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Rename TileImage active to readyToDisplay for clarity and prevent Til…
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…eImages with no errorImage from being marked as ready to display.

Also fixed handling of errors when tile fading is disabled.
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@rorystephenson
rorystephenson committed Jul 24, 2023
1 parent 436b7dc commit e60fa0c
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Showing 2 changed files with 57 additions and 45 deletions.
90 changes: 51 additions & 39 deletions lib/src/layer/tile_layer/tile_image.dart
View file
Original file line number Diff line number Diff line change
Expand Up @@ -5,6 +5,12 @@ import 'package:flutter_map/src/layer/tile_layer/tile_display.dart';
class TileImage extends ChangeNotifier {
bool _disposed = false;

// Controls fade-in opacity.
AnimationController? _animationController;

// Whether the tile is displayable. See [readyToDisplay].
bool _readyToDisplay = false;

/// Used by animationController. Still required if animation is disabled in
/// case the tile display is changed at a later point.
final TickerProvider vsync;
Expand All @@ -13,8 +19,6 @@ class TileImage extends ChangeNotifier {
/// indicate the position of the tile at that zoom level.
final TileCoordinates coordinates;

AnimationController? _animationController;

/// Callback fired when loading finishes with or withut an error. This
/// callback is not triggered after this TileImage is disposed.
final void Function(TileCoordinates coordinates) onLoadComplete;
Expand All @@ -26,20 +30,14 @@ class TileImage extends ChangeNotifier {
onLoadError;

/// Options for how the tile image is displayed.
TileDisplay _display;
TileDisplay _tileDisplay;

/// An optional image to show when a loading error occurs.
final ImageProvider? errorImage;

ImageProvider imageProvider;

/// Whether the tile is displayable. This means that either:
/// * Loading errored but there is a tile error image.
/// * Loading succeeded and the fade animation has finished.
/// * Loading succeeded and there is no fade animation.
bool _active = false;

// True if an error occurred during loading.
/// True if an error occurred during loading.
bool loadError = false;

/// When loading started.
Expand All @@ -60,7 +58,7 @@ class TileImage extends ChangeNotifier {
required this.onLoadError,
required TileDisplay tileDisplay,
required this.errorImage,
}) : _display = tileDisplay,
}) : _tileDisplay = tileDisplay,
_animationController = tileDisplay.when(
instantaneous: (_) => null,
fadeIn: (fadeIn) => AnimationController(
Expand All @@ -69,25 +67,33 @@ class TileImage extends ChangeNotifier {
),
);

double get opacity => _display.when(
instantaneous: (instantaneous) => _active ? instantaneous.opacity : 0.0,
double get opacity => _tileDisplay.when(
instantaneous: (instantaneous) =>
_readyToDisplay ? instantaneous.opacity : 0.0,
fadeIn: (fadeIn) => _animationController!.value,
)!;

AnimationController? get animation => _animationController;

String get coordinatesKey => coordinates.key;

bool get active => _active;
/// Whether the tile is displayable. This means that either:
/// * Loading errored but an error image is configured.
/// * Loading succeeded and the fade animation has finished.
/// * Loading succeeded and there is no fade animation.
///
/// Note that [opacity] can be less than 1 when this is true if instantaneous
/// tile display is used with a maximum opacity less than 1.
bool get readyToDisplay => _readyToDisplay;

// Used to sort TileImages by their distance from the current zoom.
double zIndex(double maxZoom, int currentZoom) =>
maxZoom - (currentZoom - coordinates.z).abs();

// Change the tile display options.
set tileDisplay(TileDisplay newTileDisplay) {
final oldTileDisplay = _display;
_display = newTileDisplay;
final oldTileDisplay = _tileDisplay;
_tileDisplay = newTileDisplay;

