Use LayeredIcon for mixin classes (#2340)

* Use layered icons for mixin classes

* Resize icons

* Remove outlines

* Use `IconLayerProvider`

* Clean up svg

src/main/kotlin/asset/MixinAssets.kt

@@ -27,4 +27,6 @@ object MixinAssets : Assets() {
 
     val MIXIN_CLASS_ICON = loadIcon("/assets/icons/mixin/mixin_class_gutter.png")
     val MIXIN_CLASS_ICON_DARK = loadIcon("/assets/icons/mixin/mixin_class_gutter_dark.png")
+
+    val MIXIN_MARK = loadIcon("/assets/icons/mixin/mixin_mark.svg")
 }

src/main/kotlin/platform/mixin/framework/MixinIconProvider.kt

@@ -21,15 +21,19 @@
 package com.demonwav.mcdev.platform.mixin.framework
 
 import com.demonwav.mcdev.MinecraftSettings
-import com.demonwav.mcdev.asset.PlatformAssets
+import com.demonwav.mcdev.asset.MixinAssets
 import com.demonwav.mcdev.platform.mixin.util.isMixin
-import com.intellij.ide.IconProvider
+import com.intellij.ide.IconLayerProvider
+import com.intellij.openapi.util.Iconable
 import com.intellij.psi.PsiClass
-import com.intellij.psi.PsiElement
+import javax.swing.Icon
 
-class MixinIconProvider : IconProvider() {
-    override fun getIcon(element: PsiElement, flags: Int) =
-        PlatformAssets.MIXIN_ICON.takeIf {
+class MixinIconProvider : IconLayerProvider {
+    override fun getLayerIcon(element: Iconable, isLocked: Boolean): Icon? =
+        MixinAssets.MIXIN_MARK.takeIf {
             MinecraftSettings.instance.mixinClassIcon && element is PsiClass && element.isMixin
         }
+
+    override fun getLayerDescription(): String =
+        "Mixin class"
 }

src/main/resources/META-INF/plugin.xml

@@ -534,7 +534,7 @@
 
         <library.presentationProvider implementation="com.demonwav.mcdev.platform.mixin.framework.MixinPresentationProvider" />
 
-        <iconProvider implementation="com.demonwav.mcdev.platform.mixin.framework.MixinIconProvider" />
+        <iconLayerProvider implementation="com.demonwav.mcdev.platform.mixin.framework.MixinIconProvider" />
 
         <!--region MixinExtras Expression Language-->
         <fileType name="MixinExtras Expression File"