Re: grid

[z pekar gmail com]

Thank you Damon,

I'll try to explain what I need it for so it might bring more clear
view of the matter.
I have an ultrasound image where I have to mark certain areas; once
the image is clicked I put a small circle on that place.
I need the grid/GtkRulers in order to make positioning(/reading
coordinates of already placed markers) more accurate and reality tied.
I think this kind of things are pretty generic and common to
scientific applications. So the API could look smth. like this:

GooCanvas *place_grid(GooCanvas canvas, GdkColor color, gdouble x,
gdouble y, /* GtkRulers specific stuff */);

returns a GooCanvas * - canvas with the grid on it

canvas - canvas to place the grid on
color - color of the grid
/* GtkRulers specific stuff */
x, y - marks on the horizontal and vertical rulers that correspond to
canvas's corners
(where x should corespond to canvas's top right corner, and y to its
left bottom corner; and in a case where canvas(surrounded by rulers,
with the grid upon it) is smaller than the widget it is packed into in
expanded manner - the canvas should be enlarged proportionally in
order to fit completely either horizontally or vertically (depending
on which scaling factor is smaller in order not to loose the
proportions) and the ruler of the opposite dimension should be
continued until it fills the widget.
For example if the vertical scaling factor turns to be smaller than
the horizontal one - we enlarge the canvas both verticaly and
horizontally by the vertical scaling factor - then left bottom corner
would correspond to y and it will be the edge of the widget, and
horizontally there will be free space, so the top right corner should
correspond to x, but then the ruler will continue to the right with
x+1, x+2, etc until it reachs the end of the widget.

I hope despite my bad English you'll understand what I mean :)

and thank you again!

On Wed, Sep 17, 2008 at 3:27 PM, Damon Chaplin
<damon karuna eclipse co uk> wrote:
>
> On Tue, 2008-09-16 at 21:25 +0300, z pekar gmail com wrote:
>> On Mon, Sep 15, 2008 at 11:56 AM, Damon Chaplin
>> <damon karuna eclipse co uk> wrote:
>> >
>> > On Thu, 2008-09-11 at 17:45 +0200, Murray Cumming wrote:
>> >> On Thu, 2008-09-11 at 17:35 +0300, z pekar gmail com wrote:
>> >> > Hi,
>> >> > I have a GooCanvasImage with GooCanvasEllipse being added and removed
>> >> > from it. I need to place a grid on all this stuff in order to make
>> >> > placing of GooCanvasEllipse upon the image more accurate. What is the
>> >> > best way to do it? - draw it with paths or maybe use tables somehow?
>> >> > thank you
>> >> > Z. Pekar
>> >>
>> >> I did this with lines.
>> >>
>> >> Using C++ (and some awkward multiple inheritance) I created a whole
>> >> heirarchy of canvas items that can snap to the grid, or to rules. That's
>> >> in Glom. for its (unfinished) print layouts. If you are using C then
>> >> it's probably not that useful to you, but maybe it helps to know that
>> >> somebody else has done this.
>> >>
>> >> I think this kind of high-level functionality should be in a library
>> >> really.
>> >
>> > I think it might be difficult to come up with an API that everyone is
>> > happy with - it could be a bit too application-specific.
>> so maybe to find some common denominator and leave the rest to the programmer.
>>
>>
>> > Though demo code would be useful, or items that can be easily subclassed
>> > so they can be customized to suit a particular application.
>> does this mean we have a hope(i.e. you'll give it a try)?
>
> I might do a simple grid item, but probably not much more. But someone
> else might have a go.
>
> If people listed their particular requirements that might help. I don't
> really have a clear idea of what people need.
>
> Damon
>
>
>