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July 16, 2023 14:40
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package com.zhangke.framework.composable | |
import androidx.compose.foundation.Canvas | |
import androidx.compose.runtime.Composable | |
import androidx.compose.runtime.getValue | |
import androidx.compose.runtime.mutableStateOf | |
import androidx.compose.runtime.remember | |
import androidx.compose.runtime.setValue | |
import androidx.compose.ui.Modifier | |
import androidx.compose.ui.geometry.Offset | |
import androidx.compose.ui.graphics.Brush | |
import androidx.compose.ui.graphics.Path | |
import androidx.compose.ui.graphics.drawscope.DrawScope | |
import androidx.compose.ui.graphics.drawscope.Fill | |
import androidx.compose.ui.graphics.drawscope.Stroke | |
import androidx.compose.ui.layout.onSizeChanged | |
import androidx.compose.ui.unit.IntSize | |
@Composable | |
fun BezierCurve( | |
modifier: Modifier, | |
points: List<Float>, | |
minPoint: Float? = null, | |
maxPoint: Float? = null, | |
style: BezierCurveStyle, | |
) { | |
var size by remember { | |
mutableStateOf(IntSize.Zero) | |
} | |
Canvas( | |
modifier = modifier.onSizeChanged { | |
size = it | |
}, | |
onDraw = { | |
if (size != IntSize.Zero && points.size > 1) { | |
drawBezierCurve( | |
size = size, | |
points = points, | |
fixedMinPoint = minPoint, | |
fixedMaxPoint = maxPoint, | |
style = style, | |
) | |
} | |
}, | |
) | |
} | |
private fun DrawScope.drawBezierCurve( | |
size: IntSize, | |
points: List<Float>, | |
fixedMinPoint: Float? = null, | |
fixedMaxPoint: Float? = null, | |
style: BezierCurveStyle, | |
) { | |
val maxPoint = fixedMaxPoint ?: points.max() | |
val minPoint = fixedMinPoint ?: points.min() | |
val total = maxPoint - minPoint | |
val height = size.height | |
val width = size.width | |
val xSpacing = width / (points.size - 1F) | |
var lastPoint: Offset? = null | |
val path = Path() | |
var firstPoint = Offset(0F, 0F) | |
for (index in points.indices) { | |
val x = index * xSpacing | |
val y = height - height * ((points[index] - minPoint) / total) | |
if (lastPoint != null) { | |
buildCurveLine(path, lastPoint, Offset(x, y)) | |
} | |
lastPoint = Offset(x, y) | |
if (index == 0) { | |
path.moveTo(x, y) | |
firstPoint = Offset(x, y) | |
} | |
} | |
fun closeWithBottomLine() { | |
path.lineTo(width.toFloat(), height.toFloat()) | |
path.lineTo(0F, height.toFloat()) | |
path.lineTo(firstPoint.x, firstPoint.y) | |
} | |
when (style) { | |
is BezierCurveStyle.Fill -> { | |
closeWithBottomLine() | |
drawPath( | |
path = path, | |
style = Fill, | |
brush = style.brush, | |
) | |
} | |
is BezierCurveStyle.CurveStroke -> { | |
drawPath( | |
path = path, | |
brush = style.brush, | |
style = style.stroke, | |
) | |
} | |
is BezierCurveStyle.StrokeAndFill -> { | |
drawPath( | |
path = path, | |
brush = style.strokeBrush, | |
style = style.stroke, | |
) | |
closeWithBottomLine() | |
drawPath( | |
path = path, | |
brush = style.fillBrush, | |
style = Fill, | |
) | |
} | |
} | |
} | |
private fun buildCurveLine(path: Path, startPoint: Offset, endPoint: Offset) { | |
val firstControlPoint = Offset( | |
x = startPoint.x + (endPoint.x - startPoint.x) / 2F, | |
y = startPoint.y, | |
) | |
val secondControlPoint = Offset( | |
x = startPoint.x + (endPoint.x - startPoint.x) / 2F, | |
y = endPoint.y, | |
) | |
path.cubicTo( | |
x1 = firstControlPoint.x, | |
y1 = firstControlPoint.y, | |
x2 = secondControlPoint.x, | |
y2 = secondControlPoint.y, | |
x3 = endPoint.x, | |
y3 = endPoint.y, | |
) | |
} | |
sealed class BezierCurveStyle { | |
class Fill(val brush: Brush) : BezierCurveStyle() | |
class CurveStroke( | |
val brush: Brush, | |
val stroke: Stroke, | |
) : BezierCurveStyle() | |
class StrokeAndFill( | |
val fillBrush: Brush, | |
val strokeBrush: Brush, | |
val stroke: Stroke, | |
) : BezierCurveStyle() | |
} |
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