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Magnifier cleanup (#143558)

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- Introduces the ability to control whether RawMagnifier uses a clip on
its decoration. (It still has to use a clip for its magnified image.)
- Uses `BlurStyle.outer` to remove the clip for CupertinoMagnifier.
- Many changes to the documentation around magnifiers and shadows.
- Implements `BoxShadow.copyWith` which somehow we had never needed
before.
- Makes `debugDisableShadows` handle `BlurStyle.outer` correctly.
- Adds `MagnifierInfo.toString`.
- Aligns various `operator ==`s with the style guide.
- Makes MagnifierDecoration a separate concept from Decoration, since
it's not actually compatible anywhere.
- Removes some dead code and makes other minor code simplifications.
- Uses double syntax rather than integer syntax for various double
literals for clarity.

I expect one minor golden image change (antialiasing change on
Cupertino's magnifier test).
This commit is contained in:
Ian Hickson
2024-04-03 15:49:38 -07:00
committed by GitHub
parent 29ed214e7f
commit 13bec286bd
12 changed files with 395 additions and 195 deletions
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42
packages/flutter/lib/src/cupertino/magnifier.dart
View File

@@ -245,29 +245,60 @@ class CupertinoMagnifier extends StatelessWidget {
color: Color.fromARGB(25, 0, 0, 0),
blurRadius: 11,
spreadRadius: 0.2,
blurStyle: BlurStyle.outer,
),
],
this.clipBehavior = Clip.none,
this.borderSide =
const BorderSide(color: Color.fromARGB(255, 232, 232, 232)),
this.inOutAnimation,
});
/// The shadows displayed under the magnifier.
/// A list of shadows cast by the [Magnifier].
///
/// If the shadows use a [BlurStyle] that paints inside the shape, or if they
/// are offset, then a [clipBehavior] that enables clipping (such as
/// [Clip.hardEdge]) is recommended, otherwise the shadow will occlude the
/// magnifier (the shadow is drawn above the magnifier so as to not be
/// included in the magnified image).
///
/// A shadow that uses [BlurStyle.outer] and is not offset does not need
/// clipping.
///
/// By default, the [shadows] are not offset and use [BlurStyle.outer], and
/// correspondingly the default [clipBehavior] is [Clip.none].
final List<BoxShadow> shadows;
/// Whether and how to clip the [shadows] that render inside the loupe.
///
/// Defaults to [Clip.none], which is useful if the shadow will not paint
/// where the magnified image appears, or if doing so is intentional (e.g. to
/// blur the edges of the magnified image).
///
/// The default configuration of [CupertinoMagnifier] does not render inside
/// the loupe (the shadows are not offset and use [BlurStyle.outer]).
///
/// Other values (e.g. [Clip.hardEdge]) are recommended when the [shadows]
/// have an offset.
///
/// See the discussion at [shadows].
final Clip clipBehavior;
/// The border, or "rim", of this magnifier.
///
/// This border is drawn on a [RoundedRectangleBorder] with radius
/// [borderRadius], and increases the [size] of the magnifier by the
/// [BorderSide.width].
final BorderSide borderSide;
/// The vertical offset that the magnifier is along the Y axis above
/// the focal point.
@visibleForTesting
static const double kMagnifierAboveFocalPoint = -26;
/// The default size of the magnifier.
///
/// This is public so that positioners can choose to depend on it, although
/// it is overridable.
@visibleForTesting
static const Size kDefaultSize = Size(80, 47.5);
/// The duration that this magnifier animates in / out for.
@@ -278,9 +309,13 @@ class CupertinoMagnifier extends StatelessWidget {
static const Duration _kInOutAnimationDuration = Duration(milliseconds: 150);
/// The size of this magnifier.
///
/// The size does not include the [borderSide] or [shadows].
final Size size;
/// The border radius of this magnifier.
///
/// The magnifier's shape is a [RoundedRectangleBorder] with this radius.
final BorderRadius borderRadius;
/// This [RawMagnifier]'s controller.
@@ -317,6 +352,7 @@ class CupertinoMagnifier extends StatelessWidget {
),
shadows: shadows,
),
clipBehavior: clipBehavior,
),
);
}

