[goocanvas/new-api: 5/7] added "line-width-is-unscaled" property.

[Damon Chaplin <damon src gnome org>]

commit 80cb9f717cd4309707e8532cb2a262593dfad791
Author: Damon Chaplin <damon gnome org>
Date:   Thu Jun 24 15:10:32 2010 +0100

    added "line-width-is-unscaled" property.

 demo/demo.c               |    3 ++-
 demo/scalability-demo.c   |   15 ++++++++++-----
 src/goocanvasitemsimple.c |   45 +++++++++++++++++++++++++++++++++------------
 src/goocanvasstyle.c      |   17 ++++++++++++++++-
 src/goocanvasstyle.h      |    1 +
 5 files changed, 62 insertions(+), 19 deletions(-)
---
diff --git a/demo/demo.c b/demo/demo.c
index 208c043..7094ea4 100644
--- a/demo/demo.c
+++ b/demo/demo.c
@@ -877,7 +877,8 @@ setup_rectangles (GooCanvasItem *root)
   item = goo_canvas_rect_new (root, 20, 90, 70, 60,
 			      "fill-color-rgba", 0x3cb37180,
 			      "stroke-color", "blue",
-			      "line-width", 2.0,
+			      "line-width", 1.0,
+			      "line-width-is-unscaled", TRUE,
 			      "tooltip", "Partially transparent rectangle",
 			      NULL);
   setup_item_signals (item);
diff --git a/demo/scalability-demo.c b/demo/scalability-demo.c
index 913a996..b507060 100644
--- a/demo/scalability-demo.c
+++ b/demo/scalability-demo.c
@@ -116,8 +116,7 @@ setup_canvas (GtkWidget *canvas)
   GooCanvasItem *root, *group, *item;
   int group_i, group_j, i, j;
   int total_items = 0, id_item_num = 0;;
-  GooCanvasStyle *style, *style2;
-  PangoFontDescription *font_desc;
+  GooCanvasStyle *style, *style2, *text_style;
   cairo_matrix_t item_matrix;
   GQuark id_quark = g_quark_from_static_string ("id");
 
@@ -126,8 +125,6 @@ setup_canvas (GtkWidget *canvas)
   g_signal_connect (root, "motion_notify_event",
 		    G_CALLBACK (on_motion_notify), NULL);
 
-  font_desc = pango_font_description_from_string ("Sans 8");
-
   style = g_object_new (GOO_TYPE_CANVAS_STYLE,
 			"fill-color", "mediumseagreen",
 			NULL);
@@ -136,6 +133,10 @@ setup_canvas (GtkWidget *canvas)
 			 "fill-color", "steelblue",
 			 NULL);
 
+  text_style = g_object_new (GOO_TYPE_CANVAS_STYLE,
+			     "font", "Sans 8",
+			     NULL);
+
   for (group_i = 0; group_i < N_GROUP_COLS; group_i++)
     {
       for (group_j = 0; group_j < N_GROUP_ROWS; group_j++)
@@ -194,13 +195,17 @@ setup_canvas (GtkWidget *canvas)
 					      item_x + item_width / 2,
 					      item_y + item_height / 2,
 					      item_width, GTK_ANCHOR_CENTER,
-					      /*"font-desc", font_desc,*/
 					      /*"height", item_height,*/
 					      /*"alignment", PANGO_ALIGN_CENTER,*/
 					      NULL);
 		  /* FIXME: This is slightly naughty, but much faster. */
 		  GOO_CANVAS_TEXT (item)->height = item_height;
 		  GOO_CANVAS_TEXT (item)->alignment = PANGO_ALIGN_CENTER;
+
+#ifdef SET_STYLE
+		  goo_canvas_item_simple_set_style ((GooCanvasItemSimple*) item, text_style);
+#endif
+
 #else
 		  item = goo_canvas_rect_new (group, item_x + 20, item_y + 4,
 					      item_width - 40, item_height - 8,
diff --git a/src/goocanvasitemsimple.c b/src/goocanvasitemsimple.c
index a5a43a1..b042d88 100644
--- a/src/goocanvasitemsimple.c
+++ b/src/goocanvasitemsimple.c
@@ -51,6 +51,7 @@ enum {
   /* Line style & width properties. */
   PROP_LINE_WIDTH,
   PROP_LINE_WIDTH_TOLERANCE,
+  PROP_LINE_WIDTH_IS_UNSCALED,
   PROP_LINE_CAP,
   PROP_LINE_JOIN,
   PROP_LINE_JOIN_MITER_LIMIT,
@@ -178,6 +179,9 @@ goo_canvas_item_simple_get_property (GObject              *object,
     case PROP_LINE_WIDTH_TOLERANCE:
       g_value_set_double (value, style ? style->line_width_tolerance : 0);
       break;
+    case PROP_LINE_WIDTH_IS_UNSCALED:
+      g_value_set_boolean (value, style ? style->line_width_is_unscaled : FALSE);
+      break;
     case PROP_LINE_CAP:
       g_value_set_enum (value, style ? style->line_cap : CAIRO_LINE_CAP_BUTT);
       break;
@@ -313,6 +317,9 @@ goo_canvas_item_simple_set_property (GObject              *object,
       style->line_width_tolerance = g_value_get_double (value);
       need_update = FALSE;
       break;
+    case PROP_LINE_WIDTH_IS_UNSCALED:
+      style->line_width_is_unscaled = g_value_get_boolean (value);
+      break;
     case PROP_LINE_CAP:
       style->line_cap = g_value_get_enum (value);
       recompute_bounds = TRUE;
@@ -1276,7 +1283,7 @@ goo_canvas_item_simple_set_stroke_options (GooCanvasItemSimple   *simple,
 					   gboolean		  add_tolerance)
 {
   GooCanvasStyle *style = simple->style;
-  gdouble line_width;
+  gdouble line_width, scale;
 
