/* rotate.c 1.1 */
/*
    Copyright 1992, 1993 O'Reilly and Associates, Inc.  Permission to
    use, copy, and modify this program is hereby granted, as long as
    this copyright notice appears in each copy of the program source
    code.
*/

#include "book_utils.h"

/* The triangle's coordinates. */
static PEXCoord2D points[] = {{.4,.5},{.6,.5},{.5,.9}};

void
redraw( dpy, window, renderer, angle )
    Display		*dpy;
    Window		window;
    PEXRenderer		renderer;
    double		angle;
{
    PEXColor		colr;
    PEXVector2D		shift;
    PEXMatrix3x3	translation, rotation;
    
    /* Redraw the window, after first erasing (clearing) it. */
    XClearWindow( dpy, window );
    PEXBeginRendering( dpy, window, renderer ); {

#ifdef PRECONCAT	
	/* Translate back to center of screen. */
	shift.x = shift.y = 0.5;
	PEXTranslate2D( &shift, translation );
	PEXSetLocalTransform2D( dpy, renderer, PEXOCRender,
			        PEXReplace, translation );
	
	/* Apply the rotation. */
	PEXRotate2D( angle, rotation );
	PEXSetLocalTransform2D( dpy, renderer, PEXOCRender,
			        PEXPreConcatenate, rotation );
#elif USE_BUILD_TRANSFORM
    {	PEXVector2D	shift, scale;
	PEXCoord2D	center;

	center.x = center.y = 0.5;
	shift.x = shift.y = 0;
	scale.x = scale.y = 1;
	PEXBuildTransform2D( &center, &shift, angle, &scale,
			     rotation );
	PEXSetLocalTransform2D( dpy, renderer, PEXOCRender,
			        PEXReplace, rotation );
    }
#else
	/* Translate center of bar to the origin. */
	shift.x = shift.y = -0.5;
	PEXTranslate2D( &shift, translation );
	PEXSetLocalTransform2D( dpy, renderer, PEXOCRender,
			        PEXPreConcatenate, translation );

	/* Translate center of bar to the origin. */
	shift.x = shift.y = -0.5;
	PEXTranslate2D( &shift, translation );
	PEXSetLocalTransform2D( dpy, renderer, PEXOCRender,
			        PEXReplace, translation );
	
	/* Apply the rotation. */
	PEXRotate2D( angle, rotation );
	PEXSetLocalTransform2D( dpy, renderer, PEXOCRender,
			        PEXPostConcatenate, rotation );
	
	/* Translate back to center of screen. */
	shift.x = shift.y = 0.5;
	PEXTranslate2D( &shift, translation );
	PEXSetLocalTransform2D( dpy, renderer, PEXOCRender,
			        PEXPostConcatenate, translation );
#endif				
	
	/* Create the primitive. */
	PEXSetInteriorStyle( dpy, renderer, PEXOCRender,
			    PEXInteriorStyleSolid );
	SET_COLOR( 1, 0, 0, colr ); /* red */
	PEXSetSurfaceColor( dpy, renderer, PEXOCRender,
			    PEXColorTypeRGB, &colr );
	PEXFillArea2D( dpy, renderer, PEXOCRender, PEXShapeConvex,
		       True, 3, points );
    }
    PEXEndRendering( dpy, renderer, True );
    XFlush( dpy );
}

#define WIN_GEOM	"500x500+50+50"

main( argc, argv )
    int		argc;
    char	*argv[];
{
    Display			*dpy;
    Window			window;
    XEvent			event;
    XVisualInfo			vis_info;
    XColor			bkgd_color;
    XStandardColormap		cmap_info;
    PEXColorApproxEntry		capx_info;
    XWindowAttributes		wattrs;
    PEXRenderer			renderer;
    PEXRendererAttributes	rattrs;
    PEXExtensionInfo		*pexinfo;
    int				done = 0;
    double			angle = 0, delta;
    
    /* Open a display and initialize PEX. */
    dpy = ora_init_pex( argv, &pexinfo );
    if ( !dpy ) exit(1);
    
    /* Determine the best visual to use. */
    ora_find_best_visual( dpy, &vis_info );
    
    /* Get a standard colormap for the visual. */
    if ( !ora_get_standard_colormap( dpy, &vis_info, &cmap_info ) ) {
	fprintf ( stderr, "Cannot find a standard colormap\n" );
	exit(1);
    }
    ora_set_stdcmap_approx( &vis_info, &cmap_info, &capx_info );

    /* Create the window, giving it a gray background. */
    bkgd_color.red = bkgd_color.green = bkgd_color.blue = 0x5555;
    bkgd_color.flags = DoRed | DoGreen | DoBlue;
    window = ora_create_window( dpy, &vis_info, &cmap_info, WIN_GEOM,
			        &bkgd_color );

    /* Set up the PEX renderer. */
    if ( IMMED_MODE_SPT( pexinfo ) ) {
	renderer = ora_setup_renderer( dpy, window, &capx_info,
				       &rattrs );
    } else {
	fprintf( stderr, "No immediate mode.\n" );
	exit(1);
    }
    
    /* Read and respond to X events. */
    XSelectInput( dpy, window, ExposureMask | ButtonPressMask );
    while ( !done ) {
	XNextEvent( dpy, &event );
	switch ( event.type ) {
	case Expose:
	    /* Flush remaining Expose events, then redraw. */
	    while ( XCheckTypedWindowEvent( dpy, window,
					    Expose, &event ) )
		; /* empty statement */
	    redraw( dpy, window, renderer, angle );
	    break;
	case ButtonPress:
	    switch( event.xbutton.button ) {
	    case Button1:
		/* Rotate. */
		delta = M_PI/10;
		for ( angle = delta; angle < 2*M_PI; angle += delta ) {
		    redraw( dpy, window, renderer, angle );
		    sleep( 1 );
		}		    
		
		/* Reset to initial position. */
		angle = 0;
		redraw( dpy, window, renderer, angle );
		break;
	    default:
		done = 1;
		break;
	    }
	    break;
	}
    }

    XCloseDisplay( dpy );
    return 0;
}