¿Cómo puedo dibujar el rectángulo de selección en la pantalla para mi script?

5

Estoy tratando de hacer un simple guión bash de screencasting. Quiero obtener coordenadas de selección de pantalla dibujando un rectángulo rojo con el mouse. Puedo usar xdotools para obtener coordenadas, pero ¿cómo puedo dibujar un rectángulo en la pantalla?

    
pregunta kenn 24.06.2014 - 17:43

1 respuesta

3

Acabo de encontrar enlace y modifiqué el código para deshacerme del cerdo 100% CPU; parece funcionar bien en Ubuntu 14.04 - simplemente ejecútalo desde un terminal, dibuja el área de tu rectángulo, y el programa saldrá, imprimiendo las coordenadas en el terminal:

xrectsel.c :

#include<stdio.h>
#include<stdlib.h>
#include<X11/Xlib.h>
#include<X11/cursorfont.h>
#include<unistd.h> // added for sleep/usleep

// original from [https://bbs.archlinux.org/viewtopic.php?id=85378 Select a screen area with mouse and return the geometry of this area? / Programming & Scripting / Arch Linux Forums]
// build with (Ubuntu 14.04):
// gcc -Wall xrectsel.c -o xrectsel -lX11

int main(void)
{
  int rx = 0, ry = 0, rw = 0, rh = 0;
  int rect_x = 0, rect_y = 0, rect_w = 0, rect_h = 0;
  int btn_pressed = 0, done = 0;

  XEvent ev;
  Display *disp = XOpenDisplay(NULL);

  if(!disp)
    return EXIT_FAILURE;

  Screen *scr = NULL;
  scr = ScreenOfDisplay(disp, DefaultScreen(disp));

  Window root = 0;
  root = RootWindow(disp, XScreenNumberOfScreen(scr));

  Cursor cursor, cursor2;
  cursor = XCreateFontCursor(disp, XC_left_ptr);
  cursor2 = XCreateFontCursor(disp, XC_lr_angle);

  XGCValues gcval;
  gcval.foreground = XWhitePixel(disp, 0);
  gcval.function = GXxor;
  gcval.background = XBlackPixel(disp, 0);
  gcval.plane_mask = gcval.background ^ gcval.foreground;
  gcval.subwindow_mode = IncludeInferiors;

  GC gc;
  gc = XCreateGC(disp, root,
                 GCFunction | GCForeground | GCBackground | GCSubwindowMode,
                 &gcval);

  /* this XGrab* stuff makes XPending true ? */
  if ((XGrabPointer
       (disp, root, False,
        ButtonMotionMask | ButtonPressMask | ButtonReleaseMask, GrabModeAsync,
        GrabModeAsync, root, cursor, CurrentTime) != GrabSuccess))
    printf("couldn't grab pointer:");

  if ((XGrabKeyboard
       (disp, root, False, GrabModeAsync, GrabModeAsync,
        CurrentTime) != GrabSuccess))
    printf("couldn't grab keyboard:");

  // see also: http://stackoverflow.com/questions/19659486/xpending-cycle-is-making-cpu-100
  while (!done) {
    //~ while (!done && XPending(disp)) {
      //~ XNextEvent(disp, &ev);
    if (!XPending(disp)) { usleep(1000); continue; } // fixes the 100% CPU hog issue in original code
    if ( (XNextEvent(disp, &ev) >= 0) ) {
      switch (ev.type) {
        case MotionNotify:
        /* this case is purely for drawing rect on screen */
          if (btn_pressed) {
            if (rect_w) {
              /* re-draw the last rect to clear it */
              XDrawRectangle(disp, root, gc, rect_x, rect_y, rect_w, rect_h);
            } else {
              /* Change the cursor to show we're selecting a region */
              XChangeActivePointerGrab(disp,
                                       ButtonMotionMask | ButtonReleaseMask,
                                       cursor2, CurrentTime);
            }
            rect_x = rx;
            rect_y = ry;
            rect_w = ev.xmotion.x - rect_x;
            rect_h = ev.xmotion.y - rect_y;

            if (rect_w < 0) {
              rect_x += rect_w;
              rect_w = 0 - rect_w;
            }
            if (rect_h < 0) {
              rect_y += rect_h;
              rect_h = 0 - rect_h;
            }
            /* draw rectangle */
            XDrawRectangle(disp, root, gc, rect_x, rect_y, rect_w, rect_h);
            XFlush(disp);
          }
          break;
        case ButtonPress:
          btn_pressed = 1;
          rx = ev.xbutton.x;
          ry = ev.xbutton.y;
          break;
        case ButtonRelease:
          done = 1;
          break;
      }
    }
  }
  /* clear the drawn rectangle */
  if (rect_w) {
    XDrawRectangle(disp, root, gc, rect_x, rect_y, rect_w, rect_h);
    XFlush(disp);
  }
  rw = ev.xbutton.x - rx;
  rh = ev.xbutton.y - ry;
  /* cursor moves backwards */
  if (rw < 0) {
    rx += rw;
    rw = 0 - rw;
  }
  if (rh < 0) {
    ry += rh;
    rh = 0 - rh;
  }

  XCloseDisplay(disp);

  printf("%dx%d+%d+%d\n",rw,rh,rx,ry);

  return EXIT_SUCCESS;
}
    
respondido por el sdbbs 27.04.2016 - 11:51