Transparency in window support. (#232)

Transparency support.

samples/SkiaJvmSample/build.gradle.kts

@@ -71,6 +71,11 @@ tasks.register("runSoftware") {
     dependsOn(casualRun)
 }
 
+tasks.register("runWithTransparency") {
+    additionalArguments += mapOf("skiko.transparency" to "true")
+    dependsOn(casualRun)
+}
+
 tasks.withType<KotlinCompile>().configureEach {
     kotlinOptions.freeCompilerArgs += "-Xopt-in=kotlin.RequiresOptIn"
 }

samples/SkiaJvmSample/src/main/kotlin/SkiaJvmSample/App.kt

@@ -110,6 +110,16 @@ fun createWindow(title: String, exitOnClose: Boolean) = SwingUtilities.invokeLat
         }
     })
 
+    // Window transparency
+    if (System.getProperty("skiko.transparency") == "true") {
+        window.setUndecorated(true)
+        // On Windows we don't set transparent background to avoid event input issues (JDK specific)
+        if (hostOs != OS.Windows) {
+            window.background = java.awt.Color(0, 0, 0, 0)
+        }
+        window.layer.transparency = true
+    }
+
     // MANDATORY: set window preferred size before calling pack()
     window.preferredSize = Dimension(800, 600)
     window.pack()

skiko/src/commonMain/kotlin/org/jetbrains/skiko/SkiaLayer.kt

@@ -10,6 +10,8 @@ interface SkiaRenderer {
 expect open class SkiaLayer {
     var renderApi: GraphicsApi
     val contentScale: Float
+    var fullscreen: Boolean
+    var transparency: Boolean
 }
 
 internal class PictureHolder(val instance: Picture, val width: Int, val height: Int)

skiko/src/commonMain/kotlin/org/jetbrains/skiko/context/ContextHandler.kt

@@ -5,13 +5,13 @@ import org.jetbrains.skia.Canvas
 import org.jetbrains.skia.DirectContext
 import org.jetbrains.skia.Picture
 import org.jetbrains.skia.Surface
-import org.jetbrains.skiko.OS
+import org.jetbrains.skiko.GraphicsApi
 import org.jetbrains.skiko.SkiaLayer
 import org.jetbrains.skiko.hostArch
 import org.jetbrains.skiko.hostOs
 
 internal abstract class ContextHandler(val layer: SkiaLayer) {
-    open val bleachConstant = if (hostOs == OS.MacOS) 0 else -1
+    open val clearColor = if (layer.transparency) 0 else -1
     var context: DirectContext? = null
     var renderTarget: BackendRenderTarget? = null
     var surface: Surface? = null
@@ -21,7 +21,8 @@ internal abstract class ContextHandler(val layer: SkiaLayer) {
     abstract fun initCanvas()
 
     fun clearCanvas() {
-        canvas?.clear(bleachConstant)
+        val color = if (layer.fullscreen) -1 else clearColor
+        canvas?.clear(color)
     }
 
     open fun drawOnCanvas(picture: Picture) {

skiko/src/iosMain/kotlin/org/jetbrains/skiko/SkiaLayer.ios.kt

@@ -6,4 +6,10 @@ actual open class SkiaLayer {
         set(value) {}
     actual val contentScale: Float
         get() = TODO("Not yet implemented")
+    actual var fullscreen: Boolean
+        get() = TODO("Not yet implemented")
+        set(value) {}
+    actual var transparency: Boolean
+        get() = TODO("Not yet implemented")
+        set(value) {}
 }
\ No newline at end of file

skiko/src/jsMain/kotlin/org/jetbrains/skiko/SkiaLayer.js.kt

@@ -4,4 +4,10 @@ actual open class SkiaLayer {
     actual var renderApi: GraphicsApi = GraphicsApi.WEBGL
     actual val contentScale: Float
         get() = 1.0f
+    actual var fullscreen: Boolean
+        get() = false
+        set(value) = throw Exception("Fullscreen is not supported!")
+    actual var transparency: Boolean
+        get() = false
+        set(value) = throw Exception("Transparency is not supported!")
 }

skiko/src/jvmMain/cpp/include/window_util.h

+#if SK_BUILD_FOR_WIN
+#include <dwmapi.h>
+
+void enableTransparentWindow(HWND hwnd);
+
+#endif

skiko/src/jvmMain/cpp/linux/redrawer.cc

@@ -63,13 +63,30 @@ extern "C"
         glXMakeCurrent(display, window, *context);
     }
 