// Handle disabling/enabling of animation controller if necessary
oldTileDisplay.when(
Expand All @@ -98,7 +104,7 @@ class TileImage extends ChangeNotifier {
_animationController = AnimationController(
duration: fadeIn.duration,
vsync: vsync,
value: _active ? 1.0 : 0.0,
value: _readyToDisplay ? 1.0 : 0.0,
);
},
);
Expand Down Expand Up @@ -146,7 +152,7 @@ class TileImage extends ChangeNotifier {
this.imageInfo = imageInfo;

if (!_disposed) {
_activate();
_display();
onLoadComplete(coordinates);
}
}
Expand All @@ -155,42 +161,49 @@ class TileImage extends ChangeNotifier {
loadError = true;

if (!_disposed) {
_activate();
if (errorImage != null) _display();
onLoadError(this, exception, stackTrace);
onLoadComplete(coordinates);
}
}

void _activate() {
// Initiates fading in and marks this TileImage as readyToDisplay when fading
// finishes. If fading is disabled or a loading error occurred this TileImage
// becomes readyToDisplay immediately.
void _display() {
final previouslyLoaded = loadFinishedAt != null;
loadFinishedAt = DateTime.now();

_display.when(
if (loadError) {
assert(
errorImage != null,
'A TileImage should not be displayed if loading errors and there is no '
'errorImage to show.',
);
_readyToDisplay = true;
if (!_disposed) notifyListeners();
return;
}

_tileDisplay.when(
instantaneous: (_) {
_active = true;
_readyToDisplay = true;
if (!_disposed) notifyListeners();
},
fadeIn: (fadeIn) {
if (loadError && errorImage != null) {
_active = true;
if (!_disposed) notifyListeners();
return;
}

final fadeStartOpacity =
previouslyLoaded ? fadeIn.reloadStartOpacity : fadeIn.startOpacity;

if (fadeStartOpacity == 1.0) {
_active = true;
_readyToDisplay = true;
if (!_disposed) notifyListeners();
return;
} else {
_animationController!.reset();
_animationController!.forward(from: fadeStartOpacity).then((_) {
_readyToDisplay = true;
if (!_disposed) notifyListeners();
});
}

_animationController!.reset();
_animationController!.forward(from: fadeStartOpacity).then((_) {
_active = true;
if (!_disposed) notifyListeners();
});
},
);
}
Expand All @@ -213,8 +226,7 @@ class TileImage extends ChangeNotifier {
}
}

// Mark the image as inactive.
_active = false;
_readyToDisplay = false;
_animationController?.stop(canceled: false);
_animationController?.value = 0.0;
notifyListeners();
Expand All @@ -234,6 +246,6 @@ class TileImage extends ChangeNotifier {

@override
String toString() {
return 'TileImage($coordinates, active: $_active)';
return 'TileImage($coordinates, readyToDisplay: $_readyToDisplay)';
}
}
12 changes: 6 additions & 6 deletions lib/src/layer/tile_layer/tile_removal_state.dart
View file
Original file line number Diff line number Diff line change
Expand Up @@ -53,7 +53,7 @@ class TileRemovalState {
final retain = Set<TileImage>.from(_keepTiles);

for (final tile in _tileImages.values) {
if (_keepTiles.contains(tile) && !tile.active) {
if (_keepTiles.contains(tile) && !tile.readyToDisplay) {
final coords = tile.coordinates;
if (!_retainAncestor(
retain, coords.x, coords.y, coords.z, coords.z - 5)) {
Expand All @@ -68,8 +68,8 @@ class TileRemovalState {
}

// Recurses through the ancestors of the Tile at the given coordinates adding
// them to [retain] if they are active or loaded. Returns true if any of the
// ancestor tiles were active.
// them to [retain] if they are ready to display or loaded. Returns true if
// any of the ancestor tiles were ready to display.
bool _retainAncestor(
Set<TileImage> retain,
int x,
Expand All @@ -84,7 +84,7 @@ class TileRemovalState {

final tile = _tileImages[coords2];
if (tile != null) {
if (tile.active) {
if (tile.readyToDisplay) {
retain.add(tile);
return true;
} else if (tile.loadFinishedAt != null) {
Expand All @@ -100,7 +100,7 @@ class TileRemovalState {
}

// Recurses through the descendants of the Tile at the given coordinates
// adding them to [retain] if they are active or loaded.
// adding them to [retain] if they are ready to display or loaded.
void _retainChildren(
Set<TileImage> retain,
int x,
Expand All @@ -114,7 +114,7 @@ class TileRemovalState {

final tile = _tileImages[coords];
if (tile != null) {
if (tile.active || tile.loadFinishedAt != null) {
if (tile.readyToDisplay || tile.loadFinishedAt != null) {
retain.add(tile);
}
}
Expand Down

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