135
packages/flutter/lib/src/material/magnifier.dart
View File

@@ -7,39 +7,38 @@ import 'dart:async';
import 'package:flutter/cupertino.dart';
import 'package:flutter/foundation.dart';
/// {@template widgets.material.magnifier.magnifier}
/// A [Magnifier] positioned by rules dictated by the native Android magnifier.
/// {@endtemplate}
///
/// {@template widgets.material.magnifier.positionRules}
/// Positions itself based on [magnifierInfo]. Specifically, follows the
/// following rules:
/// - Tracks the gesture's x coordinate, but clamped to the beginning and end of the
/// currently editing line.
/// - Focal point may never contain anything out of bounds.
/// - Never goes out of bounds vertically; offset until the entire magnifier is in the screen. The
/// focal point, regardless of this transformation, always points to the touch y coordinate.
/// - If just jumped between lines (prevY != currentY) then animate for duration
/// [jumpBetweenLinesAnimationDuration].
/// {@endtemplate}
/// The positioning rules are based on [magnifierInfo], as follows:
///
/// - The loupe tracks the gesture's _x_ coordinate, clamping to the beginning
/// and end of the currently editing line.
///
/// - The focal point never contains anything out of the bounds of the text
/// field or other widget being magnified (the [MagnifierInfo.fieldBounds]).
///
/// - The focal point always remains aligned with the _y_ coordinate of the touch.
///
/// - The loupe always remains on the screen.
///
/// - When the line targeted by the touch's _y_ coordinate changes, the position
/// is animated over [jumpBetweenLinesAnimationDuration].
///
/// This behavior was based on the Android 12 source code, where possible, and
/// on eyeballing a Pixel 6 running Android 12 otherwise.
class TextMagnifier extends StatefulWidget {
/// {@macro widgets.material.magnifier.magnifier}
/// Creates a [TextMagnifier].
///
/// {@template widgets.material.magnifier.androidDisclaimer}
/// These constants and default parameters were taken from the
/// Android 12 source code where directly transferable, and eyeballed on
/// a Pixel 6 running Android 12 otherwise.
/// {@endtemplate}
///
/// {@macro widgets.material.magnifier.positionRules}
/// The [magnifierInfo] must be provided, and must be updated with new values
/// as the user's touch changes.
const TextMagnifier({
super.key,
required this.magnifierInfo,
});
/// A [TextMagnifierConfiguration] that returns a [CupertinoTextMagnifier] on iOS,
/// [TextMagnifier] on Android, and null on all other platforms, and shows the editing handles
/// only on iOS.
/// A [TextMagnifierConfiguration] that returns a [CupertinoTextMagnifier] on
/// iOS, [TextMagnifier] on Android, and null on all other platforms, and
/// shows the editing handles only on iOS.
static TextMagnifierConfiguration adaptiveMagnifierConfiguration = TextMagnifierConfiguration(
shouldDisplayHandlesInMagnifier: defaultTargetPlatform == TargetPlatform.iOS,
magnifierBuilder: (
@@ -55,7 +54,7 @@ class TextMagnifier extends StatefulWidget {
);
case TargetPlatform.android:
return TextMagnifier(
magnifierInfo: magnifierInfo,
magnifierInfo: magnifierInfo,
);
case TargetPlatform.fuchsia:
case TargetPlatform.linux:
@@ -68,15 +67,14 @@ class TextMagnifier extends StatefulWidget {
/// The duration that the position is animated if [TextMagnifier] just switched
/// between lines.
@visibleForTesting
static const Duration jumpBetweenLinesAnimationDuration =
Duration(milliseconds: 70);
static const Duration jumpBetweenLinesAnimationDuration = Duration(milliseconds: 70);
/// [TextMagnifier] positions itself based on [magnifierInfo].
/// The current status of the user's touch.
///
/// {@macro widgets.material.magnifier.positionRules}
final ValueNotifier<MagnifierInfo>
magnifierInfo;
/// As the value of the [magnifierInfo] changes, the position of the loupe is
/// adjusted automatically, according to the rules described in the
/// [TextMagnifier] class description.
final ValueNotifier<MagnifierInfo> magnifierInfo;
@override
State<TextMagnifier> createState() => _TextMagnifierState();
@@ -130,7 +128,6 @@ class _TextMagnifierState extends State<TextMagnifier> {
super.didUpdateWidget(oldWidget);
}
/// {@macro widgets.material.magnifier.positionRules}
void _determineMagnifierPositionAndFocalPoint() {
final MagnifierInfo selectionInfo =
widget.magnifierInfo.value;
@@ -250,16 +247,19 @@ class _TextMagnifierState extends State<TextMagnifier> {
}
}
/// A Material styled magnifying glass.
/// A Material-styled magnifying glass.
///
/// {@macro flutter.widgets.magnifier.intro}
///
/// This widget focuses on mimicking the _style_ of the magnifier on material. For a
/// widget that is focused on mimicking the behavior of a material magnifier, see [TextMagnifier].
