path: root/base/gspath.c

/* Copyright (C) 2001-2023 Artifex Software, Inc.
   All Rights Reserved.

   This software is provided AS-IS with no warranty, either express or
   implied.

   This software is distributed under license and may not be copied,
   modified or distributed except as expressly authorized under the terms
   of the license contained in the file LICENSE in this distribution.

   Refer to licensing information at http://www.artifex.com or contact
   Artifex Software, Inc.,  39 Mesa Street, Suite 108A, San Francisco,
   CA 94129, USA, for further information.
*/


/* Basic path routines for Ghostscript library */
#include "gx.h"
#include "math_.h"
#include "gserrors.h"
#include "gxfixed.h"
#include "gxmatrix.h"
#include "gscoord.h"		/* requires gsmatrix.h */
#include "gspath.h"		/* for checking prototypes */
#include "gzstate.h"
#include "gzpath.h"
#include "gxdevice.h"		/* for gxcpath.h */
#include "gxdevmem.h"		/* for gs_device_is_memory */
#include "gzcpath.h"
#include "gxpaint.h"

/* ------ Miscellaneous ------ */

int
gs_newpath(gs_gstate * pgs)
{
    pgs->current_point_valid = false;
    return gx_path_new(pgs->path);
}

int
gs_closepath(gs_gstate * pgs)
{
    gx_path *ppath = pgs->path;
    int code = gx_path_close_subpath(ppath);

    if (code < 0)
        return code;
    pgs->current_point = pgs->subpath_start;
    return code;
}

int
gs_upmergepath(gs_gstate * pgs)
{
    /*
     * We really should be able to implement this as simply
     *   return gx_path_add_path(pgs->saved->path, pgs->path);
     * But because of the current_point members in the gs_gstate,
     * we can't.
     */
    gs_gstate *saved = pgs->saved;
    int code;

    code = gx_path_add_path(saved->path, pgs->path);
    if (code < 0)
        return code;
    if (pgs->current_point_valid) {
        saved->current_point = pgs->current_point;
        saved->subpath_start = pgs->subpath_start;
        saved->current_point_valid = true;
    }
    return code;
}

/* Get the current path (for internal use only). */
gx_path *
gx_current_path(const gs_gstate * pgs)
{
    return pgs->path;
}

/* ------ Points and lines ------ */

static inline void
clamp_point(gs_fixed_point * ppt, double x, double y)
{
    ppt->x = clamp_coord(x);
    ppt->y = clamp_coord(y);
}

int
gs_currentpoint(gs_gstate * pgs, gs_point * ppt)
{
    if (!pgs->current_point_valid)
        return_error(gs_error_nocurrentpoint);
    return gs_itransform(pgs, pgs->current_point.x,
                              pgs->current_point.y, ppt);
}

static inline int
gs_point_transform_compat(double x, double y, const gs_matrix_fixed *m, gs_point *pt)
{
#if !PRECISE_CURRENTPOINT
    gs_fixed_point p;
    int code = gs_point_transform2fixed(m, x, y, &p);

    if (code < 0)
        return code;
    pt->x = fixed2float(p.x);
    pt->y = fixed2float(p.y);
    return 0;
#else
    return gs_point_transform(x, y, (const gs_matrix *)m, pt);
#endif
}

static inline int
gs_distance_transform_compat(double x, double y, const gs_matrix_fixed *m, gs_point *pt)
{
#if !PRECISE_CURRENTPOINT
    gs_fixed_point p;
    int code = gs_distance_transform2fixed(m, x, y, &p);

    if (code < 0)
        return code;
    pt->x = fixed2float(p.x);
    pt->y = fixed2float(p.y);
    return 0;
#else
    return gs_distance_transform(x, y, (const gs_matrix *)m, pt);
#endif
}

static inline int
clamp_point_aux(bool clamp_coordinates, gs_fixed_point *ppt, double x, double y)
{
    if (!f_fits_in_bits(x, fixed_int_bits) || !f_fits_in_bits(y, fixed_int_bits)) {
        if (!clamp_coordinates)
            return_error(gs_error_limitcheck);
        clamp_point(ppt, x, y);
    } else {
        /* 181-01.ps" fails with no rounding in
           "Verify as last element of a userpath and effect on setbbox." */
        ppt->x = float2fixed_rounded(x);
        ppt->y = float2fixed_rounded(y);
    }
    return 0;
}

