aves/lib/widgets/editor/transform/cropper.dart
Thibault Deckers 6f9a581d99 minor
2025-05-26 23:39:43 +02:00

769 lines
30 KiB
Dart

import 'dart:async';
import 'dart:math';
import 'package:aves/model/viewer/view_state.dart';
import 'package:aves/theme/durations.dart';
import 'package:aves/widgets/common/extensions/geometry.dart';
import 'package:aves/widgets/common/fx/dashed_path_painter.dart';
import 'package:aves/widgets/editor/transform/controller.dart';
import 'package:aves/widgets/editor/transform/crop_region.dart';
import 'package:aves/widgets/editor/transform/handles.dart';
import 'package:aves/widgets/editor/transform/painter.dart';
import 'package:aves/widgets/editor/transform/transformation.dart';
import 'package:aves_magnifier/aves_magnifier.dart';
import 'package:aves_model/aves_model.dart';
import 'package:aves_utils/aves_utils.dart';
import 'package:collection/collection.dart';
import 'package:flutter/foundation.dart';
import 'package:flutter/material.dart';
import 'package:provider/provider.dart';
class Cropper extends StatefulWidget {
final AvesMagnifierController magnifierController;
final TransformController transformController;
final ValueNotifier<EdgeInsets> marginNotifier;
static const double handleDimension = kMinInteractiveDimension;
static const EdgeInsets imageMargin = EdgeInsets.all(kMinInteractiveDimension);
const Cropper({
super.key,
required this.magnifierController,
required this.transformController,
required this.marginNotifier,
});
@override
State<Cropper> createState() => _CropperState();
}
class _CropperState extends State<Cropper> with SingleTickerProviderStateMixin {
final Set<StreamSubscription> _subscriptions = {};
final ValueNotifier<Rect> _outlineNotifier = ValueNotifier(Rect.zero);
final ValueNotifier<int> _gridDivisionNotifier = ValueNotifier(0);
late AnimationController _gridAnimationController;
late CurvedAnimation _gridOpacity;
static const double minDimension = Cropper.handleDimension;
static const int panResizeGridDivision = 3;
static const int straightenGridDivision = 9;
static const double overOutlineFactor = .25;
AvesMagnifierController get magnifierController => widget.magnifierController;
TransformController get transformController => widget.transformController;
Transformation get transformation => transformController.transformation;
CropAspectRatio get cropAspectRatio => transformController.aspectRatioNotifier.value;
@override
void initState() {
super.initState();
_gridAnimationController = AnimationController(
duration: context.read<DurationsData>().viewerOverlayAnimation,
vsync: this,
);
_gridOpacity = CurvedAnimation(
parent: _gridAnimationController,
curve: Curves.easeOutQuad,
);
_registerWidget(widget);
}
@override
void didUpdateWidget(covariant Cropper oldWidget) {
super.didUpdateWidget(oldWidget);
_unregisterWidget(oldWidget);
_registerWidget(widget);
}
@override
void dispose() {
_outlineNotifier.dispose();
_gridDivisionNotifier.dispose();
_gridOpacity.dispose();
_gridAnimationController.dispose();
_unregisterWidget(widget);
super.dispose();
}
void _registerWidget(Cropper widget) {
_subscriptions.add(widget.magnifierController.stateStream.listen(_onViewStateChanged));
_subscriptions.add(widget.magnifierController.scaleBoundariesStream.map((v) => v.viewportSize).distinct().listen(_onViewportSizeChanged));
_subscriptions.add(widget.transformController.activityStream.listen(_onTransformActivity));
_subscriptions.add(widget.transformController.transformationStream.map((v) => v.orientation).distinct().listen(_onOrientationChanged));
