Get X background via Xlib, to remove flicker and obscuring issues

Currently, this does not work for non-image backgrounds, like when a color is set via icewmbg. Will then produce a black border.

Author: onli

Makefile

@@ -8,7 +8,7 @@ SRCDIR ?= src/
 SHELL ?= /bin/sh
 CC = g++
 CCFLAGS ?= -O2
-DEPS = $(shell pkg-config --libs --cflags glib-2.0 gtk+-3.0 libwnck-3.0 xcb-ewmh librsvg-2.0)
+DEPS = $(shell pkg-config --libs --cflags glib-2.0 gtk+-3.0 libwnck-3.0 xcb-ewmh librsvg-2.0 x11)
 ifneq (, $(shell which wx-config))
 	DEPS += $(shell wx-config --cflags --libs)
 else

README.md

@@ -19,7 +19,7 @@ Currently, simdock has to be compiled manually. The main dependencies are wxWidg
 
     Under Void Linux:
 
-        sudo xbps-install pkg-config wxWidgets-gtk3-devel librsvg-devel xcb-ewmh libwnck-devel make gcc
+        sudo xbps-install pkg-config wxWidgets-gtk3-devel librsvg-devel xcb-ewmh libwnck-devel libX11-devel make gcc
 
 1. Type `make` to compile
 1. Type `sudo make install` to install

src/background.cc

@@ -19,64 +19,86 @@
 
 using namespace std;
 
+// Function to fetch the root window background pixmap
+Pixmap getRootPixmap(Display* display, Window root) {
+    Atom actual_type;
+    int actual_format;
+    unsigned long nitems, bytes_after;
+    unsigned char* prop = nullptr;
+    Atom prop_root = XInternAtom(display, "_XROOTPMAP_ID", True);
+
+    if (XGetWindowProperty(display, root, prop_root, 0, 1, False, XA_PIXMAP, 
+                           &actual_type, &actual_format, &nitems, &bytes_after, 
+                           &prop) == Success) {
+        if (nitems == 1) {
+            Pixmap pixmap = *(Pixmap*)prop;
+            XFree(prop);
+            return pixmap;
+        }
+    }
+    return None;
+}
+
+// Function to convert X11 Pixmap into wxImage
+wxImage ConvertPixmapToWxImage(Display* display, Pixmap pixmap, int width, int height) {
+    XImage* ximage = XGetImage(display, pixmap, 0, 0, width, height, AllPlanes, ZPixmap);
+    if (!ximage) {
+        std::cerr << "Failed to get XImage from Pixmap!" << std::endl;
+        return wxImage(width, height);
+    }
+
+    wxImage image(width, height);
+    unsigned char* data = image.GetData();
+    if (!data) {
+        std::cerr << "Failed to allocate memory for wxImage data!" << std::endl;
+        XDestroyImage(ximage);
+        return wxImage(width, height);
+    }
+
+    // Convert pixel data
+    for (int y = 0; y < height; ++y) {
+        for (int x = 0; x < width; ++x) {
+            unsigned long pixel = XGetPixel(ximage, x, y);
+            unsigned char red   = (pixel >> 16) & 0xFF;
+            unsigned char green = (pixel >> 8) & 0xFF;
+            unsigned char blue  = pixel & 0xFF;
+
+            data[(y * width + x) * 3 + 0] = red;
+            data[(y * width + x) * 3 + 1] = green;
+            data[(y * width + x) * 3 + 2] = blue;
+        }
+    }
+
+    XDestroyImage(ximage);
+    return image;
+}
+
 //get the currently used background 
 wxBitmap* getRootWallpaper()
 {
-    wxBitmap* backImage = new wxBitmap();
-    WnckScreen *screen = wnck_screen_get_default ();
+	wxBitmap* backImage;
+	Display* display = XOpenDisplay(nullptr);
+    if (!display) {
+        std::cerr << "Unable to open X display" << std::endl;
+        return NULL;
+    }
 
