# Call signal handler or parent class

**URL:** <https://www.ruby-forum.com/t/call-signal-handler-or-parent-class/239857>\
**Category:** Ruby-Gnome 2\
**Created:** [March 17, 2014, 5:50pm UTC](https://www.ruby-forum.com/t/call-signal-handler-or-parent-class/239857 "2014-03-17T17:50:24Z")\
**Posts on this page:** 5\
**Page:** 1

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**Author:** ![Detlef\_R](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/d/58f4c7/32.png) [@Detlef\_R](https://www.ruby-forum.com/u/Detlef_R)\
**Post date:** [March 17, 2014, 5:50pm UTC](https://www.ruby-forum.com/t/call-signal-handler-or-parent-class/239857/1 "2014-03-17T17:50:24Z")

</div>

Hi,

I have a Gtk::Table, where I on the :draw signal first want to draw on  
the background of the table, than call the tables original draw handler,  
so that the widgets packed into the table are drawn, and then call  
another own program part, that draws over it all. How can I achieve  
this?

If I use signal\_connect the widgets in the table doesn’t get drawn cause  
the original :draw handler isn’t called and if I use  
signal\_connect\_after I can’t draw on the “background” cause I would draw  
over all widgets.

Cheers, detlef

---

<div class="post-metadata">

**Author:** ![Detlef\_R](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/d/58f4c7/32.png) [@Detlef\_R](https://www.ruby-forum.com/u/Detlef_R)\
**Post date:** [March 18, 2014, 3:43pm UTC](https://www.ruby-forum.com/t/call-signal-handler-or-parent-class/239857/2 "2014-03-18T15:43:15Z")

</div>

Hi,

In [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid)  
“[ruby-gnome2-devel-en] call signal handler or parent class” on Mon,  
17 Mar 2014 17:35:37 +0100,  
Detlef R. [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote:

> I have a Gtk::Table, where I on the :draw signal first want to draw on  
> the background of the table, than call the tables original draw handler,  
> so that the widgets packed into the table are drawn, and then call  
> another own program part, that draws over it all. How can I achieve this?
> 
> If I use signal\_connect the widgets in the table doesn’t get drawn cause  
> the original :draw handler isn’t called and if I use  
> signal\_connect\_after I can’t draw on the “background” cause I would draw  
> over all widgets.

Could you show a sample program to start to confirm the  
behavior?

## Thanks,

kou

---

<div class="post-metadata">

**Author:** ![Detlef\_R](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/d/58f4c7/32.png) [@Detlef\_R](https://www.ruby-forum.com/u/Detlef_R)\
**Post date:** [March 18, 2014, 6:51pm UTC](https://www.ruby-forum.com/t/call-signal-handler-or-parent-class/239857/3 "2014-03-18T18:51:57Z")

</div>

On Tue, 2014-03-18 at 17:31 +0100, Detlef R. wrote:

> Hi,
> 
> here we go! In this example the Gtk::Entry’s are drawn

Sorry for polluting this list – I really guess it is more for serious  
developer discussion…

For the code of Detlef R. it is obvious that he did not care much  
about the return value of signal handlers.

See GTK+ original documentation or  
[http://ruby-gnome2.sourceforge.jp/hiki.cgi?tut-gtk-events](http://ruby-gnome2.sourceforge.jp/hiki.cgi?tut-gtk-events)

Depending of the return value of the block code, GTK will decide if the  
event should be spread or not:

```
  * if true, GTK will stop the event processing here;
  * if false, GTK will continue to propagate the event

```

---

<div class="post-metadata">

**Author:** ![Detlef\_R](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/d/58f4c7/32.png) [@Detlef\_R](https://www.ruby-forum.com/u/Detlef_R)\
**Post date:** [March 18, 2014, 5:33pm UTC](https://www.ruby-forum.com/t/call-signal-handler-or-parent-class/239857/4 "2014-03-18T17:33:05Z")

</div>

Am 18.03.2014 15:42, schrieb Kouhei S.:

> > If I use signal\_connect the widgets in the table doesn’t get drawn cause  
> > the original :draw handler isn’t called and if I use  
> > signal\_connect\_after I can’t draw on the “background” cause I would draw  
> > over all widgets.  
> > Could you show a sample program to start to confirm the  
> > behavior?

Hi,

here we go! In this example the Gtk::Entry’s are drawn and then the  
rectangles and the arrows are drawn in the signal\_connect\_after(:draw)  
callback “above” it all. What I now want is, to draw in a part of the  
window “under” the Gtk::Entry’s.

