gvtextlayout_gd.c

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/*************************************************************************
 * Copyright (c) 2011 AT&T Intellectual Property 
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * https://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors: Details at https://graphviz.org
 *************************************************************************/
 
#include "config.h"
#include "gd_psfontResolve.h"
#include <stdbool.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <gvc/gvplugin_textlayout.h>
#include <gd.h>
#include <common/const.h>
#include <util/agxbuf.h>
#include <util/strcasecmp.h>
#include <util/strview.h>
 
#ifdef HAVE_GD_FREETYPE
 
/* fontsize at which text is omitted entirely */
#define FONTSIZE_MUCH_TOO_SMALL 0.15
/* fontsize at which text is rendered by a simple line */
#define FONTSIZE_TOO_SMALL 1.5
 
#ifndef HAVE_GD_FONTCONFIG
/* gd_alternate_fontlist;
 * Sometimes fonts are stored under a different name,
 * especially on Windows. Without fontconfig, we provide
 * here some rudimentary name mapping.
 */
char *gd_alternate_fontlist(const char *font) {
    char *p;
 
    /* fontbuf to contain font without style descriptions like -Roman or -Italic */
    strview_t fontlist = strview(font, '\0');
    if ((p = strchr(font, '-')) || (p = strchr(font, '_')))
        fontlist.size = (size_t)(p - font);
 
    if (strcasecmp(font, "times-bold") == 0
        || strview_case_str_eq(fontlist, "timesbd")
        || strview_case_str_eq(fontlist, "timesb"))
        fontlist = strview("timesbd;Timesbd;TIMESBD;timesb;Timesb;TIMESB", '\0');
 
    else if (strcasecmp(font, "times-italic") == 0
             || strview_case_str_eq(fontlist, "timesi"))
        fontlist = strview("timesi;Timesi;TIMESI", '\0');
 
    else if (strcasecmp(font, "timesnewroman") == 0
             || strcasecmp(font, "timesnew") == 0
             || strcasecmp(font, "timesroman") == 0
             || strview_case_str_eq(fontlist, "times"))
        fontlist = strview("times;Times;TIMES", '\0');
 
    else if (strcasecmp(font, "arial-bold") == 0
             || strview_case_str_eq(fontlist, "arialb"))
        fontlist = strview("arialb;Arialb;ARIALB", '\0');
 
    else if (strcasecmp(font, "arial-italic") == 0
             || strview_case_str_eq(fontlist, "ariali"))
        fontlist = strview("ariali;Ariali;ARIALI", '\0');
 
    else if (strview_case_str_eq(fontlist, "helvetica"))
        fontlist = strview("helvetica;Helvetica;HELVETICA;arial;Arial;ARIAL", '\0');
 
    else if (strview_case_str_eq(fontlist, "arial"))
        fontlist = strview("arial;Arial;ARIAL", '\0');
 
    else if (strview_case_str_eq(fontlist, "courier"))
        fontlist = strview("courier;Courier;COURIER;cour", '\0');
 
    return strview_str(fontlist);
}
#endif                          /* HAVE_GD_FONTCONFIG */
 
char* gd_psfontResolve (PostscriptAlias* pa)
{
    agxbuf buf = {0};
    agxbput(&buf, pa->family);
 
    const char *separator = " ";
    const char *const attributes[] = {pa->weight, pa->stretch, pa->style};
    for (size_t i = 0; i < sizeof(attributes) / sizeof(attributes[0]); ++i) {
        const char *const a = attributes[i];
        if (a != NULL) {
            agxbprint(&buf, "%s%s", separator, a);
            separator = ", ";
        }
    }
   
    return agxbdisown(&buf);
}
 
static bool gd_textlayout(textspan_t * span, char **fontpath)
{
    char *err, *fontlist, *fontname;
    double fontsize;
    int brect[8];
    gdFTStringExtra strex;
#ifdef HAVE_GD_FONTCONFIG
    PostscriptAlias *pA;
#endif
 
    fontname = span->font->name;
    fontsize = span->font->size;
 
    strex.fontpath = NULL;
    strex.flags = gdFTEX_RETURNFONTPATHNAME | gdFTEX_RESOLUTION;
    strex.hdpi = strex.vdpi = POINTS_PER_INCH;
 
    if (strchr(fontname, '/'))
        strex.flags |= gdFTEX_FONTPATHNAME;
    else
        strex.flags |= gdFTEX_FONTCONFIG;
 
    span->size.x = 0.0;
    span->size.y = 0.0;
    span->yoffset_layout = 0.0;
 
    span->layout = NULL;
    span->free_layout = NULL;
 
    span->yoffset_centerline = 0.05 * fontsize;
 
    if (fontname) {
        if (fontsize <= FONTSIZE_MUCH_TOO_SMALL) {
            return true; /* OK, but ignore text entirely */
        } else if (fontsize <= FONTSIZE_TOO_SMALL) {
            /* draw line in place of text */
            /* fake a finite fontsize so that line length is calculated */
            fontsize = FONTSIZE_TOO_SMALL;
        }
        /* call gdImageStringFT with null *im to get brect and to set font cache */
        bool fontlist_needs_free = false;
#ifdef HAVE_GD_FONTCONFIG
        gdFTUseFontConfig(1);  /* tell gd that we really want to use fontconfig, 'cos it s not the default */
        pA = span->font->postscript_alias;
        if (pA)
            fontlist = gd_psfontResolve (pA);
        else
            fontlist = fontname;
#else
        fontlist = gd_alternate_fontlist(fontname);
        fontlist_needs_free = true;
#endif
 
        err = gdImageStringFTEx(NULL, brect, -1, fontlist,
                                fontsize, 0, 0, 0, span->str, &strex);
        if (fontlist_needs_free) {
            free(fontlist);
        }
 
        if (err) {
            agerrorf("%s\n", err);
            return false; /* indicate error */
        }
 
        if (fontpath)
            *fontpath = strex.fontpath;
        else
            free (strex.fontpath); /* strup'ed in libgd */
 
        if (span->str && span->str[0]) {
            /* can't use brect on some archtectures if strlen 0 */
            span->size.x = (double) (brect[4] - brect[0]);
            // LINESPACING specifies how much extra space to leave between lines
            span->size.y = fontsize * LINESPACING;
        }
    }
    return true;
}
 
static gvtextlayout_engine_t gd_textlayout_engine = {
    gd_textlayout,
};
#endif
 
gvplugin_installed_t gvtextlayout_gd_types[] = {
#ifdef HAVE_GD_FREETYPE
    {0, "textlayout", 2, &gd_textlayout_engine, NULL},
#endif
    {0, NULL, 0, NULL, NULL}
};