proste_bezier_curve

Description:

proste bezier curve

English | 中文
Introduction #
The control points of Bezier curve are obtained through data calculation, and then the points are drawn into curves through the drawing function of flutter.

The difference between using package and drawing your own path

The common method of tracing points according to the position of elements will leave a gap. Only after the control points are calculated can the element information be completely filled. For example, in the following picture, the coordinates of the points used are the same, but the styles cut out are different. The function I want to provide is to restore the design style as much as possible. And after using the package, you only need to confirm the coordinates of each point, without other complex calculations, and the code is more concise.


draw your own

Stack(
children: [
Container(
height: 200,
color: Colors.grey,
),
ClipPath(
clipper: NativeClipper(),
child: Container(
height: 200,
color: Colors.red,
),
),
],
)

class NativeClipper extends CustomClipper<Path> {
@override
Path getClip(Size size) {
Path path = Path();

path.lineTo(0, 0);
path.lineTo(0, size.height - 50);
path.quadraticBezierTo(size.width / 2, size.height, size.width, size.height - 50);
path.lineTo(size.width, 0);
path.lineTo(0, 0);
return path;
}

@override
bool shouldReclip(covariant CustomClipper<Path> oldClipper) => true;
}
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use package


Stack(
children: [
Container(
height: 200,
color: Colors.grey,
),
ClipPath(
clipper: ProsteBezierCurve(
position: ClipPosition.bottom,
list: [
BezierCurveSection(
start: Offset(0, 150),
top: Offset(screenWidth / 2, 200),
end: Offset(screenWidth, 150),
),
],
),
child: Container(
height: 200,
color: Colors.red,
),
),
],
),

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Usage #
Second order Bezier curve #




more preview
Examples #
ClipPath(
clipper: ProsteBezierCurve(
position: ClipPosition.top,
list: [
BezierCurveSection(
start: Offset(screenWidth, 0),
top: Offset(screenWidth / 2, 30),
end: Offset(0, 0),
),
],
),
child: Container(
color: Colors.red,
height: 150,
),
)


/// Wavy line
ClipPath(
clipper: ProsteBezierCurve(
position: ClipPosition.bottom,
list: [
BezierCurveSection(
start: Offset(0, 125),
top: Offset(screenWidth / 4, 150),
end: Offset(screenWidth / 2, 125),
),
BezierCurveSection(
start: Offset(screenWidth / 2, 125),
top: Offset(screenWidth / 4 * 3, 100),
end: Offset(screenWidth, 150),
),
],
),
child: Container(
height: 150,
color: Colors.red,
),
)
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class #

ProsteBezierCurve Used to draw and return the clipping path




parameter
type
default
describe




list
List<BezierCurveSection>

Used to draw Bezier curve, you can pass in more than one


reclip
bool
true
Allow redrawing elements


position
ClipPosition
ClipPosition.left
Used to determine the drawing position of the curve



ClipPath(
clipper: ProsteBezierCurve(
position: ClipPosition.top,
reclip: false,
list: [
...
],
),
child: ...,
),
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BezierCurveSection Clips for drawing curves




parameter
type
default
describe




start
Offset

start point of Bezier curve


top
Offset

top point of Bezier curve


end
Offset

end point of Bezier curve


proportion
double
1/2
the proportion of the top position of the Bezier curve,It doesn't need to be modified




ClipPath(
clipper: ProsteBezierCurve(
position: ClipPosition.top,
reclip: false,
list: [
BezierCurveSection(
proportion: 1 / 3,
start: Offset(..,..),
top: Offset(..,..),
end: Offset(..,..),
),
],
),
child: ...,
)

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BezierCurveDots Coordinates of Bezier curve control points




parameter
type
default
describe




x1
double

The X-coordinate of the first point


y1
double

The Y-coordinate of the first point


x2
double

The X-coordinate of the second point


y2
double

The Y-coordinate of the second point



Static function of ProsteBezierCurve #

BezierCurveDots calcCurveDots(BezierCurveSection param) Obtain the coordinates of the control points after calculation, and draw the path after obtaining the control points, such as drawing curves with multiple edges or combining the curves with other drawing rules