Thanks in advance! detlef

#!/usr/bin/env ruby  
#encoding: UTF-8

require ‘gtk3’

module Etti  
class PageLayout \< Gtk::Box  
LABELS\_H = 3  
LABELS\_V = 3  
LABEL\_PADDING = 24.0  
def initialize  
super(:vertical)  
self.border\_width = 0  
@entries = {}  
@boxes =   
@tableData = { :borderTop =\>  
{:pos =\> [2, 3, 0, 1],  
:label =\> ‘Rand oben’,  
:tooltip =\> ‘Der Abstand vom oberen  
Etikett zum Blattrand’},  
:borderLeft =\>  
{:pos =\> [0, 1, 2, 3],  
:label =\> ‘Rand links’,  
:tooltip =\> ‘Der Abstand vom linken  
Etikett zum Blattrand’},  
:height =\>  
{:pos =\> [2, 3, 1, 2],  
:label =\> ‘Etikett Hhe’,  
:tooltip =\> ‘Die Hhe eines  
einzelnen Etiketts’},  
:width =\>  
{:pos =\> [1, 2, 2, 3],  
:label =\> ‘Etikett Breite’,  
:tooltip =\> ‘Die Breite eines  
einzelnen Etiketts’},  
:paddingH =\>  
{:pos =\> [2,3, 3, 4],  
:label =\> ‘Abstand horizonal’,  
:tooltip =\> “Der horizontale  
Abstand zwischen den Etiketten\n”   
“0, wenn es keinen  
Zwischenraum gibt”},  
:paddingV =\>  
{:pos =\> [3, 4, 2, 3],  
:label =\> ‘Abstand vertikal’,  
:tooltip =\> “Der vertikale Abstand  
zwischen den Etiketten\n”   
“0, wenn es keinen  
Zwischenraum gibt”}  
}

```
        @sizeGroup = Gtk::SizeGroup.new :both
        widget = make_entry :name, 'Name', "Name des

```

Etiketts\nDieser muss einmalig sein"  
self.pack\_start widget, :expand =\> false, :fill =\> false,  
:padding =\> 12

```
        @table = Gtk::Table.new 4, 4, true
        self.pack_start @table, :expand => false, :fill => false

        @tableData.each_pair do |key, val|
            box = Gtk::Box.new :vertical
            @boxes << box

            @table.attach box, *val[:pos], 0, 0, LABEL_PADDING,

```

LABEL\_PADDING

```
            box.pack_start Gtk::Label.new(val[:label]), :expand =>

```

false, :fill =\> false

```
            entry = Gtk::Entry.new
            @entries[key] = entry
            entry.name = key
            box.pack_start entry, :expand => false, :fill => false

            entry.set_max_length 7
            entry.width_chars = 8

            entry.tooltip_text = val[:tooltip]
            entry.editable = true

            entry.signal_connect(:changed) {|entry| on_entry_changed

```

entry}  
end

```
        @boxData = { :manufacture =>
                        {:label => 'Hersteller',
                         :tooltip => 'Hersteller der Etiketten'},
                     :orderNr =>
                        {:label => 'Bestellnummer',
                         :tooltip => 'Die 

```

Hersteller-Bestellnummer’},  
:description =\>  
{:label =\> ‘Beschreibung’,  
:tooltip =\> ‘Eine zustzliche Beschreibung  
der Etiketten’},  
:pageSize =\>  
{:label =\> ‘Seitengre’,  
:tooltip =\> ‘Die Gre eines Bogens, z.B.  
“a4”’}  
}

```
        @boxData.each_pair do |key, val|
            widget = make_entry key, val[:label], val[:tooltip]
            self.pack_start widget, :expand => false, :fill =>

```

false, :padding =\> 4  
end  
# TODO hier muss ich noch wissen, wie ich den original draw  
aufrufe…  
# signal\_connect(:draw) {draw\_bg}  
signal\_connect(:map) {on\_map}

=begin  
signal\_connect(:draw) do |widget|  
draw\_bg  
widget.do\_draw  
on\_draw  
end  
=end  
signal\_connect\_after(:draw) {on\_draw}  
end

private  
def make\_entry id, label, tooltip, head=nil  
hbox = Gtk::Box.new :horizontal

```
        label = Gtk::Label.new.set_markup("<b>#{label}</b>: ")
        hbox.pack_start label, :expand => false, :fill => false
        @sizeGroup.add_widget label
        label.xalign = 0.0

        entry = Gtk::Entry.new
        entry.name = id
        @entries[id] = entry
        hbox.pack_start entry, :expand => false, :fill => false
        entry.tooltip_text = tooltip
        entry.signal_connect(:changed) {|entry| on_entry_changed 