-	// This is the X window ID of the desktop
-    Pixmap pm = wnck_screen_get_background_pixmap(screen);
-    int i = 0;
-    while(i < 5)
-    {
-        if (pm != None) {
-            break;
+    Window root = DefaultRootWindow(display);
+
+    // Get the root window background pixmap
+    Pixmap rootPixmap = getRootPixmap(display, root);
+    if (rootPixmap != None) {
+        int screen_width = DisplayWidth(display, DefaultScreen(display));
+        int screen_height = DisplayHeight(display, DefaultScreen(display));
+
+        // Convert Pixmap to wxImage and then to wxBitmap
+        wxImage image = ConvertPixmapToWxImage(display, rootPixmap, screen_width, screen_height);
+        if (image.IsOk()) {
+		  backImage = new wxBitmap(image);
         }
-        wxMilliSleep(1000);
-        pm = wnck_screen_get_background_pixmap(screen);
-        i++;
-    }
-    
-    if (pm != None) {
-		wxSize sz = wxGetDisplaySize();
-		// Note: This code to hide the app is duplicated with the outer call in tasks.cc, but this is needed for first app start
-		wxGetApp().frame->SetTransparent(0);
-		wxGetApp().frame->Hide();
-		wxGetApp().frame->Disable();
-		// Give the main UI thread a chance to hide the app first
-		while(wxGetApp().frame->IsShown()) {
-			wxMilliSleep(20);
-		}
-		// This sleep should be unnecessary, but without it the UI will not be hidden in the next step
-		wxMilliSleep(20);
-		wxBitmap* backImage = new wxBitmap(
-			gdk_pixbuf_get_from_window(
-				gdk_x11_window_foreign_new_for_display(
-					gdk_display_get_default(),
-					gdk_x11_get_default_root_xwindow()
-				),
-				0,
-				0,
-				sz.GetWidth(),
-				sz.GetHeight()
-			)
-		  );
-		wxGetApp().frame->Show();
-		wxGetApp().frame->SetTransparent(255);
-		wxGetApp().frame->Enable();
-		return backImage;
-    } else {
-        wxSize sz = wxGetDisplaySize();
-		wxBitmap* backImage = new wxBitmap(sz.GetWidth(), sz.GetHeight());
-        wxMemoryDC dc;
-        dc.SelectObject(*backImage);
-        dc.SetBackground(*wxTRANSPARENT_BRUSH);
-        dc.Clear();
-        dc.SelectObject(*backImage);
-		return backImage;
     }
-    return backImage;
+	XCloseDisplay(display);
+	return backImage;
 }
 
 wxBitmap *fixImage (wxString url, int type, wxColour c)

src/background.h

@@ -20,6 +20,8 @@
 #define BACKGROUND_H_
 
 #include "main.h"
+#include <X11/Xlib.h>
+#include <X11/Xatom.h>
 
 wxBitmap *fixImage (wxString img, int type, wxColour c);
 wxBitmap* getRootWallpaper();

src/main.h

@@ -118,16 +118,6 @@ WX_DEFINE_ARRAY (simImage *, ImagesArray);
 #define NONE_STR  "none"
 #define WALLPAPER_STR "wallpaper"
 
-//#include <wx/arrimpl.cpp>
-//WX_DEFINE_OBJARRAY(simImage)
-//WX_DEFINE_OBJARRAY(ImagesList);
-
-
-//WX_DECLARE_LIST(simImage, ImagesList);
-
-// the ID we'll use to identify our event
-//const int BACKGROUND_UPDATE_ID = 100000;
-
 
 /* wxString to std::string converter. Useful for printing stuff */
 std::string wx2std (const wxString & input);

src/myFrame.cc

@@ -62,10 +62,6 @@ EVT_MENU (ID_Keep, MyFrame::OnKeep)
 EVT_MENU (ID_Edit, MyFrame::OnEdit) 
 EVT_MENU (ID_Delete, MyFrame::OnDelete)
 /*
-*  Custom
-*/
-//EVT_COMMAND (BACKGROUND_UPDATE_ID, wxEVT_COMMAND_TEXT_UPDATED, MyFrame::OnDelayedBackground)
-/*
 * Painting 
 */
 EVT_PAINT (MyFrame::OnPaint)
@@ -250,12 +246,6 @@ MyFrame::GetWallpaper ()
 {
   return backImage;
 }
-
-//void 
-//MyFrame::OnDelayedBackground(wxCommandEvent &event) {
-    //std::cout << "got update background event" << std::endl;
-    //update_background();
-//}
 
 void MyFrame::SetMarkBitmap (wxBitmap * newBmp)
 {

src/myFrame.h

@@ -126,7 +126,6 @@ class MyFrame:public wxFrame
 
     SettingsDialog *settingsDialog;
     void OnClose (wxCloseEvent &event);
-    //void OnDelayedBackground(wxCommandEvent &event);
 
