Re: Box graphic tweak

[Eli Zaretskii <eliz@gnu.org>]

> From: Chong Yidong <cyd@stupidchicken.com>
> Date: Fri, 08 Oct 2010 01:14:02 -0400
> 
> I just made a tweak to the way 3D boxes are drawn, to make them more
> legible.  The W32 code looks like it could use a similar change, but I
> didn't want to do the translation without being able to test it.  Could
> someone on W32 take a look?  Thanks.
> 
>   * xterm.c (x_draw_relief_rect): If box width is larger than 1,
>   draw the outermost line using the black relief, for legibility.
>   Omit drawing the four corner pixels.

Jason, could you please do this?  I tried, but the differences between
the X and the w32 code are substantial to the degree that sufficient
knowledge of the underlying primitives is required to DTRT, and I lack
that knowledge.

Thanks.

For reference, here are the diffs for the changes done by Chong:

=== modified file 'src/xterm.c'
--- src/xterm.c	2010-10-03 15:39:21 +0000
+++ src/xterm.c	2010-10-09 03:30:31 +0000
@@ -1942,18 +1942,38 @@ x_draw_relief_rect (struct frame *f,
     gc = f->output_data.x->black_relief.gc;
   XSetClipRectangles (dpy, gc, 0, 0, clip_rect, 1, Unsorted);
 
+  /* This code is more complicated than it has to be, because of two
+     minor hacks to make the boxes look nicer: (i) if width > 1, draw
+     the outermost line using the black relief.  (ii) Omit the four
+     corner pixels.  */
+
   /* Top.  */
   if (top_p)
-    for (i = 0; i < width; ++i)
-      XDrawLine (dpy, window, gc,
-		 left_x + i * left_p, top_y + i,
-		 right_x + 1 - i * right_p, top_y + i);
+    {
+      if (width == 1)
+	XDrawLine (dpy, window, gc,
+		   left_x  + (left_p  ? 1 : 0), top_y,
+		   right_x + (right_p ? 0 : 1), top_y);
+
+      for (i = 1; i < width; ++i)
+	XDrawLine (dpy, window, gc,
+		   left_x  + i * left_p, top_y + i,
+		   right_x + 1 - i * right_p, top_y + i);
+    }
 
   /* Left.  */
   if (left_p)
-    for (i = 0; i < width; ++i)
-      XDrawLine (dpy, window, gc,
-		 left_x + i, top_y + i, left_x + i, bottom_y - i + 1);
+    {
+      if (width == 1)
+	XDrawLine (dpy, window, gc, left_x, top_y + 1, left_x, bottom_y);
+
+      XClearArea (dpy, window, left_x, top_y, 1, 1, False);
+      XClearArea (dpy, window, left_x, bottom_y, 1, 1, False);
+
+      for (i = (width > 1 ? 1 : 0); i < width; ++i)
+	XDrawLine (dpy, window, gc,
+		   left_x + i, top_y + i, left_x + i, bottom_y - i + 1);
+    }
 
   XSetClipMask (dpy, gc, None);
   if (raised_p)
@@ -1962,18 +1982,40 @@ x_draw_relief_rect (struct frame *f,
     gc = f->output_data.x->white_relief.gc;
   XSetClipRectangles (dpy, gc, 0, 0, clip_rect, 1, Unsorted);
 
+  if (width > 1)
+    {
+      /* Outermost top line.  */
+      if (top_p)
+	XDrawLine (dpy, window, gc,
+		   left_x  + (left_p  ? 1 : 0), top_y,
+		   right_x + (right_p ? 0 : 1), top_y);
+
+      /* Outermost left line.  */
+      if (left_p)
+	XDrawLine (dpy, window, gc, left_x, top_y + 1, left_x, bottom_y);
+    }
+
   /* Bottom.  */
   if (bot_p)
-    for (i = 0; i < width; ++i)
+    {
       XDrawLine (dpy, window, gc,
-		 left_x + i * left_p, bottom_y - i,
-		 right_x + 1 - i * right_p, bottom_y - i);
+		 left_x  + (left_p  ? 1 : 0), bottom_y,
+		 right_x + (right_p ? 0 : 1), bottom_y);
+      for (i = 1; i < width; ++i)
+	XDrawLine (dpy, window, gc,
+		   left_x  + i * left_p, bottom_y - i,
+		   right_x + 1 - i * right_p, bottom_y - i);
+    }
 
   /* Right.  */
   if (right_p)
-    for (i = 0; i < width; ++i)
-      XDrawLine (dpy, window, gc,
-		 right_x - i, top_y + i + 1, right_x - i, bottom_y - i);
+    {
+      XClearArea (dpy, window, right_x, top_y, 1, 1, False);
+      XClearArea (dpy, window, right_x, bottom_y, 1, 1, False);
+      for (i = 0; i < width; ++i)
+	XDrawLine (dpy, window, gc,
+		   right_x - i, top_y + i + 1, right_x - i, bottom_y - i);
+    }
 
   XSetClipMask (dpy, gc, None);
 }