ClipPath(
clipper: CustomSelfClipper1(),
child: Container(
height: 150,
color: Colors.red,
),
)

class CustomSelfClipper1 extends CustomClipper<Path> {
@override
Path getClip(Size size) {
Path path = Path();
BezierCurveSection section1 = BezierCurveSection(
start: Offset(0, 30),
top: Offset(10, 45),
end: Offset(0, 60),
);
BezierCurveSection section2 = BezierCurveSection(
start: Offset(size.width, size.height - 90),
top: Offset(size.width - 10, size.height - 105),
end: Offset(size.width, size.height - 120),
);
BezierCurveDots dot1 = ProsteBezierCurve.calcCurveDots(section1);
BezierCurveDots dot2 = ProsteBezierCurve.calcCurveDots(section2);

List<double> dot1List = dot1.getList(); // Return to list<double>
Map<String, double> dot2Map = dot1.getMap(); // Return to Map<String, double>

print(dot1List); // [20.0, 45.0, 0.0, 60.0]
print(dot2Map); // {x1: 20.0, y1: 45.0, x2: 0.0, y2: 60.0}

path.lineTo(0, 0);
path.lineTo(0, 30);
path.quadraticBezierTo(dot1.x1, dot1.y1, dot1.x2, dot1.y2);
path.lineTo(0, size.height);
path.lineTo(size.width, size.height);
path.lineTo(size.width, size.height - 90);
path.quadraticBezierTo(dot2.x1, dot2.y1, dot2.x2, dot2.y2);
path.lineTo(size.width, 0);
path.lineTo(0, 0);
return path;
}

@override
bool shouldReclip(covariant CustomClipper<Path> oldClipper) => true;
}

/// This method can splice the third-order Bezier curve, but is not recommended. You can use the ProsteThirdOrderBezierCurve

class CustomSelfClipper2 extends CustomClipper<Path> {
@override
Path getClip(Size size) {
Path path = Path();
BezierCurveSection section1 = BezierCurveSection(
start: Offset(0, size.height),
top: Offset(30, size.height - 50),
end: Offset(80, size.height - 70),
);
BezierCurveSection section2 = BezierCurveSection(
start: Offset(size.width - 100, size.height - 70),
top: Offset(size.width - 30, size.height - 95),
end: Offset(size.width, size.height - 160),
);
BezierCurveDots dot1 = ProsteBezierCurve.calcCurveDots(section1);
BezierCurveDots dot2 = ProsteBezierCurve.calcCurveDots(section2);

path.lineTo(0, 0);
path.lineTo(0, size.height);
path.quadraticBezierTo(dot1.x1, dot1.y1, dot1.x2, dot1.y2);
path.lineTo(size.width - 100, size.height - 70);
path.quadraticBezierTo(dot2.x1, dot2.y1, dot2.x2, dot2.y2);
path.lineTo(size.width, 0);
path.lineTo(0, 0);
return path;
}

@override
bool shouldReclip(covariant CustomClipper<Path> oldClipper) => true;
}

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Third order Bezier curve #




more preview
Examples #

ClipPath(
clipper: ProsteThirdOrderBezierCurve(
position: ClipPosition.bottom,
list: [
ThirdOrderBezierCurveSection(
p1: Offset(0, 100),
p2: Offset(0, 200),
p3: Offset(screenWidth, 100),
p4: Offset(screenWidth, 200),
),
],
),
child: Container(
height: 200,
color: Colors.red,
),
)

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class #

ProsteThirdOrderBezierCurve Clipping path for drawing and returning third order Bezier curves




parameter
type
default
describe




list
List<ThirdOrderBezierCurveSection>

Used to draw Bezier curve, you can pass in more than one


reclip
bool
true
Allow redrawing elements


position
ClipPosition
ClipPosition.left
Used to determine the drawing position of the curve



