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Relative-Hook: prepare to split the abstraction into two levels

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Level-1 : generic attachment into some kind of view
Level-2 : attachment by coordinates onto some kind of canvas
This commit is contained in:
Fischlurch 2020-03-22 16:37:58 +01:00
parent 030fbd74c4
commit 22bc2167f9
3 changed files with 324 additions and 6 deletions
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219
src/stage/model/canvas-hook.hpp Normal file
View file

@ -0,0 +1,219 @@
/*
CANVAS-HOOK.hpp - abstracted attachment to a canvas with free positioning
Copyright (C) Lumiera.org
2020, Hermann Vosseler <Ichthyostega@web.de>
This program is free software; you can redistribute it and/or
modify it under the terms of the GNU General Public License as
published by the Free Software Foundation; either version 2 of
the License, or (at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
/** @file canvas-hook.hpp
** Specialised (abstracted) presentation context with positioning by coordinates.
** This extends the generic abstraction of a ViewHook, and works in a similar way,
** in close collaboration with the corresponding CanvasHooked entity (abstraction).
** Elements relying on those abstractions maintain an attachment to "their view",
** while remaining agnostic about the view's implementation details. But the key
** point with this extended abstraction is that elements can be placed onto a
** coordinate system or canvas, and they can be moved to a different position.
** A CanvasHooked element is basically a decorator directly attached to the
** element, adding automatic detachment on destruction, similar to a smart-ptr.
** So the "hooked" widget will live within the common allocation, together with
** its attachment; the whole arrangement must be set up at construction time
** - the combined `CanvasHooked<W>` must be non-copyable, since it can be expected
** for the canvas to store some pointer to the attached widget.
** - moreover, the canvas/presentation need to be available and activated when
** constructing the widget(s) due to the interwoven lifecycle.
** - and, most notably, the presentation/canvas (the ViewHook) must be arranged to
** outlive the attached widgets, since they call back on destruction.
** In the typical usage situation these points can be ensured naturally by housing
** the widgets in some detail data structure owned by the top level presentation frame.
**
** @see ViewHook_test
**
*/
#ifndef STAGE_MODEL_CANVAS_HOOK_H
#define STAGE_MODEL_CANVAS_HOOK_H
#include "lib/time/timevalue.hpp"
#include "lib/nocopy.hpp"
#include "lib/util.hpp"
#include <utility>
namespace stage {
namespace model {
using lib::time::Time;
/**
* Interface to represent _"some presentation layout entity",_
* with the ability to _attach_ widgets (managed elsewhere), to
* relocate those widgets to another position, and to re-establish
* a different sequence of the widgets (whatever this means).
* @remark some typical examples for the kind of collaboration modelled here:
* - a _canvas widget,_ (e.g. `Gtk::Layout`), allowing to attach
* child widgets at specific positions, together with custom drawing.
* - a tree or grid control, allowing to populate some row with a given widget.
* @warning please ensure the ViewHook outlives any attached ViewHooked.
*/
template<class WID>
class ViewHook
{
public:
virtual ~ViewHook() { } ///< this is an interface
virtual void hook (WID& widget, int xPos=0, int yPos=0) =0;
virtual void move (WID& widget, int xPos, int yPos) =0;
virtual void remove (WID& widget) =0;
virtual void rehook (WID& widget) noexcept =0;
template<class IT>
void reOrder (IT newOrder);
struct Pos
{
ViewHook& view;
int x,y;
};
Pos
hookedAt (int x, int y)
{
return Pos{*this, x,y};
}
/** build the "construction hook" for a \ref ViewHooked element,
* which is to be attached to some timeline canvas view.
* @param start anchor point / nominal start point of the element
* @param downshift (optional) vertical shift down from the baseline
* @return opaque registration argument for the ViewHooked ctor */
Pos
hookedAt (Time start, int downshift=0)
{
return hookedAt (translateTimeToPixels (start), downshift);
}
/** Anchor point to build chains of related View Hooks */
virtual ViewHook<WID>&
getAnchorHook() noexcept
{
return *this;
}
protected:
/** extension point for time axis zoom management. */
int translateTimeToPixels (Time) const =0;
};
/**
* A widget attached onto a display canvas or similar central presentation context.
