CHANGELOG.md

@@ -3,6 +3,7 @@
 ## Unreleased
 
 ### Added
+- `alpha` extension for feature attribute builder
 
 ### Changed
 
@@ -11,6 +12,7 @@
 ### Removed
 
 ### Fixed
+- Add alpha attribute comprehension for all standard features.
 
 ### Security
 

build.gradle.kts

@@ -9,7 +9,7 @@ val kmathVersion: String by extra("0.4.0")
 
 allprojects {
     group = "space.kscience"
-    version = "0.3.0"
+    version = "0.3.1-dev"
 
     repositories {
         mavenLocal()

maps-kt-features/src/commonMain/kotlin/space/kscience/maps/features/drawFeature.kt

@@ -29,7 +29,8 @@ public fun <T : Any> FeatureDrawScope<T>.drawFeature(
         is CircleFeature -> drawCircle(
             color,
             feature.radius.toPx(),
-            center = feature.center.toOffset()
+            center = feature.center.toOffset(),
+            alpha = alpha
         )
 
         is RectangleFeature -> drawRect(
@@ -38,7 +39,8 @@ public fun <T : Any> FeatureDrawScope<T>.drawFeature(
                 feature.size.width.toPx() / 2,
                 feature.size.height.toPx() / 2
             ),
-            size = feature.size.toSize()
+            size = feature.size.toSize(),
+            alpha = alpha
         )
 
         is LineFeature -> drawLine(
@@ -46,7 +48,8 @@ public fun <T : Any> FeatureDrawScope<T>.drawFeature(
             feature.a.toOffset(),
             feature.b.toOffset(),
             strokeWidth = feature.attributes[StrokeAttribute] ?: Stroke.HairlineWidth,
-            pathEffect = feature.attributes[PathEffectAttribute]
+            pathEffect = feature.attributes[PathEffectAttribute],
+            alpha = alpha
         )
 
         is ArcFeature -> {
@@ -67,14 +70,14 @@ public fun <T : Any> FeatureDrawScope<T>.drawFeature(
 
         }
 
-        is BitmapIconFeature -> drawImage(feature.image, feature.center.toOffset())
+        is BitmapIconFeature -> drawImage(feature.image, feature.center.toOffset(), alpha = alpha)
 
         is VectorIconFeature -> {
             val offset = feature.center.toOffset()
             val size = feature.size.toSize()
             translate(offset.x - size.width / 2, offset.y - size.height / 2) {
                 with(this@drawFeature.painterFor(feature)) {
-                    draw(size, colorFilter = feature.color?.let { ColorFilter.tint(it) })
+                    draw(size, colorFilter = feature.color?.let { ColorFilter.tint(it) }, alpha = alpha)
                 }
             }
         }
@@ -152,7 +155,7 @@ public fun <T : Any> FeatureDrawScope<T>.drawFeature(
 
             translate(offset.x, offset.y) {
                 with(this@drawFeature.painterFor(feature)) {
-                    draw(rect.size)
+                    draw(rect.size, alpha = alpha)
                 }
             }
         }
@@ -175,7 +178,8 @@ public fun <T : Any> FeatureDrawScope<T>.drawFeature(
                                 x = i * xStep,
                                 y = rect.height - j * yStep
                             ),
-                            size = pixelSize
+                            size = pixelSize,
+                            alpha = alpha
                         )
                     }
                 }

maps-kt-features/src/commonMain/kotlin/space/kscience/maps/features/mapFeatureAttributes.kt

@@ -46,6 +46,11 @@ public fun <T : Any, F : Feature<T>> FeatureRef<T, F>.zoomRange(range: FloatRang
 
 public object AlphaAttribute : Attribute<Float>
 
+public fun <T : Any, F : Feature<T>> FeatureRef<T, F>.alpha(alpha: Float): FeatureRef<T, F> {
+    require(alpha in 0f..1f) { "Alpha value must be between 0 and 1" }
+    return modifyAttribute(AlphaAttribute, alpha)
+}
+
 public fun <T : Any, F : Feature<T>> FeatureRef<T, F>.modifyAttributes(
     modification: AttributesBuilder<F>.() -> Unit,
 ): FeatureRef<T, F> {