int
gs_moveto_aux(gs_gstate *pgs, gx_path *ppath, double x, double y)
{
    gs_fixed_point pt;
    int code;

    code = clamp_point_aux(pgs->clamp_coordinates, &pt, x, y);
    if (code < 0)
        return code;
    if (pgs->hpgl_path_mode && path_subpath_open(ppath))
    {
        code = gx_path_add_gap_notes(ppath, pt.x, pt.y, 0);
        if (code < 0)
            return code;
        gx_setcurrentpoint(pgs, x, y);
    }
    else
    {
        code = gx_path_add_point(ppath, pt.x, pt.y);
        if (code < 0)
            return code;
        ppath->start_flags = ppath->state_flags;
        gx_setcurrentpoint(pgs, x, y);
        pgs->subpath_start = pgs->current_point;
    }
    pgs->current_point_valid = true;
    return 0;
}

int
gs_moveto(gs_gstate * pgs, double x, double y)
{
    gs_point pt;
    int code = gs_point_transform_compat(x, y, &pgs->ctm, &pt);

    if (code < 0)
        return code;
    return gs_moveto_aux(pgs, pgs->path, pt.x, pt.y);
}

int
gs_rmoveto(gs_gstate * pgs, double x, double y)
{
    gs_point dd;
    int code;

    if (!pgs->current_point_valid)
        return_error(gs_error_nocurrentpoint);
    code = gs_distance_transform_compat(x, y, &pgs->ctm, &dd);
    if (code < 0)
        return code;
    /* fixme : check in range. */
    return gs_moveto_aux(pgs, pgs->path,
                dd.x + pgs->current_point.x, dd.y + pgs->current_point.y);
}

static inline int
gs_lineto_aux(gs_gstate * pgs, double x, double y)
{
    gx_path *ppath = pgs->path;
    gs_fixed_point pt;
    int code;

    code = clamp_point_aux(pgs->clamp_coordinates, &pt, x, y);
    if (code < 0)
        return code;
    code = gx_path_add_line(ppath, pt.x, pt.y);
    if (code < 0)
        return code;
    gx_setcurrentpoint(pgs, x, y);
    return 0;
}

int
gs_lineto(gs_gstate * pgs, double x, double y)
{
    gs_point pt;
    int code = gs_point_transform_compat(x, y, &pgs->ctm, &pt);

    if (code < 0)
        return code;
    return gs_lineto_aux(pgs, pt.x, pt.y);
}

int
gs_rlineto(gs_gstate * pgs, double x, double y)
{
    gs_point dd;
    int code;

    if (!pgs->current_point_valid)
        return_error(gs_error_nocurrentpoint);
    code = gs_distance_transform_compat(x, y, &pgs->ctm, &dd);
    if (code < 0)
        return code;
    /* fixme : check in range. */
    return gs_lineto_aux(pgs, dd.x + pgs->current_point.x,
                              dd.y + pgs->current_point.y);
}

/* ------ Curves ------ */

static inline int
gs_curveto_aux(gs_gstate * pgs,
           double x1, double y1, double x2, double y2, double x3, double y3)
{
    gs_fixed_point p1, p2, p3;
    int code;
    gx_path *ppath = pgs->path;

    code = clamp_point_aux(pgs->clamp_coordinates, &p1, x1, y1);
    if (code < 0)
        return code;
    code = clamp_point_aux(pgs->clamp_coordinates, &p2, x2, y2);
    if (code < 0)
        return code;
    code = clamp_point_aux(pgs->clamp_coordinates, &p3, x3, y3);
    if (code < 0)
        return code;
    code = gx_path_add_curve(ppath, p1.x, p1.y, p2.x, p2.y, p3.x, p3.y);
    if (code < 0)
        return code;
    gx_setcurrentpoint(pgs, x3, y3);
    return 0;
}

int
gs_curveto(gs_gstate * pgs,
           double x1, double y1, double x2, double y2, double x3, double y3)
{
    gs_point pt1, pt2, pt3;
    int code;

