[Pharo-dev] [bloc] shape size?

Aliaksei Syrel alex.syrel at gmail.com
Sun Apr 3 05:08:45 EDT 2016


If you want to change clicking behaviour you need to override one single
method.

Everything you wrote with unreadable amount of characters is for nothing.

All mentioned stuff is possible.
On Apr 3, 2016 10:30 AM, "Igor Stasenko" <siguctua at gmail.com> wrote:

>
>
> On 3 April 2016 at 10:18, Tudor Girba <tudor at tudorgirba.com> wrote:
>
>> Hi Igor,
>>
>> Thanks for this nice description :).
>>
>> Indeed, the Shape in Bloc is primarily a clipping shape that knows how to
>> draw the path around and to fill itself. Of course, it also handles the
>> interaction.
>>
>> When you want to have a composition, you are encouraged to create
>> multiple elements (morphs). This is a way to handle both more complicated
>> interaction and more complicated drawing. Of course, you can still override
>> the drawing method and draw whatever you want on it, but we would rather
>> have a simple composition.
>>
>> The disadvantage of this design is that indeed, is that it is not
>> sophisticated. The advantage of this design is that it is not sophisticated
>> :) and you get only one tree of compositions for the elements without
>> another level of composition at the shape level. The main reason we went
>> this route is because we want Bloc to pose as little constraints for the
>> things built on top as possible without losing power.
>>
>> Does this make sense for you?
>>
>
> It makes sense, sure thing.
> But it does not solves the problem.
> As i explained before, a single shape cannot serve as both clipping, UI
> handling and drawing all together. Because it is three separate roles,
> which is good if they coincide, but causing a lot of problems, when they
> are not.
> It is not matters how you compose or decompose shapes.. there is simply no
> composition which can turn rectangle into, lets say circle.
>  it simply impossible to construct required clipping shape, or UI shape
> from set of drawing shapes, in case when they are completely different from
> each other.
>
> For instance if i want morph with rectangular appearance (rectangle shape)
> to respond on clicks only within circular subregion inside that rectangle,
> i will be forced to create a submorph and then rewire event handling back
> to its parent. And that happens every time i need a different shape for
> mouse clicks than shape for drawing. Now add clipping here... and you will
> get a nightmare of bells and whistles, composing and whatsnot.
>
> As for 'sophisticated'.. let see:
> so, in my proposition, i do:
> - draw rectangle and circle inside
> - define that circle as UI shape
> - define that rectangle as clipping shape
> done.
> In your design, i have to:
> - make a morph with rectangular shape
> - create submorph with circular shape
> - wire clicking of a submorph to propagate event to its parent
>
> or think about some kind of composition.. composing what with what?
> does it union of circle and rectangle? or intersection? depending the way
> how you composing those two shapes you receive one or another outcome..
> and that event wiring is extra work..
> So, it may look that what i proposing is more sophisticated..
> But i just wanna see a separate roles taking own places, nothing else.
> I do not inventing new concepts, that wasn't there before:
> - you need clipping,
> - you need drawing
> - you need UI handling
>
> You see, it is not a framework, that forcing you to be 'sophisticated' ..
> it is domain itself. It draws a clear border between things that are
> optional and things that are absolutely necessary, since they are separate
> concepts and roles.
>
> You simply cannot represent an infinite dimension of drawing compositions
> by a composition of UI elements. Only the simplest cases..
> It is big mistake to imply that anything that you drawing on screen must
> be a full-blown UI element (which is morph is) or their composition.
> It makes you quite limited in terms of what you can draw and what not.
> Morph is UI building brick.. but it is not graphical building brick..
> making such parallel gives more troubles than it solves.
>
> To me concept where morph==shape==clipping shape==ui shape is just:
> - you can have bike of any color, as long as it's black.
>
> Can you enlighten me, what composition of black bikes can result in a
> green one?
>
>
>>
>> Cheers,
>> Doru
>>
>>
>> > On Apr 3, 2016, at 6:38 AM, Igor Stasenko <siguctua at gmail.com> wrote:
>> >
>> > Oh, yeah.. i missed one more kind of shape, you may want to introduce:
>> >  - clipping shape.
>> >
>> > For optimizing drawing operations, you may want to define a region,
>> which guarantees, that anything you paint, nothing outside defined region
>> will affect the screen. Because else, you will allow morph to render
>> anywhere and therefore, it is really hard for UI subsystem to account
>> damage on the screen.
>> > But once you define such shape, then you can clearly tell, which
>> portion of the screen may or may not be damaged and therefore act
>> accordingly.
>> >
>> > So, overall when we talking about shapes, we need to talk about three
>> different kinds of them:
>> >
>> > - UI interaction shape
>> > - clipping shape
>> > - shape(s) used to draw
>> >
>> > those three may or may not coincide into single one, depending on
>> complexity and what you wanna do..
>> > But they can be completely different from each other and in order to
>> avoid confusion and frustration, i would really introduce them in such
>> manner, that users have clear vision on what happens with their morphs and
>> how to achieve what they want.
>> >
>> > Clearly, a single #shape: is not enough, if you want a non-conflicting
>> representation of these concepts in UI.
>> >
>> >
>> > On 3 April 2016 at 07:15, Igor Stasenko <siguctua at gmail.com> wrote:
>> >
>> >
>> > On 2 April 2016 at 20:59, stepharo <stepharo at free.fr> wrote:
>> >
>> >
>> > Le 2/4/16 17:31, Aliaksei Syrel a écrit :
>> >> You don't want to draw a shape, you configure it. Shape can not be
>> drawn, it is not an AthensPath.
>> >>
>> >> cell shape: (BlShape new
>> >>   path: BlCirclePath new;
>> >>   strokePaint: (BlStrokePaint new
>> >>      paint: Color blue;
>> >>      width: 1)).
>> >> cell extent: 50 at 50.
>> >>
>> >
>> > But this is not what I want! As I mentioned in a mail that was sent but
>> never arrived.
>> > I want a square and this is why I did
>> >
>> > BlCell>>initialize
>> >     super initialize.
>> >     self
>> >         shape:
>> >             (BlShape new
>> >                 fillPaint: (BlColorPaint new color: (Color yellow));
>> >                 path: BlRectanglePath new);
>> >         extent: self extent
>> >
>> >
>> > then I want to draw something extra this is why I overrode
>> drawOnAthensCanvas: aCanvas
>> >
>> > Now I stop but I find bloc too complex.
>> >
>> > Sorry but I cannot lose time like that and just get frustrated at the
>> end.
>> > I will use the athens canvas directly and stay in morph for now.
>> >
>> >
>> > I think there's a bit of misconception.
>> > In Athens, shape representing any area you wanna fill with paint.
>> Period.
>> > It can be of any complexity, self-intersecting yadda yadda.. the main
>> point is that it defines a region(s), that going to be filled with chosen
>> paint during draw operation.
>> > From perspective of morphs, as UI elements, most of them require some
>> shape(s) to represent themselves on the screen. But there are morphs, that
>> while still taking part in UI, don't need any shapes since they never drawn
>> on the screen.
>> > Another point is that nowhere said that morph can be represented by a
>> one and only one shape period. Because as in your case, you want to, say,
>> draw rectangle with paint A, and circle with paint B, then you basically
>> need two different shapes (overlapping or not - not really matters) to
>> represent morph on the screen.
>> >
>> > So, the first point in misconception comes from 'self shape:'..
>> > It is wrong from that perspective, because it is all fine, when morph
>> using only single shape to represent itself.. but when you need multiple
>> shapes, you are in trouble. It at least misleading, because provoking you
>> to think that there can be only one.
>> >
>> > Then you need to invent a 'composite shape' that basically a collection
>> of shapes for a single morph, that will represent it on the screen.
>> >
>> > A tangent to that, is that since most of morphs has mostly static
>> geometry/topology and changing it very rarely and much less often comparing
>> to drawing same shape(s) over and over again, it is right thing to define
>> and initialize shape(s) and reuse them later in #draw method. Since you
>> don't change shape(s), you don't have to generate new object(s).
>> > From that perspective, this is nice, resource saving, approach.
>> > But let us not forget, that this is just a 'statistical observation'
>> and hence good to be a default setup. But it should not dictate you the
>> rule(s).
>> > You should still be able to define shape(s) on the fly or change it on
>> the fly, dynamically.
>> >
>> > Another problematic is that you may want to use different shapes for
>> > a) painting morph on screen
>> > b) defining geometry of the morph for UI interactions.
>> > As an example, let say, you want a rectangle with circle in centre on
>> the screen, but also want morph to react on mouse over/clicks only if mouse
>> cursor is inside a circle, but not when it's over an area covered by
>> rectangle.
>> >
>> > What it means, that from UI perspective, you want from morph to define
>> its shape, lets call it 'UI interaction shape'.. and from that perspective
>> 'self shape:' is a good choice. But as example says, it has nothing to do
>> with 'drawing shape(s)', which may or may not coincide with shape you using
>> for UI interaction(s).
>> >
>> > Because it defines an area, where UI stuff could happen. And indeed,
>> you really need one, and only one. You don't need multiple shapes there,
>> since it serves to answer a simple question: 'are my mouse in interesting
>> region or not'?.
>> > Like in your case, when you having box with circle inside , which is
>> two shapes, but only one shape that can define an interesting region, it
>> could be:
>> > - intersection of
>> > - union
>> > - subtraction
>> >
>> > And that could be completely different from shape(s) you may need to
>> draw it on the screen.
>> >
>> > Stef
>> >
>> >> On Apr 2, 2016 4:57 PM, "stepharo" <stepharo at free.fr> wrote:
>> >> Hi
>> >>
>> >> I want a square morph with a circle or a line at 45 degree inside
>> >> Now I do not get it.
>> >>
>> >> I thought that I needed to specialize drawOnAthensCanvas: so I did
>> >>
>> >> BlCell >> drawOnAthensCanvas: aCanvas
>> >>
>> >>     super drawOnAthensCanvas: aCanvas.
>> >>     aCanvas
>> >>         drawShape: (BlShape new
>> >>                                 strokePaint:
>> >>                                    (BlStrokePaint new
>> >>                                         paint: (BlColorPaint new
>> color: (Color blue));
>> >>                                           width: 15);
>> >>                             path: BlCirclePath new).
>> >>
>> >> Now I do not know how I can specify a shape size
>> >>
>> >> So I will use another API than drawShape:
>> >>
>> >> Stef
>> >>
>> >
>> >
>> >
>> >
>> > --
>> > Best regards,
>> > Igor Stasenko.
>> >
>> >
>> >
>> > --
>> > Best regards,
>> > Igor Stasenko.
>>
>> --
>> www.tudorgirba.com
>> www.feenk.com
>>
>> "Reasonable is what we are accustomed with."
>>
>>
>>
>
>
> --
> Best regards,
> Igor Stasenko.
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.pharo.org/pipermail/pharo-dev_lists.pharo.org/attachments/20160403/3793dd14/attachment.html>


More information about the Pharo-dev mailing list