ClipPath(
clipper: ProsteThirdOrderBezierCurve(
position: ClipPosition.bottom,
list: [
...
],
),
child: ...,
)
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ThirdOrderBezierCurveSection Fragment for drawing third order Bezier curve




parameter
type
default
describe




p1
Offset

The coordinates of the first point


p2
Offset

The coordinates of the second point


p3
Offset

The coordinates of the third point


p4
Offset

The coordinates of the fourth point


smooth
double
.5
The greater the value of smoothness 0 ~ 1, the straighter the value is, the smaller the value is, and the larger the arc is. When the drawing distance is short and saw tooth appears, try to increase this value



ClipPath(
clipper: ProsteThirdOrderBezierCurve(
position: ClipPosition.bottom,
list: [
ThirdOrderBezierCurveSection(
smooth: .7,
p1: Offset(0, 100),
p2: Offset(0, 200),
p3: Offset(screenWidth, 100),
p4: Offset(screenWidth, 200),
),
],
),
child: Container(
height: 200,
color: Colors.red,
),
)

/// Spire shape
ClipPath(
clipper: ProsteThirdOrderBezierCurve(
position: ClipPosition.top,
list: [
ThirdOrderBezierCurveSection(
p1: Offset(screenWidth, 0),
p2: Offset(screenWidth, 100),
p4: Offset(screenWidth / 2, 100),
p3: Offset(screenWidth / 2, 0),
),
ThirdOrderBezierCurveSection(
p1: Offset(screenWidth / 2, 100),
p2: Offset(screenWidth / 2, 0),
p3: Offset(0, 100),
p4: Offset(0, 0),
),
],
),
child: Container(
height: 200,
color: Colors.teal,
),
)
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The position coordinates of the four points can refer to the figure below. The starting and ending points are P1 and P4 respectively.Picture sample URL。You can understand that four points form a rectangle, and the four coordinates are the positions of the four points. The curve will be drawn in the rectangle.

We can also draw a single arc graph through the third-order Bessel function, need P1 and P4 are on the same side，But that brings up the problem that was stated at the beginning，The arc does not cling to the bottom.


ThirdOrderBezierCurveDots Coordinates of third order Bezier curve control points




parameter
type
default
describe




x1
double

The X-coordinate of the first point


y1
double

The Y-coordinate of the first point


x2
double

The X-coordinate of the second point


y2
double

The Y-coordinate of the second point


x3
double

The X-coordinate of the third point


y3
double

The Y-coordinate of the third point



Static function of ProsteThirdOrderBezierCurve #

ThirdOrderBezierCurveDots calcCurveDots(ThirdOrderBezierCurveSection param) Obtain the coordinates of the control points after calculation, and draw the path after obtaining the control points, such as drawing curves with multiple edges or combining the curves with other drawing rules


ClipPath(
clipper: CustomSelfClipper1(),
child: Container(
height: 200,
color: Colors.teal,
),
)

class CustomSelfClipper1 extends CustomClipper<Path> {
@override
Path getClip(Size size) {
Path path = Path();
ThirdOrderBezierCurveSection param = ThirdOrderBezierCurveSection(
smooth: 0.3,
p1: Offset(0, size.height),
p2: Offset(0, 0),
p3: Offset(size.width, size.height),
p4: Offset(size.width, 0),
);
ThirdOrderBezierCurveDots dots = ProsteThirdOrderBezierCurve.calcCurveDots(param);

List<double> dotsList = dots.getList(); // Return to list<double>
Map<String, double> dotsMap = dots.getMap(); // Return to Map<String, double>

print(dotsList); // [71.56809408040556, 0.0, 339.8604773481659, 200.0, 411.42857142857144, 0.0]
print(dotsMap); // {x1: 71.56809408040556, y1: 0.0, x2: 339.8604773481659, y2: 200.0, x3: 411.42857142857144, y3: 0.0}

path.lineTo(0, 0);
path.lineTo(0, size.height);
path.cubicTo(dots.x1, dots.y1, dots.x2, dots.y2, dots.x3, dots.y3);
path.lineTo(0, 0);

return path;
}

@override
bool shouldReclip(covariant CustomClipper<Path> oldClipper) => true;
}

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If you have any issue, please submit them to issues, I will deal with them as soon as I see them. Thank you!