#include <stdio.h>
#include <X11/Xlib.h>
#include <X11/extensions/Xrender.h>
#include <stdlib.h>
#include <math.h>
#include <stdlib.h>
#include <sys/time.h>

static Picture createPicture(Display *display)
{
    Pixmap pixmap;
    XRenderPictFormat *fmt;
    XRenderPictureAttributes pict_attr;
    XRenderColor red = {
	.red = 0xffff,
	.alpha = 0xffff
    };
    Picture picture;

    fmt = XRenderFindStandardFormat(display, PictStandardRGB24);

    pixmap = XCreatePixmap(display, DefaultRootWindow(display), 128, 128, fmt->depth);
    pict_attr.repeat=RepeatNone;
    picture = XRenderCreatePicture(display, pixmap, fmt, CPRepeat, &pict_attr);
    XFreePixmap(display, pixmap);

    XRenderFillRectangle (display, PictOpSrc, picture, &red, 0, 0, 128, 128);

    return picture;
}

int main(int argc, char *argv[])
{
    Display *display;
    Visual *visual;
    Window window;
    Picture source, picture;
    XRenderPictFormat *fmt;
    XRectangle clip;
    XRenderColor color_white = {.red=0xffff, .green=0xffff, .blue=0xffff, .alpha=0xffff};
    int render_event_base, render_error_base;

    display = XOpenDisplay(NULL);

    if (!XRenderQueryExtension(display, &render_event_base, &render_error_base)) {
	fprintf(stderr, "RENDER extension missing!\n");
	abort();
    }

    visual = DefaultVisual (display, DefaultScreen (display));
    fmt = XRenderFindVisualFormat (display, visual);

    window = XCreateWindow (display, DefaultRootWindow (display), 0, 0,
			    640, 480, 0, fmt->depth,
			    InputOutput, visual, 0, NULL);
    XMapWindow (display, window);

    picture = XRenderCreatePicture(display, window, fmt, 0, NULL);

    XSelectInput(display, window, KeyPressMask|KeyReleaseMask|ExposureMask
		 |ButtonPressMask|StructureNotifyMask);


    /* now make the window visible */
    XMapWindow(display, window);

    source = createPicture(display);
    XRenderSetPictureFilter(display, source, "fast", NULL, 0);

    fmt = XRenderFindStandardFormat(display, PictStandardA8);

    //Shear
    XTransform xf;
    xf.matrix[0][0] = XDoubleToFixed(1); 
    xf.matrix[0][1] = XDoubleToFixed(0.5);
    xf.matrix[0][2] = 0;
    xf.matrix[1][0] = XDoubleToFixed(0);
    xf.matrix[1][1] = XDoubleToFixed(1);
    xf.matrix[1][2] = 0;
    xf.matrix[2][0] = 0;
    xf.matrix[2][1] = 0;
    xf.matrix[2][2] = 1<<16;
    XRenderSetPictureTransform (display, source, &xf);

    while(1) {
	XEvent event;
	XNextEvent(display, &event);

	switch(event.type) {
	case Expose:
	    XRenderFillRectangle(display, PictOpOver, picture, &color_white, 0, 0, 1000, 1000);
	    XRenderComposite (display, PictOpOver, source, None, picture, -100, -100, 0, 0, 0, 0, 500, 500);
	    break;
	case DestroyNotify:
	    return 0;
	}
    }
    return 0;
}