1 /* 2 * Copyright (c) 2022 Huawei Device Co., Ltd. 3 * Licensed under the Apache License, Version 2.0 (the "License"); 4 * you may not use this file except in compliance with the License. 5 * You may obtain a copy of the License at 6 * 7 * http://www.apache.org/licenses/LICENSE-2.0 8 * 9 * Unless required by applicable law or agreed to in writing, software 10 * distributed under the License is distributed on an "AS IS" BASIS, 11 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 12 * See the License for the specific language governing permissions and 13 * limitations under the License. 14 */ 15 16 #ifndef FOUNDATION_ACE_FRAMEWORKS_CORE_COMPONENTS_NG_PATTERN_SCROLL_SCROLL_LAYOUT_ALGORITHM_H 17 #define FOUNDATION_ACE_FRAMEWORKS_CORE_COMPONENTS_NG_PATTERN_SCROLL_SCROLL_LAYOUT_ALGORITHM_H 18 19 #include <map> 20 21 #include "base/geometry/axis.h" 22 #include "base/memory/referenced.h" 23 #include "core/components/common/layout/grid_system_manager.h" 24 #include "core/components/common/properties/alignment.h" 25 #include "core/components_ng/layout/layout_algorithm.h" 26 #include "core/components_ng/layout/layout_wrapper.h" 27 28 namespace OHOS::Ace::NG { 29 30 constexpr int32_t SCROLL_FROM_JUMP = 3; 31 32 class ACE_EXPORT ScrollLayoutAlgorithm : public LayoutAlgorithm { 33 DECLARE_ACE_TYPE(ScrollLayoutAlgorithm, LayoutAlgorithm); 34 35 public: 36 explicit ScrollLayoutAlgorithm(float currentOffset, float crossOffset = 0.0f) crossOffset_(crossOffset)37 : crossOffset_(crossOffset), currentOffset_(currentOffset) 38 {} 39 ~ScrollLayoutAlgorithm() override = default; 40 OnReset()41 void OnReset() override {} 42 GetCurrentOffset()43 float GetCurrentOffset() const 44 { 45 return currentOffset_; 46 } 47 GetFreeOffset()48 OffsetF GetFreeOffset() const 49 { 50 return { currentOffset_, crossOffset_ }; 51 } 52 GetScrollableDistance()53 float GetScrollableDistance() const 54 { 55 return scrollableDistance_; 56 } 57 58 /** 59 * @return 2D scrollable distance for free mode. 60 */ GetScrollableArea()61 SizeF GetScrollableArea() const 62 { 63 return { scrollableDistance_, viewPortExtent_.Height() - viewPort_.Height() }; 64 } 65 GetViewPortLength()66 float GetViewPortLength() const 67 { 68 return viewPortLength_; 69 } 70 GetViewPort()71 const SizeF& GetViewPort() const 72 { 73 return viewPort_; 74 } 75 GetViewSize()76 const SizeF& GetViewSize() const 77 { 78 return viewSize_; 79 } 80 GetViewPortExtent()81 const SizeF& GetViewPortExtent() const 82 { 83 return viewPortExtent_; 84 } 85 86 void Measure(LayoutWrapper* layoutWrapper) override; 87 88 void Layout(LayoutWrapper* layoutWrapper) override; 89 void UpdateOverlay(LayoutWrapper* layoutWrapper); 90 void MarkAndCheckNewOpIncNode(const RefPtr<LayoutWrapper>& layoutWrapper, Axis axis); 91 92 private: 93 void UseInitialOffset(Axis axis, SizeF selfSize, LayoutWrapper* layoutWrapper); 94 bool UnableOverScroll(LayoutWrapper* layoutWrapper) const; 95 void OnSurfaceChanged(LayoutWrapper* layoutWrapper, float contentMainSize); 96 97 float crossOffset_; 98 float currentOffset_ = 0.0f; 99 float scrollableDistance_ = 0.0f; 100 float viewPortLength_ = 0.0f; 101 SizeF viewPort_; // content area size (viewSize_ minus padding) 102 SizeF viewPortExtent_; // size of child (scrollable area) 103 SizeF viewSize_; // size of the Scroll component 104 void UpdateScrollAlignment(Alignment& scrollAlignment); 105 }; 106 107 } // namespace OHOS::Ace::NG 108 109 #endif // FOUNDATION_ACE_FRAMEWORKS_CORE_COMPONENTS_NG_PATTERN_SCROLL_SCROLL_LAYOUT_ALGORITHM_H 110