main.c

 + main.c  [No Name]                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                 X
#include <stdio.h>
#include <unistd.h>
#include <stdlib.h>

#include <X11/Xlib.h>
#include <X11/Xatom.h>
#include <X11/Xutil.h>
#include <X11/extensions/Xcomposite.h>
#include <X11/extensions/Xrender.h>
#include <X11/extensions/Xdamage.h>
#include <X11/extensions/shape.h>

Window root;
int scr;
Display* dpy;

Picture frontbuffer;
Picture backbuffer;

#define WIDTH DisplayWidth(dpy, scr)
#define HEIGHT DisplayHeight(dpy, scr)
#define DEPTH DefaultDepth(dpy, scr)

// Register a CM
int reg_cm() {
  Window w;
  Atom a;
  static char net_wm_cm[] = "_NET_WM_CM_Sxx";

  snprintf(net_wm_cm, sizeof(net_wm_cm), "_NET_WM_CM_S%d", scr);
  a = XInternAtom(dpy, net_wm_cm, False);

  // Error Handling
  w = XGetSelectionOwner(dpy, a);
  if(w != None) {
    XTextProperty tp;
    char** strs;
    int count;
    Atom win_name_atom = XInternAtom(dpy, "_NET_WM_NAME", False);

    if(!XGetTextProperty(dpy, w, &tp, win_name_atom) && !XGetTextProperty(dpy, w, &tp, XA_WM_NAME)) {
      fprintf(stderr,"Another composite manager is already running (0x%lx)\n",(unsigned long) w);
      return False;
    }
    if(XmbTextPropertyToTextList(dpy, &tp, &strs, &count) == Success) {
      fprintf(stderr,"Another composite manager is already running (%s)\n",strs[0]);
      XFreeStringList(strs);
    }

    XFree(tp.value);

    return False;
  }

  // Actual Registering
  w = XCreateSimpleWindow(dpy, root, 0, 0, 1, 1, 0, None, None);

  Xutf8SetWMProperties(dpy, w, "jacc", "jacc", NULL, 0, NULL, NULL, NULL);

  XSetSelectionOwner(dpy, a, w, 0);

  return True;
}

void setup_events() {
  XGrabServer(dpy);
  XCompositeRedirectSubwindows(dpy, root, CompositeRedirectManual);
  XSelectInput(dpy, root,
          SubstructureNotifyMask|
          ExposureMask|
          StructureNotifyMask|
          PropertyChangeMask);
  XUngrabServer(dpy);
}

void setup_xrender() {
  XRenderPictFormat* d_format = XRenderFindVisualFormat(dpy, DefaultVisual(dpy, scr));

  XRenderPictureAttributes pa;
  pa.subwindow_mode = IncludeInferiors;
  frontbuffer = XRenderCreatePicture(dpy, root, d_format, CPSubwindowMode, &pa);

  Pixmap root_pixmap = XCreatePixmap(dpy, root, WIDTH, HEIGHT, DEPTH);
  backbuffer = XRenderCreatePicture(dpy, root_pixmap, d_format, 0, NULL);
  XFreePixmap(dpy, root_pixmap);
  XSync(dpy, False);
}


void damage_all() {
  Window* children;
  uint children_count;
  Window root_o, parent;
  XShapeSelectInput (dpy, root, ShapeNotifyMask);
  XQueryTree(dpy, root, &root_o, &parent, &children, &children_count);
  XSync(dpy, False);
  for(uint i = 0; i < children_count; i++) {
    //usleep(1000*10);
    XWindowAttributes attrs;
    XGetWindowAttributes(dpy, children[i], &attrs);
    if(attrs.class != InputOnly) {
      XDamageCreate(dpy, children[i], XDamageReportNonEmpty);
      XSync(dpy, False);
    }
  }
}

void paint() {
  Window* children;
  uint children_count;
  Window root_o, parent;
  XQueryTree(dpy, root, &root_o, &parent, &children, &children_count);

  XRenderColor color;
  color.alpha = 50000;
  color.red = 0;
  color.green = 20000;
  color.blue = 40000;

  XRenderFillRectangle(dpy, PictOpSrc, backbuffer, &color,
    0, 0, WIDTH, HEIGHT);

  for(uint i = 0; i < children_count; i++) {
    XSync(dpy, False);
    XWindowAttributes attrs;
    XGetWindowAttributes(dpy, children[i], &attrs);
    XSync(dpy, False);

    XRenderPictFormat* pict_format = XRenderFindVisualFormat(dpy, attrs.visual);
    XSync(dpy, False);

    if(!pict_format || (pict_format->type == picttypedirect || pict_format->direct.alphamask)) {
      printf("discard:%ld(%d,%d)\n", children[i], pict_format->type, pict_format->direct.alphaMask);
      continue;
    }

    printf("naming:%ld(%d,%d)\n", children[i], pict_format->type, pict_format->direct.alphaMask);
    Pixmap pixmap = XCompositeNameWindowPixmap(dpy, children[i]);
    XSync(dpy, False);

    printf("pict:%ld\n", children[i]);
    Picture picture = XRenderCreatePicture(dpy, pixmap, pict_format, 0, 0);
    XSync(dpy, False);

    XRenderComposite(dpy, PictOpOver,
      picture, None, backbuffer,
      0, 0, 0, 0,
      attrs.x, attrs.y, attrs.width, attrs.height);
    XSync(dpy, False);
  }

  XRenderComposite(dpy, PictOpSrc,
    backbuffer, None, frontbuffer,
    0, 0, 0, 0,
    0, 0, WIDTH, HEIGHT);
  XSync(dpy, False);
  XFlush(dpy);
}

int main() {
  dpy = XOpenDisplay(NULL);
  scr = DefaultScreen(dpy);
  root = DefaultRootWindow(dpy);

  XGrabServer(dpy);
  if(!reg_cm(dpy)) {
    exit(1);
  }

  setup_events();
  setup_xrender();

  XUngrabServer(dpy);
  int damage_event, damage_error;
  if (!XDamageQueryExtension(dpy, &damage_event, &damage_error)) {
    fprintf(stderr, "No damage extension\n");
    exit(1);
  }

  damage_all();
  usleep(100*1000);
  paint();

  while(1) {
    XEvent e;
    XNextEvent(dpy, &e);

    if(e.type == MapNotify) {
      XCreateWindowEvent ev = e.xcreatewindow;
      XWindowAttributes attrs;
      XGetWindowAttributes(dpy, ev.window, &attrs);
      if(attrs.class != InputOnly) {
        XDamageCreate(dpy, ev.window, XDamageReportNonEmpty);
      }
    } else if(e.type == damage_event + XDamageNotify) {
      paint();
      printf("paint\n");
      XDamageNotifyEvent* ev = (XDamageNotifyEvent*)&e;
      XDamageSubtract(dpy, ev->damage, None, None);
    } else {
      printf("uncaught event:%d\n", e.type);
    }
  }
}