_subscriptions.add(widget.transformController.transformationStream.map((v) => v.straightenDegrees).distinct().listen(_onStraightenDegreesChanged));
widget.transformController.aspectRatioNotifier.addListener(_onCropAspectRatioChanged);
}
void _unregisterWidget(Cropper widget) {
_subscriptions
..forEach((sub) => sub.cancel())
..clear();
widget.transformController.aspectRatioNotifier.removeListener(_onCropAspectRatioChanged);
}
@override
Widget build(BuildContext context) {
return Positioned.fill(
child: ValueListenableBuilder<EdgeInsets>(
valueListenable: widget.marginNotifier,
builder: (context, margin, child) {
return ValueListenableBuilder<Rect>(
valueListenable: _outlineNotifier,
builder: (context, outline, child) {
if (outline.isEmpty) return const SizedBox();
final outlineVisualRect = outline.translate(margin.left, margin.top);
return Stack(
children: [
Positioned.fill(
child: IgnorePointer(
child: Stack(
children: [
_buildDashLine([outlineVisualRect.topLeft, outlineVisualRect.topRight]),
_buildDashLine([outlineVisualRect.bottomLeft, outlineVisualRect.bottomRight]),
_buildDashLine([outlineVisualRect.topLeft, outlineVisualRect.bottomLeft]),
_buildDashLine([outlineVisualRect.topRight, outlineVisualRect.bottomRight]),
Positioned.fill(
child: ValueListenableBuilder<int>(
valueListenable: _gridDivisionNotifier,
builder: (context, gridDivision, child) {
return ValueListenableBuilder<double>(
valueListenable: _gridOpacity,
builder: (context, gridOpacity, child) {
return CustomPaint(
painter: CropperPainter(
rect: outlineVisualRect,
gridOpacity: gridOpacity,
gridDivision: gridDivision,
),
);
},
);
},
),
),
],
),
),
),
_buildVertexHandle(
margin: margin,
getPosition: () => outline.topLeft,
setPosition: (v) => _handleOutline(
left: min(outline.right - minDimension, v.dx),
top: min(outline.bottom - minDimension, v.dy),
),
),
_buildVertexHandle(
margin: margin,
getPosition: () => outline.topRight,
setPosition: (v) => _handleOutline(
right: max(outline.left + minDimension, v.dx),
top: min(outline.bottom - minDimension, v.dy),
),
),
_buildVertexHandle(
margin: margin,
getPosition: () => outline.bottomRight,
setPosition: (v) => _handleOutline(
right: max(outline.left + minDimension, v.dx),
bottom: max(outline.top + minDimension, v.dy),
),
),
_buildVertexHandle(
margin: margin,
getPosition: () => outline.bottomLeft,
setPosition: (v) => _handleOutline(
left: min(outline.right - minDimension, v.dx),
bottom: max(outline.top + minDimension, v.dy),
),
),
_buildEdgeHandle(
margin: margin,
getEdge: () => Rect.fromPoints(outline.bottomLeft, outline.topLeft),
setEdge: (v) => _handleOutline(
left: min(outline.right - minDimension, v.left),
),
),
_buildEdgeHandle(
margin: margin,
getEdge: () => Rect.fromPoints(outline.topLeft, outline.topRight),
setEdge: (v) => _handleOutline(
top: min(outline.bottom - minDimension, v.top),
),
),
_buildEdgeHandle(
margin: margin,
getEdge: () => Rect.fromPoints(outline.bottomRight, outline.topRight),
setEdge: (v) => _handleOutline(
right: max(outline.left + minDimension, v.right),
),
),
_buildEdgeHandle(
margin: margin,
getEdge: () => Rect.fromPoints(outline.bottomLeft, outline.bottomRight),
setEdge: (v) => _handleOutline(
bottom: max(outline.top + minDimension, v.bottom),
),
),
],
);
},
);
},
),
);
}
// use 1 painter per line so that the dashes of one line
// do not get offset depending on the previous line length
Widget _buildDashLine(List<Offset> points) => CustomPaint(
painter: DashedPathPainter(
originalPath: Path()..addPolygon(points, false),
pathColor: CropperPainter.borderColor,
strokeWidth: CropperPainter.borderWidth,
),
);
