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Migrate pie_chart_painter to new functional approach
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@imaNNeo
imaNNeo committed Mar 17, 2021
1 parent c35f678 commit fdc78df
Showing 1 changed file with 52 additions and 45 deletions.
97 changes: 52 additions & 45 deletions lib/src/chart/pie_chart/pie_chart_painter.dart
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Original file line number Diff line number Diff line change
Expand Up @@ -21,28 +21,22 @@ class PieChartPainter extends BaseChartPainter<PieChartData> {
/// [textScale] used for scaling texts inside the chart,
/// parent can use [MediaQuery.textScaleFactor] to respect
/// the system's font size.
PieChartPainter(PieChartData data, PieChartData targetData, {double textScale = 1})
: super(
data,
targetData,
textScale: textScale,
) {
PieChartPainter() : super() {
_sectionPaint = Paint()..style = PaintingStyle.stroke;

_sectionsSpaceClearPaint = Paint()
..style = PaintingStyle.fill
..color = const Color(0x000000000)
..blendMode = BlendMode.srcOut;

_centerSpacePaint = Paint()
..style = PaintingStyle.fill
..color = data.centerSpaceColor;
_centerSpacePaint = Paint()..style = PaintingStyle.fill;
}

/// Paints [PieChartData] into the provided canvas.
@override
void paint(Canvas canvas, Size size) {
super.paint(canvas, size);
void paint(Canvas canvas, Size size, PaintHolder<PieChartData> holder) {
super.paint(canvas, size, holder);
final data = holder.data;
if (data.sections.isEmpty) {
return;
}
Expand All @@ -51,9 +45,9 @@ class PieChartPainter extends BaseChartPainter<PieChartData> {

final sectionsAngle = _calculateSectionsAngle(data.sections, data.sumValue);

_drawCenterSpace(canvasWrapper);
_drawSections(canvasWrapper, sectionsAngle);
_drawTexts(canvasWrapper);
_drawCenterSpace(canvasWrapper, holder);
_drawSections(canvasWrapper, sectionsAngle, holder);
_drawTexts(canvasWrapper, holder);
}

List<double> _calculateSectionsAngle(List<PieChartSectionData> sections, double sumValue) {
Expand All @@ -62,15 +56,22 @@ class PieChartPainter extends BaseChartPainter<PieChartData> {
}).toList();
}

void _drawCenterSpace(CanvasWrapper canvasWrapper) {
void _drawCenterSpace(CanvasWrapper canvasWrapper, PaintHolder<PieChartData> holder) {
final data = holder.data;
final viewSize = canvasWrapper.size;
final centerX = viewSize.width / 2;
final centerY = viewSize.height / 2;

_centerSpacePaint.color = data.centerSpaceColor;
canvasWrapper.drawCircle(Offset(centerX, centerY), data.centerSpaceRadius, _centerSpacePaint);
}

void _drawSections(CanvasWrapper canvasWrapper, List<double> sectionsAngle) {
void _drawSections(
CanvasWrapper canvasWrapper,
List<double> sectionsAngle,
PaintHolder<PieChartData> holder,
) {
final data = holder.data;
final shouldDrawSeparators = data.sectionsSpace != 0 && data.sections.length != 1;

final viewSize = canvasWrapper.size;
Expand All @@ -89,7 +90,7 @@ class PieChartPainter extends BaseChartPainter<PieChartData> {

final rect = Rect.fromCircle(
center: center,
radius: _calculateCenterRadius(viewSize, data.centerSpaceRadius) + (section.radius / 2),
radius: _calculateCenterRadius(viewSize, holder) + (section.radius / 2),
);

_sectionPaint.color = section.color;
Expand All @@ -109,13 +110,14 @@ class PieChartPainter extends BaseChartPainter<PieChartData> {
}

if (shouldDrawSeparators) {
_removeSectionsSpace(canvasWrapper);
_removeSectionsSpace(canvasWrapper, holder);
}
}

/// firstly the sections draw close to eachOther without any space,
/// then here we clear a line with given [PieChartData.width]
void _removeSectionsSpace(CanvasWrapper canvasWrapper) {
void _removeSectionsSpace(CanvasWrapper canvasWrapper, PaintHolder<PieChartData> holder) {
final data = holder.data;
final viewSize = canvasWrapper.size;
const extraLineSize = 1;
final center = Offset(viewSize.width / 2, viewSize.height / 2);
Expand All @@ -133,21 +135,17 @@ class PieChartPainter extends BaseChartPainter<PieChartData> {
final sectionsStartFrom = center +
Offset(
math.cos(radians(startAngle)) *
(_calculateCenterRadius(viewSize, data.centerSpaceRadius) - extraLineSize),
(_calculateCenterRadius(viewSize, holder) - extraLineSize),
math.sin(radians(startAngle)) *
(_calculateCenterRadius(viewSize, data.centerSpaceRadius) - extraLineSize),
(_calculateCenterRadius(viewSize, holder) - extraLineSize),
);

final sectionsStartTo = center +
Offset(
math.cos(radians(startAngle)) *
(_calculateCenterRadius(viewSize, data.centerSpaceRadius) +
maxSectionRadius +
extraLineSize),
(_calculateCenterRadius(viewSize, holder) + maxSectionRadius + extraLineSize),
math.sin(radians(startAngle)) *
(_calculateCenterRadius(viewSize, data.centerSpaceRadius) +
maxSectionRadius +
extraLineSize),
(_calculateCenterRadius(viewSize, holder) + maxSectionRadius + extraLineSize),
);