* This decorator inherits from the widget to be attached, i.e. the widget itself becomes
* embedded; moreover, the attachment is immediately performed at construction time and
* managed automatically thereafter. When the `ViewHooked` element goes out of scope, it is
* automatically detached from presentation. With the help of ViewHooked, a widget (or similar
* entity) may control some aspects of its presentation placement, typically the coordinates
* on some kind of _canvas_ (-> `Gtk::Layout`), while remaining agnostic regarding the
* implementation details of the canvas and its placement thereon.
*
* The prominent example of a `ViewHooked` element is the stage::timeline::DisplayFrame, maintained
* by the TrackPresenter within the timeline UI. This connection entity allows to place ClipWidget
* elements into the appropriate display region for this track, without exposing the actual
* stage::timeline::BodyCanvasWidget to each and every Clip or Label widget.
*
* @tparam WID type of the embedded widget, which is to be hooked-up into the view/canvas.
* @remark since ViewHooked represents one distinct attachment to some view or canvas,
* is has a clear-cut identity and thus may be moved, but not copied.
* @warning since ViewHooked entities call back into the ViewHook on destruction,
* the latter still needs to be alive at that point. Which basically means
* you must ensure the ViewHooked "Widgets" are destroyed prior to the "Canvas".
*/
template<class WID, class BASE =WID>
class ViewHooked
: public WID
, util::NonCopyable
{
using View = ViewHook<BASE>;
View* view_;
public:
template<typename...ARGS>
ViewHooked (View& view, ARGS&& ...args)
: WID{std::forward<ARGS>(args)...}
, view_{&view}
{
view_->hook (*this);
}
template<typename...ARGS>
ViewHooked (typename View::Pos viewPos, ARGS&& ...args)
: WID{std::forward<ARGS>(args)...}
, view_{&viewPos.view}
{
view_->hook (*this, viewPos.x, viewPos.y);
}
~ViewHooked() noexcept
{
try {
if (view_)
view_->remove (*this);
}
ERROR_LOG_AND_IGNORE (progress, "Detaching of ViewHooked widgets from the presentation")
}
void
moveTo (int xPos, int yPos)
{
view_->move (*this, xPos,yPos);
}
};
/**
* re-attach elements in a given, new order.
* @param newOrder a Lumiera Forward Iterator to yield a reference to
* all attached elements, and in the new order to be established.
* @remark this operation becomes relevant, when "attaching an element" also
* constitutes some kind of arrangement in the visual presentation, like
* e.g. a stacking order, or by populating some table cells in sequence.
* The expected semantics is for this operation to detach each given element,
* and then immediately re-attach it _at the "beginning"_ (whatever this means).
* The element as such, and all associated presentation entities are not destroyed,
* but continue to exist with the same identity (and possibly all signal wirings).
* Just they now appear as if attached with the new ordering.
*/
template<class WID>
template<class IT>
void
ViewHook<WID>::reOrder (IT newOrder)
{
for (ViewHooked<WID>& existingHook : newOrder)
this->rehook (existingHook);
}
}}// namespace stage::model
#endif /*STAGE_MODEL_CANVAS_HOOK_H*/

27
src/stage/model/view-hook.hpp
View file

@ -35,9 +35,12 @@
** modelled by a smart-handle stage::timeline::ViewHooked, which -- on destruction --
** automatically detaches the widget from the presentation.
**
** As it turns out in practice, such a "hooked" widget will never exist apart from its
** attachment. Consequently, we locate the widget within the smart-handle itself, thus
** tightly linking together the lifecycle of the widget and the presentation attachment.
** As it turns out in practice, we get two flavours or _view attachment:_
** - Widgets just somehow placed into a grid or widget layout
** - Widgets attached to a canvas with positioning by coordinates
** Moreover, such a "hooked" widget will never exist apart from its attachment.
** Consequently, we locate the widget within the smart-handle itself, thus tightly
** linking together the lifecycle of the widget and the presentation attachment.
** However, this combined memory layout incurs some liabilities:
** - the combined `ViewHooked<W>` must be non-copyable, since it can be expected
** for the canvas to store some pointer to the attached widget.
@ -56,6 +59,7 @@
#ifndef STAGE_MODEL_VIEW_HOOK_H
#define STAGE_MODEL_VIEW_HOOK_H
#include "lib/time/timevalue.hpp"
#include "lib/nocopy.hpp"
#include "lib/util.hpp"
@ -65,6 +69,8 @@
namespace stage {
namespace model {
using lib::time::Time;
/**
@ -104,12 +110,27 @@ namespace model {
return Pos{*this, x,y};
}
/** build the "construction hook" for a \ref ViewHooked element,
* which is to be attached to some timeline canvas view.