void _handleOutline({
double? left,
double? top,
double? right,
double? bottom,
}) {
final currentOutline = _outlineNotifier.value;
var targetOutline = Rect.fromLTRB(
left ?? currentOutline.left,
top ?? currentOutline.top,
right ?? currentOutline.right,
bottom ?? currentOutline.bottom,
);
_RatioStrategy? ratioStrategy;
if (left != null && top != null && right != null) {
ratioStrategy = _RatioStrategy.pinBottom;
} else if (top != null && right != null && bottom != null) {
ratioStrategy = _RatioStrategy.pinLeft;
} else if (left != null && right != null && bottom != null) {
ratioStrategy = _RatioStrategy.pinTop;
} else if (left != null && top != null && bottom != null) {
ratioStrategy = _RatioStrategy.pinRight;
} else if (left != null && top != null) {
ratioStrategy = _RatioStrategy.pinBottomRight;
} else if (left != null) {
ratioStrategy = _RatioStrategy.pinTopRight;
} else if (top != null) {
ratioStrategy = _RatioStrategy.pinBottomLeft;
} else if (right != null) {
ratioStrategy = _RatioStrategy.pinTopLeft;
} else if (bottom != null) {
ratioStrategy = _RatioStrategy.pinTopLeft;
}
if (ratioStrategy != null) {
targetOutline = _applyCropRatioToOutline(targetOutline, ratioStrategy);
}
// do not try to coerce outline handled outside tilted image
if (transformation.straightenDegrees != 0 && !_isOutlineContained(targetOutline)) return;
// dismiss if we could not honour aspect ratio
if (cropAspectRatio != CropAspectRatio.free && !_isOutlineContained(targetOutline)) return;
final currentState = _getViewState();
final boundaries = magnifierController.scaleBoundaries;
if (currentState == null || boundaries == null) return;
final gestureRegion = _regionFromOutline(currentState, targetOutline);
final viewportSize = boundaries.viewportSize;
final gestureOutline = _containedOutlineFromRegion(currentState, gestureRegion);
final clampedOutline = Rect.fromLTRB(
max(gestureOutline.left, 0),
max(gestureOutline.top, 0),
min(gestureOutline.right, viewportSize.width),
min(gestureOutline.bottom, viewportSize.height),
);
var nextOutline = clampedOutline;
if (max(gestureOutline.width - clampedOutline.width, gestureOutline.height - clampedOutline.height) > precisionErrorTolerance) {
// zoom out when user gesture reaches outer edges
final targetOutline = Rect.lerp(clampedOutline, gestureOutline, overOutlineFactor)!;
final targetRegion = _regionFromOutline(currentState, targetOutline);
final nextState = _viewStateForContainedRegion(boundaries, targetRegion);
if (nextState != currentState) {
magnifierController.update(
position: nextState.position,
scale: nextState.scale,
source: ChangeSource.animation,
);
nextOutline = _containedOutlineFromRegion(nextState, targetRegion);
}
}
_setOutline(nextOutline);
}
bool _isOutlineContained(Rect outline) {
final currentState = _getViewState();
final boundaries = magnifierController.scaleBoundaries;
if (currentState == null || boundaries == null) return false;
final regionToOutlineMatrix = _getRegionToOutlineMatrix(currentState);
final outlineToRegionMatrix = Matrix4.inverted(regionToOutlineMatrix);
final regionCorners = {
outline.topLeft,
outline.topRight,
outline.bottomRight,
outline.bottomLeft,
}.map(outlineToRegionMatrix.transformOffset).toSet();
final contentRect = Offset.zero & boundaries.contentSize;
return regionCorners.every((v) => contentRect.containsIncludingBottomRight(v, tolerance: precisionErrorTolerance));
}
VertexHandle _buildVertexHandle({
required EdgeInsets margin,
required ValueGetter<Offset> getPosition,
required ValueSetter<Offset> setPosition,
}) {
return VertexHandle(
margin: margin,
getPosition: getPosition,
