C

#include <stdlib.h>#include <stdio.h>#include <unistd.h>#include <X11/Xlib.h>#include <X11/keysymdef.h>#include <X11/extensions/Xrender.h>#define KERNEL_SIZE 6/* create_a8_picture is heavily based (99%) on code** from cairo/src/cairo-xlib-surface.c */Picturecreate_a8_picture (Display* pDisplay,				   Drawable drawable,				   XRenderColor* pColor,				   int iWidth,				   int iHeight,				   Bool bRepeat){	XRenderPictureAttributes pa;	unsigned long ulMask = 0;	Picture picture;	Pixmap pixmap;	pixmap = XCreatePixmap (pDisplay,							drawable,							iWidth <= 0 ? 1 : iWidth,							iHeight <= 0 ? 1 : iHeight,							8);	if (bRepeat)	{		pa.repeat = True;		ulMask = CPRepeat;	}	picture = XRenderCreatePicture (pDisplay,									pixmap,									XRenderFindStandardFormat (pDisplay,															   PictStandardA8),									ulMask,									&pa);    XRenderFillRectangle (pDisplay,						  PictOpSrc,						  picture,						  pColor,						  0,						  0,						  iWidth,						  iHeight);	XFreePixmap (pDisplay, pixmap);	return picture;}intmain (int argc,	  char** argv){	Display* pDisplay = NULL;	XEvent event;	Bool bKeepGoing = True;	Bool bGotEvent = False;	int iEventBase;	int iErrorBase;	int iMajorVersion;	int iMinorVersion;	XSetWindowAttributes values;	Window window;	Visual* pVisual = NULL;	XRenderPictFormat* pPictFormatDefault = NULL;	XRenderPictFormat* pPictFormatA8 = NULL;	XRenderPictFormat* pPictFormatRGB24 = NULL;	XRenderPictFormat* pPictFormatARGB32 = NULL;	XRenderPictureAttributes pictAttribs;	XRenderColor colorTrans = {0x0000, 0x0000, 0x0000, 0x0000};	XRenderColor colorWhite = {0xffff, 0xffff, 0xffff, 0xffff};	XRenderColor colorRed =   {0xffff, 0x0000, 0x0000, 0x7fff};	XRenderColor colorGreen = {0x0000, 0xffff, 0x0000, 0xffff};	XRenderColor colorBlue =  {0x0000, 0x0000, 0xffff, 0xffff};	Picture redFillPict;	Picture greenFillPict;	Picture blueFillPict;	Picture maskPict;	Picture solidPict;	Picture destPict;	int iWindowAttribsMask;	XTrapezoid trapezoid;	XTriangle triangle;	XFixed convolutionKernel[KERNEL_SIZE] = {												XDoubleToFixed (1.0f),												XDoubleToFixed (7.0f),												XDoubleToFixed (10.0f),												XDoubleToFixed (10.0f),												XDoubleToFixed (7.0f),												XDoubleToFixed (1.0f)											};	trapezoid.top = XDoubleToFixed (20.0f);	trapezoid.bottom = XDoubleToFixed (200.0f);	trapezoid.left.p1.x = XDoubleToFixed (140.0f);	trapezoid.left.p1.y = XDoubleToFixed (20.0f);	trapezoid.left.p2.x = XDoubleToFixed (120.0f);	trapezoid.left.p2.y = XDoubleToFixed (200.0f);	trapezoid.right.p1.x = XDoubleToFixed (180.0f);	trapezoid.right.p1.y = XDoubleToFixed (20.0f);	trapezoid.right.p2.x = XDoubleToFixed (250.0f);	trapezoid.right.p2.y = XDoubleToFixed (200.0f);	triangle.p1.x = XDoubleToFixed (225.0f);	triangle.p1.y = XDoubleToFixed (110.0f);	triangle.p2.x = XDoubleToFixed (275.0f);	triangle.p2.y = XDoubleToFixed (210.0f);	triangle.p3.x = XDoubleToFixed (175.0f);	triangle.p3.y = XDoubleToFixed (210.0f);	/* connect to display */	pDisplay = XOpenDisplay (NULL);	if (!pDisplay)	{		printf ("Could not open display\n");		return 1;	}	/* check for Xrender-extension */	if (!XRenderQueryExtension (pDisplay, &iEventBase, &iErrorBase))	{		XCloseDisplay (pDisplay);		printf ("Xrender-extension not found\n");		return 2;	}	/* see which version is available */	XRenderQueryVersion (pDisplay, &iMajorVersion, &iMinorVersion);	printf ("Found Xrender %d.