Fixes on scrollbars

[tinchodias]

• Fix bug on vertical scrollbar (use wheel to scroll, and then drag thumb)
• Make horizontal scrollbar work

This PR requires changes in other repos:

• scrollbars branch in https://github.com/plantec/onbloc
• scrollbars branch in https://github.com/pharo-graphics/Bloc

Commit comments have information

[plantec]

thanks again. is it possible to have the 2 scrollbars (H and V) on the same element ? InfiniteElement ?

[tinchodias]

Hi, in infinite element I didn't check, but in a regular element yes, this is my example:

largeElement := OBlElement new
    size: 1000 asPoint;
    background: (BlRadialGradientPaint new
        stops: { 0 -> Color blue . 1 -> Color red};
        center: 500 asPoint;
        radius: 500;
        yourself);
    yourself.
scrollableElement := largeElement asScrollableElement.

hBar :=
    OBlHorizontalScrollbarElement new
        constraintsDo: [ :c |
            c ignoreByLayout.
            c ignored vertical alignBottom ];
        attachTo: scrollableElement;
        yourself.

vBar :=
    OBlVerticalScrollbarElement new
        constraintsDo: [ :c |
            c ignoreByLayout.
            c ignored horizontal alignRight ];
        attachTo: scrollableElement;
        yourself.

scrollPane :=
    BlElement new
        addChild: scrollableElement;
        addChild: vBar;
        addChild: hBar;
        constraintsDo: [ :c |
            c horizontal matchParent.
            c vertical matchParent ];
        yourself.

space := OBlSpace new.
space root
    layout: BlLinearLayout new;
    padding: (BlInsets all: 10);
    background: Color blue muchDarker;
    addChild: scrollPane.
space
    extent: 500@500;
    show

[plantec]

in an infinite it works differently, scrolling is managed by the layout by updating the infinite children. In the case of a vertical infinite layout, the horizontal scrolling should work as in your example. In the case of horizontal infinite layout, the vertical scrolling should work as in your example.

[tinchodias]

@plantec The album editor has an infinite layout, or am I wrong? Do you have a snippet, to be sure? Thanks in advance