gtk/gdk/linux-fb/mifillarc.c

/* $XFree86: xc/programs/Xserver/mi/mifillarc.c,v 3.4 1999/04/11 13:11:20 dawes Exp $ */
/************************************************************

Copyright 1989, 1998  The Open Group

All Rights Reserved.

The above copyright notice and this permission notice shall be included in
all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL THE
OPEN GROUP BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

Except as contained in this notice, the name of The Open Group shall not be
used in advertising or otherwise to promote the sale, use or other dealings
in this Software without prior written authorization from The Open Group.

Author:  Bob Scheifler, MIT X Consortium

********************************************************/

/* $TOG: mifillarc.c /main/20 1998/02/09 14:46:52 kaleb $ */

#include <config.h>
#include <math.h>
#include "mi.h"
#include "mifillarc.h"
#include "gdkprivate-fb.h"

#define QUADRANT (90 * 64)
#define HALFCIRCLE (180 * 64)
#define QUADRANT3 (270 * 64)

#ifndef M_PI
#define M_PI	3.14159265358979323846
#endif

#define Dsin(d)	sin((double)d*(M_PI/11520.0))
#define Dcos(d)	cos((double)d*(M_PI/11520.0))

void
miFillArcSetup(register miArc *arc, register miFillArcRec *info)
{
    info->y = arc->height >> 1;
    info->dy = arc->height & 1;
    info->yorg = arc->y + info->y;
    info->dx = arc->width & 1;
    info->xorg = arc->x + (arc->width >> 1) + info->dx;
    info->dx = 1 - info->dx;
    if (arc->width == arc->height)
    {
	/* (2x - 2xorg)^2 = d^2 - (2y - 2yorg)^2 */
	/* even: xorg = yorg = 0   odd:  xorg = .5, yorg = -.5 */
	info->ym = 8;
	info->xm = 8;
	info->yk = info->y << 3;
	if (!info->dx)
	{
	    info->xk = 0;
	    info->e = -1;
	}
	else
	{
	    info->y++;
	    info->yk += 4;
	    info->xk = -4;
	    info->e = - (info->y << 3);
	}
    }
    else
    {
	/* h^2 * (2x - 2xorg)^2 = w^2 * h^2 - w^2 * (2y - 2yorg)^2 */
	/* even: xorg = yorg = 0   odd:  xorg = .5, yorg = -.5 */
	info->ym = (arc->width * arc->width) << 3;
	info->xm = (arc->height * arc->height) << 3;
	info->yk = info->y * info->ym;
	if (!info->dy)
	    info->yk -= info->ym >> 1;
	if (!info->dx)
	{
	    info->xk = 0;
	    info->e = - (info->xm >> 3);
	}
	else
	{
	    info->y++;
	    info->yk += info->ym;
	    info->xk = -(info->xm >> 1);
	    info->e = info->xk - info->yk;
	}
    }
}

void
miFillArcDSetup(register miArc *arc, register miFillArcDRec *info)
{
    /* h^2 * (2x - 2xorg)^2 = w^2 * h^2 - w^2 * (2y - 2yorg)^2 */
    /* even: xorg = yorg = 0   odd:  xorg = .5, yorg = -.5 */
    info->y = arc->height >> 1;
    info->dy = arc->height & 1;
    info->yorg = arc->y + info->y;
    info->dx = arc->width & 1;
    info->xorg = arc->x + (arc->width >> 1) + info->dx;
    info->dx = 1 - info->dx;
    info->ym = ((double)arc->width) * (arc->width * 8);
    info->xm = ((double)arc->height) * (arc->height * 8);
    info->yk = info->y * info->ym;
    if (!info->dy)
	info->yk -= info->ym / 2.0;
    if (!info->dx)
    {
	info->xk = 0;
	info->e = - (info->xm / 8.0);
    }
    else
    {
	info->y++;
	info->yk += info->ym;
	info->xk = -info->xm / 2.0;
	info->e = info->xk - info->yk;
    }
}

static void
miGetArcEdge(register miArc *arc, register miSliceEdgePtr edge, int k,
             gboolean top, gboolean left)
{
    register int xady, y;