/// This widget focuses on mimicking the _style_ of the magnifier on material.
/// For a widget that is focused on mimicking the _behavior_ of a material
/// magnifier, see [TextMagnifier], which uses [Magnifier].
///
/// The styles implemented in this widget were based on the Android 12 source
/// code, where possible, and on eyeballing a Pixel 6 running Android 12
/// otherwise.
class Magnifier extends StatelessWidget {
/// Creates a [RawMagnifier] in the Material style.
///
/// {@macro widgets.material.magnifier.androidDisclaimer}
const Magnifier({
super.key,
this.additionalFocalPointOffset = Offset.zero,
@@ -267,11 +267,13 @@ class Magnifier extends StatelessWidget {
this.filmColor = const Color.fromARGB(8, 158, 158, 158),
this.shadows = const <BoxShadow>[
BoxShadow(
blurRadius: 1.5,
offset: Offset(0, 2),
spreadRadius: 0.75,
color: Color.fromARGB(25, 0, 0, 0))
blurRadius: 1.5,
offset: Offset(0.0, 2.0),
spreadRadius: 0.75,
color: Color.fromARGB(25, 0, 0, 0),
)
],
this.clipBehavior = Clip.hardEdge,
this.size = Magnifier.kDefaultMagnifierSize,
});
@@ -280,14 +282,13 @@ class Magnifier extends StatelessWidget {
/// The size of the magnifier may be modified through the constructor;
/// [kDefaultMagnifierSize] is extracted from the default parameter of
/// [Magnifier]'s constructor so that positioners may depend on it.
@visibleForTesting
static const Size kDefaultMagnifierSize = Size(77.37, 37.9);
/// The vertical distance that the magnifier should be above the focal point.
///
/// [kStandardVerticalFocalPointShift] is an unmodifiable constant so that positioning of this
/// [Magnifier] can be done with a guaranteed size, as opposed to an estimate.
@visibleForTesting
/// The [kStandardVerticalFocalPointShift] value is a constant so that
/// positioning of this [Magnifier] can be done with a guaranteed size, as
/// opposed to an estimate.
static const double kStandardVerticalFocalPointShift = 22;
static const double _borderRadius = 40;
@@ -296,11 +297,16 @@ class Magnifier extends StatelessWidget {
/// Any additional offset the focal point requires to "point"
/// to the correct place.
///
/// This is useful for instances where the magnifier is not pointing to something
/// directly below it.
/// This value is added to [kStandardVerticalFocalPointShift] to obtain the
/// actual offset.
///
/// This is useful for instances where the magnifier is not pointing to
/// something directly below it.
final Offset additionalFocalPointOffset;
/// The border radius for this magnifier.
///
/// The magnifier's shape is a [RoundedRectangleBorder] with this radius.
final BorderRadius borderRadius;
/// The color to tint the image in this [Magnifier].
@@ -310,12 +316,35 @@ class Magnifier extends StatelessWidget {
/// the background.
final Color filmColor;
/// The shadows for this [Magnifier].
/// A list of shadows cast by the [Magnifier].
///
/// If the shadows use a [BlurStyle] that paints inside the shape, or if they
/// are offset, then a [clipBehavior] that enables clipping (such as the
/// default [Clip.hardEdge]) is recommended, otherwise the shadow will occlude
/// the magnifier (the shadow is drawn above the magnifier so as to not be
/// included in the magnified image).
///
/// By default, the shadows are offset vertically by two logical pixels, so
/// clipping is recommended.
///
/// A shadow that uses [BlurStyle.outer] and is not offset does not need
/// clipping; in that case, consider setting [clipBehavior] to [Clip.none].
final List<BoxShadow> shadows;
/// Whether and how to clip the [shadows] that render inside the loupe.
///
/// Defaults to [Clip.hardEdge].
///
/// A value of [Clip.none] can be used if the shadow will not paint where the
/// magnified image appears, or if doing so is intentional (e.g. to blur the
/// edges of the magnified image).
///
/// See the discussion at [shadows].
final Clip clipBehavior;
/// The [Size] of this [Magnifier].
///
/// This size does not include the border.
/// The [shadows] are drawn outside of the [size].
final Size size;
@override
@@ -325,11 +354,17 @@ class Magnifier extends StatelessWidget {
shape: RoundedRectangleBorder(borderRadius: borderRadius),
shadows: shadows,
),
clipBehavior: clipBehavior,
magnificationScale: _magnification,
focalPointOffset: additionalFocalPointOffset +
Offset(0, kStandardVerticalFocalPointShift + kDefaultMagnifierSize.height / 2),
size: size,
child: ColoredBox(
// This couldn't be part of the decoration (even if the
// MagnifierDecoration supported specifying a color) because the
// decoration's shadows are offset and therefore we set a clipBehavior
// that clips the inner part of the decoration to avoid occluding the
// magnified image with the shadow.
color: filmColor,
),
);