    code = gs_point_transform_compat(x1, y1, &pgs->ctm, &pt1);
    if (code < 0)
        return code;
    code = gs_point_transform_compat(x2, y2, &pgs->ctm, &pt2);
    if (code < 0)
        return code;
    code = gs_point_transform_compat(x3, y3, &pgs->ctm, &pt3);
    if (code < 0)
        return code;
    return gs_curveto_aux(pgs,   pt1.x, pt1.y,   pt2.x, pt2.y,   pt3.x, pt3.y);
}

int
gs_rcurveto(gs_gstate * pgs,
     double dx1, double dy1, double dx2, double dy2, double dx3, double dy3)
{
    gs_point dd1, dd2, dd3;
    int code;

    if (!pgs->current_point_valid)
        return_error(gs_error_nocurrentpoint);
    code = gs_distance_transform_compat(dx1, dy1, &pgs->ctm, &dd1);
    if (code < 0)
        return code;
    code = gs_distance_transform_compat(dx2, dy2, &pgs->ctm, &dd2);
    if (code < 0)
        return code;
    code = gs_distance_transform_compat(dx3, dy3, &pgs->ctm, &dd3);
    if (code < 0)
        return code;
    /* fixme : check in range. */
    return gs_curveto_aux(pgs, dd1.x + pgs->current_point.x, dd1.y + pgs->current_point.y,
                               dd2.x + pgs->current_point.x, dd2.y + pgs->current_point.y,
                               dd3.x + pgs->current_point.x, dd3.y + pgs->current_point.y);
}

/* ------ Clipping ------ */

/* Forward references */
static int common_clip(gs_gstate *, int);

/* Figure out the bbox for a path and a clip path with adjustment if we are
   also doing a stroke.  This is used by the xps interpeter to deteremine
   how big of a transparency group or softmask should be pushed.  Often in
   xps we fill a path with a particular softmask and some other graphic object.
   The transparency group will be the intersection of the path and clipping
   path */
int
gx_curr_fixed_bbox(gs_gstate * pgs, gs_fixed_rect *bbox, gs_bbox_comp_t comp_type)
{
    int code;
    gx_clip_path *clip_path;
    gs_fixed_rect path_bbox;
    int expansion_code;
    bool include_path = true;
    gs_fixed_point expansion;

    code = gx_effective_clip_path(pgs, &clip_path);
    if (code < 0 || clip_path == NULL) {
        bbox->p.x = bbox->p.y = bbox->q.x = bbox->q.y = 0;
        return (code < 0) ? code : gs_error_unknownerror;
    } else {
        *bbox = clip_path->outer_box;
    }
    if (comp_type == NO_PATH) {
       return 0;
    }
    code = gx_path_bbox(pgs->path, &path_bbox);
    if (code < 0)
        return code;
    if (comp_type == PATH_STROKE) {
        /* Handle any stroke expansion of our bounding box */
        expansion_code = gx_stroke_path_expansion(pgs, pgs->path, &expansion);
        if (expansion_code >= 0) {
            path_bbox.p.x -= expansion.x;
            path_bbox.p.y -= expansion.y;
            path_bbox.q.x += expansion.x;
            path_bbox.q.y += expansion.y;
        } else {
            /* Stroke is super wide or we could not figure out the stroke bbox
               due to wacky joints etc. Just use the clip path */
            include_path = false;
        }
    }
    if (include_path) {
        rect_intersect(*bbox, path_bbox);
    }
    return 0;
}

/* A variation of the above that returns a gs_rect (double) bbox */
int
gx_curr_bbox(gs_gstate * pgs, gs_rect *bbox, gs_bbox_comp_t comp_type)
{
    gs_fixed_rect curr_fixed_bbox;

    gx_curr_fixed_bbox(pgs, &curr_fixed_bbox, comp_type);
    bbox->p.x = fixed2float(curr_fixed_bbox.p.x);
    bbox->p.y = fixed2float(curr_fixed_bbox.p.y);
    bbox->q.x = fixed2float(curr_fixed_bbox.q.x);
    bbox->q.y = fixed2float(curr_fixed_bbox.q.y);
    return 0;
}