    y = arc->height >> 1;
    if (!(arc->width & 1))
	y++;
    if (!top)
    {
	y = -y;
	if (arc->height & 1)
	    y--;
    }
    xady = k + y * edge->dx;
    if (xady <= 0)
	edge->x = - ((-xady) / edge->dy + 1);
    else
	edge->x = (xady - 1) / edge->dy;
    edge->e = xady - edge->x * edge->dy;
    if ((top && (edge->dx < 0)) || (!top && (edge->dx > 0)))
	edge->e = edge->dy - edge->e + 1;
    if (left)
	edge->x++;
    edge->x += arc->x + (arc->width >> 1);
    if (edge->dx > 0)
    {
	edge->deltax = 1;
	edge->stepx = edge->dx / edge->dy;
	edge->dx = edge->dx % edge->dy;
    }
    else
    {
	edge->deltax = -1;
	edge->stepx = - ((-edge->dx) / edge->dy);
	edge->dx = (-edge->dx) % edge->dy;
    }
    if (!top)
    {
	edge->deltax = -edge->deltax;
	edge->stepx = -edge->stepx;
    }
}

void
miEllipseAngleToSlope (int angle, int width, int height, int *dxp, int *dyp,
                       double *d_dxp, double *d_dyp)
{
    int	    dx, dy;
    double  d_dx, d_dy, scale;
    gboolean    negative_dx, negative_dy;

    switch (angle) {
    case 0:
	*dxp = -1;
	*dyp = 0;
	if (d_dxp) {
	    *d_dxp = width / 2.0;
	    *d_dyp = 0;
	}
	break;
    case QUADRANT:
	*dxp = 0;
	*dyp = 1;
	if (d_dxp) {
	    *d_dxp = 0;
	    *d_dyp = - height / 2.0;
	}
	break;
    case HALFCIRCLE:
	*dxp = 1;
	*dyp = 0;
	if (d_dxp) {
	    *d_dxp = - width / 2.0;
	    *d_dyp = 0;
	}
	break;
    case QUADRANT3:
	*dxp = 0;
	*dyp = -1;
	if (d_dxp) {
	    *d_dxp = 0;
	    *d_dyp = height / 2.0;
	}
	break;
    default:
	d_dx = Dcos(angle) * width;
	d_dy = Dsin(angle) * height;
	if (d_dxp) {
	    *d_dxp = d_dx / 2.0;
	    *d_dyp = - d_dy / 2.0;
	}
	negative_dx = FALSE;
	if (d_dx < 0.0)
	{
	    d_dx = -d_dx;
	    negative_dx = TRUE;
	}
	negative_dy = FALSE;
	if (d_dy < 0.0)
	{
	    d_dy = -d_dy;
	    negative_dy = TRUE;
	}
	scale = d_dx;
	if (d_dy > d_dx)
	    scale = d_dy;
	dx = floor ((d_dx * 32768) / scale + 0.5);
	if (negative_dx)
	    dx = -dx;
	*dxp = dx;
	dy = floor ((d_dy * 32768) / scale + 0.5);
	if (negative_dy)
	    dy = -dy;
	*dyp = dy;
	break;
    }
}

static void
miGetPieEdge(register miArc *arc, register int angle,
             register miSliceEdgePtr edge, gboolean top, gboolean left)
{
    register int k;
    int	dx, dy;

    miEllipseAngleToSlope (angle, arc->width, arc->height, &dx, &dy, NULL, NULL);

    if (dy == 0)
    {
	edge->x = left ? -65536 : 65536;
	edge->stepx = 0;
	edge->e = 0;
	edge->dx = -1;
	return;
    }
    if (dx == 0)
    {
	edge->x = arc->x + (arc->width >> 1);
	if (left && (arc->width & 1))
	    edge->x++;
	else if (!left && !(arc->width & 1))
	    edge->x--;
	edge->stepx = 0;
	edge->e = 0;
	edge->dx = -1;
	return;
    }
    if (dy < 0) {
	dx = -dx;
	dy = -dy;
    }
    k = (arc->height & 1) ? dx : 0;
    if (arc->width & 1)
	k += dy;
    edge->dx = dx << 1;
    edge->dy = dy << 1;
    miGetArcEdge(arc, edge, k, top, left);
}

void
miFillArcSliceSetup(register miArc *arc, register miArcSliceRec *slice,
                    GdkGC *pGC)
{
    register int angle1, angle2;

