Calculating rectangles relative to a SubCanvas for dynamic scroll bars

Hi,

I’m trying to implement the dynamic showing/hiding of scroll bars within a sub canvas depending on whether any widgets on it are “out of bounds”.

The idea is that I merge the rectangles of each widget (relative to the sub canvas) and then test the result.

However, I’m struggling with how to derive the rectangle relative to the sub canvas.

Any help greatly appreciated.

Thanks,

Stewart

Thanks Andre,

After some visual representation of the algorithm (see the comments), I managed to figure this out.

Thanks for your reply.

Cheers,

Stewart

checkEventPanelScrollBars

            | requiredArea decorator available widget localBounds |

            [requiredArea := ((eventPanel builder namedComponents associations select:

                        [: each | each value widget isVisible & each value widget isComposite not]) collect:

                                    [: each |

                                    localBounds := (widget := (eventPanel builder namedComponents at: each key) widget) bounds.

                                    Rectangle

                                                origin: (widget localPointToGlobal: localBounds origin)

                                                extent: localBounds extent])

                                                            inject: (Rectangle origin: ((self widgetAt: #eventPanel) localPointToGlobal: 0@0) corner: 0@0) into:

                                                                        [: result : each |

                                                                        "self mainWindow graphicsContext displayRectangle: each.

                                                                        (Delay forMilliseconds: 500) wait.

                                                                        self mainWindow graphicsContext

                                                                                    paint: SymbolicPaint buttonHilite;

                                                                                    displayRectangle: (result merge: each).

                                                                        (Delay forMilliseconds: 500) wait."

                                                                        result merge: each].

            "self mainWindow graphicsContext displayRectangle: requiredArea.

            (Delay forMilliseconds: 1500) wait."

            decorator := (self widgetAt: #eventPanel) container container container container.

            available := ((self widgetAt: #eventPanel) container container container bounds) translatedBy: ((self widgetAt: #eventPanel) localPointToGlobal: 0@0).

            available

                        corner x < requiredArea corner x

                                    ifTrue: [decorator useHorizontalScrollBar]

                                    ifFalse: [decorator noHorizontalScrollBar].

            "self mainWindow graphicsContext

                        paint: SymbolicPaint traversalHilite;

                        displayRectangle: available.

            (Delay forMilliseconds: 1500) wait."

            available corner y < requiredArea corner y

                        ifTrue: [decorator useVerticalScrollBar]

                        ifFalse: [decorator noVerticalScrollBar]] on: Error do: [: ex | ex return]