%d\n", iMajorVersion, iMinorVersion);	/* make behaviour synchronous */	XSynchronize (pDisplay, True);	/* get the default visual for this display */	pVisual = DefaultVisual (pDisplay, 0);	/* create and open window */	values.background_pixel = WhitePixel (pDisplay, 0);	values.event_mask = KeyPressMask;	iWindowAttribsMask = CWEventMask | CWBackPixel;	window = XCreateWindow (pDisplay,							RootWindow (pDisplay, 0),							50, 50, 400, 400, 0,							DefaultDepth (pDisplay, 0),							InputOutput,							pVisual,							iWindowAttribsMask,							&values);	XMapWindow (pDisplay, window);	/* now the guessing work starts,	** because Xrender is so "thoroughly" documented :-( */	pPictFormatDefault = XRenderFindVisualFormat (pDisplay, pVisual);	pPictFormatA8 = XRenderFindStandardFormat (pDisplay, PictStandardA8);	pPictFormatRGB24 = XRenderFindStandardFormat (pDisplay, PictStandardRGB24);	pPictFormatARGB32 = XRenderFindStandardFormat (pDisplay, PictStandardARGB32);	printf ("default PictFormat-depth %d\n", pPictFormatDefault->depth);	printf ("A8 PictFormat-depth %d\n", pPictFormatA8->depth);	printf ("RGB24 PictFormat-depth %d\n", pPictFormatRGB24->depth);	printf ("ARGB32 PictFormat-depth %d\n", pPictFormatARGB32->depth);	/* as far as I get it this should give	** me three colored "infinite pictures" */	redFillPict = XRenderCreateSolidFill (pDisplay, &colorRed);	greenFillPict = XRenderCreateSolidFill (pDisplay, &colorGreen);	blueFillPict = XRenderCreateSolidFill (pDisplay, &colorBlue);	/* this is my target- or destination-drawable derived from the window...	** at least I think so */	/*pictAttribs.repeat = True;*/	destPict = XRenderCreatePicture (pDisplay,									 window,									 pPictFormatDefault,									 0,									 &pictAttribs);    maskPict = create_a8_picture (pDisplay,								  window,								  &colorTrans,								  400,								  400,								  False);    solidPict = create_a8_picture (pDisplay,								   window,								   &colorWhite,								   400,								   400,								   True);	/*XRenderSetPictureFilter (pDisplay,							 maskPict,							 "convolution",							 convolutionKernel,							 KERNEL_SIZE);*/	/* this trapezoid show up too now */	XRenderCompositeTrapezoids (pDisplay,								PictOpAdd,								solidPict,								maskPict,								pPictFormatA8,								0, 0,								&trapezoid,								1);	XRenderComposite (pDisplay,					  PictOpOver,					  blueFillPict,					  maskPict,					  destPict,					  0, 0,					  0, 0,					  0, 0,					  400, 400);		XRenderFreePicture (pDisplay, maskPict);	XRenderFreePicture (pDisplay, solidPict);    maskPict = create_a8_picture (pDisplay,								  window,								  &colorTrans,								  400,								  400,								  False);    solidPict = create_a8_picture (pDisplay,								   window,								   &colorWhite,								   400,								   400,								   True);	XRenderCompositeTriangles (pDisplay,							   PictOpAdd,							   solidPict,							   maskPict,							   pPictFormatA8,							   0, 0,							   &triangle,							   1);	XRenderComposite (pDisplay,					  PictOpOver,					  redFillPict,					  maskPict,					  destPict,					  0, 0,					  0, 0,					  0, 0,					  400, 400);	while (bKeepGoing)	{		bGotEvent = XCheckWindowEvent (pDisplay,									   window,									   KeyPressMask,									   &event);		if (bGotEvent)		{			switch (event.type)			{				case KeyPress :					if (XLookupKeysym (&event.xkey, 0) == XK_Escape)						bKeepGoing = False;				break;			}		}		else			usleep (10000);	}	XRenderFreePicture (pDisplay, redFillPict);	XRenderFreePicture (pDisplay, greenFillPict);	XRenderFreePicture (pDisplay, blueFillPict);	XRenderFreePicture (pDisplay, destPict);	XRenderFreePicture (pDisplay, maskPict);	XRenderFreePicture (pDisplay, solidPict);	XUnmapWindow (pDisplay, window);	XDestroyWindow (pDisplay, window);	XCloseDisplay (pDisplay);	return 0;}