mirror of
https://github.com/bggRGjQaUbCoE/PiliPlus.git
synced 2026-04-20 11:08:03 +08:00
119 lines
3.5 KiB
Dart
119 lines
3.5 KiB
Dart
/*
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* This file is part of PiliPlus
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*
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* PiliPlus is free software: you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation, either version 3 of the License, or
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* (at your option) any later version.
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*
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* PiliPlus is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with PiliPlus. If not, see <https://www.gnu.org/licenses/>.
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*/
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import 'dart:math' as math;
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import 'package:flutter/foundation.dart' show clampDouble;
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import 'package:flutter/rendering.dart'
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show RenderSliverSingleBoxAdapter, SliverGeometry;
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import 'package:flutter/widgets.dart';
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/// ref [SliverPersistentHeader]
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class SliverPinnedHeader extends SingleChildRenderObjectWidget {
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const SliverPinnedHeader({
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super.key,
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required Widget super.child,
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this.backgroundColor,
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});
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final Color? backgroundColor;
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@override
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RenderObject createRenderObject(BuildContext context) =>
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RenderSliverPinnedHeader(backgroundColor: backgroundColor);
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@override
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void updateRenderObject(
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BuildContext context,
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RenderSliverPinnedHeader renderObject,
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) {
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renderObject.backgroundColor = backgroundColor;
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}
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}
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class RenderSliverPinnedHeader extends RenderSliverSingleBoxAdapter {
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RenderSliverPinnedHeader({
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required Color? backgroundColor,
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}) : _backgroundColor = backgroundColor;
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Color? _backgroundColor;
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set backgroundColor(Color? value) {
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if (_backgroundColor == value) return;
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_backgroundColor = value;
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if (_isPinned) markNeedsPaint();
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}
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bool _isPinned = false;
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@override
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void performLayout() {
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final constraints = this.constraints;
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child!.layout(constraints.asBoxConstraints(), parentUsesSize: true);
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final double childExtent = child!.size.height;
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final double effectiveRemainingPaintExtent = math.max(
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0,
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constraints.remainingPaintExtent - constraints.overlap,
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);
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final double layoutExtent = clampDouble(
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childExtent - constraints.scrollOffset,
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0.0,
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effectiveRemainingPaintExtent,
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);
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_isPinned = constraints.overlap > 0.0 || constraints.scrollOffset > 0.0;
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geometry = SliverGeometry(
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scrollExtent: childExtent,
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paintOrigin: constraints.overlap,
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paintExtent: math.min(childExtent, effectiveRemainingPaintExtent),
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layoutExtent: layoutExtent,
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maxPaintExtent: childExtent,
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maxScrollObstructionExtent: childExtent,
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cacheExtent: layoutExtent > 0.0
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? -constraints.cacheOrigin + layoutExtent
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: layoutExtent,
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hasVisualOverflow: false,
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);
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}
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@override
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void paint(PaintingContext context, Offset offset) {
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if (child != null && geometry!.visible) {
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if (_isPinned && _backgroundColor != null) {
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final size = child!.size;
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context.canvas.drawRect(
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Rect.fromLTWH(
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offset.dx,
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offset.dy - 2,
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size.width,
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size.height + 2,
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),
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Paint()..color = _backgroundColor!,
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);
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}
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context.paintChild(child!, offset);
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}
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}
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@override
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double childMainAxisPosition(RenderBox child) => 0.0;
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@override
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bool hitTestSelf({
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required double mainAxisPosition,
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required double crossAxisPosition,
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}) => true;
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}
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