9
packages/flutter/lib/src/material/shadows.dart
View File

@@ -18,6 +18,15 @@ import 'package:flutter/painting.dart';
/// This is useful when simulating a shadow with a [BoxDecoration] or other
/// class that uses a list of [BoxShadow] objects.
///
/// Shadows defined by [kElevationToShadow] use [BlurStyle.normal]. To convert a
/// shadow from [kElevationToShadow] to use a different [BlurStyle] (e.g. to use
/// it in a [MagnifierDecoration]), consider an expression such as the
/// following:
///
/// ```dart
/// kElevationToShadow[12]!.map((BoxShadow shadow) => shadow.copyWith(blurStyle: BlurStyle.outer)).toList(),
/// ```
///
/// See also:
///
/// * [Material], which takes an arbitrary double for its elevation and generates

14
packages/flutter/lib/src/painting/box_decoration.dart
View File

@@ -11,6 +11,7 @@ import 'border_radius.dart';
import 'box_border.dart';
import 'box_shadow.dart';
import 'colors.dart';
import 'debug.dart';
import 'decoration.dart';
import 'decoration_image.dart';
import 'edge_insets.dart';
@@ -439,7 +440,20 @@ class _BoxDecorationPainter extends BoxPainter {
for (final BoxShadow boxShadow in _decoration.boxShadow!) {
final Paint paint = boxShadow.toPaint();
final Rect bounds = rect.shift(boxShadow.offset).inflate(boxShadow.spreadRadius);
assert(() {
if (debugDisableShadows && boxShadow.blurStyle == BlurStyle.outer) {
canvas.save();
canvas.clipRect(bounds);
}
return true;
}());
_paintBox(canvas, bounds, paint, textDirection);
assert(() {
if (debugDisableShadows && boxShadow.blurStyle == BlurStyle.outer) {
canvas.restore();
}
return true;
}());
}
}

30
packages/flutter/lib/src/painting/box_shadow.dart
View File

@@ -44,6 +44,9 @@ class BoxShadow extends ui.Shadow {
/// The [BlurStyle] to use for this shadow.
///
/// Defaults to [BlurStyle.normal].
///
/// When [debugDisableShadows] is true, [toPaint] ignores the [blurStyle] and
/// acts as if [BlurStyle.normal] was used.
final BlurStyle blurStyle;
/// Create the [Paint] object that corresponds to this shadow description.
@@ -52,6 +55,12 @@ class BoxShadow extends ui.Shadow {
/// To honor those as well, the shape should be inflated by [spreadRadius] pixels
/// in every direction and then translated by [offset] before being filled using
/// this [Paint].
///
/// The [blurStyle] is ignored if [debugDisableShadows] is true. This causes
/// an especially significant change to the rendering when [BlurStyle.outer]
/// is used; the caller is responsible for adjusting for that case if
/// necessary. (This only matters when using [debugDisableShadows], e.g. in
/// tests that use [matchesGoldenFile].)
@override
Paint toPaint() {
final Paint result = Paint()
@@ -66,7 +75,8 @@ class BoxShadow extends ui.Shadow {
return result;
}
/// Returns a new box shadow with its offset, blurRadius, and spreadRadius scaled by the given factor.
/// Returns a new box shadow with its offset, blurRadius, and spreadRadius
/// scaled by the given factor.
@override
BoxShadow scale(double factor) {
return BoxShadow(
@@ -78,6 +88,24 @@ class BoxShadow extends ui.Shadow {
);
}
/// Creates a copy of this object but with the given fields replaced with the
/// new values.
BoxShadow copyWith({
Color? color,
Offset? offset,
double? blurRadius,
double? spreadRadius,
BlurStyle? blurStyle,
}) {
return BoxShadow(
color: color ?? this.color,
offset: offset ?? this.offset,
blurRadius: blurRadius ?? this.blurRadius,
spreadRadius: spreadRadius ?? this.spreadRadius,
blurStyle: blurStyle ?? this.blurStyle,
);
}
/// Linearly interpolate between two box shadows.
///
/// If either box shadow is null, this function linearly interpolates from

14
packages/flutter/lib/src/painting/debug.dart
View File

@@ -13,11 +13,17 @@ import 'package:flutter/foundation.dart';
/// the rendering of shadows is not guaranteed to be pixel-for-pixel identical from
/// version to version (or even from run to run).
///
/// In those tests, this is usually set to false at the beginning of a test and back
/// to true before the end of the test case.
/// This is set to true in [AutomatedTestWidgetsFlutterBinding]. Tests will fail
/// if they change this value and do not reset it before the end of the test.
///
/// If it remains true when the test ends, an exception is thrown to avoid state
/// leaking from one test case to another.
/// When this is set, [BoxShadow.toPaint] acts as if the [BoxShadow.blurStyle]
/// was [BlurStyle.normal] regardless of the actual specified blur style. This
/// is compensated for in [BoxDecoration] and [ShapeDecoration] but may need to
/// be explicitly considered in other situations.
///
/// This property should not be changed during a frame (e.g. during a call to
/// [ShapeBorder.paintInterior] or [ShapeBorder.getOuterPath]); doing so may
/// cause undefined effects.
bool debugDisableShadows = false;
/// Signature for a method that returns an [HttpClient].

