[gnumeric] GUI: Smooth ants.

[Morten Welinder <mortenw src gnome org>]

commit 43d7dbdd27faf0ae83d45fcc5ce3519f0c4c5678
Author: Morten Welinder <terra gnome org>
Date:   Thu Jan 30 10:39:19 2014 -0500

    GUI: Smooth ants.
    
    This also improves performance: we used to draw with hard light which
    requires looking at existing pixels.  For the same it didn't work with
    the current animation drawing.

 ChangeLog         |    7 +++++++
 src/item-cursor.c |   34 +++++++++++++++++++---------------
 2 files changed, 26 insertions(+), 15 deletions(-)
---
diff --git a/ChangeLog b/ChangeLog
index 9755a35..e662f80 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,10 @@
+2014-01-30  Morten Welinder  <terra gnome org>
+
+       * src/item-cursor.c (item_cursor_draw): Make the ant animation
+       smoother (when not using the fallback).  Avoid using hard light
+       for ant-ing -- that doesn't work for the same reason as alpha not
+       working.  Always use phase=0 for non-ant stipples.
+
 2014-01-29  Morten Welinder  <terra gnome org>
 
        * src/wbc-gtk.c (wbc_gtk_init): Add style classes for toolbar zones.
diff --git a/src/item-cursor.c b/src/item-cursor.c
index 8f3308f..00a33b4 100644
--- a/src/item-cursor.c
+++ b/src/item-cursor.c
@@ -59,7 +59,7 @@ struct _GnmItemCursor {
        GnmCellPos last_tip_pos;
 
        GnmItemCursorStyle style;
-       int      state;
+       guint    ant_state;
        guint    animation_timer;
 
        /*
@@ -152,7 +152,7 @@ cb_item_cursor_animation (GnmItemCursor *ic)
        GocItem *item = GOC_ITEM (ic);
        static int use_fallback = -1;
 
-       ic->state = !ic->state;
+       ic->ant_state++;
 
        if (use_fallback != 1) {
                GdkWindow *w = gtk_widget_get_window (GTK_WIDGET (item->canvas));
@@ -177,8 +177,10 @@ cb_item_cursor_animation (GnmItemCursor *ic)
                cairo_destroy (cr);
        }
 
-       if (use_fallback == 1)
-               goc_item_invalidate (item);
+       if (use_fallback == 1) {
+               if (ic->ant_state % 2 == 1)
+                       goc_item_invalidate (item);
+       }
 
        return TRUE;
 }
@@ -208,7 +210,7 @@ item_cursor_realize (GocItem *item)
        if (ic->style == GNM_ITEM_CURSOR_ANTED) {
                g_return_if_fail (ic->animation_timer == 0);
                ic->animation_timer = g_timeout_add (
-                       150, (GSourceFunc) cb_item_cursor_animation,
+                       75, (GSourceFunc) cb_item_cursor_animation,
                        ic);
        }
 }
@@ -272,6 +274,7 @@ item_cursor_draw (GocItem const *item, cairo_t *cr)
        gboolean draw_center, draw_external, draw_internal, draw_xor;
        double scale = item->canvas->pixels_per_unit;
        GdkRGBA *fore = NULL, *back = NULL;
+       double phase0 = 0;
 
 #if 0
        g_printerr ("draw[%d] %lx,%lx %lx,%lx\n",
@@ -362,13 +365,11 @@ item_cursor_draw (GocItem const *item, cairo_t *cr)
        case GNM_ITEM_CURSOR_ANTED:
                draw_center   = TRUE;
                draw_thick    = 2;
+               draw_xor = FALSE;
                fore = &ic->ant_color;
                back = &ic->ant_background_color;
-               if (ic->state) {
-                       GdkRGBA *swap = fore;
-                       fore = back;
-                       back = swap;
-               }
+               phase0 = (~ic->ant_state & 3) * 0.25;
+               break;
        }
 
        if (ic->use_color) {
@@ -479,18 +480,21 @@ item_cursor_draw (GocItem const *item, cairo_t *cr)
 
        if (draw_center) {
                double dashes[2];
+               double phase1 = fmod (phase0 + 0.5, 1);
 
                /* Stay in the boundary */
                x0 += (draw_thick / 2.0);
                y0 += (draw_thick / 2.0);
 
-               dashes[0] = dashes[1] = draw_stippled;
-               cairo_set_dash (cr, dashes, 2, 0.);
                cairo_set_line_width (cr, draw_thick);
-               gdk_cairo_set_source_rgba (cr, back);
                cairo_rectangle (cr, x0, y0, abs (x1 - x0), abs (y1 - y0));
+               dashes[0] = dashes[1] = draw_stippled;
+
+               cairo_set_dash (cr, dashes, 2, phase0 * 2 * draw_stippled);
+               gdk_cairo_set_source_rgba (cr, back);
                cairo_stroke_preserve (cr);
-               cairo_set_dash (cr, dashes, 2, dashes[1]);
+
+               cairo_set_dash (cr, dashes, 2, phase1 * 2 * draw_stippled);
                gdk_cairo_set_source_rgba (cr, fore);
                cairo_stroke (cr);
        }
@@ -1530,7 +1534,7 @@ gnm_item_cursor_init (GnmItemCursor *ic)
        ic->last_y = 0;
 
        ic->style = GNM_ITEM_CURSOR_SELECTION;
-       ic->state = 0;
+       ic->ant_state = 0;
        ic->animation_timer = 0;
 
        ic->visible = TRUE;