-    JNIEXPORT jlong JNICALL Java_org_jetbrains_skiko_redrawer_LinuxOpenGLRedrawerKt_createContext(JNIEnv *env, jobject redrawer, jlong displayPtr)
+    JNIEXPORT jlong JNICALL Java_org_jetbrains_skiko_redrawer_LinuxOpenGLRedrawerKt_createContext(JNIEnv *env, jobject redrawer, jlong displayPtr, jboolean transparency)
     {
         Display *display = fromJavaPointer<Display *>(displayPtr);
         if (!display) return 0;
 
+        XVisualInfo *vi;
+
+        if (transparency)
+        {
+            GLint att[] = {
+                GLX_RGBA,
+                GLX_RED_SIZE, 8,
+                GLX_GREEN_SIZE, 8,
+                GLX_BLUE_SIZE, 8,
+                GLX_ALPHA_SIZE, 8,
+                GLX_DEPTH_SIZE, 32,
+                GLX_DOUBLEBUFFER, True, None
+            };
+            vi = glXChooseVisual(display, 0, att);
+        }
+        else {
             GLint att[] = {GLX_RGBA, GLX_DOUBLEBUFFER, True, None};
-        XVisualInfo *vi = glXChooseVisual(display, 0, att);
+            vi = glXChooseVisual(display, 0, att);
+        }
 
         if (!vi) return 0;
 

skiko/src/jvmMain/cpp/windows/SoftwareRedrawer.cc

@@ -2,6 +2,7 @@
 #include <jawt_md.h>
 #include "jni_helpers.h"
 #include "exceptions_handler.h"
+#include "window_util.h"
 
 #include "SkSurface.h"
 #include "src/core/SkAutoMalloc.h"
@@ -20,10 +21,15 @@ public:
 extern "C"
 {
     JNIEXPORT jlong JNICALL Java_org_jetbrains_skiko_redrawer_WindowsSoftwareRedrawer_createDevice(
-        JNIEnv *env, jobject redrawer, jlong contentHandle)
+        JNIEnv *env, jobject redrawer, jlong contentHandle, jboolean transparency)
     {
         SoftwareDevice *device = new SoftwareDevice();
         device->window = (HWND)contentHandle;
+        if (transparency)
+        {
+            HWND parent = GetAncestor(device->window, GA_PARENT);
+            enableTransparentWindow(parent);
+        }
         GetClientRect(device->window, &device->clientRect);
         return toJavaPointer(device);
     }

skiko/src/jvmMain/cpp/windows/directXRedrawer.cc

@@ -4,6 +4,7 @@
 #include <jawt_md.h>
 #include "jni_helpers.h"
 #include "exceptions_handler.h"
+#include "window_util.h"
 
 #include "GrBackendSurface.h"
 #include "GrDirectContext.h"
@@ -289,7 +290,7 @@ extern "C"
     }
 
     JNIEXPORT jlong JNICALL Java_org_jetbrains_skiko_redrawer_Direct3DRedrawer_createDirectXDevice(
-        JNIEnv *env, jobject redrawer, jint adapterPriority, jlong contentHandle)
+        JNIEnv *env, jobject redrawer, jint adapterPriority, jlong contentHandle, jboolean transparency)
     {
         gr_cp<IDXGIFactory4> deviceFactory;
         if (!SUCCEEDED(CreateDXGIFactory1(IID_PPV_ARGS(&deviceFactory))))
@@ -329,6 +330,14 @@ extern "C"
         d3dDevice->queue = queue;
         d3dDevice->window = (HWND)contentHandle;
 