setPosition: setPosition,
onDragStart: _onResizeStart,
onDragEnd: _onResizeEnd,
);
}
EdgeHandle _buildEdgeHandle({
required EdgeInsets margin,
required ValueGetter<Rect> getEdge,
required ValueSetter<Rect> setEdge,
}) {
return EdgeHandle(
margin: margin,
getEdge: getEdge,
setEdge: setEdge,
onDragStart: _onResizeStart,
onDragEnd: _onResizeEnd,
);
}
void _onResizeStart() {
transformController.activity = TransformActivity.resize;
}
void _onResizeEnd() {
transformController.activity = TransformActivity.none;
_showRegion();
}
void _showRegion() {
final boundaries = magnifierController.scaleBoundaries;
if (boundaries == null) return;
final region = transformation.region;
final nextState = _viewStateForContainedRegion(boundaries, region);
magnifierController.update(
position: nextState.position,
scale: nextState.scale,
source: ChangeSource.animation,
);
_setOutline(_containedOutlineFromRegion(nextState, region));
}
ViewState _viewStateForContainedRegion(ScaleBoundaries boundaries, CropRegion imageRegion) {
final matrix = transformation.matrix;
final displayRegion = imageRegion.corners.map(matrix.transformOffset).toSet();
final xMin = displayRegion.map((v) => v.dx).min;
final xMax = displayRegion.map((v) => v.dx).max;
final yMin = displayRegion.map((v) => v.dy).min;
final yMax = displayRegion.map((v) => v.dy).max;
final displayRegionSize = Size(xMax - xMin, yMax - yMin);
final nextScale = boundaries.clampScale(ScaleLevel.scaleForContained(boundaries.viewportSize, displayRegionSize));
final nextPosition = boundaries.clampPosition(
position: boundaries.contentToStatePosition(nextScale, imageRegion.center),
scale: nextScale,
);
return ViewState(
position: nextPosition,
scale: nextScale,
viewportSize: boundaries.viewportSize,
contentSize: boundaries.contentSize,
);
}
void _onTransformActivity(TransformActivity activity) {
switch (activity) {
case TransformActivity.none:
_showRegion();
case TransformActivity.pan:
case TransformActivity.resize:
_gridDivisionNotifier.value = panResizeGridDivision;
case TransformActivity.straighten:
_gridDivisionNotifier.value = straightenGridDivision;
}
if (activity == TransformActivity.none) {
_gridAnimationController.reverse();
} else {
_gridAnimationController.forward();
}
}
void _onOrientationChanged(TransformOrientation orientation) {
_showRegion();
}
void _onStraightenDegreesChanged(double degrees) {
_updateCropRegion();
}
void _onCropAspectRatioChanged() {
final viewState = _getViewState();
if (viewState == null) return;
var targetOutline = _applyCropRatioToOutline(_outlineNotifier.value, _RatioStrategy.keepArea);
if (!_isOutlineContained(targetOutline)) {
targetOutline = _applyCropRatioToOutline(_outlineNotifier.value, _RatioStrategy.contain);
}
transformController.cropRegion = _regionFromOutline(viewState, targetOutline);
_showRegion();
}
void _onViewStateChanged(MagnifierState state) {
switch (transformController.activity) {
case TransformActivity.none:
break;
case TransformActivity.straighten:
case TransformActivity.pan:
final currentOutline = _outlineNotifier.value;
_setOutline(_applyCropRatioToOutline(currentOutline, _RatioStrategy.contain));
case TransformActivity.resize:
break;
}
}
void _onViewportSizeChanged(Size viewportSize) {
final boundaries = magnifierController.scaleBoundaries;
if (boundaries != null) {
magnifierController.setScaleBoundaries(
boundaries.copyWith(
padding: _getBoundariesPadding,
),
);
}
_showRegion();
}
EdgeInsets _getBoundariesPadding(double scale) {
// TODO TLAD handle orientation
if (transformation.orientation != TransformOrientation.normal) {
