cairo_samples/cairo_xlib_simple.d

   1 /*! Simple Cairo/Xlib example.
   2  * @author Bernhard R. Fischer, 2048R/5C5FFD47 <bf@abenteuerland.at>.
   3  * @version 2014110801
   4  * Compile with
   5  * gcc -Wall $(pkg-config --libs --cflags cairo x11) -o cairo_xlib_simple cairo_xlib_simple.c
   6  */
   7 import iv.cairo;
   8 import iv.x11;
   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 /*! Open an X11 window and create a cairo surface base on that window.
  37  * @param x Width of window.
  38  * @param y Height of window.
  39  * @return Returns a pointer to a valid Xlib cairo surface. The function does
  40  * not return on error (exit(3)).
  41  */
  42 cairo_surface_t* cairo_create_x11_surface0 (int x, int y) {
  43   Display *dsp;
  44   Drawable da;
  45   int screen;
  46   cairo_surface_t *sfc;
  47
  48   if ((dsp = XOpenDisplay(null)) is null) assert(0, "can't open X11 display");
  49   screen = DefaultScreen(dsp);
  50   da = XCreateSimpleWindow(dsp, DefaultRootWindow(dsp), 0, 0, x, y, 0, 0, 0);
  51   XSelectInput(dsp, da, ButtonPressMask|KeyPressMask);
  52   XMapWindow(dsp, da);
  53
  54   sfc = cairo_xlib_surface_create(dsp, da, DefaultVisual(dsp, screen), x, y);
  55   cairo_xlib_surface_set_size(sfc, x, y);
  56
  57   return sfc;
  58 }
  59
  60
  61 /*! Destroy cairo Xlib surface and close X connection.
  62  */
  63 void cairo_close_x11_surface (cairo_surface_t* sfc) {
  64   Display *dsp = cairo_xlib_surface_get_display(sfc);
  65   cairo_surface_destroy(sfc);
  66   XCloseDisplay(dsp);
  67 }
  68
  69
  70 void main () {
  71   cairo_surface_t *sfc;
  72   cairo_t *ctx;
  73
  74   sfc = cairo_create_x11_surface0(500, 500);
  75
  76   ctx = cairo_create(sfc);
  77   cairo_set_source_rgb(ctx, 1, 1, 1);
  78   cairo_paint(ctx);
  79   cairo_move_to(ctx, 20, 20);
  80   cairo_line_to(ctx, 200, 400);
  81   cairo_line_to(ctx, 450, 100);
  82   cairo_line_to(ctx, 20, 20);
  83   cairo_set_source_rgb(ctx, 0, 0, 1);
  84   cairo_fill_preserve(ctx);
  85   cairo_set_line_width(ctx, 5);
  86   cairo_set_source_rgb(ctx, 1, 1, 0);
  87   cairo_stroke(ctx);
  88   cairo_destroy(ctx);
  89
  90   cairo_check_event(sfc, 1);
  91
  92   cairo_close_x11_surface(sfc);
  93 }
  94