harvey/sys/src/cmd/gs/src/gdevpdfd.c

/* Copyright (C) 1997, 2000 Aladdin Enterprises.  All rights reserved.
  
  This file is part of AFPL Ghostscript.
  
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  distributor accepts any responsibility for the consequences of using it, or
  for whether it serves any particular purpose or works at all, unless he or
  she says so in writing.  Refer to the Aladdin Free Public License (the
  "License") for full details.
  
  Every copy of AFPL Ghostscript must include a copy of the License, normally
  in a plain ASCII text file named PUBLIC.  The License grants you the right
  to copy, modify and redistribute AFPL Ghostscript, but only under certain
  conditions described in the License.  Among other things, the License
  requires that the copyright notice and this notice be preserved on all
  copies.
*/

/*$Id: gdevpdfd.c,v 1.16 2001/07/27 22:28:31 lpd Exp $ */
/* Path drawing procedures for pdfwrite driver */
#include "math_.h"
#include "gx.h"
#include "gxdevice.h"
#include "gxfixed.h"
#include "gxistate.h"
#include "gxpaint.h"
#include "gzpath.h"
#include "gzcpath.h"
#include "gdevpdfx.h"
#include "gdevpdfg.h"

/* ---------------- Drawing ---------------- */

/* Fill a rectangle. */
int
gdev_pdf_fill_rectangle(gx_device * dev, int x, int y, int w, int h,
			gx_color_index color)
{
    gx_device_pdf *pdev = (gx_device_pdf *) dev;
    int code;

    /* Make a special check for the initial fill with white, */
    /* which shouldn't cause the page to be opened. */
    if (color == pdev->white && !is_in_page(pdev))
	return 0;
    code = pdf_open_page(pdev, PDF_IN_STREAM);
    if (code < 0)
	return code;
    /* Make sure we aren't being clipped. */
    pdf_put_clip_path(pdev, NULL);
    pdf_set_pure_color(pdev, color, &pdev->fill_color,
		       &psdf_set_fill_color_commands);
    pprintd4(pdev->strm, "%d %d %d %d re f\n", x, y, w, h);
    return 0;
}

/* ---------------- Path drawing ---------------- */

/* ------ Vector device implementation ------ */

private int
pdf_setlinewidth(gx_device_vector * vdev, floatp width)
{
    /* Acrobat Reader doesn't accept negative line widths. */
    return psdf_setlinewidth(vdev, fabs(width));
}

private int
pdf_setfillcolor(gx_device_vector * vdev, const gx_drawing_color * pdc)
{
    gx_device_pdf *const pdev = (gx_device_pdf *)vdev;

    return pdf_set_drawing_color(pdev, pdc, &pdev->fill_color,
				 &psdf_set_fill_color_commands);
}

private int
pdf_setstrokecolor(gx_device_vector * vdev, const gx_drawing_color * pdc)
{
    gx_device_pdf *const pdev = (gx_device_pdf *)vdev;

    return pdf_set_drawing_color(pdev, pdc, &pdev->stroke_color,
				 &psdf_set_stroke_color_commands);
}

private int
pdf_dorect(gx_device_vector * vdev, fixed x0, fixed y0, fixed x1, fixed y1,
	   gx_path_type_t type)
{
    fixed xmax = int2fixed(vdev->width), ymax = int2fixed(vdev->height);
    fixed xmin = 0, ymin = 0;

    /*
     * If we're doing a stroke operation, expand the checking box by the
     * stroke width.
     */
    if (type & gx_path_type_stroke) {
	double w = vdev->state.line_params.half_width;
	double xw = w * (fabs(vdev->state.ctm.xx) + fabs(vdev->state.ctm.yx));
	double yw = w * (fabs(vdev->state.ctm.xy) + fabs(vdev->state.ctm.yy));

	xmin = -(float2fixed(xw) + fixed_1);
	xmax -= xmin;
	ymin = -(float2fixed(yw) + fixed_1);
	ymax -= ymin;
    }
    if (!(type & gx_path_type_clip) &&
	(x0 > xmax || x1 < xmin || y0 > ymax || y1 < ymin ||
	 x0 > x1 || y0 > y1)
	)
	return 0;		/* nothing to fill or stroke */
    /*
     * Clamp coordinates to avoid tripping over Acrobat Reader's limit
     * of 32K on user coordinate values.
     */
    if (x0 < xmin)
	x0 = xmin;
    if (x1 > xmax)
	x1 = xmax;
    if (y0 < ymin)
	y0 = ymin;
    if (y1 > ymax)
	y1 = ymax;
    return psdf_dorect(vdev, x0, y0, x1, y1, type);
}

private int
pdf_endpath(gx_device_vector * vdev, gx_path_type_t type)
{
    return 0;			/* always handled by caller */
}

const gx_device_vector_procs pdf_vector_procs = {
	/* Page management */
    NULL,
	/* Imager state */
    pdf_setlinewidth,
    psdf_setlinecap,
    psdf_setlinejoin,
    psdf_setmiterlimit,
    psdf_setdash,
    psdf_setflat,
    psdf_setlogop,
	/* Other state */
    pdf_setfillcolor,
    pdf_setstrokecolor,
	/* Paths */
    psdf_dopath,
    pdf_dorect,
    psdf_beginpath,
    psdf_moveto,
    psdf_lineto,
    psdf_curveto,
    psdf_closepath,
    pdf_endpath
};

