41 lines
1.3 KiB
Dart
41 lines
1.3 KiB
Dart
import 'package:aves/widgets/common/grid/sections/section_layout.dart';
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class FixedExtentSectionLayout extends SectionLayout {
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final double tileHeight, mainAxisStride;
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@override
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List<Object?> get props => [sectionKey, firstIndex, lastIndex, minOffset, maxOffset, headerExtent, tileHeight, spacing];
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const FixedExtentSectionLayout({
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required super.sectionKey,
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required super.firstIndex,
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required super.lastIndex,
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required super.minOffset,
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required super.maxOffset,
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required super.headerExtent,
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required this.tileHeight,
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required super.spacing,
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required super.builder,
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}) : mainAxisStride = tileHeight + spacing;
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@override
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double indexToLayoutOffset(int index) {
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index -= bodyFirstIndex;
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if (index < 0) return minOffset;
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return bodyMinOffset + index * mainAxisStride;
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}
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@override
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int getMinChildIndexForScrollOffset(double scrollOffset) {
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scrollOffset -= bodyMinOffset;
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if (scrollOffset < 0) return firstIndex;
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return bodyFirstIndex + scrollOffset ~/ mainAxisStride;
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}
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@override
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int getMaxChildIndexForScrollOffset(double scrollOffset) {
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scrollOffset -= bodyMinOffset;
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if (scrollOffset < 0) return firstIndex;
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return bodyFirstIndex + (scrollOffset / mainAxisStride).ceil() - 1;
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}
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}
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