[goffice] GOArrow: one drawing routine is enough.

[Morten Welinder <mortenw src gnome org>]

commit 44185e4f7f9d708f016621cebda6ec4b00faa122
Author: Morten Welinder <terra gnome org>
Date:   Wed Feb 11 10:51:17 2015 -0500

    GOArrow: one drawing routine is enough.

 ChangeLog                 |    7 +++++
 goffice/canvas/goc-line.c |   56 ++++++++++----------------------------------
 goffice/utils/go-line.c   |   10 +++++---
 3 files changed, 26 insertions(+), 47 deletions(-)
---
diff --git a/ChangeLog b/ChangeLog
index 7537306..afc136c 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,12 @@
 2015-02-11  Morten Welinder  <terra gnome org>
 
+       * goffice/canvas/goc-line.c (goc_line_draw): Avoid overflow.
+       Round a bit more consistently.
+       (draw_arrow): Use go_arrow_draw.
+
+       * goffice/utils/go-line.c (go_arrow_draw): Only draw oval heads
+       when sizes are positive.
+
        * goffice/gtk/go-font-sel.c (GOFontSelClass): Fix base class.
 
        * goffice/utils/go-line.c (go_arrow_draw): New function extracted
diff --git a/goffice/canvas/goc-line.c b/goffice/canvas/goc-line.c
index 174c41c..30946cd 100644
--- a/goffice/canvas/goc-line.c
+++ b/goffice/canvas/goc-line.c
@@ -206,49 +206,18 @@ static void
 draw_arrow (GOArrow const *arrow, cairo_t *cr, GOStyle *style,
            double *endx, double *endy, double phi)
 {
-       double l, w;
+       double dx, dy;
 
        if (arrow->typ == GO_ARROW_NONE)
                return;
 
-       l = hypot (*endx, *endy);
-       w = style->line.width ? style->line.width / 2.0 : 0.5;
-
-       switch (arrow->typ) {
-       case GO_ARROW_KITE:
-               cairo_save (cr);
-               cairo_translate (cr, (int) *endx, (int) *endy);
-               cairo_rotate (cr, phi);
-               cairo_move_to (cr, -arrow->a, w);
-               cairo_line_to (cr, -arrow->b, w + arrow->c);
-               cairo_line_to (cr, 0., 0.);
-               cairo_line_to (cr, -arrow->b, -w - arrow->c);
-               cairo_line_to (cr, -arrow->a, -w);
-               cairo_close_path (cr);
-               cairo_set_source_rgba (cr, GO_COLOR_TO_CAIRO (style->line.color));
-               cairo_fill (cr);
-               cairo_restore (cr);
-               if (l > 0.) {
-                       (*endx) -= arrow->a * *endx / l;
-                       (*endy) -= arrow->a * *endy / l;
-               } else
-                       *endx = *endy = 0.;
-               break;
-
-       case GO_ARROW_OVAL:
-               cairo_save (cr);
-               cairo_translate (cr, *endx, *endy);
-               cairo_rotate (cr, phi);
-               cairo_scale (cr, arrow->a, arrow->b);
-               cairo_arc (cr, 0., 0., 1., 0., 2 * M_PI);
-               cairo_set_source_rgba (cr, GO_COLOR_TO_CAIRO (style->line.color));
-               cairo_fill (cr);
-               cairo_restore (cr);
-               break;
-
-       default:
-               g_assert_not_reached ();
-       }
+       cairo_save (cr);
+       cairo_translate (cr, *endx, *endy);
+       cairo_set_source_rgba (cr, GO_COLOR_TO_CAIRO (style->line.color));
+       go_arrow_draw (arrow, cr, &dx, &dy, phi - M_PI / 2);
+       *endx += dx;
+       *endy += dy;
+       cairo_restore (cr);
 }
 
 static void
@@ -276,8 +245,11 @@ goc_line_draw (GocItem const *item, cairo_t *cr)
        cairo_save (cr);
        _goc_item_transform (item, cr, TRUE);
        goc_group_cairo_transform (item->parent, cr,
-                                  hoffs + (int) line->startx,
-                                  voffs + (int) line->starty);
+                                  hoffs + floor (line->startx),
+                                  voffs + floor (line->starty));
+
+       endx = (endx > 0.)? ceil (endx): floor (endx);
+       endy = (endy > 0.)? ceil (endy): floor (endy);
 
        phi = atan2 (endy, endx);
        draw_arrow (&line->start_arrow, cr, style,
@@ -289,8 +261,6 @@ goc_line_draw (GocItem const *item, cairo_t *cr)
            go_styled_object_set_cairo_line (GO_STYLED_OBJECT (item), cr)) {
                /* try to avoid horizontal and vertical lines between two pixels */
                cairo_move_to (cr, 0., 0.);
-               endx = (endx > 0.)? ceil (endx): floor (endx);
-               endy = (endy > 0.)? ceil (endy): floor (endy);
                cairo_line_to (cr, endx, endy);
                cairo_stroke (cr);
        }
diff --git a/goffice/utils/go-line.c b/goffice/utils/go-line.c
index 8b20c47..c4fc2ac 100644
--- a/goffice/utils/go-line.c
+++ b/goffice/utils/go-line.c
@@ -550,10 +550,12 @@ go_arrow_draw (const GOArrow *arrow, cairo_t *cr,
                break;
 
        case GO_ARROW_OVAL:
-               cairo_rotate (cr, phi);
-               cairo_scale (cr, arrow->a, arrow->b);
-               cairo_arc (cr, 0., 0., 1., 0., 2 * M_PI);
-               cairo_fill (cr);
+               if (arrow->a > 0 && arrow->b > 0) {
+                       cairo_rotate (cr, phi);
+                       cairo_scale (cr, arrow->a, arrow->b);
+                       cairo_arc (cr, 0., 0., 1., 0., 2 * M_PI);
+                       cairo_fill (cr);
+               }
                break;
        }
 }