    angle1 = arc->angle1;
    if (arc->angle2 < 0)
    {
	angle2 = angle1;
	angle1 += arc->angle2;
    }
    else
	angle2 = angle1 + arc->angle2;
    while (angle1 < 0)
	angle1 += FULLCIRCLE;
    while (angle1 >= FULLCIRCLE)
	angle1 -= FULLCIRCLE;
    while (angle2 < 0)
	angle2 += FULLCIRCLE;
    while (angle2 >= FULLCIRCLE)
	angle2 -= FULLCIRCLE;
    slice->min_top_y = 0;
    slice->max_top_y = arc->height >> 1;
    slice->min_bot_y = 1 - (arc->height & 1);
    slice->max_bot_y = slice->max_top_y - 1;
    slice->flip_top = FALSE;
    slice->flip_bot = FALSE;
    if (1 /* pGC->arcMode == ArcPieSlice */)
    {
	slice->edge1_top = (angle1 < HALFCIRCLE);
	slice->edge2_top = (angle2 <= HALFCIRCLE);
	if ((angle2 == 0) || (angle1 == HALFCIRCLE))
	{
	    if (angle2 ? slice->edge2_top : slice->edge1_top)
		slice->min_top_y = slice->min_bot_y;
	    else
		slice->min_top_y = arc->height;
	    slice->min_bot_y = 0;
	}
	else if ((angle1 == 0) || (angle2 == HALFCIRCLE))
	{
	    slice->min_top_y = slice->min_bot_y;
	    if (angle1 ? slice->edge1_top : slice->edge2_top)
		slice->min_bot_y = arc->height;
	    else
		slice->min_bot_y = 0;
	}
	else if (slice->edge1_top == slice->edge2_top)
	{
	    if (angle2 < angle1)
	    {
		slice->flip_top = slice->edge1_top;
		slice->flip_bot = !slice->edge1_top;
	    }
	    else if (slice->edge1_top)
	    {
		slice->min_top_y = 1;
		slice->min_bot_y = arc->height;
	    }
	    else
	    {
		slice->min_bot_y = 0;
		slice->min_top_y = arc->height;
	    }
	}
	miGetPieEdge(arc, angle1, &slice->edge1,
		     slice->edge1_top, !slice->edge1_top);
	miGetPieEdge(arc, angle2, &slice->edge2,
		     slice->edge2_top, slice->edge2_top);
    }
    else
    {
	double w2, h2, x1, y1, x2, y2, dx, dy, scale;
	int signdx, signdy, y, k;
	gboolean isInt1 = TRUE, isInt2 = TRUE;