30
packages/flutter/lib/src/painting/shape_decoration.dart
View File

@@ -11,6 +11,7 @@ import 'box_decoration.dart';
import 'box_shadow.dart';
import 'circle_border.dart';
import 'colors.dart';
import 'debug.dart';
import 'decoration.dart';
import 'decoration_image.dart';
import 'edge_insets.dart';
@@ -359,14 +360,43 @@ class _ShapeDecorationPainter extends BoxPainter {
}
void _paintShadows(Canvas canvas, Rect rect, TextDirection? textDirection) {
// The debugHandleDisabledShadowStart and debugHandleDisabledShadowEnd
// methods are used in debug mode only to support BlurStyle.outer when
// debugDisableShadows is set. Without these clips, the shadows would extend
// to the inside of the shape, which would likely obscure important
// portions of the rendering and would cause unit tests of widgets that use
// BlurStyle.outer to significantly diverge from the original intent.
// It is assumed that [debugDisableShadows] will not change when calling
// paintInterior or getOuterPath; if it does, the results are undefined.
bool debugHandleDisabledShadowStart(Canvas canvas, BoxShadow boxShadow, Path path) {
if (debugDisableShadows && boxShadow.blurStyle == BlurStyle.outer) {
canvas.save();
final Path clipPath = Path();
clipPath.fillType = PathFillType.evenOdd;
clipPath.addRect(Rect.largest);
clipPath.addPath(path, Offset.zero);
canvas.clipPath(clipPath);
}
return true;
}
bool debugHandleDisabledShadowEnd(Canvas canvas, BoxShadow boxShadow) {
if (debugDisableShadows && boxShadow.blurStyle == BlurStyle.outer) {
canvas.restore();
}
return true;
}
if (_shadowCount != null) {
if (_decoration.shape.preferPaintInterior) {
for (int index = 0; index < _shadowCount!; index += 1) {
assert(debugHandleDisabledShadowStart(canvas, _decoration.shadows![index], _decoration.shape.getOuterPath(_shadowBounds[index], textDirection: textDirection)));
_decoration.shape.paintInterior(canvas, _shadowBounds[index], _shadowPaints[index], textDirection: textDirection);
assert(debugHandleDisabledShadowEnd(canvas, _decoration.shadows![index]));
}
} else {
for (int index = 0; index < _shadowCount!; index += 1) {
assert(debugHandleDisabledShadowStart(canvas, _decoration.shadows![index], _shadowPaths[index]));
canvas.drawPath(_shadowPaths[index], _shadowPaints[index]);
assert(debugHandleDisabledShadowEnd(canvas, _decoration.shadows![index]));
}
}
}