return const EdgeInsets.all(double.infinity);
}
// TODO TLAD handle straightening
if (transformation.straightenDegrees != 0) {
return const EdgeInsets.all(double.infinity);
}
final viewState = _getViewState();
if (viewState != null) {
final viewportSize = viewState.viewportSize;
final contentSize = viewState.contentSize;
if (viewportSize != null && contentSize != null) {
final fullRegion = CropRegion.fromRect(Offset.zero & contentSize);
final fullOutline = _containingOutlineFromRegion(viewState, fullRegion);
final cropOutline = _outlineNotifier.value;
final paddingWidth = max(0.0, (min(fullOutline.width, viewportSize.width) - cropOutline.width) / 2);
final paddingHeight = max(0.0, (min(fullOutline.height, viewportSize.height) - cropOutline.height) / 2);
return EdgeInsets.symmetric(vertical: paddingHeight, horizontal: paddingWidth);
}
}
return EdgeInsets.zero;
}
ViewState? _getViewState() {
final scaleBoundaries = magnifierController.scaleBoundaries;
if (scaleBoundaries == null) return null;
final state = magnifierController.currentState;
return ViewState(
position: state.position,
scale: state.scale,
viewportSize: scaleBoundaries.viewportSize,
contentSize: scaleBoundaries.contentSize,
);
}
void _setOutline(Rect targetOutline) {
final viewState = _getViewState();
final viewportSize = viewState?.viewportSize;
if (targetOutline.isEmpty || viewState == null || viewportSize == null) return;
// ensure outline is within content
var targetRegion = _regionFromOutline(viewState, targetOutline);
var newOutline = _containedOutlineFromRegion(viewState, targetRegion);
final outlineWidthDelta = targetOutline.width - newOutline.width;
final outlineHeightDelta = targetOutline.height - newOutline.height;
if (outlineWidthDelta > precisionErrorTolerance || outlineHeightDelta > precisionErrorTolerance) {
// keep outline area if possible, otherwise trim
final regionToOutlineMatrix = _getRegionToOutlineMatrix(viewState);
final rect = Offset.zero & viewState.contentSize!;
final edgeRegionCorners = targetRegion.corners.where((v) => v.dx == rect.left || v.dx == rect.right || v.dy == rect.top || v.dy == rect.bottom).toSet();
final edgeOutlineCorners = edgeRegionCorners.map(regionToOutlineMatrix.transformOffset).toSet();
if (edgeOutlineCorners.isNotEmpty) {
final direction = edgeOutlineCorners.map((v) => newOutline.center - v).reduce((prev, v) => prev + v);
final movedOutline = targetOutline.shift(Offset(
outlineWidthDelta * direction.dx.sign,
outlineHeightDelta * direction.dy.sign,
));
targetRegion = _regionFromOutline(viewState, movedOutline);
newOutline = _containedOutlineFromRegion(viewState, targetRegion);
}
}
// ensure outline is large enough to be handled
newOutline = Rect.fromLTWH(
newOutline.left,
newOutline.top,
max(newOutline.width, minDimension),
max(newOutline.height, minDimension),
);
_outlineNotifier.value = newOutline;
switch (transformController.activity) {
case TransformActivity.pan:
case TransformActivity.resize:
_updateCropRegion();
break;
case TransformActivity.none:
case TransformActivity.straighten:
break;
}
}
void _updateCropRegion() {
final viewState = _getViewState();
final outline = _outlineNotifier.value;
if (viewState != null && !outline.isEmpty) {
transformController.cropRegion = _regionFromOutline(viewState, outline);
}
}
Matrix4 _getRegionToOutlineMatrix(ViewState viewState) {
final magnifierMatrix = viewState.matrix;
final viewportCenter = viewState.viewportSize!.center(Offset.zero);
final transformOrigin = Matrix4.inverted(magnifierMatrix).transformOffset(viewportCenter);
final transformMatrix = Matrix4.identity()
