fix: Fix and simplify backdrop logic to a usable state (#44)

Author: MSDarwish2000

window-styler/src/jvmMain/kotlin/com/mayakapps/compose/windowstyler/TransparencyUtils.kt

@@ -62,9 +62,10 @@ private fun <T : JComponent> findComponent(
     }.map { klass.cast(it) }.firstOrNull()
 }
 
-private inline fun <reified T : JComponent> Container.findComponent() = findComponent(this, T::class.java)
+private inline fun <reified T : JComponent> Container.findComponent() =
+    findComponent(this, T::class.java)
 
-fun ComposeWindow.findSkiaLayer(): SkiaLayer? = findComponent<SkiaLayer>()
+private fun ComposeWindow.findSkiaLayer(): SkiaLayer? = findComponent<SkiaLayer>()
 
 internal val Window.isTransparent
     get() = when (this) {

window-styler/src/jvmMain/kotlin/com/mayakapps/compose/windowstyler/windows/Utils.kt

@@ -17,11 +17,8 @@
 package com.mayakapps.compose.windowstyler.windows
 
 import androidx.compose.ui.awt.ComposeWindow
-import com.mayakapps.compose.windowstyler.WindowBackdrop
 import com.mayakapps.compose.windowstyler.WindowCornerPreference
 import com.mayakapps.compose.windowstyler.windows.jna.Nt
-import com.mayakapps.compose.windowstyler.windows.jna.enums.AccentState
-import com.mayakapps.compose.windowstyler.windows.jna.enums.DwmSystemBackdrop
 import com.mayakapps.compose.windowstyler.windows.jna.enums.DwmWindowCornerPreference
 import com.sun.jna.Native
 import com.sun.jna.Pointer
@@ -40,27 +37,10 @@ internal val windowsBuild by lazy {
     buildNumber
 }
 
-internal fun WindowBackdrop.toDwmSystemBackdrop(): DwmSystemBackdrop =
-    when (this) {
-        is WindowBackdrop.Mica -> DwmSystemBackdrop.DWMSBT_MAINWINDOW
-        is WindowBackdrop.Acrylic -> DwmSystemBackdrop.DWMSBT_TRANSIENTWINDOW
-        is WindowBackdrop.Tabbed -> DwmSystemBackdrop.DWMSBT_TABBEDWINDOW
-        else -> DwmSystemBackdrop.DWMSBT_DISABLE
-    }
-
-internal fun WindowBackdrop.toAccentState(): AccentState =
-    when (this) {
-        is WindowBackdrop.Default, is WindowBackdrop.Solid -> AccentState.ACCENT_ENABLE_GRADIENT
-        is WindowBackdrop.Transparent -> AccentState.ACCENT_ENABLE_TRANSPARENTGRADIENT
-        is WindowBackdrop.Aero -> AccentState.ACCENT_ENABLE_BLURBEHIND
-        is WindowBackdrop.Acrylic -> AccentState.ACCENT_ENABLE_ACRYLICBLURBEHIND
-        else -> AccentState.ACCENT_DISABLED
-    }
-
 internal fun WindowCornerPreference.toDwmWindowCornerPreference(): DwmWindowCornerPreference =
     when (this) {
         WindowCornerPreference.DEFAULT -> DwmWindowCornerPreference.DWMWCP_DEFAULT
         WindowCornerPreference.NOT_ROUNDED -> DwmWindowCornerPreference.DWMWCP_DONOTROUND
         WindowCornerPreference.ROUNDED -> DwmWindowCornerPreference.DWMWCP_ROUND
         WindowCornerPreference.SMALL_ROUNDED -> DwmWindowCornerPreference.DWMWCP_ROUNDSMALL
-    }
+    }

window-styler/src/jvmMain/kotlin/com/mayakapps/compose/windowstyler/windows/WindowsBackdropApis.kt

@@ -25,68 +25,56 @@ import com.mayakapps.compose.windowstyler.windows.jna.enums.DwmWindowAttribute
 import com.sun.jna.platform.win32.WinDef
 
 internal class WindowsBackdropApis(private val hwnd: WinDef.HWND) {
-    private var isSystemBackdropSet = false
-    private var isMicaEnabled = false
-    private var isAccentPolicySet = false
-    private var isSheetOfGlassApplied = false
 