241
packages/flutter/lib/src/widgets/magnifier.dart
View File

@@ -3,9 +3,9 @@
// found in the LICENSE file.
import 'dart:async';
import 'dart:math' as math;
import 'dart:ui';
import 'package:flutter/foundation.dart';
import 'package:flutter/rendering.dart';
import 'basic.dart';
@@ -68,8 +68,8 @@ class MagnifierInfo {
@override
bool operator ==(Object other) {
if (identical(this, other)) {
return true;
if (other.runtimeType != runtimeType) {
return false;
}
return other is MagnifierInfo
&& other.globalGesturePosition == globalGesturePosition
@@ -85,6 +85,16 @@ class MagnifierInfo {
fieldBounds,
currentLineBoundaries,
);
@override
String toString() {
return '${objectRuntimeType(this, 'MagnifierInfo')}('
'position: $globalGesturePosition, '
'line: $currentLineBoundaries, '
'caret: $caretRect, '
'field: $fieldBounds'
')';
}
}
/// A configuration object for a magnifier (e.g. in a text field).
@@ -135,9 +145,6 @@ class TextMagnifierConfiguration {
/// [Overlay].
///
/// To check the status of the magnifier, see [MagnifierController.shown].
// TODO(antholeole): This whole paradigm can be removed once portals
// lands - then the magnifier can be controlled though a widget in the tree.
// https://github.com/flutter/flutter/pull/105335
class MagnifierController {
/// If there is no in / out animation for the magnifier, [animationController] should be left
/// null.
@@ -350,37 +357,83 @@ class MagnifierController {
}
}
/// A decoration for a [RawMagnifier].
/// The decorations to put around the loupe in a [RawMagnifier].
///
/// [MagnifierDecoration] does not expose [ShapeDecoration.color], [ShapeDecoration.image],
/// or [ShapeDecoration.gradient], since they will be covered by the [RawMagnifier]'s lens.
/// See also:
///
/// Also takes an [opacity] (see https://github.com/flutter/engine/pull/34435).
class MagnifierDecoration extends ShapeDecoration {
/// * [Decoration], a more general solution for [DecoratedBox].
@immutable
class MagnifierDecoration {
/// Constructs a [MagnifierDecoration].
///
/// By default, [MagnifierDecoration] is a rectangular magnifier with no shadows, and
/// fully opaque.
/// By default, [MagnifierDecoration] is a rectangular magnifier with no
/// shadows, and fully opaque.
const MagnifierDecoration({
this.opacity = 1,
super.shadows,
super.shape = const RoundedRectangleBorder(),
this.opacity = 1.0,
this.shadows,
this.shape = const RoundedRectangleBorder(),
});
/// The magnifier's opacity.
// TODO(ianh): deprecate [opacity] (moving it to [RawMagnifier]), and then
// once [opacity] can be removed, replace [MagnifierDecoration] with a
// `typedef` to [ShapeDecoration] and make anywhere that accepts a
// [MagnifierDecoration] accept a [ShapeDecoration] instead. This would allow
// magnifiers that don't offset the shadows to use the decoration to paint
// over the loupe rather than having to have a Stack of widgets to do so.
/// The opacity of the magnifier and decorations around the magnifier.
///
/// When this is 1.0, the magnified image shows in the [shape] of the
/// magnifier. When this is less than 1.0, the magnified image is transparent
/// and shows through the unmagnified background.
///
/// Generally this is only useful for animating the magnifier in and out, as a
/// transparent magnifier looks quite confusing.
final double opacity;
/// A list of shadows cast by the [shape].
///
/// If the shadows are offset, consider setting [RawMagnifier.clipBehavior] to
/// [Clip.hardEdge] (or similar) to ensure the shadow does not occlude the
/// magnifier (the shadow is drawn above the magnifier).
///
/// If the shadows are _not_ offset, consider using [BlurStyle.outer] in the
/// shadows instead, to avoid having to introduce a clip.
///
/// In the event that [shape] consists of a stack of borders, the shadow is
/// drawn using the bounds of the last one.
///
/// See also:
///
/// * [kElevationToShadow], which defines some shadows for Material design.
/// Those shadows use [BlurStyle.normal] and may need to be converted to
/// [BlurStyle.outer] for use with [MagnifierDecoration].
final List<BoxShadow>? shadows;
/// The shape of the magnifier and the outline (border) around it.
///
/// Shapes can be stacked (using the `+` operator). In that case, the
/// magnifier and shadow are drawn according to the outside edge of the last
/// shape, with the borders painted on top.
final ShapeBorder shape;
@override
bool operator ==(Object other) {
if (identical(this, other)) {
return true;
if (other.runtimeType != runtimeType) {
return false;
}
return super == other && other is MagnifierDecoration && other.opacity == opacity;
return other is MagnifierDecoration
&& other.opacity == opacity
&& listEquals<BoxShadow>(other.shadows, shadows)
&& other.shape == shape;
}
@override
int get hashCode => Object.hash(super.hashCode, opacity);
int get hashCode => Object.hash(
opacity,
shape,
shadows == null ? null : Object.hashAll(shadows!),
);
}
/// A common base class for magnifiers.
@@ -406,17 +459,16 @@ class MagnifierDecoration extends ShapeDecoration {
class RawMagnifier extends StatelessWidget {
/// Constructs a [RawMagnifier].
///
/// {@template flutter.widgets.magnifier.RawMagnifier.invisibility_warning}
/// By default, this magnifier uses the default [MagnifierDecoration],
/// the focal point is directly under the magnifier, and there is no magnification:
/// This means that a default magnifier will be entirely invisible to the naked eye,
/// since it is painting exactly what is under it, exactly where it was painted
/// originally.
/// {@endtemplate}
/// By default, this magnifier uses the default [MagnifierDecoration] (which
/// draws nothing), the focal point is directly under the magnifier, and there
/// is no magnification; this means that a default magnifier will be entirely
/// invisible to the naked eye, painting exactly what is under it, exactly
/// where it was painted originally.
const RawMagnifier({
super.key,
this.child,
this.decoration = const MagnifierDecoration(),
this.clipBehavior = Clip.none,
this.focalPointOffset = Offset.zero,
this.magnificationScale = 1,
required this.size,
@@ -426,14 +478,29 @@ class RawMagnifier extends StatelessWidget {
/// An optional widget to position inside the len of the [RawMagnifier].
///