/*
 * Return the effective clipping path of a graphics state.  Sometimes this
 * is the intersection of the clip path and the view clip path; sometimes it
 * is just the clip path.  We aren't sure what the correct algorithm is for
 * this: for now, we use view clipping unless the current device is a memory
 * device.  This takes care of the most important case, where the current
 * device is a cache device.
 */
int
gx_effective_clip_path(gs_gstate * pgs, gx_clip_path ** ppcpath)
{
    gs_id view_clip_id =
        (pgs->view_clip == 0 || pgs->view_clip->rule == 0 ? gs_no_id :
         pgs->view_clip->id);

    if (pgs->device == NULL || gs_device_is_memory(pgs->device) || pgs->clip_path == NULL) {
        *ppcpath = pgs->clip_path;
        return 0;
    }
    if (pgs->effective_clip_id == pgs->clip_path->id &&
        pgs->effective_view_clip_id == view_clip_id
        ) {
        *ppcpath = pgs->effective_clip_path;
        return 0;
    }
    /* Update the cache. */
    if (view_clip_id == gs_no_id) {
        if (!pgs->effective_clip_shared)
            gx_cpath_free(pgs->effective_clip_path, "gx_effective_clip_path");
        pgs->effective_clip_path = pgs->clip_path;
        pgs->effective_clip_shared = true;
    } else {
        gs_fixed_rect cbox, vcbox;

        gx_cpath_inner_box(pgs->clip_path, &cbox);
        gx_cpath_outer_box(pgs->view_clip, &vcbox);
        if (rect_within(vcbox, cbox)) {
            if (!pgs->effective_clip_shared)
                gx_cpath_free(pgs->effective_clip_path,
                              "gx_effective_clip_path");
            pgs->effective_clip_path = pgs->view_clip;
            pgs->effective_clip_shared = true;
        } else {
            /* Construct the intersection of the two clip paths. */
            int code;
            gx_clip_path ipath;
            gx_path vpath;
            gx_clip_path *npath = pgs->effective_clip_path;

            if (pgs->effective_clip_shared) {
                npath = gx_cpath_alloc(pgs->memory, "gx_effective_clip_path");
                if (npath == 0)
                    return_error(gs_error_VMerror);
            }
            gx_cpath_init_local(&ipath, pgs->memory);
            code = gx_cpath_assign_preserve(&ipath, pgs->clip_path);
            if (code < 0)
                return code;
            gx_path_init_local(&vpath, pgs->memory);
            code = gx_cpath_to_path(pgs->view_clip, &vpath);
            if (code < 0 ||
                (code = gx_cpath_clip(pgs, &ipath, &vpath,
                                      gx_rule_winding_number)) < 0 ||
                (code = gx_cpath_assign_free(npath, &ipath)) < 0
                )
                DO_NOTHING;
            gx_path_free(&vpath, "gx_effective_clip_path");
            gx_cpath_free(&ipath, "gx_effective_clip_path");
            if (code < 0)
                return code;
            pgs->effective_clip_path = npath;
            pgs->effective_clip_shared = false;
        }
    }
    pgs->effective_clip_id = pgs->effective_clip_path->id;
    pgs->effective_view_clip_id = view_clip_id;
    *ppcpath = pgs->effective_clip_path;
    return 0;
}

#ifdef DEBUG
/* Note that we just set the clipping path (internal). */
static void
note_set_clip_path(const gs_gstate * pgs)
{
    if (gs_debug_c('P')) {
        dmlprintf(pgs->memory, "[P]Clipping path:\n");
        gx_cpath_print(pgs->memory, pgs->clip_path);
    }
}
#else
#  define note_set_clip_path(pgs) DO_NOTHING
#endif

int
gs_clippath(gs_gstate * pgs)
{
    gx_path cpath;
    int code;

    gx_path_init_local(&cpath, pgs->path->memory);
    code = gx_cpath_to_path(pgs->clip_path, &cpath);
    if (code >= 0) {
        code = gx_path_assign_free(pgs->path, &cpath);
        pgs->current_point.x = fixed2float(pgs->path->position.x);
        pgs->current_point.y = fixed2float(pgs->path->position.y);
        pgs->current_point_valid = true;
    }
    if (code < 0)
        gx_path_free(&cpath, "gs_clippath");
    return code;
}

