cairo_samples/cairo_xlib.d

   1 /*! Cairo graphics and X11/Xlib motion example.
   2  * @author Bernhard R. Fischer, 2048R/5C5FFD47 <bf@abenteuerland.at>.
   3  * @version 2014110801
   4  * Compile with gcc -Wall $(pkg-config --cflags --libs cairo x11) -o cairo_xlib cairo_xlib.c
   5  */
   6 import iv.cairo;
   7 import iv.x11;
   8
   9
  10 /*! Check for Xlib Mouse/Keypress events. All other events are discarded.
  11  * @param sfc Pointer to Xlib surface.
  12  * @param block If block is set to 0, this function always returns immediately
  13  * and does not block. if set to a non-zero value, the function will block
  14  * until the next event is received.
  15  * @return The function returns 0 if no event occured (and block is set). A
  16  * positive value indicates that a key was pressed and the X11 key symbol as
  17  * defined in <X11/keysymdef.h> is returned. A negative value indicates a mouse
  18  * button event. -1 is button 1 (left button), -2 is the middle button, and -3
  19  * the right button.
  20  */
  21 int cairo_check_event (cairo_surface_t* sfc, int block) {
  22   char[8] keybuf;
  23   KeySym key;
  24   XEvent e;
  25   for (;;) {
  26     if (block || XPending(cairo_xlib_surface_get_display(sfc))) XNextEvent(cairo_xlib_surface_get_display(sfc), &e); else return 0;
  27     switch (e.type) {
  28       case ButtonPress: return -e.xbutton.button;
  29       case KeyPress: XLookupString(&e.xkey, keybuf.ptr, keybuf.length, &key, null); return key;
  30       default: //fprintf(stderr, "Dropping unhandled XEevent.type = %d.\n", e.type);
  31     }
  32   }
  33 }
  34
  35
  36 void fullscreen (Display* dpy, Window win) {
  37   Atom[2] atoms = None;
  38   atoms[0] = XInternAtom(dpy, "_NET_WM_STATE_FULLSCREEN", False);
  39   XChangeProperty(dpy, win, XInternAtom(dpy, "_NET_WM_STATE", False), XA_ATOM, 32, PropModeReplace, cast(ubyte*)atoms.ptr, 1);
  40 }
  41
  42
  43 /*! Open an X11 window and create a cairo surface base on that window. If x and
  44  * y are set to 0 the function opens a full screen window and stores to window
  45  * dimensions to x and y.
  46  * @param x Pointer to width of window.
  47  * @param y Pointer to height of window.
  48  * @return Returns a pointer to a valid Xlib cairo surface. The function does
  49  * not return on error (exit(3)).
  50  */
  51 cairo_surface_t* cairo_create_x11_surface (int* x, int* y) {
  52   Display* dsp;
  53   Drawable da;
  54   Screen* scr;
  55   int screen;
  56   cairo_surface_t *sfc;
  57
  58   if ((dsp = XOpenDisplay(null)) is null) assert(0, "cannot open X11 display");
  59   screen = DefaultScreen(dsp);
  60   scr = DefaultScreenOfDisplay(dsp);
  61   if (*x == 0 || *y == 0) {
  62     *x = WidthOfScreen(scr);
  63     *y = HeightOfScreen(scr);
  64     da = XCreateSimpleWindow(dsp, DefaultRootWindow(dsp), 0, 0, *x, *y, 0, 0, 0);
  65     fullscreen(dsp, da);
  66   } else {
  67     da = XCreateSimpleWindow(dsp, DefaultRootWindow(dsp), 0, 0, *x, *y, 0, 0, 0);
  68   }
  69   XSelectInput(dsp, da, ButtonPressMask | KeyPressMask);
  70   XMapWindow(dsp, da);
  71
  72   sfc = cairo_xlib_surface_create(dsp, da, DefaultVisual(dsp, screen), *x, *y);
  73   cairo_xlib_surface_set_size(sfc, *x, *y);
  74
  75   return sfc;
  76 }
  77
  78
  79 /*! Destroy cairo Xlib surface and close X connection.
