Re: GtkCanvas requirements?

["Marco Pesenti Gritti" <mpgritti gmail com>]

On 4/19/07, Havoc Pennington <hp redhat com> wrote:

Marco Pesenti Gritti wrote:
> * Key navigation (which is obviously also a prerequisite for a11y)

I'd add to this bullet "anything GtkWidget has that HippoCanvasItem does
not" - basically HippoCanvas is the "GtkWidget/GtkContainer replacement"
school of canvas thought.

Yeah.

> * Ability to set a global scaling factor for the canvas and support for
> units.

Would this require modifying individual canvas items, or can the
HippoCanvas widget just transform the cairo_t it passes to the root item
(and also transform event coords of course)

I don't think it would require modifying items (embedded widgets being the exception, in their current incarnation at least). cairo_t and events coords transformations should do it.

There is something which bothers me though. Support for some units, points for example, would require floating points measures. And I suspect we don't want to do layout in floating point (instability issues). Mozilla converts css units in twips (an arbitrary integer unit, 1/20 of a point). That's a way to go about it I guess, though it requires conversions it in the canvas items. Better ideas?

Marco