int
gs_initclip(gs_gstate * pgs)
{
    gs_fixed_rect box;
    int code = gx_default_clip_box(pgs, &box);

    if (code < 0)
        return code;
    return gx_clip_to_rectangle(pgs, &box);
}

int
gs_clip(gs_gstate * pgs)
{
    return common_clip(pgs, gx_rule_winding_number);
}

int
gs_eoclip(gs_gstate * pgs)
{
    return common_clip(pgs, gx_rule_even_odd);
}

static int
common_clip(gs_gstate * pgs, int rule)
{
    int code = gx_cpath_clip(pgs, pgs->clip_path, pgs->path, rule);
    if (code < 0)
        return code;
    pgs->clip_path->rule = rule;
    note_set_clip_path(pgs);
    return 0;
}

/* Establish a rectangle as the clipping path. */
/* Used by initclip and by the character and Pattern cache logic. */
int
gx_clip_to_rectangle(gs_gstate * pgs, gs_fixed_rect * pbox)
{
    int code = gx_cpath_from_rectangle(pgs->clip_path, pbox);

    if (code < 0)
        return code;
    pgs->clip_path->rule = gx_rule_winding_number;
    /* We are explicitly setting the clip to a specific rectangle, the path list
     * must therefore be reset (it bears no relation to the actual clip now).
     */
    rc_decrement(pgs->clip_path->path_list, "gx_clip_to_rectangle");
    pgs->clip_path->path_list = 0;
    note_set_clip_path(pgs);
    return 0;
}

/* Set the clipping path to the current path, without intersecting. */
/* This is very inefficient right now. */
int
gx_clip_to_path(gs_gstate * pgs)
{
    gs_fixed_rect bbox;
    int code;

    if ((code = gx_path_bbox(pgs->path, &bbox)) < 0 ||
        (code = gx_clip_to_rectangle(pgs, &bbox)) < 0 ||
        (code = gs_clip(pgs)) < 0
        )
        return code;
    note_set_clip_path(pgs);
    return 0;
}

/* Get the default clipping box. */
int
gx_default_clip_box(const gs_gstate * pgs, gs_fixed_rect * pbox)
{
    register gx_device *dev = gs_currentdevice(pgs);
    gs_rect bbox;
    gs_matrix imat;
    int code;

    if (dev->ImagingBBox_set) {	/* Use the ImagingBBox, relative to default user space. */
        gs_defaultmatrix(pgs, &imat);
        bbox.p.x = dev->ImagingBBox[0];
        bbox.p.y = dev->ImagingBBox[1];
        bbox.q.x = dev->ImagingBBox[2];
        bbox.q.y = dev->ImagingBBox[3];
    } else {			/* Use the MediaSize indented by the HWMargins, */
        /* relative to unrotated user space adjusted by */
        /* the Margins.  (We suspect this isn't quite right, */
        /* but the whole issue of "margins" is such a mess that */
        /* we don't think we can do any better.) */
        (*dev_proc(dev, get_initial_matrix)) (dev, &imat);
        /* Adjust for the Margins. */
        imat.tx += dev->Margins[0];
        imat.ty += dev->Margins[1];
        bbox.p.x = dev->HWMargins[0];
        bbox.p.y = dev->HWMargins[1];
        bbox.q.x = dev->MediaSize[0] - dev->HWMargins[2];
        bbox.q.y = dev->MediaSize[1] - dev->HWMargins[3];
    }
    code = gs_bbox_transform(&bbox, &imat, &bbox);
    if (code < 0)
        return code;
    /* Round the clipping box so that it doesn't get ceilinged. */
    pbox->p.x = fixed_rounded(float2fixed(bbox.p.x));
    pbox->p.y = fixed_rounded(float2fixed(bbox.p.y));
    pbox->q.x = fixed_rounded(float2fixed(bbox.q.x));
    pbox->q.y = fixed_rounded(float2fixed(bbox.q.y));
    return 0;
}