_sectionsSpaceClearPaint.strokeWidth = data.sectionsSpace;
Expand All @@ -160,7 +158,8 @@ class PieChartPainter extends BaseChartPainter<PieChartData> {
/// Calculates layout of overlaying elements, includes:
/// - title text
/// - badge widget positions
void _drawTexts(CanvasWrapper canvasWrapper) {
void _drawTexts(CanvasWrapper canvasWrapper, PaintHolder<PieChartData> holder) {
final data = holder.data;
final viewSize = canvasWrapper.size;
final center = Offset(viewSize.width / 2, viewSize.height / 2);

Expand All @@ -176,11 +175,9 @@ class PieChartPainter extends BaseChartPainter<PieChartData> {
center +
Offset(
math.cos(radians(sectionCenterAngle)) *
(_calculateCenterRadius(viewSize, data.centerSpaceRadius) +
(section.radius * percentageOffset)),
(_calculateCenterRadius(viewSize, holder) + (section.radius * percentageOffset)),
math.sin(radians(sectionCenterAngle)) *
(_calculateCenterRadius(viewSize, data.centerSpaceRadius) +
(section.radius * percentageOffset)),
(_calculateCenterRadius(viewSize, holder) + (section.radius * percentageOffset)),
);

final sectionCenterOffsetTitle = sectionCenter(section.titlePositionPercentageOffset);
Expand All @@ -194,7 +191,7 @@ class PieChartPainter extends BaseChartPainter<PieChartData> {
text: span,
textAlign: TextAlign.center,
textDirection: TextDirection.ltr,
textScaleFactor: textScale);
textScaleFactor: holder.textScale);

tp.layout();
canvasWrapper.drawText(tp, sectionCenterOffsetTitle - Offset(tp.width / 2, tp.height / 2));
Expand All @@ -204,9 +201,10 @@ class PieChartPainter extends BaseChartPainter<PieChartData> {
}
}

double _calculateCenterRadius(Size viewSize, double givenCenterRadius) {
if (!givenCenterRadius.isInfinite) {
return givenCenterRadius;
double _calculateCenterRadius(Size viewSize, PaintHolder<PieChartData> holder) {
final data = holder.data;
if (!data.centerSpaceRadius.isInfinite) {
return data.centerSpaceRadius;
}

var maxRadius = 0.0;
Expand All @@ -227,14 +225,24 @@ class PieChartPainter extends BaseChartPainter<PieChartData> {
/// Processes [PointerEvent.localPosition] and checks
/// the elements of the chart that are near the offset,
/// then makes a [PieTouchResponse] from the elements that has been touched.
PieTouchResponse handleTouch(PointerEvent touchInput, Size size) {
PieTouchResponse handleTouch(
PointerEvent touchInput,
Size size,
PaintHolder<PieChartData> holder,
) {
final data = holder.data;
final sectionsAngle = _calculateSectionsAngle(data.sections, data.sumValue);
return _getTouchedDetails(size, touchInput, sectionsAngle);
return _getTouchedDetails(size, touchInput, sectionsAngle, holder);
}

/// find touched section by the value of [touchInputNotifier]
PieTouchResponse _getTouchedDetails(
Size viewSize, PointerEvent touchInput, List<double> sectionsAngle) {
Size viewSize,
PointerEvent touchInput,
List<double> sectionsAngle,
PaintHolder<PieChartData> holder,
) {
final data = holder.data;
final center = Offset(viewSize.width / 2, viewSize.height / 2);

final touchedPoint2 = touchInput.localPosition - center;
Expand Down Expand Up @@ -270,7 +278,7 @@ class PieChartPainter extends BaseChartPainter<PieChartData> {
final isInDegree = relativeTouchAngle >= fromDegree && relativeTouchAngle <= toDegree;

/// radius criteria
final centerRadius = _calculateCenterRadius(viewSize, data.centerSpaceRadius);
final centerRadius = _calculateCenterRadius(viewSize, holder);
final sectionRadius = centerRadius + section.radius;
final isInRadius = touchR > centerRadius && touchR <= sectionRadius;

Expand All @@ -288,7 +296,8 @@ class PieChartPainter extends BaseChartPainter<PieChartData> {
}

/// Exposes offset for laying out the badge widgets upon the chart.
Map<int, Offset> getBadgeOffsets(Size viewSize) {
Map<int, Offset> getBadgeOffsets(Size viewSize, PaintHolder<PieChartData> holder) {
final data = holder.data;
final center = viewSize.center(Offset.zero);
final badgeWidgetsOffsets = <int, Offset>{};

Expand All @@ -305,11 +314,9 @@ class PieChartPainter extends BaseChartPainter<PieChartData> {
center +
Offset(
math.cos(radians(sectionCenterAngle)) *
(_calculateCenterRadius(viewSize, data.centerSpaceRadius) +
(section.radius * percentageOffset)),
(_calculateCenterRadius(viewSize, holder) + (section.radius * percentageOffset)),
math.sin(radians(sectionCenterAngle)) *
(_calculateCenterRadius(viewSize, data.centerSpaceRadius) +
(section.radius * percentageOffset)),
(_calculateCenterRadius(viewSize, holder) + (section.radius * percentageOffset)),
);

final sectionCenterOffsetBadgeWidget = sectionCenter(section.badgePositionPercentageOffset);
Expand Down

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