AScrollAreaViewport

Inner component of AScrollArea that manages rendering and event handling with custom offset (scroll).

Header:	#include <AUI/View/AScrollAreaViewport.h>
CMake:	aui_link(my_target PUBLIC aui::views)

Detailed Description

This view is intended to store only one single view with setContents()/contents() methods.

This view does not handle scroll events and touch events related to scroll. Use AScrollArea for such case.

Expanding contents fill the viewport

A child set via setContents() that has ass::Expanding will always occupy at least the full viewport size on the expanding axis. The scrollable surface size (setScrollSurfaceSize) acts as a lower bound; the viewport's own size acts as another lower bound — the child receives max(scrollSurfaceSize, viewportSize). This means an expanding widget fills the visible area instead of collapsing to its minimum content size.

Prefer AScrollArea over using this class directly.

Examples

examples/ui/backdrop/src/main.cpp

Backdrop — Backdrop effects demo.

              Padding { 80_dp, 0, 0 },
            } AUI_LET { it->setExtraStylesheet(
                     AStylesheet {
                         {
                             t<AScrollAreaViewport>(),
                             AOverflow::VISIBLE,
                         },
                     }
                     ); },
        Vertical::Expanding {

Public Types

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Inner

class AScrollAreaViewport::Inner

Empty structure.

Public Methods

compensateLayoutUpdatesByScroll

---

template<aui::invocable ApplyLayoutUpdate >
void AScrollAreaViewport::compensateLayoutUpdatesByScroll(_<AView> anchor, ApplyLayoutUpdate&& applyLayoutUpdate, glm::ivec2 diffMask = glm::ivec2(1, 1))

Compensates layout updates made in applyLayoutUpdate by scrolling by a diff of relative position of anchor.

Arguments

anchor

direct or indirect child used as an anchor.

applyLayoutUpdate

layout update procedure.

diffMask

mask that is used to control axes of the compensation. Default is `{1, 1}`.

Helps preventing visual layout jittering by querying relative to AScrollAreaViewport position of anchor before and after applyLayoutUpdate. The diff of relative position is then used to scroll the viewport, maintaining consistent visual position of anchor.

anchor must be direct or indirect child to this AScrollAreaViewport before and after applyLayoutUpdate.

The scroll operation made within this method does not prevent scroll animation nor kinetic effects.