Fix Palettes

gartwork/src/main/kotlin/dev/oblac/gart/gfx/Palettes.kt

@@ -75,14 +75,22 @@ object Palettes {
         return Palette(colors)
     }
 
+    /**
+     * Grows (expands) palette by adding gradients between each pair of colors.
+     */
     fun gradient(palette: Palette, steps: Int): Palette {
-        val delta = steps / palette.size
+        val delta = steps.toFloat() / (palette.size - 1)
         var i = 0
 
         var gradient = Palette()
+        var colorCounter = 0f
         while (i < palette.size - 1) {
-            gradient += gradient(palette[i], palette[i + 1], delta)
+            // since delta is float, some gradients will have more steps than others
+            val gradientSteps = (colorCounter + delta).toInt() - colorCounter.toInt()
+
+            gradient += gradient(palette[i], palette[i + 1], gradientSteps)
             i++
+            colorCounter += delta
         }
 
         return gradient

gartwork/src/main/kotlin/dev/oblac/gart/gfx/PointsTrail.kt

@@ -0,0 +1,35 @@
+package dev.oblac.gart.gfx
+
+import dev.oblac.gart.skia.Point
+
+/**
+ * Just a queue of points.
+ */
+class PointsTrail(val size: Int) {
+    private val points = ArrayDeque<Point>(size)
+
+    /**
+     * Adds a point to the trail.
+     */
+    fun add(p: Point) {
+        if (points.size == size) {
+            points.removeFirst()
+        }
+        points.add(p)
+    }
+
+    /**
+     * Iterates over the points in the trail.
+     */
+    fun forEach(action: (Point) -> Unit) {
+        points.forEach(action)
+    }
+
+    /**
+     * Iterates over the points in the trail in reverse order.
+     */
+    fun forEachReverse(action: (Point) -> Unit) {
+        points.asReversed().forEach(action)
+    }
+
+}

gartwork/src/main/kotlin/dev/oblac/gart/gfx/path.kt

@@ -10,6 +10,18 @@ fun pathOf(first: Point, vararg points: Point): Path {
     return path
 }
 
+fun pathOf(list: List<Point>): Path {
+    val path = Path()
+    list.forEachIndexed { index, point ->
+        if (index == 0) {
+            path.moveTo(point)
+        } else {
+            path.lineTo(point)
+        }
+    }
+    return path
+}
+
 fun closedPathOf(first: Point, vararg points: Point): Path {
     val path = Path().moveTo(first)
     points.forEach { path.lineTo(it) }

gartwork/src/test/kotlin/dev/oblac/gart/gfx/PalettesTest.kt

@@ -0,0 +1,14 @@
+package dev.oblac.gart.gfx
+
+import kotlin.test.Test
+import kotlin.test.assertEquals
+
+class PalettesTest {
+
+    @Test
+    fun testPaletteToGradient() {
+        val p = Palettes.cool27
+        val g = Palettes.gradient(p, 256)
+        assertEquals(256, g.size)
+    }
+}