/// This is positioned over the [RawMagnifier] - it may be useful for tinting the
/// [RawMagnifier], or drawing a crosshair like UI.
/// [RawMagnifier], or drawing a crosshair-like UI.
final Widget? child;
/// This magnifier's decoration.
///
/// {@macro flutter.widgets.magnifier.RawMagnifier.invisibility_warning}
/// This sets the shape of the loupe, plus any borders and shadows that it
/// casts. The default has no border and no shadow; combined with the default
/// [magnificationScale] of 1.0, this results in the magnifier having no
/// visible effect.
///
/// If the [decoration] has a [MagnifierDecoration.shadows] that uses offset
/// shadows or uses a [BlurStyle] that would obscure the magnified image,
/// consider setting [clipBehavior] to [Clip.hardEdge] (or similar) to ensure
/// the magnified image is visible.
final MagnifierDecoration decoration;
/// Whether and how to clip the parts of [decoration] that render inside the
/// loupe.
///
/// Defaults to [Clip.none].
///
/// See the discussion at [decoration].
final Clip clipBehavior;
/// The offset of the magnifier from [RawMagnifier]'s center.
///
@@ -448,11 +515,13 @@ class RawMagnifier extends StatelessWidget {
final Offset focalPointOffset;
/// How "zoomed in" the magnification subject is in the lens.
///
/// The default is 1.0, which is no magnification.
final double magnificationScale;
/// The size of the magnifier.
///
/// This does not include added border; it only includes
/// This does not include the border from the [decoration]; it only includes
/// the size of the magnifier.
final Size size;
@@ -462,12 +531,12 @@ class RawMagnifier extends StatelessWidget {
clipBehavior: Clip.none,
alignment: Alignment.center,
children: <Widget>[
// The magnified image is clipped to the outer path of the shape.
ClipPath.shape(
shape: decoration.shape,
child: Opacity(
opacity: decoration.opacity,
child: _Magnifier(
shape: decoration.shape,
focalPointOffset: focalPointOffset,
magnificationScale: magnificationScale,
child: SizedBox.fromSize(
@@ -477,86 +546,53 @@ class RawMagnifier extends StatelessWidget {
),
),
),
// Because `BackdropFilter` will filter any widgets before it, we should
// apply the style after (i.e. in a younger sibling) to avoid the magnifier
// Because `BackdropFilter` will filter any widgets before it, we apply
// these styles after (i.e. in a younger sibling) to avoid the magnifier
// from seeing its own styling.
Opacity(
opacity: decoration.opacity,
child: _MagnifierStyle(
decoration,
size: size,
IgnorePointer(
child: Opacity(
opacity: decoration.opacity,
child: ClipPath(
clipBehavior: clipBehavior,
clipper: _NegativeClip(shape: decoration.shape),
child: DecoratedBox(
decoration: ShapeDecoration(
shape: decoration.shape,
shadows: decoration.shadows,
),
child: SizedBox.fromSize(
size: size,
),
),
),
),
)
),
],
);
}
}
class _MagnifierStyle extends StatelessWidget {
const _MagnifierStyle(this.decoration, {required this.size});
// A clip that renders everything except the inside of a shape.
class _NegativeClip extends CustomClipper<Path> {
_NegativeClip({required this.shape});
final MagnifierDecoration decoration;
final Size size;
@override
Widget build(BuildContext context) {
double largestShadow = 0;
for (final BoxShadow shadow in decoration.shadows ?? <BoxShadow>[]) {
largestShadow = math.max(
largestShadow,
(shadow.blurRadius + shadow.spreadRadius) +
math.max(shadow.offset.dy.abs(), shadow.offset.dx.abs()));
}
return ClipPath(
clipBehavior: Clip.hardEdge,
clipper: _DonutClip(
shape: decoration.shape,
spreadRadius: largestShadow,
),
child: DecoratedBox(
decoration: decoration,
child: SizedBox.fromSize(
size: size,
),
),
);
}
}
/// A `clipPath` that looks like a donut if you were to fill its area.
///
/// This is necessary because the shadow must be added after the magnifier is drawn,
/// so that the shadow does not end up in the magnifier. Without this clip, the magnifier would be
/// entirely covered by the shadow.
///
/// The negative space of the donut is clipped out (the donut hole, outside the donut).
/// The donut hole is cut out exactly like the shape of the magnifier.
class _DonutClip extends CustomClipper<Path> {
_DonutClip({required this.shape, required this.spreadRadius});
final double spreadRadius;
final ShapeBorder shape;
@override
Path getClip(Size size) {
final Path path = Path();
final Rect rect = Offset.zero & size;
path.fillType = PathFillType.evenOdd;
path.addPath(shape.getOuterPath(rect.inflate(spreadRadius)), Offset.zero);
path.addPath(shape.getInnerPath(rect), Offset.zero);
return path;
return Path()
..fillType = PathFillType.evenOdd
..addRect(Rect.largest)
..addPath(shape.getInnerPath(Offset.zero & size), Offset.zero);
}
@override
bool shouldReclip(_DonutClip oldClipper) => oldClipper.shape != shape;
bool shouldReclip(_NegativeClip oldClipper) => oldClipper.shape != shape;
}
class _Magnifier extends SingleChildRenderObjectWidget {
const _Magnifier({
super.child,
required this.shape,
this.magnificationScale = 1,
this.focalPointOffset = Offset.zero,
});
@@ -571,12 +607,9 @@ class _Magnifier extends SingleChildRenderObjectWidget {
// If greater than 1.0, the content appears bigger in the magnifier.
final double magnificationScale;
// Shape of the magnifier.
final ShapeBorder shape;
@override
RenderObject createRenderObject(BuildContext context) {
return _RenderMagnification(focalPointOffset, magnificationScale, shape);
return _RenderMagnification(focalPointOffset, magnificationScale);
}
@override
@@ -584,7 +617,6 @@ class _Magnifier extends SingleChildRenderObjectWidget {
BuildContext context, _RenderMagnification renderObject) {
renderObject
..focalPointOffset = focalPointOffset
..shape = shape
..magnificationScale = magnificationScale;
}
}
@@ -592,8 +624,7 @@ class _Magnifier extends SingleChildRenderObjectWidget {
class _RenderMagnification extends RenderProxyBox {
_RenderMagnification(
this._focalPointOffset,
this._magnificationScale,
this._shape, {
this._magnificationScale, {
RenderBox? child,
}) : super(child);
@@ -617,16 +648,6 @@ class _RenderMagnification extends RenderProxyBox {
markNeedsPaint();
}
ShapeBorder get shape => _shape;
ShapeBorder _shape;
set shape(ShapeBorder value) {
if (_shape == value) {
return;
}
_shape = value;
markNeedsPaint();
}
@override
bool get alwaysNeedsCompositing => true;