/* ------ Utilities ------ */

/* Test whether we will need to put the clipping path. */
bool
pdf_must_put_clip_path(gx_device_pdf * pdev, const gx_clip_path * pcpath)
{
    if (pcpath == NULL)
	return pdev->clip_path_id != pdev->no_clip_path_id;
    if (pdev->clip_path_id == pcpath->id)
	return false;
    if (gx_cpath_includes_rectangle(pcpath, fixed_0, fixed_0,
				    int2fixed(pdev->width),
				    int2fixed(pdev->height))
	)
	return pdev->clip_path_id != pdev->no_clip_path_id;
    return true;
}

/* Put a clipping path on the output file. */
int
pdf_put_clip_path(gx_device_pdf * pdev, const gx_clip_path * pcpath)
{
    stream *s = pdev->strm;

    if (pcpath == NULL) {
	if (pdev->clip_path_id == pdev->no_clip_path_id)
	    return 0;
	stream_puts(s, "Q\nq\n");
	pdev->clip_path_id = pdev->no_clip_path_id;
    } else {
	if (pdev->clip_path_id == pcpath->id)
	    return 0;
	if (gx_cpath_includes_rectangle(pcpath, fixed_0, fixed_0,
					int2fixed(pdev->width),
					int2fixed(pdev->height))
	    ) {
	    if (pdev->clip_path_id == pdev->no_clip_path_id)
		return 0;
	    stream_puts(s, "Q\nq\n");
	    pdev->clip_path_id = pdev->no_clip_path_id;
	} else {
	    gdev_vector_dopath_state_t state;
	    gs_cpath_enum cenum;
	    gs_fixed_point vs[3];
	    int pe_op;

	    stream_puts(s, "Q\nq\n");
	    gdev_vector_dopath_init(&state, (gx_device_vector *)pdev,
				    gx_path_type_fill, NULL);
	    /*
	     * We have to break 'const' here because the clip path
	     * enumeration logic uses some internal mark bits.
	     * This is very unfortunate, but until we can come up with
	     * a better algorithm, it's necessary.
	     */
	    gx_cpath_enum_init(&cenum, (gx_clip_path *) pcpath);
	    while ((pe_op = gx_cpath_enum_next(&cenum, vs)) > 0)
		gdev_vector_dopath_segment(&state, pe_op, vs);
	    pprints1(s, "%s n\n", (pcpath->rule <= 0 ? "W" : "W*"));
	    if (pe_op < 0)
		return pe_op;
	    pdev->clip_path_id = pcpath->id;
	}
    }
    pdev->text.font = 0;
    if (pdev->context == PDF_IN_TEXT)
	pdev->context = PDF_IN_STREAM;
    pdf_reset_graphics(pdev);
    return 0;
}

/*
 * Compute the scaling to ensure that user coordinates for a path are within
 * Acrobat's range.  Return true if scaling was needed.  In this case, the
 * CTM will be multiplied by *pscale, and all coordinates will be divided by
 * *pscale.
 */
private bool
make_path_scaling(const gx_device_pdf *pdev, gx_path *ppath,
		  floatp prescale, double *pscale)
{
    gs_fixed_rect bbox;
    double bmin, bmax;

    gx_path_bbox(ppath, &bbox);
    bmin = min(bbox.p.x / pdev->scale.x, bbox.p.y / pdev->scale.y) * prescale;
    bmax = max(bbox.q.x / pdev->scale.x, bbox.q.y / pdev->scale.y) * prescale;
    if (bmin <= int2fixed(-MAX_USER_COORD) ||
	bmax > int2fixed(MAX_USER_COORD)
	) {
	/* Rescale the path. */
	*pscale = max(bmin / int2fixed(-MAX_USER_COORD),
		      bmax / int2fixed(MAX_USER_COORD));
	return true;
    } else {
	*pscale = 1;
	return false;
    }
#undef MAX_USER_COORD
}

/* ------ Driver procedures ------ */

/* Fill a path. */
int
gdev_pdf_fill_path(gx_device * dev, const gs_imager_state * pis, gx_path * ppath,
		   const gx_fill_params * params,
	      const gx_drawing_color * pdcolor, const gx_clip_path * pcpath)
{
    gx_device_pdf *pdev = (gx_device_pdf *) dev;
    int code;
    /*
     * HACK: we fill an empty path in order to set the clipping path
     * and the color for writing text.  If it weren't for this, we
     * could detect and skip empty paths before putting out the clip
     * path or the color.  We also clip with an empty path in order
     * to advance currentpoint for show operations without actually
     * drawing anything.
     */
    bool have_path;

