Josef Wolf wrote:
$canv->bind("foobar", '<1>' => sub {
canvas.itembind(tag, '1', '%x %y') do |x, y|
In this case, we're binding mouse single click events (I assume that's the same as perl's '<1>') and we're grabbing the pointer location into block args x and y.
--
vjoel : Joel VanderWerf : path berkeley edu : 510 665 3407
Yeah, that works. Thanks!
BTW: do you have a description of the "%x %y" formatting specification?
On Thu, Sep 10, 2009 at 10:27:54AM -0700, Joel VanderWerf wrote:
Josef Wolf wrote:
$canv->bind("foobar", '<1>' => sub {
canvas.itembind(tag, '1', '%x %y') do |x, y|
In this case, we're binding mouse single click events (I assume that's the
same as perl's '<1>') and we're grabbing the pointer location into block
args x and y.
Josef Wolf wrote:
BTW: do you have a description of the "%x %y" formatting specification?
http://www.tcl.tk/man/tcl8.4/TkCmd/bind.htm#M41
--
vjoel : Joel VanderWerf : path berkeley edu : 510 665 3407
Ough. Every time I think I get closer (remember? I am trying to implement
a zoomable canvas), I find there is a lot more work to do :-()
My first attempt to adopt event handling to the zoom operation was like
this:
class TkEvent::Event
# FIXME: need a better name than "nonzoomed". Recommendations?
attr_accessor :x_nonzoomed, :y_nonzoomed
end
class TkZoomCanvas < TkCanvas
def itembind(tag, ev, cb)
super(tag, ev, proc{ |e|
if e.x then e.x_nonzoomed = e.x/@zoom ; end
if e.y then e.y_nonzoomed = e.y/@zoom ; end
cb.call e
})
end
def bind(ev, cb)
# looks similar to itembind
end
end
Now, itembind (and bind?) seem to accept various forms:
1. canvas.itembind("mytag", "1", proc{|e| ... })
This form works fine with above code
2. canvas.itembind("mytag", "1", "%x %y") {|x, y| ... }
In this case, I will have to build the argument list. Seems to be a
tedious task. Maybe there already exist a Tk method I could use to
build that list?
Are this the only two existing forms?
On Sat, Sep 12, 2009 at 02:23:30AM +0900, Joel VanderWerf wrote:
Josef Wolf wrote:
BTW: do you have a description of the "%x %y" formatting specification?
Josef Wolf wrote:
Ough. Every time I think I get closer (remember? I am trying to implement
a zoomable canvas), I find there is a lot more work to do :-()
Do you need to exactly replicate the TkCanvas interface in the zoomable canvas? Why not get creative and develop a class with a new (possibly better) interface? (And maybe use delegation rather than inheritance.) The TkCanvas interface is close to Tcl/Tk's canvas, which is great for documentation and porting, but it's not necessarily very ruby-like.
--
vjoel : Joel VanderWerf : path berkeley edu : 510 665 3407
Thanks for your suggestion (and sorry for my late reply).
Well, as you might have already guessed, I'm very new to ruby, so I don't
yet have a good feeling about what is "very ruby like". I'd love to see
suggestions.
For the particular topic about the binding, after some thought, I've come
to the conclusion that extending the format string is not the best idea.
The format string consists of one-letter formats. I'd pollute this
one-letter-namespace if I would introduce my own letters. Thus, I decided
to let the base class do the job if a string is passed.
Attached is my current implementation of the zoomable+scrollable canvas.
It works fine, AFAICS. I'd love to hear any suggestions about how to make
it more ruby-like.
