source/graphics/x11/drawcontext.cpp

   1 #include <stdexcept>
   2 #include <sys/ipc.h>
   3 #include <sys/shm.h>
   4 #include <X11/Xlib.h>
   5 #include <X11/extensions/XShm.h>
   6 #include <X11/Xutil.h>
   7 #include "display_private.h"
   8 #include "drawcontext.h"
   9 #include "window_private.h"
  10
  11 using namespace std;
  12
  13 namespace Msp {
  14 namespace Graphics {
  15
  16 struct DrawContext::Private
  17 {
  18         XImage *image;
  19         bool use_shm;
  20         XShmSegmentInfo shminfo;
  21 };
  22
  23 DrawContext::DrawContext(Window &w):
  24         display(w.get_display()),
  25         window(w),
  26         priv(new Private)
  27 {
  28         DisplayHandle dpy = display.get_private().display;
  29
  30         priv->use_shm = XShmQueryExtension(dpy);
  31
  32         XWindowAttributes wa;
  33         XGetWindowAttributes(dpy, window.get_private().window, &wa);
  34
  35         if(priv->use_shm)
  36         {
  37                 priv->image = XShmCreateImage(dpy, wa.visual, wa.depth, ZPixmap, 0, &priv->shminfo, wa.width, wa.height);
  38                 if(!priv->image)
  39                         throw runtime_error("XShmCreateImage");
  40
  41                 priv->shminfo.shmid = shmget(IPC_PRIVATE, priv->image->bytes_per_line*priv->image->height, IPC_CREAT|0666);
  42                 priv->shminfo.shmaddr=priv->image->data = reinterpret_cast<char *>(shmat(priv->shminfo.shmid, 0, 0));
  43                 priv->shminfo.readOnly = false;
  44
  45                 XShmAttach(dpy, &priv->shminfo);
  46
  47                 XSync(dpy, false);
  48                 display.check_error();
  49         }
  50         else
  51         {
  52                 priv->image = XCreateImage(dpy, wa.visual, wa.depth, ZPixmap, 0, 0, wa.width, wa.height, 8, 0);
  53                 if(!priv->image)
  54                         throw runtime_error("XCreateImage");
  55                 priv->image->data = new char[priv->image->bytes_per_line*priv->image->height];
  56         }
  57 }
  58
  59 DrawContext::~DrawContext()
  60 {
  61         if(priv->use_shm)
  62         {
  63                 XShmDetach(display.get_private().display, &priv->shminfo);
  64                 shmdt(priv->shminfo.shmaddr);
  65                 shmctl(priv->shminfo.shmid, IPC_RMID, 0);
  66         }
  67
  68         XDestroyImage(priv->image);
  69
  70         delete priv;
  71 }
  72
  73 unsigned DrawContext::get_depth() const
  74 {
  75         return priv->image->bits_per_pixel;
  76 }
  77
  78 unsigned char *DrawContext::get_data()
  79 {
  80         return reinterpret_cast<unsigned char *>(priv->image->data);
  81 }
  82
  83 void DrawContext::update()
  84 {
  85         DisplayHandle dpy = display.get_private().display;
  86         WindowHandle wnd = window.get_private().window;
  87
  88         GC gc = XCreateGC(dpy, wnd, 0, 0);
  89
  90         if(priv->use_shm)
  91                 XShmPutImage(dpy, wnd, gc, priv->image, 0, 0, 0, 0, priv->image->width, priv->image->height, false);
  92         else
  93                 XPutImage(dpy, wnd, gc, priv->image, 0, 0, 0, 0, priv->image->width, priv->image->height);
  94
  95         XFreeGC(dpy, gc);
  96 }
  97
  98 } // namespace Graphics
  99 } // namespace Msp