17
packages/flutter/test/cupertino/magnifier_test.dart
View File

@@ -23,15 +23,14 @@ void main() {
ValueNotifier<MagnifierInfo> magnifierInfo,
) async {
final Future<void> magnifierShown = magnifierController.show(
context: context,
builder: (_) => CupertinoTextMagnifier(
controller: magnifierController,
magnifierInfo: magnifierInfo,
));
WidgetsBinding.instance.scheduleFrame();
await tester.pumpAndSettle();
context: context,
builder: (BuildContext context) => CupertinoTextMagnifier(
controller: magnifierController,
magnifierInfo: magnifierInfo,
),
);
await tester.pump();
await tester.pump(const Duration(seconds: 2));
await magnifierShown;
}

5
packages/flutter/test/material/magnifier_test.dart
View File

@@ -168,8 +168,9 @@ void main() {
await showMagnifier(context, tester, magnifierInfo);
// Should show two red squares; original, and one in the magnifier,
// directly ontop of one another.
// Should show two red crossed-out squares: the original in the center,
// and one in the magnifier, in the upper half of the image, surrounded
// by a faint offset rounded rectangle shadow.
await expectLater(
find.byType(MaterialApp),
matchesGoldenFile('magnifier.position.default.png'),

13
packages/flutter/test/painting/decoration_test.dart
View File

@@ -812,4 +812,17 @@ void main() {
info.dispose();
}, skip: kIsWeb); // https://github.com/flutter/flutter/issues/87442
test('BoxShadow.copyWith', () {
expect(const BoxShadow(), isNot(const BoxShadow(color: Color(0xFF112233))));
expect(const BoxShadow().copyWith(color: const Color(0xFF112233)), const BoxShadow(color: Color(0xFF112233)));
expect(const BoxShadow(), isNot(const BoxShadow(offset: Offset(1.0, 2.0))));
expect(const BoxShadow().copyWith(offset: const Offset(1.0, 2.0)), const BoxShadow(offset: Offset(1.0, 2.0)));
expect(const BoxShadow(), isNot(const BoxShadow(blurRadius: 123.0)));
expect(const BoxShadow().copyWith(blurRadius: 123.0), const BoxShadow(blurRadius: 123.0));
expect(const BoxShadow(), isNot(const BoxShadow(spreadRadius: 123.0)));
expect(const BoxShadow().copyWith(spreadRadius: 123.0), const BoxShadow(spreadRadius: 123.0));
expect(const BoxShadow(), isNot(const BoxShadow(blurStyle: BlurStyle.outer)));
expect(const BoxShadow().copyWith(blurStyle: BlurStyle.outer), const BoxShadow(blurStyle: BlurStyle.outer));
});
}

40
packages/flutter/test/widgets/magnifier_test.dart
View File

@@ -53,7 +53,7 @@ void main() {
await tester.pumpWidget(MaterialApp(
key: appKey,
home: Container(
color: Colors.orange,
color: Colors.blue,
width: double.infinity,
height: double.infinity,
child: Stack(
@@ -64,7 +64,7 @@ void main() {
left: magnifierPosition.dx + magnifierFocalPoint.dx,
top: magnifierPosition.dy + magnifierFocalPoint.dy,
child: Container(
color: Colors.pink,
color: Colors.black,
// Since it is the size of the magnifier but over its
// magnificationScale, it should take up the whole magnifier.
width: (magnifierSize.width * 1.5) / magnificationScale,
@@ -78,26 +78,27 @@ void main() {
size: magnifierSize,
focalPointOffset: magnifierFocalPoint,
magnificationScale: magnificationScale,
decoration: MagnifierDecoration(shadows: <BoxShadow>[
BoxShadow(
spreadRadius: 10,
blurRadius: 10,
color: Colors.green,
offset: Offset(5, 5),
),
]),
clipBehavior: Clip.hardEdge,
decoration: MagnifierDecoration(
shadows: <BoxShadow>[
BoxShadow(
spreadRadius: 10.0,
blurRadius: 10.0,
color: Colors.yellow,
offset: Offset(5.0, 5.0),
),
],
opacity: 0.5,
),
),
),
],
),
)));
await tester.pumpAndSettle();
// Should look like an orange screen, with two pink boxes.
// One pink box is in the magnifier (so has a green shadow) and is double
// size (from magnification). Also, the magnifier should be slightly orange
// since it has opacity.
// Should look like a blue screen, with two black boxes. The larger black
// box is in the magnifier, is outlined in yellow, and is doubled in size
// (from magnification). The magnifier should be slightly transparent.
await expectLater(
find.byKey(appKey),
matchesGoldenFile('widgets.magnifier.styled.png'),
@@ -325,4 +326,11 @@ void main() {
}
});
});
testWidgets('MagnifierInfo.toString', (WidgetTester tester) async {
expect(MagnifierInfo.empty.toString(),
'MagnifierInfo(position: Offset(0.0, 0.0), line: Rect.fromLTRB(0.0, 0.0, 0.0, 0.0), '
'caret: Rect.fromLTRB(0.0, 0.0, 0.0, 0.0), field: Rect.fromLTRB(0.0, 0.0, 0.0, 0.0))',
);
});
}