src/java.desktop/unix/native/libawt_xawt/awt/awt_Robot.c

rev 15059 : 8150954: Taking screenshots on x11 composite desktop produce wrong result
Summary: The AWT Robot X11 code that takes screenshots uses the default root window, which may not contain the final composited desktop.
Reviewed-by: alexsch, ssadetsky

*** 25,34 ****
--- 25,37 ----
  
  #ifdef HEADLESS
      #error This file should not be included in headless library
  #endif
  
+ #include "jvm_md.h"
+ #include <dlfcn.h>
+ 
  #include "awt_p.h"
  #include "awt_GraphicsEnv.h"
  #define XK_MISCELLANY
  #include <X11/keysymdef.h>
  #include <X11/Xutil.h>
*** 48,62 ****
--- 51,100 ----
  
  #if defined(__linux__) || defined(MACOSX)
  #include <sys/socket.h>
  #endif
  
+ static Bool   (*compositeQueryExtension)   (Display*, int*, int*);
+ static Status (*compositeQueryVersion)     (Display*, int*, int*);
+ static Window (*compositeGetOverlayWindow) (Display *, Window);
+ 
  extern struct X11GraphicsConfigIDs x11GraphicsConfigIDs;
  
  static jint * masks;
  static jint num_buttons;
  
+ static void *xCompositeHandle;
+ 
+ static const char* XCOMPOSITE = JNI_LIB_NAME("Xcomposite");
+ static const char* XCOMPOSITE_VERSIONED = VERSIONED_JNI_LIB_NAME("Xcomposite", "1");
+ 
+ static Bool checkXCompositeFunctions(void) {
+     return (compositeQueryExtension   != NULL   &&
+             compositeQueryVersion     != NULL   &&
+             compositeGetOverlayWindow != NULL);
+ }
+ 
+ static void initXCompositeFunctions(void) {
+ 
+     if (xCompositeHandle == NULL) {
+         xCompositeHandle = dlopen(XCOMPOSITE, RTLD_LAZY | RTLD_GLOBAL);
+         if (xCompositeHandle == NULL) {
+             xCompositeHandle = dlopen(XCOMPOSITE_VERSIONED, RTLD_LAZY | RTLD_GLOBAL);
+         }
+     }
+     //*(void **)(&asyncGetCallTraceFunction)
+     if (xCompositeHandle != NULL) {
+         *(void **)(&compositeQueryExtension) = dlsym(xCompositeHandle, "XCompositeQueryExtension");
+         *(void **)(&compositeQueryVersion) = dlsym(xCompositeHandle, "XCompositeQueryVersion");
+         *(void **)(&compositeGetOverlayWindow) = dlsym(xCompositeHandle, "XCompositeGetOverlayWindow");
+     }
+ 
+     if (xCompositeHandle && !checkXCompositeFunctions()) {
+         dlclose(xCompositeHandle);
+     }
+ }
+ 
  static int32_t isXTestAvailable() {
      int32_t major_opcode, first_event, first_error;
      int32_t  event_basep, error_basep, majorp, minorp;
      int32_t isXTestAvailable;
  
*** 87,96 ****
--- 125,163 ----
      }
  
      return isXTestAvailable;
  }
  
+ static Bool hasXCompositeOverlayExtension(Display *display) {
+ 
+     int xoverlay = False;
+     int eventBase, errorBase;
+     if (checkXCompositeFunctions() &&
+         compositeQueryExtension(display, &eventBase, &errorBase))
+     {
+         int major = 0;
+         int minor = 0;
+ 
+         compositeQueryVersion(display, &major, &minor);
+         if (major > 0 || minor >= 3) {
+             xoverlay = True;
+         }
+     }
+ 
+     return xoverlay;
+ }
+ 
+ static jboolean isXCompositeDisplay(Display *display, int screenNumber) {
+ 
+     char NET_WM_CM_Sn[25];
+     snprintf(NET_WM_CM_Sn, sizeof(NET_WM_CM_Sn), "_NET_WM_CM_S%d\0", screenNumber);
+ 
+     Atom managerSelection = XInternAtom(display, NET_WM_CM_Sn, 0);
+     Window owner = XGetSelectionOwner(display, managerSelection);
+ 
+     return owner != 0;
+ }
  
  static XImage *getWindowImage(Display * display, Window window,
                                int32_t x, int32_t y,
                                int32_t w, int32_t h) {
      XImage         *image;
*** 209,219 ****
                               jint jy,
                               jint jwidth,
                               jint jheight,
                               jint scale,
                               jintArray pixelArray,
!                              jboolean isGtkSupported) {
      XImage *image;
      jint *ary;               /* Array of jints for sending pixel values back
                                * to parent process.
                                */
      Window rootWindow;
--- 276,286 ----
                               jint jy,
                               jint jwidth,
                               jint jheight,
                               jint scale,
                               jintArray pixelArray,
!                              jboolean useGtk) {
      XImage *image;
      jint *ary;               /* Array of jints for sending pixel values back
                                * to parent process.
                                */
      Window rootWindow;
*** 236,245 ****
--- 303,320 ----
      jint swidth = jwidth * scale;
      jint sheight = jheight * scale;
  
      rootWindow = XRootWindow(awt_display, adata->awt_visInfo.screen);
  
+     if (!useGtk) {
+         if (hasXCompositeOverlayExtension(awt_display) &&
+             isXCompositeDisplay(awt_display, adata->awt_visInfo.screen))
+         {
+             rootWindow = compositeGetOverlayWindow(awt_display, rootWindow);
+         }
+     }
+ 
      if (!XGetWindowAttributes(awt_display, rootWindow, &attr)
              || sx + swidth <= attr.x
              || attr.x + attr.width <= sx
              || sy + sheight <= attr.y
              || attr.y + attr.height <= sy) {
*** 260,270 ****
      int dx = attr.x > sx ? attr.x - sx : 0;
      int dy = attr.y > sy ? attr.y - sy : 0;
  
      int index;
  
!     if (isGtkSupported) {
          gtk->gdk_threads_enter();
          gtk_failed = gtk->get_drawable_data(env, pixelArray, x, y, width,
                                              height, jwidth, dx, dy, scale);
          gtk->gdk_threads_leave();
      }
--- 335,345 ----
      int dx = attr.x > sx ? attr.x - sx : 0;
      int dy = attr.y > sy ? attr.y - sy : 0;
  
      int index;
  
!     if (useGtk) {
          gtk->gdk_threads_enter();
          gtk_failed = gtk->get_drawable_data(env, pixelArray, x, y, width,
                                              height, jwidth, dx, dy, scale);
          gtk->gdk_threads_leave();
      }
*** 452,456 ****
--- 527,536 ----
      }
      XSync(awt_display, False);
  
      AWT_UNLOCK();
  }
+ 
+ JNIEXPORT void JNICALL
+ Java_sun_awt_X11_XRobotPeer_loadNativeLibraries (JNIEnv *env, jclass cls) {
+     initXCompositeFunctions();
+ }