+        if (transparency)
+        {
+            //TODO: current swapChain does not support transparency
+            return 0;
+            // HWND wnd = GetAncestor(d3dDevice->window, GA_PARENT);
+            // enableTransparentWindow(wnd);
+        }
+
         return toJavaPointer(d3dDevice);
     }
 

skiko/src/jvmMain/cpp/windows/openGLRedrawer.cc

@@ -5,6 +5,7 @@
 #include <dwmapi.h>
 #include "jni_helpers.h"
 #include "exceptions_handler.h"
+#include "window_util.h"
 
 extern "C"
 {
@@ -20,10 +21,11 @@ extern "C"
             memset(&pixFormatDscr, 0, sizeof(PIXELFORMATDESCRIPTOR));
             pixFormatDscr.nSize = sizeof(PIXELFORMATDESCRIPTOR);
             pixFormatDscr.nVersion = 1;
-            pixFormatDscr.dwFlags = PFD_DRAW_TO_WINDOW | PFD_SUPPORT_OPENGL | PFD_DOUBLEBUFFER;
+            pixFormatDscr.dwFlags = PFD_DRAW_TO_WINDOW | PFD_SUPPORT_OPENGL | PFD_DOUBLEBUFFER | PFD_SUPPORT_COMPOSITION;
 
             pixFormatDscr.iPixelType = PFD_TYPE_RGBA;
             pixFormatDscr.cColorBits = 32;
+            pixFormatDscr.cAlphaBits = 8;
             int iPixelFormat = ChoosePixelFormat(device, &pixFormatDscr);
             SetPixelFormat(device, iPixelFormat, &pixFormatDscr);
             DescribePixelFormat(device, iPixelFormat, sizeof(PIXELFORMATDESCRIPTOR), &pixFormatDscr);
@@ -76,10 +78,16 @@ extern "C"
         wglMakeCurrent(device, context);
     }
 
-    JNIEXPORT jlong JNICALL Java_org_jetbrains_skiko_redrawer_WindowsOpenGLRedrawerKt_createContext(JNIEnv *env, jobject redrawer, jlong devicePtr)
+    JNIEXPORT jlong JNICALL Java_org_jetbrains_skiko_redrawer_WindowsOpenGLRedrawerKt_createContext(JNIEnv *env, jobject redrawer, jlong devicePtr, jlong contentHandle, jboolean transparency)
     {
         __try
         {
+            if (transparency)
+            {
+                HWND parent = GetAncestor(fromJavaPointer<HWND>(contentHandle), GA_PARENT);
+                enableTransparentWindow(parent);
+            }
+
             HDC device = fromJavaPointer<HDC>(devicePtr);
             return toJavaPointer(wglCreateContext(device));
         }

skiko/src/jvmMain/cpp/windows/window_util.cc

+#if SK_BUILD_FOR_WIN
+
+#include "window_util.h"
+
+void enableTransparentWindow(HWND hwnd)
+{
+    HRGN region = CreateRectRgn(0, 0, -1, -1);
+    DWM_BLURBEHIND bb = {0};
+    bb.dwFlags = DWM_BB_ENABLE | DWM_BB_BLURREGION;
+    bb.hRgnBlur = region;
+    bb.fEnable = TRUE;
+    DwmEnableBlurBehindWindow(hwnd, &bb);
+    DeleteObject(region);
+}
+
+#endif
\ No newline at end of file

skiko/src/jvmMain/kotlin/org/jetbrains/skiko/SkiaLayer.jvm.kt

 package org.jetbrains.skiko
 
-import org.jetbrains.skia.*
+import org.jetbrains.skia.Canvas
+import org.jetbrains.skia.Bitmap
+import org.jetbrains.skia.ColorAlphaType
+import org.jetbrains.skia.ColorInfo
+import org.jetbrains.skia.ColorType
+import org.jetbrains.skia.ColorSpace
+import org.jetbrains.skia.ClipMode
+import org.jetbrains.skia.ImageInfo
+import org.jetbrains.skia.Picture
+import org.jetbrains.skia.PictureRecorder
+import org.jetbrains.skia.Rect
 import org.jetbrains.skiko.context.ContextHandler
 import org.jetbrains.skiko.redrawer.Redrawer
+import java.awt.Color
 import java.awt.Graphics
 import java.awt.event.*
 import java.awt.im.InputMethodRequests
@@ -25,6 +36,8 @@ actual open class SkiaLayer internal constructor(
         ContentScale,
     }
 
