2 * GooCanvas Demo. Copyright (C) 2006 Damon Chaplin.
3 * Released under the GNU LGPL license. See COPYING for details.
5 * demo-item.c - a simple demo item.
10 #include "demo-item.h"
12 /* Use the GLib convenience macro to define the type. GooDemoItem is the
13 class struct, goo_demo_item is the function prefix, and our class is a
14 subclass of GOO_TYPE_CANVAS_ITEM_SIMPLE. */
15 G_DEFINE_TYPE (GooDemoItem, goo_demo_item, GOO_TYPE_CANVAS_ITEM_SIMPLE)
17 /* The standard object initialization function. */
19 goo_demo_item_init (GooDemoItem *demo_item)
21 demo_item->width = 0.0;
22 demo_item->height = 0.0;
25 /* The convenience function to create new items. This should start with a
26 parent argument and end with a variable list of object properties to fit
27 in with the standard canvas items. */
29 goo_demo_item_new (GooCanvasItem *parent,
34 GooDemoItemPaintFunc paint,
39 GooDemoItem *demo_item;
40 const char *first_property;
42 cairo_matrix_t matrix;
44 item = g_object_new (GOO_TYPE_DEMO_ITEM, NULL);
46 demo_item = (GooDemoItem*) item;
47 demo_item->width = width;
48 demo_item->height = height;
49 demo_item->paint = paint;
50 demo_item->closure = closure;
52 va_start (var_args, closure);
53 first_property = va_arg (var_args, char*);
55 g_object_set_valist ((GObject*) item, first_property, var_args);
60 goo_canvas_item_add_child (parent, item, -1);
61 g_object_unref (item);
64 cairo_matrix_init_translate (&matrix, x, y);
65 goo_canvas_item_set_transform (item, &matrix);
70 /* The update method. This is called when the canvas is initially shown and
71 also whenever the object is updated and needs to change its size and/or
72 shape. It should calculate its new bounds, storing them in simple->bounds,
73 and it should convert these to device coordinates. */
75 goo_demo_item_update (GooCanvasItemSimple *simple,
78 GooDemoItem *demo_item = (GooDemoItem*) simple;
80 /* Compute the new bounds. */
81 simple->bounds.x1 = 0;
82 simple->bounds.y1 = 0;
83 simple->bounds.x2 = demo_item->width;
84 simple->bounds.y2 = demo_item->height;
86 /* Convert to device coordinates. */
87 goo_canvas_item_simple_user_bounds_to_device (simple, cr, &simple->bounds);
90 /* The paint method. This should draw the item on the given cairo_t, using
91 the item's own coordinate space. */
93 goo_demo_item_paint (GooCanvasItemSimple *simple,
95 GooCanvasBounds *bounds)
97 GooDemoItem *item = (GooDemoItem*) simple;
99 item->paint (cr, item->closure, item->width, item->height);
102 /* Hit detection. This should check if the given coordinate (in the item's
103 coordinate space) is within the item. If it is it should return the item,
104 otherwise it should return NULL. */
105 static GooCanvasItem*
106 goo_demo_item_get_item_at (GooCanvasItemSimple *simple,
110 gboolean is_pointer_event)
112 GooDemoItem *demo_item = (GooDemoItem*) simple;
114 if (x < 0 || (x > demo_item->width)
115 || y < 0 || (y > demo_item->height))
118 return (GooCanvasItem*) simple;
121 /* The class initialization function. Here we set the class' update(), paint()
122 and get_item_at() methods. */
124 goo_demo_item_class_init (GooDemoItemClass *klass)
126 GooCanvasItemSimpleClass *simple_class = (GooCanvasItemSimpleClass*) klass;
128 simple_class->update = goo_demo_item_update;
129 simple_class->paint = goo_demo_item_paint;
130 simple_class->get_item_at = goo_demo_item_get_item_at;