[vte/vte-0-36] drawing: Make round box drawing characters nicer

[Christian Persch <chpe src gnome org>]

commit df01bb02c3ec02f1b35bc577db77772c2f591b23
Author: Christian Persch <chpe gnome org>
Date:   Thu Oct 17 21:03:36 2013 +0200

    drawing: Make round box drawing characters nicer
    
    Replace the Bézier curves with circle arcs plus straight segments.
    
    Based on a patch by Egmont Koblinger.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=709692

 src/vte.c |   34 +++++++++++++++++++++++++++++-----
 1 files changed, 29 insertions(+), 5 deletions(-)
---
diff --git a/src/vte.c b/src/vte.c
index 3227b07..b8ed4aa 100644
--- a/src/vte.c
+++ b/src/vte.c
@@ -9923,6 +9923,7 @@ vte_terminal_draw_graphic(VteTerminal *terminal, vteunistr c,
         {
                 const guint v = c - 0x256d;
                 int line_width;
+                int radius;
 
                 cairo_set_line_cap(cr, CAIRO_LINE_CAP_BUTT);
 
@@ -9930,13 +9931,36 @@ vte_terminal_draw_graphic(VteTerminal *terminal, vteunistr c,
                 adjust = (line_width & 1) ? .5 : 0.;
                 cairo_set_line_width(cr, line_width);
 
-                cairo_move_to(cr, xcenter + adjust, (v & 2) ? y : ybottom);
-                cairo_curve_to(cr, 
-                               xcenter + adjust, ycenter + adjust,
-                               xcenter + adjust, ycenter + adjust,
-                               (v == 1 || v == 2) ? x : xright, ycenter + adjust);
+                radius = (terminal->char_width + 2) / 3;
+                radius = MAX(radius, heavy_line_width);
+
+                if (v & 2) {
+                        cairo_move_to(cr, xcenter + adjust, y);
+                        cairo_line_to(cr, xcenter + adjust, ycenter - radius + 2 * adjust);
+                } else {
+                        cairo_move_to(cr, xcenter + adjust, ybottom);
+                        cairo_line_to(cr, xcenter + adjust, ycenter + radius);
+                }
+                cairo_stroke(cr);
+
+                cairo_arc(cr,
+                          (v == 1 || v == 2) ? xcenter - radius + 2 * adjust
+                                             : xcenter + radius,
+                          (v & 2) ? ycenter - radius + 2 * adjust
+                                  : ycenter + radius,
+                          radius - adjust,
+                          (v + 2) * M_PI / 2.0, (v + 3) * M_PI / 2.0);
                 cairo_stroke(cr);
 
+                if (v == 1 || v == 2) {
+                        cairo_move_to(cr, xcenter - radius + 2 * adjust, ycenter + adjust);
+                        cairo_line_to(cr, x, ycenter + adjust);
+                } else {
+                        cairo_move_to(cr, xcenter + radius, ycenter + adjust);
+                        cairo_line_to(cr, xright, ycenter + adjust);
+                }
+
+                cairo_stroke(cr);
                 break;
         }