Thanks Alex! Cheers, Alexandre
> On Aug 28, 2016, at 5:18 AM, Aliaksei Syrel <alex.sy...@gmail.com> wrote: > > Hi > > Thanks for the example. Exactly, ability to have elements that are visible > but not participate in layout is very important. But first I would like to > describe bloc layout a bit more. > > --------------------------------- > If you think for a second about the meaning of "layout" you would realize > that layout is just "the way in which the parts of something are arranged or > laid out". So, actually, layout is all about determining the positions of > elements within the parent (origin of bounds). However, real world is a bit > more complicated, especially when it comes to visual elements. In our world > we must also compute size (extent) of every element before actually laying it > out. Bad news is that size depends on layout type and layout constraints > (match parent, fit content, take exact size) that may depend rather on > children or parent. > > In Bloc the whole process is divided in two parts: measurement and layout. > They are completely separated and do not overlap. > > During measurement step we iterate over the whole tree and depending on > layout and constraints only compute extent of every element. For optimisation > purposes layout caches previous extent and if during new measurement step it > does not change, we stop, skipping children. There is a rule: if child's > constraints didn't change and if child's measurement bit is not dirty and if > parent's extent is the same child will have the same extent. > > Than comes layout step. Because we already measured all extents we can easily > determine positions within the parent, and logic is very simple. > --------------------------------- > > Now let's think about visibility and visible: setter. What argument should it > be? How do we encode visibility. In Morphic it is a Boolean. However, in real > world it is a bit more complicated. > > Sometimes we want an element to be completely gone, it is not visible and > does not take any space within the parent and does not participate in layout. > Sometimes we want an element to be hidden, it is not visible but it still > occupies space within the parent (it is just empty) and do participate in > layout. > Sometimes we want an element to be floating, it is visible but does not > occupy any space and does not participate in layout. However, a floating > element must be measured (extent computed), we just do not want to compute > its position and simply let user set it manually. > > To conclude, instead of Boolean in Bloc visibility is defined by BlVisibility > object. > -------------------------------- > > Floating mode is exactly what you want, Alex. It can be set easily: > txt constraints beFloating. > > However, I just checked and it does not work. Looks like this feature was > removed during last iteration. I find this feature is a huge step forward, > but now we are many steps back :( > > > Cheers, > Alex > > On 28 August 2016 at 02:24, Alexandre Bergel <alexandre.ber...@me.com> wrote: > Hi! > > I am working on a popup support in Bloc and I am facing a problem. Consider > the following code: > -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-= > space := BlSpace new. > space root layout: BlLinearLayout horizontal. > 10 > timesRepeat: [ | e | > e := (BlRectangle new extent: 20 @ 20) asElement. > e background: Color random. > space root addChild: e ]. > space root children withIndexDo: [ :e :index | e translateBy: (index > * 30) @ 10 ]. > > space root children do: [ :e | > e > addEventHandler: > (BlEventHandler > on: BlMouseEnterEvent > do: [ :evt | > | txt | > txt := BlText new > position: evt > position; > fill: Color red; > text: 'Hello World'. > > e parent addChild: txt ]). > > ]. > space show > -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-= > > If you uncomment the second line (“space root layout:…”), then the string > hello world is added text to the element in which the mouse enter. With the > layout, the string is added at the end of the line. > > I like very much the idea of having the layout applied when elements are > added (even I suspect we may have scalability issues very soon), but in that > situation, this is not wished. > > Alexandre > -- > _,.;:~^~:;._,.;:~^~:;._,.;:~^~:;._,.;:~^~:;._,.;: > Alexandre Bergel http://www.bergel.eu > ^~:;._,.;:~^~:;._,.;:~^~:;._,.;:~^~:;._,.;:~^~:;. > > > > > -- _,.;:~^~:;._,.;:~^~:;._,.;:~^~:;._,.;:~^~:;._,.;: Alexandre Bergel http://www.bergel.eu ^~:;._,.;:~^~:;._,.;:~^~:;._,.;:~^~:;._,.;:~^~:;.