```

entry}  
hbox  
end

```
    def on_entry_changed entry
        return if $pageData.nil?
        key = entry.name.to_sym
        text = @entries[key].text
        return if text.length() < 1

        case key
            when :name, :manufacture, :orderNr, :description, 

```

:pageSize  
$pageData.instance\_variable\_set ‘@’ + key.to\_s, text  
when :borderLeft  
$pageData.borders[0] = text.to\_f  
when :borderTop  
$pageData.borders[1] = text.to\_f  
when :paddingH  
$pageData.padding[0] = text.to\_f  
when :paddingV  
$pageData.padding[1] = text.to\_f  
when :width  
$pageData.size[0] = text.to\_f  
when :height  
$pageData.size[1] = text.to\_f  
end  
end

```
    def draw_bg
        box_allocation = @boxes.first.allocation
        bw = box_allocation.width
        bh = box_allocation.height

        @cc = @table.window.create_cairo_context

        @cc.set_source_rgb 0.2, 0.2, 0.4
        @cc.paint
        @cc.set_source_rgb 1.0, 1.0, 1.0
        @cc.rectangle 8, 8,
                      (bw + LABEL_PADDING * 2) * (LABELS_H + 1) - 3,
                      (bh + LABEL_PADDING * 2) * (LABELS_V + 1) - 3
        @cc.fill.stroke
    end

    def on_map
        @boxW = 0
        @boxH = 0
        @boxes.each do |box|
            allo = box.allocation
            @boxW = allo.width if allo.width > @boxW
            @boxH = allo.height if allo.height > @boxH
        end
    end

    def on_draw
        box_allocation = @boxes.first.allocation

        bw = box_allocation.width
        bh = box_allocation.height

        bw = @boxW
        bh = @boxH

        @cc = @table.window.create_cairo_context
        # we don't have an own window
        @cc.translate(@table.allocation.x, @table.allocation.y)
        @cc.antialias = :none

        # border
        @cc.set_source_rgb 0.5, 0.5, 0.5
        @cc.line_width = 2.0

        @cc.move_to (bw + LABEL_PADDING * 2.0) * (LABELS_H + 1), 8
        @cc.line_to 8, 8
        @cc.line_to 8, (bh + LABEL_PADDING * 2.0) * (LABELS_V + 1)
        @cc.stroke

        @cc.set_source_rgb 0.4, 0.4, 0.9
        @cc.line_width = 1.0

        1.upto(LABELS_V) do |y|
            1.upto(LABELS_H) do |x|

                @cc.rectangle (bw + LABEL_PADDING * 2.0) * x,
                              (bh + LABEL_PADDING * 2.0) * y,
                               bw + LABEL_PADDING * 1.5,
                               bh + LABEL_PADDING * 1.5
                @cc.stroke
            end
        end

        # border arrows
        draw_arrow :h, 8, (bh + LABEL_PADDING * 2.0) * 2.0 + 24, bw

```

- LABEL\_PADDING \* 2.0 - 8  
draw\_arrow :v, (bw + LABEL\_PADDING \* 2.0) \* 2.0 + 24, 8, bh

- LABEL\_PADDING \* 2.0 - 8  
# cell arrows  
draw\_arrow :h, (bw + LABEL\_PADDING \* 2.0), (bh +  
LABEL\_PADDING \* 2.0) \* 2.0 + 24.0,  
bw + LABEL\_PADDING \* 1.5  
draw\_arrow :v, (bw + LABEL\_PADDING \* 2.0) \* 2.0 + 24, bh +  
LABEL\_PADDING \* 2.0, bh + LABEL\_PADDING \* 1.5