    /*
     * Check for an empty clipping path.
     */
    if (pcpath) {
	gs_fixed_rect box;

	gx_cpath_outer_box(pcpath, &box);
	if (box.p.x >= box.q.x || box.p.y >= box.q.y)
	    return 0;		/* empty clipping path */
    }
    code = pdf_prepare_fill(pdev, pis);
    if (code < 0)
	return code;
    if (gx_dc_is_pure(pdcolor)) {
	/*
	 * Make a special check for the initial fill with white,
	 * which shouldn't cause the page to be opened.
	 */
	if (gx_dc_pure_color(pdcolor) == pdev->white && !is_in_page(pdev))
	    return 0;
    }
    have_path = !gx_path_is_void(ppath);
    if (have_path || pdev->context == PDF_IN_NONE ||
	pdf_must_put_clip_path(pdev, pcpath)
	) {
	code = pdf_open_page(pdev, PDF_IN_STREAM);
	if (code < 0)
	    return code;
    }
    pdf_put_clip_path(pdev, pcpath);
    if (pdf_setfillcolor((gx_device_vector *)pdev, pdcolor) < 0)
	return gx_default_fill_path(dev, pis, ppath, params, pdcolor,
				    pcpath);
    if (have_path) {
	stream *s = pdev->strm;
	double scale;
	gs_matrix smat;
	gs_matrix *psmat = NULL;

	if (params->flatness != pdev->state.flatness) {
	    pprintg1(s, "%g i\n", params->flatness);
	    pdev->state.flatness = params->flatness;
	}
	if (make_path_scaling(pdev, ppath, 1.0, &scale)) {
	    gs_make_scaling(pdev->scale.x * scale, pdev->scale.y * scale,
			    &smat);
            pdf_put_matrix(pdev, "q ", &smat, "cm\n");
	    psmat = &smat;
	}
	gdev_vector_dopath((gx_device_vector *)pdev, ppath,
			   gx_path_type_fill | gx_path_type_optimize,
			   psmat);
	stream_puts(s, (params->rule < 0 ? "f\n" : "f*\n"));
	if (psmat)
	    stream_puts(s, "Q\n");
    }
    return 0;
}

/* Stroke a path. */
int
gdev_pdf_stroke_path(gx_device * dev, const gs_imager_state * pis,
		     gx_path * ppath, const gx_stroke_params * params,
	      const gx_drawing_color * pdcolor, const gx_clip_path * pcpath)
{
    gx_device_pdf *pdev = (gx_device_pdf *) dev;
    stream *s;
    int code;
    double scale, path_scale;
    bool set_ctm;
    gs_matrix mat;
    double prescale = 1;

    if (gx_path_is_void(ppath))
	return 0;		/* won't mark the page */
    code = pdf_prepare_stroke(pdev, pis);
    if (code < 0)
	return code;
    code = pdf_open_page(pdev, PDF_IN_STREAM);
    if (code < 0)
	return code;
    /*
     * If the CTM is not uniform, stroke width depends on angle.
     * We'd like to avoid resetting the CTM, so we check for uniform
     * CTMs explicitly.  Note that in PDF, unlike PostScript, it is
     * the CTM at the time of the stroke operation, not the CTM at
     * the time the path was constructed, that is used for transforming
     * the points of the path; so if we have to reset the CTM, we must
     * do it before constructing the path, and inverse-transform all
     * the coordinates.
     */
    set_ctm = (bool)gdev_vector_stroke_scaling((gx_device_vector *)pdev,
					       pis, &scale, &mat);
    if (set_ctm) {
	/*
	 * We want a scaling factor that will bring the largest reasonable
	 * user coordinate within bounds.  We choose a factor based on the
	 * minor axis of the transformation.  Thanks to Raph Levien for
	 * the following formula.
	 */
	double a = mat.xx, b = mat.xy, c = mat.yx, d = mat.yy;
	double u = fabs(a * d - b * c);
	double v = a * a + b * b + c * c + d * d;
	double minor = (sqrt(v + 2 * u) - sqrt(v - 2 * u)) * 0.5;

	prescale = (minor == 0 || minor > 1 ? 1 : 1 / minor);
    }
    if (make_path_scaling(pdev, ppath, prescale, &path_scale)) {
	scale /= path_scale;
	if (set_ctm)
	    gs_matrix_scale(&mat, path_scale, path_scale, &mat);
	else {
	    gs_make_scaling(path_scale, path_scale, &mat);
	    set_ctm = true;
	}
    }
    pdf_put_clip_path(pdev, pcpath);
    code = gdev_vector_prepare_stroke((gx_device_vector *)pdev, pis, params,
				      pdcolor, scale);
    if (code < 0)
	return gx_default_stroke_path(dev, pis, ppath, params, pdcolor,
				      pcpath);

    if (set_ctm)
  	pdf_put_matrix(pdev, "q ", &mat, "cm\n");
    code = gdev_vector_dopath((gx_device_vector *)pdev, ppath,
			      gx_path_type_stroke | gx_path_type_optimize,
			      (set_ctm ? &mat : (const gs_matrix *)0));
    if (code < 0)
	return code;
    s = pdev->strm;
    stream_puts(s, (code ? "s" : "S"));
    stream_puts(s, (set_ctm ? " Q\n" : "\n"));
    return 0;
}