#!/usr/bin/ruby
require 'tk'
class TkEvent::Event
attr_accessor :x_nonzoom, :y_nonzoom
end
class TkScrolledCanvas < TkCanvas
include TkComposite
attr_reader :zoom
def initialize_composite(keys={})
@zoom = 1.0
@h_scr = TkScrollbar.new(@frame)
@v_scr = TkScrollbar.new(@frame)
@canvas = TkCanvas.new(@frame)
@path = @canvas.path
@canvas.xscrollbar(@h_scr)
@canvas.yscrollbar(@v_scr)
TkGrid.rowconfigure(@frame, 0, :weight=>1, :minsize=>0)
TkGrid.columnconfigure(@frame, 0, :weight=>1, :minsize=>0)
@canvas.grid(:row=>0, :column=>0, :sticky=>'news')
@h_scr.grid(:row=>1, :column=>0, :sticky=>'ew')
@v_scr.grid(:row=>0, :column=>1, :sticky=>'ns')
delegate('DEFAULT', @canvas)
delegate('background', @frame, @h_scr, @v_scr)
delegate('activeforeground', @h_scr, @v_scr)
delegate('troughcolor', @h_scr, @v_scr)
delegate('repeatdelay', @h_scr, @v_scr)
delegate('repeatinterval', @h_scr, @v_scr)
delegate('borderwidth', @frame)
delegate('relief', @frame)
delegate_alias('canvasborderwidth', 'borderwidth', @canvas)
delegate_alias('canvasrelief', 'relief', @canvas)
delegate_alias('scrollbarborderwidth', 'borderwidth', @h_scr, @v_scr)
delegate_alias('scrollbarrelief', 'relief', @h_scr, @v_scr)
configure(keys) unless keys.empty?
end
def zoom_by zf
zf = Float(zf)
@zoom *= zf
vf = (1 - 1/zf) / 2
x0, x1 = xview ; xf = x0 + vf * (x1-x0)
y0, y1 = yview ; yf = y0 + vf * (y1-y0)
scale 'all', 0, 0, zf, zf
configure :scrollregion => bbox("all")
xview "moveto", xf
yview "moveto", yf
end
def zoom_to z
zoom_by(z/@zoom)
end
def bind(ev, cb)
if cb.class == String
super
else
super(ev, proc{ |e| process_event(e, cb) })
end
end
def itembind(tag, ev, cb)
if cb.class == String
super
else
super(tag, ev, proc{ |e| process_event(e, cb) })
end
end
def coords(tag, *args)
newargs = adjust_coords(@zoom, args)
ret = super(tag, *newargs)
return ret unless ret.class == Array
ret.collect { |v| v / @zoom }
end
def move(tag, x, y)
super(tag, x*@zoom, y*@zoom)
end
def create(type, *args)
newargs = adjust_coords(@zoom, args)
super(type, *newargs)
end
private
def process_event(e, cb)
if e.x then e.x_nonzoom=e.x/@zoom ; end
if e.y then e.y_nonzoom=e.y/@zoom ; end
cb.call e
end
def adjust_coords(mul, args)
args.collect do |arg|
arg.class == Array ? arg.collect { |v| v * mul } : arg
end
end
end
class TkcItem
alias orig_initialize initialize
def initialize(parent, *args)
if parent.class == TkScrolledCanvas
zoom = parent.zoom
newargs = args.collect do |arg|
arg.class == Array ? arg.collect { |v| v * zoom } : arg
end
else
newargs = args
end
orig_initialize parent, *newargs
end
def bind(ev, cb)
super(ev, proc{ |e|
if @parent.class == TkScrolledCanvas
zoom = @parent.zoom
if e.x then e.x_nonzoom=e.x/zoom ; end
if e.y then e.y_nonzoom=e.y/zoom ; end
cb.call e
end
})
end
end
On Mon, Sep 14, 2009 at 03:41:34AM +0900, Joel VanderWerf wrote:
Josef Wolf wrote:
Ough. Every time I think I get closer (remember? I am trying to implement
a zoomable canvas), I find there is a lot more work to do :-()Do you need to exactly replicate the TkCanvas interface in the zoomable
canvas? Why not get creative and develop a class with a new (possibly
better) interface? (And maybe use delegation rather than inheritance.) The
TkCanvas interface is close to Tcl/Tk's canvas, which is great for
documentation and porting, but it's not necessarily very ruby-like.