Feature/improve.curves (#693)

* Improve Curves to support multiple separated paths

* Small optimization

Author: soywiz

korma/src/commonMain/kotlin/com/soywiz/korma/geom/BoundsBuilder.kt

@@ -55,11 +55,15 @@ class BoundsBuilder {
     }
     fun add(rect: Rectangle): BoundsBuilder {
         if (rect.isNotEmpty) {
-            add(rect.left, rect.top)
-            add(rect.right, rect.bottom)
+            addEvenEmpty(rect)
         }
         return this
     }
+    fun addEvenEmpty(rect: Rectangle): BoundsBuilder {
+        add(rect.left, rect.top)
+        add(rect.right, rect.bottom)
+        return this
+    }
 
     fun add(ps: Iterable<IPoint>, transform: Matrix): BoundsBuilder {
         for (p in ps) add(p, transform)

korma/src/commonMain/kotlin/com/soywiz/korma/geom/bezier/Bezier.kt

@@ -10,10 +10,14 @@ import com.soywiz.korma.geom.PointPool
 import com.soywiz.korma.geom.Rectangle
 import com.soywiz.korma.interpolation.interpolate
 import com.soywiz.korma.math.clamp
+import kotlin.jvm.JvmName
 import kotlin.math.hypot
 import kotlin.math.max
 import kotlin.math.min
 
+@JvmName("ListCurves_toCurves")
+fun List<Curves>.toCurves() = Curves(this.flatMap { it.curves })
+@JvmName("ListCurve_toCurves")
 fun List<Curve>.toCurves() = Curves(this)
 
 data class Curves(val curves: List<Curve>) : Curve {
@@ -41,7 +45,7 @@ data class Curves(val curves: List<Curve>) : Curve {
 
     override fun getBounds(target: Rectangle): Rectangle {
         bb.reset()
-        infos.fastForEach { bb.add(it.bounds) }
+        infos.fastForEach { bb.addEvenEmpty(it.bounds) }
         return bb.getBounds(target)
     }
 

korma/src/commonMain/kotlin/com/soywiz/korma/geom/vector/VectorPath.kt

@@ -79,7 +79,9 @@ open class VectorPath(
         line: (x0: Double, y0: Double, x1: Double, y1: Double) -> Unit,
         quad: (x0: Double, y0: Double, x1: Double, y1: Double, x2: Double, y2: Double) -> Unit,
         cubic: (x0: Double, y0: Double, x1: Double, y1: Double, x2: Double, y2: Double, x3: Double, y3: Double) -> Unit,
-        close: () -> Unit = {}
+        close: () -> Unit = {},
+        move: (x: Double, y: Double) -> Unit = { x, y -> },
+        dummy: Unit = Unit // Prevents tailing lambda
     ) {
         var mx = 0.0
         var my = 0.0
@@ -89,6 +91,7 @@ open class VectorPath(
             moveTo = { x, y ->
                 mx = x; my = y
                 lx = x; ly = y
+                move(x, y)
             },
             lineTo = { x, y ->
                 line(lx, ly, x, y)
@@ -548,10 +551,20 @@ fun VectorPath.applyTransform(m: Matrix?): VectorPath {
     return this
 }
 
-fun VectorPath.getCurves(): Curves = arrayListOf<Curve>().also { out ->
+fun VectorPath.getCurvesLists(): List<Curves> = arrayListOf<List<Curve>>().also { out ->
+    var current = arrayListOf<Curve>()
+    fun flush() {
+        if (current.isEmpty()) return
+        out.add(current)
+        current = arrayListOf()
+    }
     visitEdges(
-        line = { x0, y0, x1, y1 -> out += Curve.Line(x0, y0, x1, y1) },
-        quad = { x0, y0, x1, y1, x2, y2 -> out += Bezier.Quad(x0, y0, x1, y1, x2, y2) },
-        cubic = { x0, y0, x1, y1, x2, y2, x3, y3 -> out += Bezier.Cubic(x0, y0, x1, y1, x2, y2, x3, y3) },
+        line = { x0, y0, x1, y1 -> current += Curve.Line(x0, y0, x1, y1) },
+        quad = { x0, y0, x1, y1, x2, y2 -> current += Bezier.Quad(x0, y0, x1, y1, x2, y2) },
+        cubic = { x0, y0, x1, y1, x2, y2, x3, y3 -> current += Bezier.Cubic(x0, y0, x1, y1, x2, y2, x3, y3) },
+        move = { x, y -> flush() }
     )
-}.toCurves()
+    flush()
+}.map { it.toCurves() }
+
+fun VectorPath.getCurves(): Curves = getCurvesLists().flatMap { it.curves }.toCurves()

korma/src/commonTest/kotlin/com/soywiz/korma/geom/bezier/BezierTest.kt

@@ -5,6 +5,8 @@ import com.soywiz.korma.geom.Rectangle
 import com.soywiz.korma.geom.map
 import com.soywiz.korma.geom.shape.buildVectorPath
 import com.soywiz.korma.geom.vector.getCurves
+import com.soywiz.korma.geom.vector.getCurvesLists
+import com.soywiz.korma.geom.vector.rect
 import kotlin.math.roundToInt
 import kotlin.test.Test
 import kotlin.test.assertEquals
@@ -51,4 +53,17 @@ class BezierTest {
             curves.getPoints(20).map { x, y -> "(${x.roundToInt()}, ${y.roundToInt()})" }.joinToString("\n")
         )
     }
+
+    @Test
+    fun testCurveList() {
+        val path = buildVectorPath {
+            rect(0, 0, 100, 100)
+            rect(300, 0, 100, 100)
+        }
+        val curves = path.getCurvesLists()
+        assertEquals(2, curves.size)
+        assertEquals(Rectangle(0, 0, 100, 100), curves[0].getBounds())
+        assertEquals(Rectangle(300, 0, 100, 100), curves[1].getBounds())
+        assertEquals(Rectangle(0, 0, 400, 100), curves.toCurves().getBounds())
+    }
 }