	w2 = (double)arc->width / 2.0;
	h2 = (double)arc->height / 2.0;
	if ((angle1 == 0) || (angle1 == HALFCIRCLE))
	{
	    x1 = angle1 ? -w2 : w2;
	    y1 = 0.0;
	}
	else if ((angle1 == QUADRANT) || (angle1 == QUADRANT3))
	{
	    x1 = 0.0;
	    y1 = (angle1 == QUADRANT) ? h2 : -h2;
	}
	else
	{
	    isInt1 = FALSE;
	    x1 = Dcos(angle1) * w2;
	    y1 = Dsin(angle1) * h2;
	}
	if ((angle2 == 0) || (angle2 == HALFCIRCLE))
	{
	    x2 = angle2 ? -w2 : w2;
	    y2 = 0.0;
	}
	else if ((angle2 == QUADRANT) || (angle2 == QUADRANT3))
	{
	    x2 = 0.0;
	    y2 = (angle2 == QUADRANT) ? h2 : -h2;
	}
	else
	{
	    isInt2 = FALSE;
	    x2 = Dcos(angle2) * w2;
	    y2 = Dsin(angle2) * h2;
	}
	dx = x2 - x1;
	dy = y2 - y1;
	if (arc->height & 1)
	{
	    y1 -= 0.5;
	    y2 -= 0.5;
	}
	if (arc->width & 1)
	{
	    x1 += 0.5;
	    x2 += 0.5;
	}
	if (dy < 0.0)
	{
	    dy = -dy;
	    signdy = -1;
	}
	else
	    signdy = 1;
	if (dx < 0.0)
	{
	    dx = -dx;
	    signdx = -1;
	}
	else
	    signdx = 1;
	if (isInt1 && isInt2)
	{
	    slice->edge1.dx = dx * 2;
	    slice->edge1.dy = dy * 2;
	}
	else
	{
	    scale = (dx > dy) ? dx : dy;
	    slice->edge1.dx = floor((dx * 32768) / scale + .5);
	    slice->edge1.dy = floor((dy * 32768) / scale + .5);
	}
	if (!slice->edge1.dy)
	{
	    if (signdx < 0)
	    {
		y = floor(y1 + 1.0);
		if (y >= 0)
		{
		    slice->min_top_y = y;
		    slice->min_bot_y = arc->height;
		}
		else
		{
		    slice->max_bot_y = -y - (arc->height & 1);
		}
	    }
	    else
	    {
		y = floor(y1);
		if (y >= 0)
		    slice->max_top_y = y;
		else
		{
		    slice->min_top_y = arc->height;
		    slice->min_bot_y = -y - (arc->height & 1);
		}
	    }
	    slice->edge1_top = TRUE;
	    slice->edge1.x = 65536;
	    slice->edge1.stepx = 0;
	    slice->edge1.e = 0;
	    slice->edge1.dx = -1;
	    slice->edge2 = slice->edge1;
	    slice->edge2_top = FALSE;
	}
	else if (!slice->edge1.dx)
	{
	    if (signdy < 0)
		x1 -= 1.0;
	    slice->edge1.x = ceil(x1);
	    slice->edge1_top = signdy < 0;
	    slice->edge1.x += arc->x + (arc->width >> 1);
	    slice->edge1.stepx = 0;
	    slice->edge1.e = 0;
	    slice->edge1.dx = -1;
	    slice->edge2_top = !slice->edge1_top;
	    slice->edge2 = slice->edge1;
	}
	else
	{
	    if (signdx < 0)
		slice->edge1.dx = -slice->edge1.dx;
	    if (signdy < 0)
		slice->edge1.dx = -slice->edge1.dx;
	    k = ceil(((x1 + x2) * slice->edge1.dy - (y1 + y2) * slice->edge1.dx) / 2.0);
	    slice->edge2.dx = slice->edge1.dx;
	    slice->edge2.dy = slice->edge1.dy;
	    slice->edge1_top = signdy < 0;
	    slice->edge2_top = !slice->edge1_top;
	    miGetArcEdge(arc, &slice->edge1, k,
			 slice->edge1_top, !slice->edge1_top);
	    miGetArcEdge(arc, &slice->edge2, k,
			 slice->edge2_top, slice->edge2_top);
	}
    }
}

#define ADDSPANS() \
    pts->x = xorg - x; \
    pts->y = yorg - y; \
    pts->width = slw; \
    pts++; \
    if (miFillArcLower(slw)) \
    { \
	pts->x = xorg - x; \
	pts->y = yorg + y + dy; \
        pts->width = slw; \
	pts++; \
    }

static void
miFillEllipseI(GdkDrawable *pDraw, GdkGC *pGC, miArc *arc)
{
    register int x, y, e;
    int yk, xk, ym, xm, dx, dy, xorg, yorg;
    int slw;
    miFillArcRec info;
    GdkSpan* points;
    register GdkSpan* pts;

    points = (GdkSpan*)ALLOCATE_LOCAL(sizeof(GdkSpan) * arc->height);
    if (!points)
	return;
    miFillArcSetup(arc, &info);
    MIFILLARCSETUP();
    pts = points;
    while (y > 0)
    {
	MIFILLARCSTEP(slw);
	ADDSPANS();
    }
    gdk_fb_fill_spans(pDraw, pGC, points, pts - points, FALSE);

    DEALLOCATE_LOCAL(points);
}

static void
miFillEllipseD(GdkDrawable *pDraw, GdkGC *pGC, miArc *arc)
{
    register int x, y;
    int xorg, yorg, dx, dy, slw;
    double e, yk, xk, ym, xm;
    miFillArcDRec info;
    GdkSpan* points;
    register GdkSpan* pts;

    points = (GdkSpan*)ALLOCATE_LOCAL(sizeof(GdkSpan) * arc->height);
    if (!points)
	return;
    miFillArcDSetup(arc, &info);
    MIFILLARCSETUP();
    pts = points;
    while (y > 0)
    {
	MIFILLARCSTEP(slw);
	ADDSPANS();
    }
    gdk_fb_fill_spans(pDraw, pGC, points, pts - points, FALSE);
    DEALLOCATE_LOCAL(points);
}

#define ADDSPAN(l,r) \
    if (r >= l) \
    { \
	pts->x = l; \
	pts->y = ya; \
        pts->width = r - l + 1; \
	pts++; \
    }