   /* If no style is set, just reset the source to black and return TRUE so the
      default style will be used. */
@@ -1297,21 +1304,28 @@ goo_canvas_item_simple_set_stroke_options (GooCanvasItemSimple   *simple,
   if (style->antialias != CAIRO_ANTIALIAS_GRAY)
     cairo_set_antialias (cr, style->antialias);
 
-  if (add_tolerance && style->line_width_tolerance > 0)
-    {
-      if (style->line_width >= 0.0)
-	line_width = style->line_width;
-      else
-	line_width = cairo_get_line_width (cr);
-
-      cairo_set_line_width (cr, line_width + style->line_width_tolerance);
-    }
+  /* Determine the basic line width. */
+  if (style->line_width >= 0.0)
+    line_width = style->line_width;
   else
+    line_width = cairo_get_line_width (cr);
+
+  /* Add on the tolerance, if needed. */
+  if (add_tolerance)
+    line_width += style->line_width_tolerance;
+
+  /* If the line width is supposed to be unscaled, try to reverse the effects
+     of the canvas scale. We use the maximum canvas scale, since being too
+     thin is better than being too fat. */
+  if (style->line_width_is_unscaled && simple->canvas)
     {
-      if (style->line_width >= 0.0)
-	cairo_set_line_width (cr, style->line_width);
+      scale = MAX (simple->canvas->scale_x, simple->canvas->scale_y);
+      line_width /= scale;
     }
 
+  /* Set the line width. */
+  cairo_set_line_width (cr, line_width);
+
   if (style->line_cap != CAIRO_LINE_CAP_BUTT)
     cairo_set_line_cap (cr, style->line_cap);
 
@@ -1461,6 +1475,13 @@ goo_canvas_item_simple_class_init (GooCanvasItemSimpleClass *klass)
 							0.0, G_MAXDOUBLE, 0.0,
 							G_PARAM_READWRITE));
 
+  g_object_class_install_property (gobject_class, PROP_LINE_WIDTH_IS_UNSCALED,
+				   g_param_spec_boolean ("line-width-is-unscaled",
+							 _("Line Width Is Unscaled"),
+							 _("If the line width does not grow as the canvas is scaled"),
+							 FALSE,
+							 G_PARAM_READWRITE));
+
   g_object_class_install_property (gobject_class, PROP_LINE_CAP,
 				   g_param_spec_enum ("line-cap",
 						      _("Line Cap"),
diff --git a/src/goocanvasstyle.c b/src/goocanvasstyle.c
index 422a012..a9c7b43 100644
--- a/src/goocanvasstyle.c
+++ b/src/goocanvasstyle.c
@@ -27,6 +27,7 @@ enum {
   /* Line style & width properties. */
   PROP_LINE_WIDTH,
   PROP_LINE_WIDTH_TOLERANCE,
+  PROP_LINE_WIDTH_IS_UNSCALED,
   PROP_LINE_CAP,
   PROP_LINE_JOIN,
   PROP_LINE_JOIN_MITER_LIMIT,
@@ -57,8 +58,9 @@ goo_canvas_style_init (GooCanvasStyle *style)
   style->font_desc = NULL;
 
   style->line_width = -1.0;
-  style->line_width_tolerance = -1.0;
+  style->line_width_tolerance = 0.0;
   style->line_join_miter_limit = 10.0;
+  style->line_width_is_unscaled = FALSE;
 
   style->stroke_pattern_set = FALSE;
   style->fill_pattern_set = FALSE;
@@ -137,6 +139,9 @@ goo_canvas_style_get_property (GObject              *object,
     case PROP_LINE_WIDTH_TOLERANCE:
       g_value_set_double (value, style->line_width_tolerance);
       break;
+    case PROP_LINE_WIDTH_IS_UNSCALED:
+      g_value_set_boolean (value, style->line_width_is_unscaled);
+      break;
     case PROP_LINE_CAP:
       g_value_set_enum (value, style->line_cap);
       break;
@@ -238,6 +243,9 @@ goo_canvas_style_set_property (GObject              *object,
     case PROP_LINE_WIDTH_TOLERANCE:
       style->line_width_tolerance = g_value_get_double (value);
       break;
+    case PROP_LINE_WIDTH_IS_UNSCALED:
+      style->line_width_is_unscaled = g_value_get_boolean (value);
+      break;
     case PROP_LINE_CAP:
       style->line_cap = g_value_get_enum (value);
       break;
@@ -381,6 +389,13 @@ goo_canvas_style_class_init (GooCanvasStyleClass *klass)
 							0.0, G_MAXDOUBLE, 0.0,
 							G_PARAM_READWRITE));
 
+  g_object_class_install_property (gobject_class, PROP_LINE_WIDTH_IS_UNSCALED,
+				   g_param_spec_boolean ("line-width-is-unscaled",
+							 _("Line Width Is Unscaled"),
+							 _("If the line width does not grow as the canvas is scaled"),
+							 FALSE,
+							 G_PARAM_READWRITE));
+
   g_object_class_install_property (gobject_class, PROP_LINE_CAP,
 				   g_param_spec_enum ("line-cap",
 						      _("Line Cap"),
diff --git a/src/goocanvasstyle.h b/src/goocanvasstyle.h
index 3b6d79d..d7b6afc 100644
--- a/src/goocanvasstyle.h
+++ b/src/goocanvasstyle.h
@@ -47,6 +47,7 @@ struct _GooCanvasStyle
   cairo_line_cap_t  line_cap        : 4;
   cairo_line_join_t line_join       : 4;
   guint hint_metrics		    : 2;
+  guint line_width_is_unscaled	    : 1;
 };
 
 struct _GooCanvasStyleClass