -1);
+		0, textPtr->numChars);
     }
     TkUnderlineAngledTextLayout(display, drawable, textPtr->gc,
 	    textPtr->textLayout, drawableX, drawableY, textPtr->angle,
 	    textPtr->underline);
 

Index: tests/canvText.test
==================================================================
--- tests/canvText.test
+++ tests/canvText.test
@@ -961,9 +961,23 @@
 	[expr {$bb0 eq [transpose $bb1] ? "ok" : "$bb0,$bb1"}] \
 } -cleanup {
     destroy .c
     rename transpose {}
 } -result {ok ok ok}
+
+test canvText-20.2 {crash on angled text selection (X11, without xft) - bug 2712f43f6e} -setup {
+    destroy .c
+    canvas .c -background bisque -selectforeground green2
+    grid .c
+    set id [.c create text 50 150 -anchor w -text "Angled text" \
+	    -angle 30 -font {Helvetica 32} -fill darkblue]
+} -body {
+    .c select clear
+    .c select from $id 0
+    .c select to $id 8 ; update    ;  # used to crash on X11 (--disable-xft build only)
+} -cleanup {
+    destroy .c
+} -result {}
 
 # cleanup
 cleanupTests
 return

Index: unix/tkUnixFont.c
==================================================================
--- unix/tkUnixFont.c
+++ unix/tkUnixFont.c
@@ -3064,33 +3064,35 @@
     int width, height;
     TkFont *fontPtr = (TkFont *) tkfont;
     Pixmap bitmap;
     GC bitmapGC;
     XGCValues values;
-    XImage *image;
+    XImage *image = NULL;
 
     (void) Tk_MeasureChars(tkfont, source, numBytes, -1, 0, &width);
     height = fontPtr->fm.ascent + fontPtr->fm.descent;
 
-    bitmap = Tk_GetPixmap(display, drawable, width, height, 1);
-    values.graphics_exposures = False;
-    values.foreground = BlackPixel(display, DefaultScreen(display));
-    bitmapGC = XCreateGC(display, bitmap, GCGraphicsExposures|GCForeground,
-	    &values);
-    XFillRectangle(display, bitmap, bitmapGC, 0, 0, width, height);
-
-    values.font = Tk_FontId(tkfont);
-    values.foreground = WhitePixel(display, DefaultScreen(display));
-    values.background = BlackPixel(display, DefaultScreen(display));
-    XChangeGC(display, bitmapGC, GCFont|GCForeground|GCBackground, &values);
-    Tk_DrawChars(display, bitmap, bitmapGC, tkfont, source, numBytes, 0,
-	    fontPtr->fm.ascent);
-    XFreeGC(display, bitmapGC);
-
-    image = XGetImage(display, bitmap, 0, 0, width, height, AllPlanes,
-	    ZPixmap);
-    Tk_FreePixmap(display, bitmap);
+    if ((width > 0) && (height > 0)) {
+	bitmap = Tk_GetPixmap(display, drawable, width, height, 1);
+	values.graphics_exposures = False;
+	values.foreground = BlackPixel(display, DefaultScreen(display));
+	bitmapGC = XCreateGC(display, bitmap, GCGraphicsExposures|GCForeground,
+		&values);
+	XFillRectangle(display, bitmap, bitmapGC, 0, 0, width, height);
+
+	values.font = Tk_FontId(tkfont);
+	values.foreground = WhitePixel(display, DefaultScreen(display));
+	values.background = BlackPixel(display, DefaultScreen(display));
+	XChangeGC(display, bitmapGC, GCFont|GCForeground|GCBackground, &values);
+	Tk_DrawChars(display, bitmap, bitmapGC, tkfont, source, numBytes, 0,
+		fontPtr->fm.ascent);
+	XFreeGC(display, bitmapGC);
+
+	image = XGetImage(display, bitmap, 0, 0, width, height, AllPlanes,
+		ZPixmap);
+	Tk_FreePixmap(display, bitmap);
+    }
 
     *realWidthPtr = width;
     *realHeightPtr = height;
     return image;
 }
@@ -3101,25 +3103,27 @@
     Drawable drawable,
     int width,
     int height,
     Pixmap *bitmapPtr)
 {
-    Pixmap bitmap;
-    XImage *image;
+    Pixmap bitmap = None;
+    XImage *image = NULL;
     GC bitmapGC;
     XGCValues values;
 
-    bitmap = Tk_GetPixmap(display, drawable, width, height, 1);
-    values.graphics_exposures = False;
-    values.foreground = BlackPixel(display, DefaultScreen(display));
-    bitmapGC = XCreateGC(display, bitmap, GCGraphicsExposures|GCForeground,
-	    &values);
-    XFillRectangle(display, bitmap, bitmapGC, 0, 0, width, height);
-    XFreeGC(display, bitmapGC);
-
-    image = XGetImage(display, bitmap, 0, 0, width, height, AllPlanes,
-	    ZPixmap);
+    if ((width > 0) && (height > 0)) {
+	bitmap = Tk_GetPixmap(display, drawable, width, height, 1);
+	values.graphics_exposures = False;
+	values.foreground = BlackPixel(display, DefaultScreen(display));
+	bitmapGC = XCreateGC(display, bitmap, GCGraphicsExposures|GCForeground,
+		&values);
+	XFillRectangle(display, bitmap, bitmapGC, 0, 0, width, height);
+	XFreeGC(display, bitmapGC);
+
+	image = XGetImage(display, bitmap, 0, 0, width, height, AllPlanes,
+		ZPixmap);
+    }
     *bitmapPtr = bitmap;
     return image;
 }
 
 void