AScrollAreaViewport.h

/*
 * AUI Framework - Declarative UI toolkit for modern C++20
 * Copyright (C) 2020-2025 Alex2772 and Contributors
 *
 * SPDX-License-Identifier: MPL-2.0
 *
 * This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/.
 */
 
#pragma once
 
 
#include "AViewContainer.h"
#include "AScrollbar.h"
#include "glm/fwd.hpp"
 

class API_AUI_VIEWS AScrollAreaViewport: public AViewContainerBase {
public:
   class Inner;
 
   AScrollAreaViewport();
   ~AScrollAreaViewport() override;
 
   void setContents(_<AView> content);
 
   [[nodiscard]]
   const _<AView>& contents() const noexcept {
       return mContents;
   }
 
   void applyGeometryToChildren() override;
 
   void setScroll(glm::uvec2 scroll) {
       if (mScroll == scroll) [[unlikely]] {
           return;
       }
       mScroll = scroll;
       updateContentsScroll();
   }
 
   void setScrollX(unsigned scroll) {
       if (mScroll.x == scroll) [[unlikely]] {
           return;
       }
       mScroll.x = scroll;
       updateContentsScroll();
   }
 
   void setScrollY(unsigned scroll) {
       if (mScroll.y == scroll) [[unlikely]] {
           return;
       }
       mScroll.y = scroll;
       updateContentsScroll();
   }
 
   [[nodiscard]]
   auto scroll() const noexcept {
       return APropertyDef {
           this,
           &AScrollAreaViewport::mScroll,
           &AScrollAreaViewport::setScroll,
           mScrollChanged,
       };
   }

   template<aui::invocable ApplyLayoutUpdate>
   void compensateLayoutUpdatesByScroll(_<AView> anchor, ApplyLayoutUpdate&& applyLayoutUpdate, glm::ivec2 diffMask = glm::ivec2(1, 1));
 
private:
   _<Inner> mInner;
   _<AView> mContents;
 
   glm::uvec2 mScroll = {0, 0};
   emits<glm::uvec2> mScrollChanged;
 
   void updateContentsScroll();
};
 
template <aui::invocable ApplyLayoutUpdate>
void AScrollAreaViewport::compensateLayoutUpdatesByScroll(
   _<AView> anchor, ApplyLayoutUpdate&& applyLayoutUpdate, glm::ivec2 diffMask) {
   auto queryRelativePosition = [&] {
     glm::ivec2 accumulator{};
     for (auto v = anchor.get(); v != nullptr && v->getParent() != this; v = v->getParent()) {
         accumulator += v->getPosition();
     }
     return accumulator;
   };
   auto before = queryRelativePosition();
   applyLayoutUpdate();
   auto after = queryRelativePosition();
   auto diff = after - before;
   diff *= diffMask;
   mScroll = glm::max(glm::ivec2(mScroll) + diff, glm::ivec2(0));
   updateContentsScroll();
}

© 2025 AUI Framework Contributors. Documentation contributions included herein are the copyrights of their respective owners. The documentation provided herein is licensed under the terms of the GNU Free Documentation License version 1.3 as published by the Free Software Foundation. All trademarks are property of their respective owners.