Properly compute window handle on Linux (#212)

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

-#include <jawt_md.h>
-#include <GL/gl.h>
-#include <GL/glx.h>
-#include <X11/X.h>
-#include <X11/Xlib.h>
-#include <X11/Xresource.h>
-#include <cstdlib>
-#include <unistd.h>
-#include <stdio.h>
-#include "jni_helpers.h"
-
-typedef GLXContext (*glXCreateContextAttribsARBProc)(Display *, GLXFBConfig, GLXContext, Bool, const int *);
-
-extern "C"
-{
-    JNIEXPORT void JNICALL Java_org_jetbrains_skiko_HardwareLayer_nativeInit(JNIEnv *env, jobject canvas, jlong platformInfoPtr)
-    {
-    }
-
-    JNIEXPORT void JNICALL Java_org_jetbrains_skiko_HardwareLayer_nativeDispose(JNIEnv *env, jobject canvas)
-    {
-    }
-
-    JNIEXPORT jlong JNICALL Java_org_jetbrains_skiko_HardwareLayer_getWindowHandle(JNIEnv *env, jobject canvas, jlong platformInfoPtr)
-    {
-        JAWT_X11DrawingSurfaceInfo *dsi_x11 = fromJavaPointer<JAWT_X11DrawingSurfaceInfo *>(platformInfoPtr);
-        return (jlong) dsi_x11->display;
-    }
-
-    JNIEXPORT jlong JNICALL Java_org_jetbrains_skiko_HardwareLayer_getContentHandle(JNIEnv *env, jobject canvas, jlong platformInfoPtr)
-    {
-        JAWT_X11DrawingSurfaceInfo *dsi_x11 = fromJavaPointer<JAWT_X11DrawingSurfaceInfo *>(platformInfoPtr);
-        return (jlong) dsi_x11->drawable;
-    }
-
-    double getDpiScaleByDisplay(Display *display)
-    {
-        char *resourceManager = XResourceManagerString(display);
-        if (resourceManager != nullptr)
-        {
-            XrmDatabase db = XrmGetStringDatabase(resourceManager);
-            if (db != nullptr)
-            {
-                XrmValue value;
-
-                char *type;
-                XrmGetResource(db, "Xft.dpi", "Xft.dpi", &type, &value);
-
-                if (value.addr != nullptr)
-                {
-                    return atof(value.addr) / 96.0;
-                }
-            }
-        }
-        return 1;
-    }
-
-    double getDpiScale() {
-        Display *display = XOpenDisplay(nullptr);
-        if (display != nullptr) {
-            double result = getDpiScaleByDisplay(display);
-            XCloseDisplay(display);
-            return result;
-        } else {
-            return 1;
-        }
-    }
-
-    JNIEXPORT jfloat JNICALL Java_org_jetbrains_skiko_PlatformOperationsKt_linuxGetDpiScaleNative(JNIEnv *env, jobject properties, jlong platformInfoPtr)
-    {
-        JAWT_X11DrawingSurfaceInfo *dsi_x11 = fromJavaPointer<JAWT_X11DrawingSurfaceInfo *>(platformInfoPtr);
-        return (float) getDpiScaleByDisplay(dsi_x11->display);
-    }
-
-    JNIEXPORT jint JNICALL Java_org_jetbrains_skiko_SystemThemeKt_getCurrentSystemTheme(JNIEnv *env, jobject topLevel)
-    {
-       // Unknown.