-    fun setSystemBackdrop(systemBackdrop: DwmSystemBackdrop) {
-        createSheetOfGlassEffect()
-        if (Dwm.setSystemBackdrop(hwnd, systemBackdrop)) {
-            isSystemBackdropSet = systemBackdrop == DwmSystemBackdrop.DWMSBT_DISABLE
-            if (isSystemBackdropSet) resetAccentPolicy()
+    var systemBackdrop: DwmSystemBackdrop? = null
+        set(value) {
+            requireNotNull(value)
+            if (field == value) return
+
+            val result = Dwm.setSystemBackdrop(hwnd, value)
+            if (result) field = value
         }
-    }
 
-    fun setMicaEffectEnabled(enabled: Boolean) {
-        createSheetOfGlassEffect()
-        if (Dwm.setWindowAttribute(hwnd, DwmWindowAttribute.DWMWA_MICA_EFFECT, enabled)) {
-            isMicaEnabled = enabled
-            if (isMicaEnabled) resetAccentPolicy()
+    var isMicaEffectEnabled: Boolean? = null
+        set(value) {
+            requireNotNull(value)
+            if (field == value) return
+
+            val result = Dwm.setWindowAttribute(hwnd, DwmWindowAttribute.DWMWA_MICA_EFFECT, value)
+            if (result) field = value
+        }
+
+    var isSheetOfGlassEffectEnabled: Boolean? = null
+        set(value) {
+            requireNotNull(value)
+
+            val result = if (value) {
+                // Negative margins have special meaning to DwmExtendFrameIntoClientArea.
+                // Negative margins create the "sheet of glass" effect, where the client area is
+                // rendered as a solid surface with no window border.
+                Dwm.extendFrameIntoClientArea(hwnd = hwnd, margin = -1)
+            } else {
+                // At least one margin should be non-negative in order to show the DWM window shadow
+                // created by handling [WM_NCCALCSIZE]. Matching value with bitsdojo_window:
+                // https://github.com/bitsdojo/bitsdojo_window/blob/adad0cd40be3d3e12df11d864f18a96a2d0fb4fb/bitsdojo_window_windows/windows/bitsdojo_window.cpp#L149
+                Dwm.extendFrameIntoClientArea(
+                    hwnd = hwnd,
+                    leftWidth = 0,
+                    rightWidth = 0,
+                    topHeight = 1,
+                    bottomHeight = 0,
+                )
+            }
+
+            if (result) field = value
         }
-    }
 
     fun setAccentPolicy(
         accentState: AccentState = AccentState.ACCENT_DISABLED,
         accentFlags: Set<AccentFlag> = emptySet(),
         color: Int = 0,
         animationId: Int = 0,
     ) {
-        if (User32.setAccentPolicy(hwnd, accentState, accentFlags, color, animationId)) {
-            isAccentPolicySet = accentState != AccentState.ACCENT_DISABLED
-            if (isAccentPolicySet) {
-                resetSystemBackdrop()
-                resetMicaEffectEnabled()
-                resetWindowFrame()
-            }
-        }
-    }
-
-    fun createSheetOfGlassEffect() {
-        if (!isSheetOfGlassApplied && Dwm.extendFrameIntoClientArea(hwnd, -1)) isSheetOfGlassApplied = true
-    }
-
-
-    fun resetSystemBackdrop() {
-        if (isSystemBackdropSet) setSystemBackdrop(DwmSystemBackdrop.DWMSBT_DISABLE)
-    }
-
-    fun resetMicaEffectEnabled() {
-        if (isMicaEnabled) setMicaEffectEnabled(false)
-    }
-
-    fun resetAccentPolicy() {
-        if (isAccentPolicySet) setAccentPolicy(AccentState.ACCENT_DISABLED)
-    }
-
-    fun resetWindowFrame() {
-        // At least one margin should be non-negative in order to show the DWM
-        // window shadow created by handling [WM_NCCALCSIZE].
-        //
-        // Matching value with bitsdojo_window.
-        // https://github.com/bitsdojo/bitsdojo_window/blob/adad0cd40be3d3e12df11d864f18a96a2d0fb4fb/bitsdojo_window_windows/windows/bitsdojo_window.cpp#L149
-        if (isSheetOfGlassApplied && Dwm.extendFrameIntoClientArea(hwnd, 0, 0, 1, 0)) {
-            isSheetOfGlassApplied = false
-        }
+        User32.setAccentPolicy(hwnd, accentState, accentFlags, color, animationId)
     }
-}
+}