From e1ea4934019243fd6aac566877c9796acc4dc1f1 Mon Sep 17 00:00:00 2001
From: Mikko Rasa <tdb@tdb.fi>
Date: Tue, 5 Feb 2008 16:41:32 +0000
Subject: [PATCH] Add DrawContext for 2D graphics

---
 source/drawcontext.cpp | 90 ++++++++++++++++++++++++++++++++++++++++++
 source/drawcontext.h   | 46 +++++++++++++++++++++
 2 files changed, 136 insertions(+)
 create mode 100644 source/drawcontext.cpp
 create mode 100644 source/drawcontext.h

diff --git a/source/drawcontext.cpp b/source/drawcontext.cpp
new file mode 100644
index 0000000..44ecf21
--- /dev/null
+++ b/source/drawcontext.cpp
@@ -0,0 +1,90 @@
+/* $Id$
+
+This file is part of libmspgbase
+Copyright © 2007 Mikko Rasa, Mikkosoft Productions
+Distributed under the LGPL
+*/
+
+#ifndef WIN32
+#include <sys/ipc.h>
+#include <sys/shm.h>
+#include <X11/Xutil.h>
+#endif
+#include <msp/core/except.h>
+#include "display.h"
+#include "drawcontext.h"
+#include "window.h"
+
+namespace Msp {
+namespace Graphics {
+
+DrawContext::DrawContext(Window &w):
+	display(w.get_display()),
+	window(w),
+	image(0)
+{
+#ifndef WIN32
+	::Display *dpy=display.get_display();
+
+	use_shm=false; XShmQueryExtension(dpy);
+
+	XWindowAttributes wa;
+	XGetWindowAttributes(dpy, window.get_handle(), &wa);
+
+	if(use_shm)
+	{
+		image=XShmCreateImage(dpy, wa.visual, wa.depth, ZPixmap, 0, &shminfo, wa.width, wa.height);
+		if(!image)
+			throw Exception("Could not create shared memory XImage");
+
+		shminfo.shmid=shmget(IPC_PRIVATE, image->bytes_per_line*image->height, IPC_CREAT|0666);
+		shminfo.shmaddr=image->data=reinterpret_cast<char *>(shmat(shminfo.shmid, 0, 0));
+		shminfo.readOnly=false;
+
+		XShmAttach(dpy, &shminfo);
+
+		XSync(dpy, false);
+		display.check_error();
+	}
+	else
+	{
+		image=XCreateImage(dpy, wa.visual, wa.depth, ZPixmap, 0, 0, wa.width, wa.height, 8, 0);
+		if(!image)
+			throw Exception("Could not create XImage");
+		image->data=new char[image->bytes_per_line*image->height];
+	}
+#endif
+}
+
+DrawContext::~DrawContext()
+{
+#ifndef WIN32
+	if(use_shm)
+	{
+		XShmDetach(display.get_display(), &shminfo);
+		shmdt(shminfo.shmaddr);
+		shmctl(shminfo.shmid, IPC_RMID, 0);
+	}
+
+	XDestroyImage(image);
+#endif
+}
+
+void DrawContext::update()
+{
+#ifndef WIN32
+	::Display *dpy=display.get_display();
+
+	GC gc=XCreateGC(dpy, window.get_handle(), 0, 0);
+
+	if(use_shm)
+		XShmPutImage(dpy, window.get_handle(), gc, image, 0, 0, 0, 0, image->width, image->height, false);
+	else
+		XPutImage(dpy, window.get_handle(), gc, image, 0, 0, 0, 0, image->width, image->height);
+
+	XFreeGC(dpy, gc);
+#endif
+}
+
+} // namespace Graphics
+} // namespace Msp
diff --git a/source/drawcontext.h b/source/drawcontext.h
new file mode 100644
index 0000000..15f66cb
--- /dev/null
+++ b/source/drawcontext.h
@@ -0,0 +1,46 @@
+/* $Id$
+
+This file is part of libmspgbase
+Copyright © 2007 Mikko Rasa, Mikkosoft Productions
+Distributed under the LGPL
+*/
+
+#ifndef MSP_GBASE_DRAWCONTEXT_H_
+#define MSP_GBASE_DRAWCONTEXT_H_
+
+#ifndef WIN32
+#include <X11/Xlib.h>
+#include <X11/extensions/XShm.h>
+#endif
+
+namespace Msp {
+namespace Graphics {
+
+class Display;
+class Window;
+
+class DrawContext
+{
+private:
+	Display &display;
+	Window &window;
+#ifndef WIN32
+	XImage *image;
+	bool use_shm;
+	XShmSegmentInfo shminfo;
+#endif
+
+public:
+	DrawContext(Window &);
+	~DrawContext();
+
+	Window &get_window() const { return window; }
+	unsigned get_depth() const { return image->depth; }
+	unsigned char *get_data() { return reinterpret_cast<unsigned char *>(image->data); }
+	void update();
+};
+
+} // namespace Graphics
+} // namespace Msp
+
+#endif
-- 
2.45.2