..translate(transformOrigin.dx, transformOrigin.dy)
..multiply(transformation.matrix)
..translate(-transformOrigin.dx, -transformOrigin.dy);
return magnifierMatrix..multiply(transformMatrix);
}
CropRegion _regionFromOutline(ViewState viewState, Rect outline) {
final regionToOutlineMatrix = _getRegionToOutlineMatrix(viewState);
final outlineToRegionMatrix = regionToOutlineMatrix..invert();
final rect = Offset.zero & viewState.contentSize!;
double clampX(double dx) => dx.clamp(rect.left, rect.right);
double clampY(double dy) => dy.clamp(rect.top, rect.bottom);
Offset clampPoint(Offset v) => Offset(clampX(v.dx), clampY(v.dy));
Offset transform(Offset v) => clampPoint(outlineToRegionMatrix.transformOffset(v));
final clampedRegion = CropRegion(
topLeft: transform(outline.topLeft),
topRight: transform(outline.topRight),
bottomRight: transform(outline.bottomRight),
bottomLeft: transform(outline.bottomLeft),
);
return clampedRegion;
}
Rect _containingOutlineFromRegion(ViewState viewState, CropRegion region) {
final regionToOutlineMatrix = _getRegionToOutlineMatrix(viewState);
final points = region.corners.map(regionToOutlineMatrix.transformOffset).toList();
final dxSet = points.map((v) => v.dx).toSet();
final dySet = points.map((v) => v.dy).toSet();
final topLeft = Offset(dxSet.reduce(min), dySet.reduce(min));
final bottomRight = Offset(dxSet.reduce(max), dySet.reduce(max));
return Rect.fromPoints(topLeft, bottomRight);
}
Rect _containedOutlineFromRegion(ViewState viewState, CropRegion region) {
final regionToOutlineMatrix = _getRegionToOutlineMatrix(viewState);
final points = region.corners.map(regionToOutlineMatrix.transformOffset).toList();
final sortedX = points.map((v) => v.dx).toList()..sort();
final sortedY = points.map((v) => v.dy).toList()..sort();
final topLeft = Offset(sortedX[1], sortedY[1]);
final bottomRight = Offset(sortedX[2], sortedY[2]);
return Rect.fromPoints(topLeft, bottomRight);
}
Rect _applyCropRatioToOutline(Rect outline, _RatioStrategy strategy) {
final currentState = _getViewState();
final boundaries = magnifierController.scaleBoundaries;
if (currentState == null || boundaries == null) return outline;
final contentSize = boundaries.contentSize;
late int longCoef;
late int shortCoef;
switch (cropAspectRatio) {
case CropAspectRatio.free:
return outline;
case CropAspectRatio.original:
longCoef = contentSize.longestSide.round();
shortCoef = contentSize.shortestSide.round();
case CropAspectRatio.square:
longCoef = 1;
shortCoef = 1;
case CropAspectRatio.ar_16_9:
longCoef = 16;
shortCoef = 9;
case CropAspectRatio.ar_4_3:
longCoef = 4;
shortCoef = 3;
}
final contentRect = Offset.zero & contentSize;
final isLandscape = (outline.width - outline.height).abs() > precisionErrorTolerance ? outline.width > outline.height : contentSize.width > contentSize.height;
final newRatio = isLandscape ? longCoef / shortCoef : shortCoef / longCoef;
Size sizeToKeepArea() {
final f = (outline.longestSide + outline.shortestSide) / (longCoef + shortCoef);
final newLongest = f * longCoef;
final newShortest = f * shortCoef;
return isLandscape ? Size(newLongest, newShortest) : Size(newShortest, newLongest);
}
final regionToOutlineMatrix = _getRegionToOutlineMatrix(currentState);
final outlineToRegionMatrix = Matrix4.inverted(regionToOutlineMatrix);
Rect pinnedRect(Rect Function(Size targetSize) forSize) {
final targetSize = sizeToKeepArea();
final rect = forSize(targetSize);
// do not try to coerce outline handled outside tilted image
if (transformation.straightenDegrees != 0) return rect;
final regionCorners = {
rect.topLeft,
rect.topRight,