  80  */
  81 void cairo_close_x11_surface (cairo_surface_t* sfc) {
  82   Display *dsp = cairo_xlib_surface_get_display(sfc);
  83   cairo_surface_destroy(sfc);
  84   XCloseDisplay(dsp);
  85 }
  86
  87
  88 void turn (double v, double max, double* diff) {
  89   if (v <= 0 || v >= max) *diff *= -1.0;
  90 }
  91
  92
  93 void main (string[] args) {
  94   import core.sys.posix.signal : timespec;
  95   import core.sys.posix.time : nanosleep;
  96
  97   cairo_surface_t* sfc;
  98   cairo_t* ctx;
  99   int x, y;
 100
 101   double x0 = 20, y0 = 20, x1 = 200, y1 = 400, x2 = 450, y2 = 100;
 102   double dx0 = 1, dx1 = 1.5, dx2 = 2;
 103   double dy0 = 2, dy1 = 1.5, dy2 = 1;
 104   bool running = true;
 105
 106   import std.conv : to;
 107
 108   x = y = 0;
 109   if (args.length > 1) x = to!int(args[1]);
 110   if (args.length > 2) y = to!int(args[2]);
 111   sfc = cairo_create_x11_surface(&x, &y);
 112   ctx = cairo_create(sfc);
 113
 114   while (running) {
 115     cairo_push_group(ctx);
 116     cairo_set_source_rgb(ctx, 1, 1, 1);
 117     cairo_paint(ctx);
 118     cairo_move_to(ctx, x0, y0);
 119     cairo_line_to(ctx, x1, y1);
 120     cairo_line_to(ctx, x2, y2);
 121     cairo_line_to(ctx, x0, y0);
 122     cairo_set_source_rgb(ctx, 0, 0, 1);
 123     cairo_fill_preserve(ctx);
 124     cairo_set_line_width(ctx, 5);
 125     cairo_set_source_rgb(ctx, 1, 1, 0);
 126     cairo_stroke(ctx);
 127     cairo_set_source_rgb(ctx, 0, 0, 0);
 128     cairo_move_to(ctx, x0, y0);
 129     cairo_show_text(ctx, "P0");
 130     cairo_move_to(ctx, x1, y1);
 131     cairo_show_text(ctx, "P1");
 132     cairo_move_to(ctx, x2, y2);
 133     cairo_show_text(ctx, "P2");
 134     cairo_pop_group_to_source(ctx);
 135     cairo_paint(ctx);
 136     cairo_surface_flush(sfc);
 137
 138     x0 += dx0;
 139     y0 += dy0;
 140     x1 += dx1;
 141     y1 += dy1;
 142     x2 += dx2;
 143     y2 += dy2;
 144     turn(x0, x, &dx0);
 145     turn(x1, x, &dx1);
 146     turn(x2, x, &dx2);
 147     turn(y0, y, &dy0);
 148     turn(y1, y, &dy1);
 149     turn(y2, y, &dy2);
 150
 151     switch (cairo_check_event(sfc, 0)) {
 152       case 0xff53:   // right cursor
 153         dx0 *= 2.0;
 154         dy0 *= 2.0;
 155         break;
 156       case 0xff51:   // left cursor
 157         dx0 /= 2.0;
 158         dy0 /= 2.0;
 159         break;
 160       case 0xff1b:   // Esc
 161       case -1:       // left mouse button
 162         running = false;
 163         break;
 164       default:
 165     }
 166
 167     timespec ts;
 168     ts.tv_sec = 0;
 169     ts.tv_nsec = 5000000;
 170     nanosleep(&ts, null);
 171   }
 172
 173   cairo_destroy(ctx);
 174   cairo_close_x11_surface(sfc);
 175 }