     DECLARE_EVENT_TABLE () 
 

src/tasks.cc

@@ -207,78 +207,15 @@ bool check_overlap(int x1, int y1, int width1, int height1,
     return false;
 }
 
-// Check whether our simdock window intersects with some different window
-bool is_covered(WnckScreen *screen) {
-    GdkDisplay* display = gdk_display_get_default();
-    GtkWidget* widget = wxGetApp().frame->GetHandle();
-    GdkWindow* gdkWindow = gtk_widget_get_window(widget);
-    XID xid = gdk_x11_window_get_xid(gdkWindow);
-    WnckWindow* frameWindow = wnck_window_get(xid);
-    
-    int win1_x, win1_y, win1_width, win1_height;
-    wnck_window_get_geometry(frameWindow, &win1_x, &win1_y, &win1_width, &win1_height);
-
-    GList* allWindows = wnck_screen_get_windows(screen);
-    for (GList *l = allWindows; l != NULL; l = l->next) {
-        WnckWindow* curWindow = WNCK_WINDOW(l->data);
-        if (wnck_window_is_visible_on_workspace(curWindow, wnck_screen_get_active_workspace(screen))) {
-            Window otherXid = wnck_window_get_xid(curWindow);
-
-            // We use the XID here just to avoid confusion with different pointers
-            if (xid != otherXid) {
-                int win2_x, win2_y, win2_width, win2_height;
-                wnck_window_get_geometry(curWindow, &win2_x, &win2_y, &win2_width, &win2_height);
-                if (check_overlap(win1_x, win1_y, win1_width, win1_height, win2_x, win2_y, win2_width, win2_height)) {
-                    return true;
-                }
-            }
-        }
-    }
-    return false;
-}
-
-// Change the background for pseudo transparency mode
-void update_background() {
-     std::cout << "updating background" << std::endl;
-    // The signal arrives before the background is actually changed. The small sleep workarounds this issue.
-    wxMilliSleep(20);
-    // Now we hide the app, because getRootWallpaper() since the switch to GTK3 also sees simdock itself
-    wxGetApp().frame->SetTransparent(0);
-    wxGetApp().frame->Hide();
-    wxGetApp().frame->Disable();
-    wxGetApp().CallAfter([]{
-        // The use of CallAfter is needed, otherwise the app won't be hidden while getRoootWallpaper runs
-        wxBitmap* backImage = getRootWallpaper();
-        wxGetApp().SetWallpaper(backImage);
-    });
-}
 
 void tasks_window_background_change (WnckScreen *screen, WnckWindow *window, callbackArgs* ca) {
     if (wxGetApp().frame->IsTransparentBackgroundSupported()) {
         // With real transparency enabled we have to do nothing here
         return;
     }
 
-    if (is_covered(screen)) {
-        // Without real transparency, we don't want to continue if the frame is covered. It would
-        // make us fetch the overlapping window as part of the background.
-        std::thread([]() {
-            WnckScreen* screen = wnck_screen_get_default();
-            do {
-                std::cout << "sleeping" << std::endl;
-                std::this_thread::sleep_for(std::chrono::seconds(5)); // Delay of 5 seconds
-            } while (is_covered(screen));
-            std::cout << "send event" << std::endl;
-            //wxCommandEvent event(wxEVT_COMMAND_TEXT_UPDATED, BACKGROUND_UPDATE_ID);
-            //wxGetApp().frame->GetEventHandler()->AddPendingEvent(event);
-            wxGetApp().CallAfter([]{
-                update_background();
-            });
-        }).detach();
-        return;
-    }
-    
-    update_background();
+    wxBitmap* backImage = getRootWallpaper();
+    wxGetApp().SetWallpaper(backImage);
 }
 
 void tasks_track_active_window (WnckScreen *screen, WnckWindow *window, callbackArgs* ca) {

src/tasks.h

@@ -64,6 +64,5 @@ void tasks_register_signals(ImagesArray * ImagesList,simSettings settings);
 /* Adds a new image to the images list given a window and task informations */
 void tasks_addNewImage(WnckWindow *window, ImagesArray* ImagesList, simSettings settings,const taskInfo& ti);
 wxBitmap* tasks_getRootWallpaper();
-void update_background();
 
 #endif