+    actual var transparency: Boolean = false
+
     internal val backedLayer: HardwareLayer
 
     constructor(
@@ -36,6 +49,7 @@ actual open class SkiaLayer internal constructor(
 
     init {
         isOpaque = false
+        background = Color(0, 0, 0, 0)
         layout = null
         backedLayer = object : HardwareLayer() {
             override fun paint(g: Graphics) {
@@ -98,7 +112,7 @@ actual open class SkiaLayer internal constructor(
     val windowHandle: Long
         get() = backedLayer.windowHandle
 
-    var fullscreen: Boolean
+    actual var fullscreen: Boolean
         get() = backedLayer.fullscreen
         set(value) {
             backedLayer.fullscreen = value

skiko/src/jvmMain/kotlin/org/jetbrains/skiko/context/DirectSoftwareContextHandler.kt

@@ -8,7 +8,6 @@ import org.jetbrains.skiko.redrawer.AbstractDirectSoftwareRedrawer
 import java.lang.ref.Reference
 
 internal class DirectSoftwareContextHandler(layer: SkiaLayer) : ContextHandler(layer) {
-    override val bleachConstant = -1
     var isInited = false
 
     val softwareRedrawer: AbstractDirectSoftwareRedrawer

skiko/src/jvmMain/kotlin/org/jetbrains/skiko/context/SoftwareContextHandler.kt

@@ -6,7 +6,10 @@ import org.jetbrains.skia.ColorAlphaType
 import org.jetbrains.skia.ImageInfo
 import org.jetbrains.skia.Picture
 import org.jetbrains.skiko.SkiaLayer
+import org.jetbrains.skiko.hostOs
+import org.jetbrains.skiko.OS
 import java.awt.Transparency
+import java.awt.Color
 import java.awt.color.ColorSpace
 import java.awt.image.BufferedImage
 import java.awt.image.ComponentColorModel
@@ -16,7 +19,7 @@ import java.awt.image.Raster
 import java.awt.image.WritableRaster
 
 internal class SoftwareContextHandler(layer: SkiaLayer) : ContextHandler(layer) {
-    override val bleachConstant = -1 // it looks like java.awt.Canvas doesn't support transparency
+    override val clearColor = if (layer.transparency && hostOs == OS.MacOS) 0 else -1
 
     val colorModel = ComponentColorModel(
         ColorSpace.getInstance(ColorSpace.CS_sRGB),
@@ -76,7 +79,12 @@ internal class SoftwareContextHandler(layer: SkiaLayer) : ContextHandler(layer)
                 null
             )
             image = BufferedImage(colorModel, raster!!, false, null)
-            layer.backedLayer.getGraphics()?.drawImage(image!!, 0, 0, layer.width, layer.height, null)
+            val graphics = layer.backedLayer.getGraphics()
+            if (!layer.fullscreen && layer.transparency && hostOs == OS.MacOS) {
+                graphics?.setColor(Color(0, 0, 0, 0))
+                graphics?.clearRect(0, 0, w, h)
+            }
+            graphics?.drawImage(image!!, 0, 0, layer.width, layer.height, null)
         }
     }
 

skiko/src/jvmMain/kotlin/org/jetbrains/skiko/redrawer/Direct3DRedrawer.kt

@@ -15,7 +15,7 @@ internal class Direct3DRedrawer(
     private var isDisposed = false
     private var drawLock = Any()
 