-       return 2;
-    }
-
-
-    JNIEXPORT jfloat JNICALL Java_org_jetbrains_skiko_SetupKt_linuxGetSystemDpiScale(JNIEnv *env, jobject layer)
-    {
-        return (float) getDpiScale();
-    }
-
+#include <jawt_md.h>
+#include <GL/gl.h>
+#include <GL/glx.h>
+#include <X11/X.h>
+#include <X11/Xlib.h>
+#include <X11/Xresource.h>
+#include <cstdlib>
+#include <unistd.h>
+#include <stdio.h>
+#include "jni_helpers.h"
+
+typedef GLXContext (*glXCreateContextAttribsARBProc)(Display *, GLXFBConfig, GLXContext, Bool, const int *);
+
+extern "C"
+{
+    JNIEXPORT void JNICALL Java_org_jetbrains_skiko_HardwareLayer_nativeInit(JNIEnv *env, jobject canvas, jlong platformInfoPtr)
+    {
+    }
+
+    JNIEXPORT void JNICALL Java_org_jetbrains_skiko_HardwareLayer_nativeDispose(JNIEnv *env, jobject canvas)
+    {
+    }
+
+    JNIEXPORT jlong JNICALL Java_org_jetbrains_skiko_HardwareLayer_getWindowHandle(JNIEnv *env, jobject canvas, jlong platformInfoPtr)
+    {
+        JAWT_X11DrawingSurfaceInfo *dsi_x11 = fromJavaPointer<JAWT_X11DrawingSurfaceInfo *>(platformInfoPtr);
+        Window win = dsi_x11->drawable;
+        Window parent = win;
+        Window root = None;
+        Window *children;
+        unsigned int nchildren;
+        Status s;
+
+        while (parent != root) {
+            win = parent;
+            s = XQueryTree(dsi_x11->display, win, &root, &parent, &children, &nchildren);
+
+            if (s)
+                XFree(children);
+            else
+                return 0;
+        }
+        return (jlong)win;
+    }
+
+    JNIEXPORT jlong JNICALL Java_org_jetbrains_skiko_HardwareLayer_getContentHandle(JNIEnv *env, jobject canvas, jlong platformInfoPtr)
+    {
+        JAWT_X11DrawingSurfaceInfo *dsi_x11 = fromJavaPointer<JAWT_X11DrawingSurfaceInfo *>(platformInfoPtr);
+        return (jlong) dsi_x11->drawable;
+    }
+
+    double getDpiScaleByDisplay(Display *display)
+    {
+        char *resourceManager = XResourceManagerString(display);
+        if (resourceManager != nullptr)
+        {
+            XrmDatabase db = XrmGetStringDatabase(resourceManager);
+            if (db != nullptr)
+            {
+                XrmValue value;
+
+                char *type;
+                XrmGetResource(db, "Xft.dpi", "Xft.dpi", &type, &value);
+
+                if (value.addr != nullptr)
+                {
+                    return atof(value.addr) / 96.0;
+                }
+            }
+        }
+        return 1;
+    }
+
+    double getDpiScale() {
+        Display *display = XOpenDisplay(nullptr);
+        if (display != nullptr) {
+            double result = getDpiScaleByDisplay(display);
+            XCloseDisplay(display);
+            return result;
+        } else {
+            return 1;
+        }
+    }
+
+    JNIEXPORT jfloat JNICALL Java_org_jetbrains_skiko_PlatformOperationsKt_linuxGetDpiScaleNative(JNIEnv *env, jobject properties, jlong platformInfoPtr)
+    {
+        JAWT_X11DrawingSurfaceInfo *dsi_x11 = fromJavaPointer<JAWT_X11DrawingSurfaceInfo *>(platformInfoPtr);
+        return (float) getDpiScaleByDisplay(dsi_x11->display);
+    }
+
+    JNIEXPORT jint JNICALL Java_org_jetbrains_skiko_SystemThemeKt_getCurrentSystemTheme(JNIEnv *env, jobject topLevel)
+    {
+       // Unknown.
+       return 2;
+    }
+
+
+    JNIEXPORT jfloat JNICALL Java_org_jetbrains_skiko_SetupKt_linuxGetSystemDpiScale(JNIEnv *env, jobject layer)
+    {
+        return (float) getDpiScale();
+    }
+
 } // extern "C"
\ No newline at end of file