LABEL\_PADDING \* 0.5,  
(bh + LABEL\_PADDING \* 2.0) \* 3.0 + 24,  
LABEL\_PADDING \* 0.5, true  
draw\_arrow :v, (bw + LABEL\_PADDING \* 2.0) \* 3.0 + 24,  
(bh + LABEL\_PADDING \* 2.0) \* 2.0 -  
LABEL\_PADDING \* 0.5, LABEL\_PADDING \* 0.5, true  
end

```
    ARROW_SIZE = 8.0
    def draw_arrow dir, x, y, lg, out=false
        @cc.set_source_rgb 0.2, 0.2, 0.2
        @cc.line_width = 1.0
        unless out
            if dir == :h
                @cc.antialias = :none
                @cc.move_to x, y
                @cc.line_to x + lg, y
                @cc.stroke

                @cc.antialias = :subpixel
                @cc.move_to x, y
                @cc.line_to x + ARROW_SIZE, y - (ARROW_SIZE / 4.0)
                @cc.line_to x + ARROW_SIZE, y + (ARROW_SIZE / 4.0)
                @cc.fill.stroke

                @cc.move_to x + lg, y
                @cc.line_to x + lg - ARROW_SIZE, y - (ARROW_SIZE / 

```

4.0)  
@cc.line\_to x + lg - ARROW\_SIZE, y + (ARROW\_SIZE /  
4.0)  
@cc.fill.stroke

```
            else
                @cc.antialias = :none
                @cc.move_to x, y
                @cc.line_to x, y + lg
                @cc.stroke

                @cc.antialias = :subpixel
                @cc.move_to x, y
                @cc.line_to x - (ARROW_SIZE / 4.0), y + ARROW_SIZE
                @cc.line_to x + (ARROW_SIZE / 4.0), y + ARROW_SIZE
                @cc.fill.stroke

                @cc.move_to x, y + lg
                @cc.line_to x - (ARROW_SIZE / 4.0), y + lg - 

```

ARROW\_SIZE  
@cc.line\_to x + (ARROW\_SIZE / 4.0), y + lg -  
ARROW\_SIZE  
@cc.fill.stroke  
end  
else  
if dir == :h  
@cc.antialias = :none  
@cc.move\_to x - ARROW\_SIZE \* 2.0, y  
@cc.line\_to x + lg + ARROW\_SIZE \* 8.0, y  
@cc.stroke

```
                @cc.antialias = :subpixel
                @cc.move_to x, y
                @cc.line_to x - ARROW_SIZE, y - (ARROW_SIZE / 4.0)
                @cc.line_to x - ARROW_SIZE, y + (ARROW_SIZE / 4.0)
                @cc.fill.stroke

                @cc.move_to x + lg, y
                @cc.line_to x + lg + ARROW_SIZE, y - (ARROW_SIZE / 

```

4.0)  
@cc.line\_to x + lg + ARROW\_SIZE, y + (ARROW\_SIZE /  
4.0)  
@cc.fill.stroke

```
            else
                @cc.antialias = :none
                @cc.move_to x, y - ARROW_SIZE * 2.0
                @cc.line_to x, y + lg + ARROW_SIZE * 8.0
                @cc.stroke

                @cc.antialias = :subpixel
                @cc.move_to x, y
                @cc.line_to x - (ARROW_SIZE / 4.0), y - ARROW_SIZE
                @cc.line_to x + (ARROW_SIZE / 4.0), y - ARROW_SIZE
                @cc.fill.stroke

                @cc.move_to x, y + lg
                @cc.line_to x - (ARROW_SIZE / 4.0), y + lg + 

```

ARROW\_SIZE  
@cc.line\_to x + (ARROW\_SIZE / 4.0), y + lg +  
ARROW\_SIZE  
@cc.fill.stroke  
end  
end  
end  
end  
end

win = Gtk::Window.new  
table = Etti::PageLayout.new  
win.add table  
win.show\_all  
Gtk.main

---

<div class="post-metadata">

**Author:** ![Detlef\_R](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/d/58f4c7/32.png) [@Detlef\_R](https://www.ruby-forum.com/u/Detlef_R)\
**Post date:** [March 18, 2014, 7:48pm UTC](https://www.ruby-forum.com/t/call-signal-handler-or-parent-class/239857/5 "2014-03-18T19:48:03Z")

</div>

Am 18.03.2014 18:26, schrieb Stefan S.:

> On Tue, 2014-03-18 at 17:31 +0100, Detlef R. wrote:
> 
> > Hi,
> > 
> > here we go! In this example the Gtk::Entry’s are drawn  
> > Sorry for polluting this list – I really guess it is more for serious  
> > developer discussion…
> 
> For the code of Detlef R. it is obvious that he did not care much  
> about the return value of signal handlers.

Hi,

that was it. Thanks allot! Long time ago I knew this 🙂

Cheers, detlef