* @param start anchor point / nominal start point of the element
* @param downshift (optional) vertical shift down from the baseline
* @return opaque registration argument for the ViewHooked ctor */
Pos
hookedAt (Time start, int downshift=0)
{
return hookedAt (translateTimeToPixels (start), downshift);
}
/** Anchor point to build chains of related View Hooks */
virtual ViewHook<WID>&
getAnchorHook() noexcept
{
return *this;
}
protected:
/** extension point for time axis zoom management. */
int translateTimeToPixels (Time) const =0;
};

84
wiki/thinkPad.ichthyo.mm
View file

@ -19174,8 +19174,9 @@
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</node>
</node>
<node BACKGROUND_COLOR="#eee5c3" COLOR="#990000" CREATED="1576757730509" ID="ID_1949130658" MODIFIED="1576758006669" TEXT="&#xbb;Widget-Position&#xab; heraus-abstrahieren">
<node BACKGROUND_COLOR="#eee5c3" COLOR="#990000" CREATED="1576757730509" ID="ID_1949130658" MODIFIED="1584889187771" TEXT="&#xbb;Widget-Position&#xab; heraus-abstrahieren">
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<node CREATED="1576757867075" ID="ID_1947629675" MODIFIED="1576757891150" TEXT="der Themenkomplex &quot;move()&quot; steht isoliert da">
<icon BUILTIN="idea"/>
@ -19188,6 +19189,29 @@
<node BACKGROUND_COLOR="#eee5c3" COLOR="#990000" CREATED="1576973905681" ID="ID_1230527469" MODIFIED="1576973919835" TEXT="Frage: sollte das seine Position kennen?">
<icon BUILTIN="help"/>
</node>
<node BACKGROUND_COLOR="#eee5c3" COLOR="#990000" CREATED="1584889312752" ID="ID_606340373" MODIFIED="1584889343532" TEXT="Problem: redundante Storage ">
<icon BUILTIN="messagebox_warning"/>
<node CREATED="1584889354160" ID="ID_1826251720" MODIFIED="1584889364042" TEXT="immer genau wenn es attached ist"/>
<node CREATED="1584889364726" ID="ID_1490833507" MODIFIED="1584889375017" TEXT="sind seine Koordinaten im Canvas gespeichert"/>
</node>
</node>
<node CREATED="1584889393669" ID="ID_444152936" MODIFIED="1584889595263" TEXT="eigenes Interface -- n&#xe4;her am DisplayManager">
<node CREATED="1584889606542" MODIFIED="1584889606542" TEXT="man k&#xf6;nnte es sogar direkt in den display-manager.hpp packen"/>
<node CREATED="1584889606543" MODIFIED="1584889606543" TEXT="allerdings spielt es oft die Rolle eines &quot;vereinfachten DisplayManager&quot;"/>
<node CREATED="1584889606544" ID="ID_298422140" MODIFIED="1584889621323" TEXT="und daher dann doch besser in einem eigenen Header"/>
<node CREATED="1584889621957" ID="ID_814318826" MODIFIED="1584889641912" TEXT="und ohne die Abh&#xe4;ngigkeit auf Gtk::Widget">
<richcontent TYPE="NOTE"><html>
<head>
</head>
<body>
<p>
erleichtert das Testen
</p>
</body>
</html>
</richcontent>
</node>
</node>
</node>
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@ -21891,6 +21915,8 @@
<node CREATED="1540511179218" ID="ID_1592328868" MODIFIED="1561827465261" TEXT="Problem: Ankerpunkt">
<icon BUILTIN="button_ok"/>
<node CREATED="1540511250489" ID="ID_49278916" MODIFIED="1540511273407" TEXT="wie h&#xe4;ngt man die ganze Struktur auf?"/>
<node CREATED="1584888287304" ID="ID_81420296" MODIFIED="1584888307013" TEXT="in Konstruktions-Reihenfolge verwoben">
<icon BUILTIN="button_cancel"/>
<node CREATED="1540511274366" ID="ID_1134388060" MODIFIED="1540511281241" TEXT="L&#xf6;sungsans&#xe4;tze">
<node CREATED="1540511304602" ID="ID_814037364" MODIFIED="1576282358074" TEXT="halb konstruierter Frame ohne Widgets">
<richcontent TYPE="NOTE"><html>
@ -22024,6 +22050,51 @@
<node CREATED="1540512596221" ID="ID_417702154" MODIFIED="1540588240683" TEXT="neige der 3. L&#xf6;sung zu">
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</node>
<node COLOR="#731e43" CREATED="1584888334461" HGAP="6" ID="ID_1191403237" MODIFIED="1584888393658" TEXT="trotzdem komplex und unvollst&#xe4;ndig" VSHIFT="28">