rect.bottomRight,
rect.bottomLeft,
}.map(outlineToRegionMatrix.transformOffset).toSet();
if (regionCorners.every((v) => contentRect.containsIncludingBottomRight(v, tolerance: precisionErrorTolerance))) return rect;
final clampedOutlineCorners = regionCorners.map((v) => regionToOutlineMatrix.transformOffset(Offset(v.dx.clamp(0, contentSize.width), v.dy.clamp(0, contentSize.height)))).toSet();
final minX = clampedOutlineCorners.map((v) => v.dx).min;
final maxX = clampedOutlineCorners.map((v) => v.dx).max;
final minY = clampedOutlineCorners.map((v) => v.dy).min;
final maxY = clampedOutlineCorners.map((v) => v.dy).max;
var width = rect.width;
var height = rect.height;
if (rect.left < minX - precisionErrorTolerance) {
width = rect.right - minX;
height = width / newRatio;
} else if (rect.top < minY - precisionErrorTolerance) {
height = rect.bottom - minY;
width = height * newRatio;
} else if (rect.right > maxX + precisionErrorTolerance) {
width = maxX - rect.left;
height = width / newRatio;
} else if (rect.bottom > maxY + precisionErrorTolerance) {
height = maxY - rect.top;
width = height * newRatio;
}
final clampedSize = Size(width, height);
return clampedSize < targetSize ? forSize(clampedSize) : rect;
}
switch (strategy) {
case _RatioStrategy.keepArea:
final targetSize = sizeToKeepArea();
return Rect.fromCenter(
center: outline.center,
width: targetSize.width,
height: targetSize.height,
);
case _RatioStrategy.contain:
final currentRatio = outline.width / outline.height;
if ((newRatio - currentRatio).abs() < precisionErrorTolerance) {
return outline;
} else {
late final Size targetSize;
if (newRatio > currentRatio) {
targetSize = Size(outline.width, outline.width / newRatio);
} else {
targetSize = Size(outline.height * newRatio, outline.height);
}
return Rect.fromCenter(
center: outline.center,
width: targetSize.width,
height: targetSize.height,
);
}
case _RatioStrategy.pinTopLeft:
return pinnedRect((targetSize) => Rect.fromPoints(
outline.topLeft,
outline.topLeft.translate(targetSize.width, targetSize.height),
));
case _RatioStrategy.pinTopRight:
return pinnedRect((targetSize) => Rect.fromPoints(
outline.topRight,
outline.topRight.translate(-targetSize.width, targetSize.height),
));
case _RatioStrategy.pinBottomRight:
return pinnedRect((targetSize) => Rect.fromPoints(
outline.bottomRight,
outline.bottomRight.translate(-targetSize.width, -targetSize.height),
));
case _RatioStrategy.pinBottomLeft:
return pinnedRect((targetSize) => Rect.fromPoints(
outline.bottomLeft,
outline.bottomLeft.translate(targetSize.width, -targetSize.height),
));
case _RatioStrategy.pinLeft:
return pinnedRect((targetSize) => Rect.fromLTRB(
outline.left,
outline.center.dy - targetSize.height / 2,
outline.left + targetSize.width,
outline.center.dy + targetSize.height / 2,
));
case _RatioStrategy.pinTop:
return pinnedRect((targetSize) => Rect.fromLTRB(
outline.center.dx - targetSize.width / 2,
outline.top,
outline.center.dx + targetSize.width / 2,
outline.top + targetSize.height,
));
case _RatioStrategy.pinRight:
return pinnedRect((targetSize) => Rect.fromLTRB(
outline.right - targetSize.width,
outline.center.dy - targetSize.height / 2,
outline.right,
outline.center.dy + targetSize.height / 2,
));
case _RatioStrategy.pinBottom:
return pinnedRect((targetSize) => Rect.fromLTRB(
outline.center.dx - targetSize.width / 2,
outline.bottom - targetSize.height,
outline.center.dx + targetSize.width / 2,
outline.bottom,
));
}
}
}
enum _RatioStrategy { keepArea, contain, pinTopLeft, pinTopRight, pinBottomRight, pinBottomLeft, pinLeft, pinTop, pinRight, pinBottom }