-    private val device = createDirectXDevice(getAdapterPriority(), layer.contentHandle).also {
+    private val device = createDirectXDevice(getAdapterPriority(), layer.contentHandle, layer.transparency).also {
         if (it == 0L || !isVideoCardSupported(layer.renderApi)) {
             throw RenderException("Failed to create DirectX12 device.")
         }
@@ -92,7 +92,7 @@ internal class Direct3DRedrawer(
     val adapterName get() = getAdapterName(device)
     val adapterMemorySize get() = getAdapterMemorySize(device)
 
-    private external fun createDirectXDevice(adapterPriority: Int, contentHandle: Long): Long
+    private external fun createDirectXDevice(adapterPriority: Int, contentHandle: Long, transparency: Boolean): Long
     private external fun makeDirectXContext(device: Long): Long
     private external fun makeDirectXSurface(device: Long, context: Long, width: Int, height: Int, index: Int): Long
     private external fun resizeBuffers(device: Long, width: Int, height: Int)

skiko/src/jvmMain/kotlin/org/jetbrains/skiko/redrawer/LinuxOpenGLRedrawer.kt

@@ -14,7 +14,7 @@ internal class LinuxOpenGLRedrawer(
 
     init {
     	layer.backedLayer.lockLinuxDrawingSurface {
-            context = it.createContext()
+            context = it.createContext(layer.transparency)
             if (context == 0L) {
                 throw RenderException("Cannot create Linux GL context")
             }
@@ -150,14 +150,14 @@ internal class LinuxOpenGLRedrawer(
     }
 }
 
-private fun LinuxDrawingSurface.createContext() = createContext(display)
+private fun LinuxDrawingSurface.createContext(transparency: Boolean) = createContext(display, transparency)
 private fun LinuxDrawingSurface.destroyContext(context: Long) = destroyContext(display, context)
 private fun LinuxDrawingSurface.makeCurrent(context: Long) = makeCurrent(display, window, context)
 private fun LinuxDrawingSurface.swapBuffers() = swapBuffers(display, window)
 private fun LinuxDrawingSurface.setSwapInterval(interval: Int) = setSwapInterval(display, window, interval)
 
 private external fun makeCurrent(display: Long, window: Long, context: Long)
-private external fun createContext(display: Long): Long
+private external fun createContext(display: Long, transparency: Boolean): Long
 private external fun destroyContext(display: Long, context: Long)
 private external fun setSwapInterval(display: Long, window: Long, interval: Int)
 private external fun swapBuffers(display: Long, window: Long)
\ No newline at end of file

skiko/src/jvmMain/kotlin/org/jetbrains/skiko/redrawer/MetalRedrawer.kt

@@ -21,7 +21,7 @@ internal class MetalRedrawer(
     private var isDisposed = false
     private var drawLock = Any()
     private val device = layer.backedLayer.useDrawingSurfacePlatformInfo {
-        createMetalDevice(getAdapterPriority(), it)
+        createMetalDevice(layer.windowHandle, layer.transparency, getAdapterPriority(), it)
     }
     private val windowHandle = layer.windowHandle
 
@@ -131,7 +131,7 @@ internal class MetalRedrawer(
     fun getAdapterName(): String = getAdapterName(device)
     fun getAdapterMemorySize(): Long = getAdapterMemorySize(device)
 
-    private external fun createMetalDevice(adapterPriority: Int, platformInfo: Long): Long
+    private external fun createMetalDevice(window:Long, transparency: Boolean, adapterPriority: Int, platformInfo: Long): Long
     private external fun makeMetalContext(device: Long): Long
     private external fun makeMetalRenderTarget(device: Long, width: Int, height: Int): Long
     private external fun disposeDevice(device: Long)