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<icon BUILTIN="stop-sign"/>
<node CREATED="1584888403457" ID="ID_1500365619" MODIFIED="1584888425339" TEXT="Aufruf-Verfugung schwer verst&#xe4;ndlich">
<richcontent TYPE="NOTE"><html>
<head>
</head>
<body>
<p>
da weit &#252;ber den Code verstreut
</p>
</body>
</html>
</richcontent>
</node>
<node CREATED="1584888427300" ID="ID_1626398524" MODIFIED="1584888438510" TEXT="l&#xf6;st nicht das Problem mit dem re-Konstruieren"/>
<node CREATED="1584888442705" ID="ID_1729804708" MODIFIED="1584888451663" TEXT="unterst&#xfc;tzt keine nachtr&#xe4;glichen Anpassungen"/>
<node CREATED="1584888452778" ID="ID_384525360" MODIFIED="1584888561167" TEXT="kann sich nicht aus der Anzeige ausklinken">
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</node>
</node>
</node>
<node BACKGROUND_COLOR="#eee5c3" COLOR="#990000" CREATED="1584888309716" ID="ID_236695014" MODIFIED="1584888323264" TEXT="explizit modelliert (CanvasHook)">
<icon BUILTIN="flag-yellow"/>
<node CREATED="1584888472583" ID="ID_1663593154" MODIFIED="1584888561167" TEXT="Idee: smart-Handle">
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<icon BUILTIN="idea"/>
</node>
<node COLOR="#338800" CREATED="1584888672307" ID="ID_213768440" MODIFIED="1584888703767" TEXT="brauche zus&#xe4;tzlich lokalen Offset">
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</node>
<node BACKGROUND_COLOR="#eee5c3" COLOR="#990000" CREATED="1584888686257" ID="ID_380050520" MODIFIED="1584888921383" TEXT="brauche zus&#xe4;tzlich &#xdc;bersetzung Time -&gt; pixel">
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<node BACKGROUND_COLOR="#eee5c3" COLOR="#990000" CREATED="1584889060615" ID="ID_730955223" MODIFIED="1584889187770" TEXT="mu&#xdf; Design des ViewHook ausdifferenzieren">
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<icon BUILTIN="button_ok"/>
</node>
</node>
</node>
<node CREATED="1563467223350" ID="ID_16819001" MODIFIED="1563467230773" TEXT="Problem: neu-Anordnung">
<node CREATED="1563467236241" ID="ID_711529393" MODIFIED="1563467248187" TEXT="wenn sich die Reihenfolge der Spuren &#xe4;ndert"/>
@ -22036,7 +22107,7 @@
</node>
</node>
</node>
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<node CREATED="1569711798770" ID="ID_27191288" MODIFIED="1584888645436">
<richcontent TYPE="NODE"><html>
<head>
@ -22048,6 +22119,7 @@
</body>
</html></richcontent>
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<node COLOR="#435e98" CREATED="1573315138011" FOLDED="true" ID="ID_1957325688" MODIFIED="1576876407022" TEXT="brauchen wir hier eine Erweiterung auf mehrere Typen...?">
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<icon BUILTIN="help"/>
@ -27690,7 +27762,13 @@
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<node CREATED="1568581102059" ID="ID_172612190" MODIFIED="1568581104782" TEXT="brauche....">
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<node CREATED="1568581118403" ID="ID_1096266089" MODIFIED="1573162562425" TEXT="Zugang zum DisplayManager (bzw. Timeline Layout)"/>
<node CREATED="1568581118403" ID="ID_1096266089" MODIFIED="1584888781745" TEXT="Zugang zum DisplayManager (bzw. Timeline Layout)">
<icon BUILTIN="button_cancel"/>
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<node BACKGROUND_COLOR="#eee5c3" COLOR="#990000" CREATED="1584888760695" ID="ID_1764561185" MODIFIED="1584888927450" TEXT="&#xdc;bersetzung Time -&gt; pixel (via DisplayManager)">
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<icon BUILTIN="flag-yellow"/>
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<node CREATED="1568587312669" ID="ID_178738138" MODIFIED="1576975019591" TEXT="die vertikalen Start-Offsets aus dem passenden Display-Frame">
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