Merge pull request #1 from ArystanK/main

Added function to draw custom markers with Kotlin DSL Canvas API

src/commonMain/kotlin/centre/sciprog/maps/compose/FeatureBuilder.kt

@@ -3,9 +3,12 @@ package centre.sciprog.maps.compose
 import androidx.compose.runtime.Composable
 import androidx.compose.runtime.mutableStateMapOf
 import androidx.compose.runtime.snapshots.SnapshotStateMap
+import androidx.compose.ui.geometry.Offset
 import androidx.compose.ui.geometry.Size
 import androidx.compose.ui.graphics.Color
+import androidx.compose.ui.graphics.drawscope.DrawScope
 import androidx.compose.ui.graphics.vector.ImageVector
+import centre.sciprog.maps.GmcBox
 
 typealias FeatureId = String
 
@@ -41,6 +44,21 @@ fun FeatureBuilder.circle(
     id, MapCircleFeature(centerCoordinates.toCoordinates(), zoomRange, size, color)
 )
 
+fun FeatureBuilder.custom(
+    position: Pair<Double, Double>,
+    id: FeatureId? = null,
+    customFeatureBuilder: DrawScope.(Offset) -> Unit,
+) = addFeature(id, object : MapCustomFeature(position = position.toCoordinates()) {
+    override fun drawFeature(drawScope: DrawScope, offset: Offset) {
+        customFeatureBuilder(drawScope, offset)
+    }
+
+    override fun getBoundingBox(zoom: Int): GmcBox {
+        return GmcBox(position.toCoordinates(), position.toCoordinates())
+    }
+
+})
+
 fun FeatureBuilder.line(
     aCoordinates: Pair<Double, Double>,
     bCoordinates: Pair<Double, Double>,

src/commonMain/kotlin/centre/sciprog/maps/compose/MapFeature.kt

@@ -1,9 +1,11 @@
 package centre.sciprog.maps.compose
 
 import androidx.compose.runtime.Composable
+import androidx.compose.ui.geometry.Offset
 import androidx.compose.ui.geometry.Size
 import androidx.compose.ui.graphics.Color
 import androidx.compose.ui.graphics.ImageBitmap
+import androidx.compose.ui.graphics.drawscope.DrawScope
 import androidx.compose.ui.graphics.painter.Painter
 import androidx.compose.ui.graphics.vector.ImageVector
 import androidx.compose.ui.graphics.vector.rememberVectorPainter
@@ -31,6 +33,13 @@ class MapFeatureSelector(val selector: (zoom: Int) -> MapFeature) : MapFeature(d
 
 }
 
+abstract class MapCustomFeature(
+    zoomRange: IntRange = defaultZoomRange,
+    val position: GeodeticMapCoordinates
+) : MapFeature(zoomRange) {
+    abstract fun drawFeature(drawScope: DrawScope, offset: Offset)
+}
+
 class MapCircleFeature(
     val center: GeodeticMapCoordinates,
     zoomRange: IntRange = defaultZoomRange,

src/jvmMain/kotlin/Main.kt

@@ -6,6 +6,7 @@ import androidx.compose.material.Text
 import androidx.compose.material.icons.Icons
 import androidx.compose.material.icons.filled.Home
 import androidx.compose.runtime.*
+import androidx.compose.ui.geometry.Size
 import androidx.compose.ui.graphics.Color
 import androidx.compose.ui.window.Window
 import androidx.compose.ui.window.application
@@ -53,12 +54,22 @@ fun App() {
             ) {
                 val pointOne = 55.568548 to 37.568604
                 val pointTwo = 55.929444 to 37.518434
+                val pointThree = 60.929444 to 37.518434
 
                 image(pointOne, Icons.Filled.Home)
 
                 //remember feature Id
-                val circleId: FeatureId = circle(pointTwo)
+                val circleId: FeatureId = circle(
+                    centerCoordinates = pointTwo,
+                )
 
+                custom(position = pointThree) {
+                    drawRect(
+                        color = Color.Red,
+                        topLeft = it,
+                        size = Size(20f, 20f)
+                    )
+                }
                 line(pointOne, pointTwo)
                 text(pointOne, "Home")
 

src/jvmMain/kotlin/centre/sciprog/maps/compose/MapViewJvm.kt

@@ -222,7 +222,10 @@ actual fun MapView(
                         feature.color.toPaint()
                     )
                 }
-
+                is MapCustomFeature -> drawIntoCanvas { canvas ->
+                    val offset = feature.position.toOffset()
+                    feature.drawFeature(this, offset)
+                }
             }
         }