ALayout#

Base class for all layout managers.

Header:	`#include <AUI/Layout/ALayout.h>`
CMake:	`aui_link(my_target PUBLIC aui::views)`

Public Methods#

addView#

virtual void ALayout::addView(const _<AView>& view, AOptional<size_t> index = std::nullopt)

Attaches view to the layout.

Arguments: view
view to attach.

index
index to insert at. If not specified, when the view is inserted at the end.

See ABasicLayout for basic implementation of this method.

Examples:

examples/app/minesweeper/src/MinesweeperWindow.cpp

Minesweeper Game — Minesweeper game implementation driven by ass.

        int y = i / columns;
        auto cell = _new<CellView>(fieldAt(x, y));

        setupEventHandlers(x, y, cell);
        mGrid->addView(cell);
    }

    pack();
}
/// [beginGame]

examples/ui/views/src/ExampleWindow.cpp

Views Example — All-in-one views building example.

using namespace declarative;

void fillWindow(_<AViewContainer> t) {
    t->setLayout(std::make_unique<AStackedLayout>());
    t->addView(_new<ALabel>("Window contents"));
}

class AllViewsWindow : public AWindow {
public:
    AllViewsWindow() : AWindow("All views", 300_dp, 500_dp, nullptr, WindowStyle::MODAL) {

computeMinMaxAxis#

AMinMaxAxis ALayout::computeMinMaxAxis(int height = - 1)

Returns min/max preferred inline (width) size of the layout for a given block (height).

Arguments: height
Content height in px, or -1 for unconstrained.
Returns: `AMinMaxAxis` with `min` and `max` outer widths.

Wraps onComputeIntrinsicMinMaxAxis and applies padding, ass::FixedSize, ass::MinSize, ass::MaxSize. Result is cached; invalidated by requestLayout(). Do not override this method — override onComputeIntrinsicMinMaxAxis instead. See Measurement pipeline in detail for the full pipeline.

getAllViews#

virtual AVector<_<AView>> ALayout::getAllViews()

Visits all views in the layout.

layout#

virtual void ALayout::layout(int x, int y, int width, int height)

Applies geometry to children.

Arguments: x
x coordinate in container's coordinate space, add padding if necessary.

y
y coordinate in container's coordinate space, add padding if necessary.

width
width of the container, add padding if necessary.

height
height of the container, add padding if necessary.

See layout-managers for more info.

measure#

glm::ivec2 ALayout::measure(AConstraints constraints)

Returns the preferred outer size of the layout under given constraints.

Arguments: constraints
Constraints describing the available space (see `AConstraints`).
Returns: Preferred outer `{width, height}` in px.

Wraps onIntrinsicMeasure and applies padding, ass::FixedSize, ass::MinSize, ass::MaxSize. Result is cached per AConstraints key; invalidated by requestLayout(). Do not override this method — override onIntrinsicMeasure instead. See Measurement pipeline in detail for the full pipeline.

onComputeIntrinsicMinMaxAxis#

virtual AMinMaxAxis ALayout::onComputeIntrinsicMinMaxAxis(int height)

Computes the min/max preferred content inline (width) size for a given content height.

Arguments: height
Content height in px, or -1 for unconstrained.
Returns: `AMinMaxAxis` with `min` and `max` content widths.

Override this in a layout manager to report the range of widths the managed children need. The public computeMinMaxAxis wraps this method and handles padding, ass::FixedSize, etc. automatically — never call onComputeIntrinsicMinMaxAxis directly. See Measurement pipeline in detail for the full pipeline.

onIntrinsicMeasure#

virtual glm::ivec2 ALayout::onIntrinsicMeasure(AConstraints constraints)

Computes the preferred content size under given constraints.

Arguments: constraints
Constraints describing the available **content** space (padding already subtracted).
Returns: Preferred content `{width, height}` in px.

Override this in a layout manager to report how much space the managed children need. The public measure wraps this method and handles padding, ass::FixedSize, ass::MinSize, ass::MaxSize automatically — never call onIntrinsicMeasure directly.

The default implementation delegates to onComputeIntrinsicMinMaxAxis and clamps to constraints. See Measurement pipeline in detail for the full pipeline.

Examples:

examples/app/game_of_life/src/main.cpp

Game of Life — Game of Life implementation that uses advanced large dynamic data rendering techniques such as ITexture, AImage to be GPU friendly. The computation is performed in AThreadPool.

        (*mCells)[position] = !(*mCells)[position];
        updateTexture();
    }

    glm::ivec2 onIntrinsicMeasure(AConstraints constraints) override {
      return mCells->size() * int(SCALE);
    }

private:
    _<Cells> mCells;

removeView#

virtual void ALayout::removeView(aui::no_escape<AView> view, size_t index)

Detaches view from the layout.

Arguments: view
view to detach.

index
index of the view in the container. This value is indented for optimization purposes in most cases; the value may be ignored safely.

See ABasicLayout for basic implementation of this method.

requestLayout#

virtual void ALayout::requestLayout()

Invalidates cached measurement results, triggering a layout recalculation.

Call this whenever the layout manager's content changes in a way that may affect sizes (e.g. a child was added/removed, spacing changed). Clears mMeasureCache and mMinMaxSizesCache and propagates the invalidation up the view tree so that all ancestor containers re-measure themselves.

This is the direct replacement for the old markMinContentSizeInvalid() from the Qt-style layout system. The two are equivalent — requestLayout() additionally invalidates both measure caches introduced by the new Measurement pipeline in detail.

Note

You rarely need to call this manually. It is called automatically when ASS properties change, when a view is resized, or when addView/removeView is called. Override this in a custom layout manager only if you maintain extra internal caches that also need clearing.

setSpacing#

virtual void ALayout::setSpacing(int spacing)

Layout spacing.

Arguments: spacing
spacing in px.