#define ADDSLICESPANS(flip) \
    if (!flip) \
    { \
	ADDSPAN(xl, xr); \
    } \
    else \
    { \
	xc = xorg - x; \
	ADDSPAN(xc, xr); \
	xc += slw - 1; \
	ADDSPAN(xl, xc); \
    }

static void
miFillArcSliceI(GdkDrawable *pDraw, GdkGC *pGC, miArc *arc)
{
    int yk, xk, ym, xm, dx, dy, xorg, yorg, slw;
    register int x, y, e;
    miFillArcRec info;
    miArcSliceRec slice;
    int ya, xl, xr, xc;
    GdkSpan* points;
    register GdkSpan* pts;

    miFillArcSetup(arc, &info);
    miFillArcSliceSetup(arc, &slice, pGC);
    MIFILLARCSETUP();
    slw = arc->height;
    if (slice.flip_top || slice.flip_bot)
	slw += (arc->height >> 1) + 1;
    points = (GdkSpan*)ALLOCATE_LOCAL(sizeof(GdkSpan) * slw);
    if (!points)
	return;
    pts = points;
    while (y > 0)
    {
	MIFILLARCSTEP(slw);
	MIARCSLICESTEP(slice.edge1);
	MIARCSLICESTEP(slice.edge2);
	if (miFillSliceUpper(slice))
	{
	    ya = yorg - y;
	    MIARCSLICEUPPER(xl, xr, slice, slw);
	    ADDSLICESPANS(slice.flip_top);
	}
	if (miFillSliceLower(slice))
	{
	    ya = yorg + y + dy;
	    MIARCSLICELOWER(xl, xr, slice, slw);
	    ADDSLICESPANS(slice.flip_bot);
	}
    }
    
    gdk_fb_fill_spans(pDraw, pGC, points, pts - points, FALSE);
    DEALLOCATE_LOCAL(points);
}

static void
miFillArcSliceD(GdkDrawable *pDraw, GdkGC *pGC, miArc *arc)
{
    register int x, y;
    int dx, dy, xorg, yorg, slw;
    double e, yk, xk, ym, xm;
    miFillArcDRec info;
    miArcSliceRec slice;
    int ya, xl, xr, xc;
    GdkSpan* points;
    register GdkSpan* pts;

    miFillArcDSetup(arc, &info);
    miFillArcSliceSetup(arc, &slice, pGC);
    MIFILLARCSETUP();
    slw = arc->height;
    if (slice.flip_top || slice.flip_bot)
	slw += (arc->height >> 1) + 1;
    points = (GdkSpan*)ALLOCATE_LOCAL(sizeof(GdkSpan) * slw);
    if (!points)
	return;
    pts = points;
    while (y > 0)
    {
	MIFILLARCSTEP(slw);
	MIARCSLICESTEP(slice.edge1);
	MIARCSLICESTEP(slice.edge2);
	if (miFillSliceUpper(slice))
	{
	    ya = yorg - y;
	    MIARCSLICEUPPER(xl, xr, slice, slw);
	    ADDSLICESPANS(slice.flip_top);
	}
	if (miFillSliceLower(slice))
	{
	    ya = yorg + y + dy;
	    MIARCSLICELOWER(xl, xr, slice, slw);
	    ADDSLICESPANS(slice.flip_bot);
	}
    }
    gdk_fb_fill_spans(pDraw, pGC, points, pts - points, FALSE);

    DEALLOCATE_LOCAL(points);
}

/* MIPOLYFILLARC -- The public entry for the PolyFillArc request.
 * Since we don't have to worry about overlapping segments, we can just
 * fill each arc as it comes.
 */
void
miPolyFillArc(GdkDrawable *pDraw, GdkGC *pGC, int narcs, miArc *parcs)
{
    register int i;
    register miArc *arc;

    for(i = narcs, arc = parcs; --i >= 0; arc++)
    {
	if (miFillArcEmpty(arc))
	    continue;;
	if ((arc->angle2 >= FULLCIRCLE) || (arc->angle2 <= -FULLCIRCLE))
	{
	    if (miCanFillArc(arc))
		miFillEllipseI(pDraw, pGC, arc);
	    else
		miFillEllipseD(pDraw, pGC, arc);
	}
	else
	{
	    if (miCanFillArc(arc))
		miFillArcSliceI(pDraw, pGC, arc);
	    else
		miFillArcSliceD(pDraw, pGC, arc);
	}
    }
}