Re: Coding question, canvas
- From: Miguel de Icaza <miguel nuclecu unam mx>
- To: Richard Hult <rhult hem2 passagen se>
- Cc: gnome-list gnome org
- Subject: Re: Coding question, canvas
- Date: 04 Feb 1999 17:33:24 -0600
> Would this be solved better by creating my own canvas item or by
> grouping lines and rectangles and other native canvas items?
I suggest you use the existing canvas items for that.
> When do you genereally need to create your own items?
There are a number of times, here is a small list of things that occur
to me that would be candidates for being custom items:
- When the canvas does not provide an item that does what you
need (Gnumeric implements a "Cursor" item which is a
specialized item that can can be animated and knows about
the sheet internals).
- When you only want the canvas as an anti-flicker display
engine (or if you want to mix with other items).
Gnumeric's sheet display is an example of this.
- When you have way too much information to display
efficiently by creating an item per object (for example, if
you need to display a plot or an image, you migth benefit
from a specialized item.
- If the canvas has no support for your favorite item type.
The existing canvas items are pretty powerful already, if you can use
those, you could save a lot of time.
> One more question... maybe a silly one. How do I get just a single
> point on the canvas? I can make lines, arrows, rectangles, arrows, etc,
> but not a small point. I tried to draw a line from one point to the
> same but it's "too short" too be seen...
I would create a really small rectangle :-)
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