skiko/src/jvmMain/kotlin/org/jetbrains/skiko/redrawer/WindowsOpenGLRedrawer.kt

@@ -11,7 +11,7 @@ internal class WindowsOpenGLRedrawer(
     private val properties: SkiaLayerProperties
 ) : Redrawer {
     private val device = layer.backedLayer.useDrawingSurfacePlatformInfo(::getDevice)
-    private val context = createContext(device).also {
+    private val context = createContext(device, layer.contentHandle, layer.transparency).also {
         if (it == 0L) {
             throw RenderException("Cannot create Windows GL context")
         }
@@ -115,7 +115,7 @@ internal class WindowsOpenGLRedrawer(
 
 private external fun makeCurrent(device: Long, context: Long)
 private external fun getDevice(platformInfo: Long): Long
-private external fun createContext(device: Long): Long
+private external fun createContext(device: Long, contentHandle:Long, transparency: Boolean): Long
 private external fun deleteContext(context: Long)
 private external fun setSwapInterval(interval: Int)
 private external fun swapBuffers(device: Long)

skiko/src/jvmMain/kotlin/org/jetbrains/skiko/redrawer/WindowsSoftwareRedrawer.kt

@@ -10,12 +10,12 @@ internal class WindowsSoftwareRedrawer(
 ) : AbstractDirectSoftwareRedrawer(layer, properties) {
 
     init {
-        device = createDevice(layer.contentHandle).also {
+        device = createDevice(layer.contentHandle, layer.transparency).also {
             if (it == 0L) {
                 throw RenderException("Failed to create Software device")
             }
         }
     }
 
-    private external fun createDevice(contentHandle: Long): Long
+    private external fun createDevice(contentHandle: Long, transparency: Boolean): Long
 }
\ No newline at end of file

skiko/src/jvmMain/objectiveC/macos/Drawlayer.mm

@@ -211,6 +211,4 @@ void getMetalDeviceAndQueue(void** device, void** queue)
     *queue = (__bridge void*)fQueue;
 }
 
-
-
 } // extern C
\ No newline at end of file

skiko/src/jvmMain/objectiveC/macos/MetalRedrawer.mm

@@ -183,7 +183,7 @@ id<MTLDevice> MTLCreateIntegratedDevice(int adapterPriority) {
 }
 
 JNIEXPORT jlong JNICALL Java_org_jetbrains_skiko_redrawer_MetalRedrawer_createMetalDevice(
-    JNIEnv *env, jobject redrawer, jint adapterPriority, jlong platformInfoPtr)
+    JNIEnv *env, jobject redrawer, jlong windowPtr, jboolean transparency, jint adapterPriority, jlong platformInfoPtr)
 {
     MetalDevice *device = [MetalDevice new];
 
@@ -214,6 +214,12 @@ JNIEXPORT jlong JNICALL Java_org_jetbrains_skiko_redrawer_MetalRedrawer_createMe
     device.layer.backgroundColor = CGColorCreate(CGColorSpaceCreateDeviceRGB(), transparent);
     device.layer.opaque = NO;
     
+    if (transparency)
+    {
+        NSWindow* window = (NSWindow*)windowPtr;
+        window.hasShadow = NO;
+    }
+
     return (jlong) device;
 }
 

skiko/src/linuxMain/kotlin/org/jetbrains/skiko/SkiaLayer.linux.kt

@@ -6,4 +6,10 @@ actual open class SkiaLayer {
         set(value) {}
     actual val contentScale: Float
         get() = TODO("Not yet implemented")
+    actual var fullscreen: Boolean
+        get() = TODO("Not yet implemented")
+        set(value) {}
+    actual var transparency: Boolean
+        get() = TODO("Not yet implemented")
+        set(value) {}
 }
\ No newline at end of file

skiko/src/macosMain/kotlin/org/jetbrains/skiko/SkiaLayer.macos.kt

@@ -14,6 +14,12 @@ actual open class SkiaLayer(
     actual val contentScale: Float
         get() = _contentScale
 
+    actual var fullscreen: Boolean
+        get() = TODO("Not yet implemented")
+        set(value) {}
+
+    actual var transparency: Boolean = false
+
     val nsView = NSView(NSMakeRect(0.0, 0.0, 640.0, 480.0))
     var _contentScale: Float = 1.0f