diff --git a/src/stage/model/canvas-hook.hpp b/src/stage/model/canvas-hook.hpp index a082527ac..4d3978f36 100644 --- a/src/stage/model/canvas-hook.hpp +++ b/src/stage/model/canvas-hook.hpp @@ -67,6 +67,27 @@ namespace model { + /** + * Mix-in interface to allow for concrete CanvasHooked widgets + * to adapt themselves to the metric currently employed on the canvas. + * In some cases, most notably when a timeline canvas is calibrated to + * represent temporal extension precisely, the widgets (clips, effects) + * within such a display need to adjust themselves. A relevant special + * case is when such a widget _is dragged_ -- receiving mouse move events + * in screen coordinates -- which need to be translated into a resulting + * temporal offset or change as a result of this _interaction gesture._ + */ + class DisplayMetric + { + public: + virtual ~DisplayMetric() { } ///< this is an interface + + /** extension point for time axis zoom management. */ + virtual int translateTimeToPixels (TimeValue) const =0; + }; + + + /** * Interface to represent _"some presentation layout entity",_ * with the ability to _place_ widgets (managed elsewhere) onto it, @@ -80,6 +101,7 @@ namespace model { */ template class CanvasHook + : public DisplayMetric { public: virtual ~CanvasHook() { } ///< this is an interface @@ -117,9 +139,6 @@ namespace model { { return hookedAt (translateTimeToPixels (start), downshift); } - - /** extension point for time axis zoom management. */ - virtual int translateTimeToPixels (TimeValue) const =0; }; diff --git a/src/stage/timeline/body-canvas-widget.cpp b/src/stage/timeline/body-canvas-widget.cpp index 337931c9b..eb9fe80a6 100644 --- a/src/stage/timeline/body-canvas-widget.cpp +++ b/src/stage/timeline/body-canvas-widget.cpp @@ -553,7 +553,7 @@ namespace timeline { } - /* ==== Interface: ViewHook ===== */ + /* ==== Interface: CanvasHook ===== */ void BodyCanvasWidget::hook (Gtk::Widget& widget, int xPos, int yPos) diff --git a/src/stage/timeline/display-manager.hpp b/src/stage/timeline/display-manager.hpp index 052bd1a5e..7cb17a132 100644 --- a/src/stage/timeline/display-manager.hpp +++ b/src/stage/timeline/display-manager.hpp @@ -61,6 +61,13 @@ ** This builds the foundation for implementing UI structures recursively, leading to somewhat ** simplified code, which hopefully is also easier to maintain and extend in the long run. ** + ** \par Avoiding the double-indirect calls? + ** In theory, it would be possible to avoid the double forwarding indirect calls in all the + ** operations of RelativeCanvasHook: We'd have to provide a concrete mix-in to be used already + ** within body-canvas-widget.cpp, and this mixin would hold a _direct reference_ to the embedded + ** Gtk::Layout and provide an additional API to adjust the offset. However, the savings through + ** such an implementation scheme would be dwarfed by the effort for actually rendering a widget. + ** ** @todo as of 10/2018 timeline display in the UI is rebuilt to match the architecture ** @todo WIP-WIP-WIP - drafting the DisplayEvaluation as of 3/2020 ** @todo WIP as of 1/2021 about to build a first preliminary Clip representation @@ -98,6 +105,8 @@ namespace timeline { * @note the ctor uses #getAnchorHook, thus effectively, * for a chain of RelativeCanvasHook instances, * the #refHook_ holds the top level anchor. + * @remark avoiding this 2-step indirect dispatch is not + * justified here, given the overhead of drawing. */ template class RelativeCanvasHook diff --git a/wiki/thinkPad.ichthyo.mm b/wiki/thinkPad.ichthyo.mm index d94308fdc..19e4a798b 100644 --- a/wiki/thinkPad.ichthyo.mm +++ b/wiki/thinkPad.ichthyo.mm @@ -33130,10 +33130,46 @@ - + + + + + + + + + + + + + + + + + + + + + + + + + + + +

+ das Platzieren auf den Canvas ist keine high-Performance-Operation;
vielmehr ist es sogar vernachlässigbar im Vergleich zum Aufwand der Zeichen-Operationen; und letztere werden eben genau aus Performance-Gründen gebatcht und gebündelt.... +

+ + + + + + + @@ -33143,6 +33179,24 @@ + + + + + + + + + +

+ im Gegensatz zum CanvasHook ist das hier durchaus relevant +

+ + + + + +