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Add support for internal hyperlinks.
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@michaelrsweet
michaelrsweet committed Dec 15, 2024
1 parent 4baafde commit 294f5e0
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Showing 3 changed files with 201 additions and 46 deletions.
243 changes: 199 additions & 44 deletions examples/md2pdf.c
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Original file line number Diff line number Diff line change
Expand Up @@ -20,6 +20,7 @@
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <ctype.h>
#include <math.h>
#ifdef _WIN32
# include <io.h>
Expand Down Expand Up @@ -64,11 +65,28 @@ typedef struct docimage_s // Document image info

typedef struct doclink_s // Document link info
{
const char *url; // Reference URL
const char *url; // Target URL
pdfio_rect_t box; // Link box
} doclink_t;

#define DOCLINK_MAX 1000 // Maximum number of links/page
#define DOCLINK_MAX 1000 // Maximum number of links per page

typedef struct docaction_s // Document action info
{
const char *target; // Target name
pdfio_obj_t *obj; // Link object
} docaction_t;

#define DOCACTION_MAX 10000 // Maximum number of actions per document

typedef struct doctarget_s // Document target info
{
char name[128]; // Target name
size_t page; // Target page
double y; // Target page position
} doctarget_t;

#define DOCTARGET_MAX 1000 // Maximum number of targets per document

typedef struct docdata_s // Document formatting data
{
Expand All @@ -90,6 +108,10 @@ typedef struct docdata_s // Document formatting data
pdfio_obj_t *annots_obj; // Annotations object (for links)
size_t num_links; // Number of links for this page
doclink_t links[DOCLINK_MAX]; // Links for this page
size_t num_actions; // Number of actions for this document
docaction_t actions[DOCACTION_MAX]; // Actions for this document
size_t num_targets; // Number of targets for this document
doctarget_t targets[DOCTARGET_MAX]; // Targets for this document
} docdata_t;

typedef struct linefrag_s // Line fragment
Expand Down Expand Up @@ -211,6 +233,7 @@ static void format_block(docdata_t *dd, mmd_t *block, docfont_t deffont, double
static void format_code(docdata_t *dd, mmd_t *block, double left, double right);
static void format_doc(docdata_t *dd, mmd_t *doc, double left, double right);
static void format_table(docdata_t *dd, mmd_t *table, double left, double right);
static void make_target_name(char *dst, const char *src, size_t dstsize);
static double measure_cell(docdata_t *dd, mmd_t *cell, tablecol_t *col);
static mmd_t *mmd_walk_next(mmd_t *top, mmd_t *node);
static void new_page(docdata_t *dd);
Expand All @@ -219,6 +242,7 @@ static void render_line(docdata_t *dd, double margin_left, double margin_top, do
static void render_row(docdata_t *dd, size_t num_cols, tablecol_t *cols, tablerow_t *row);
static void set_color(docdata_t *dd, doccolor_t color);
static void set_font(docdata_t *dd, docfont_t font, double fsize);
static void write_actions(docdata_t *dd);


//
Expand Down Expand Up @@ -311,6 +335,7 @@ main(int argc, // I - Number of command-line arguments
pdfioStreamClose(dd.st);
add_links(&dd);
}
write_actions(&dd);
pdfioFileClose(dd.pdf);

mmdFree(doc);
Expand Down Expand Up @@ -369,38 +394,6 @@ add_images(docdata_t *dd, // I - Document data
}


//
// 'find_image()' - Find an image in the document.
//

static pdfio_obj_t * // O - Image object or `NULL` if none
find_image(docdata_t *dd, // I - Document data
const char *url, // I - Image URL
size_t *imagenum) // O - Image number
{
size_t i; // Looping var


// Look for a matching URL...
for (i = 0; i < dd->num_images; i ++)
{
if (!strcmp(dd->images[i].url, url))
{
if (imagenum)
*imagenum = i;

return (dd->images[i].obj);
}
}

// Not found, return NULL...
if (imagenum)
*imagenum = 0;

return (NULL);
}


//
// 'add_links()' - Add the page links, if any.
//
Expand All @@ -419,13 +412,21 @@ add_links(docdata_t *dd) // I - Document data
// Add any links we have...
for (i = 0, l = dd->links; i < dd->num_links; i ++, l ++)
{
// Create the link action (remote URL)
dict = pdfioDictCreate(dd->pdf);
pdfioDictSetName(dict, "S", "URI");
pdfioDictSetString(dict, "URI", pdfioStringCreate(dd->pdf, l->url));
if (l->url[0] == '#')
{
// No remote action...
aobj = NULL;
}
else
{
// Create the link action (remote URL)
dict = pdfioDictCreate(dd->pdf);
pdfioDictSetName(dict, "S", "URI");
pdfioDictSetString(dict, "URI", pdfioStringCreate(dd->pdf, l->url));

aobj = pdfioFileCreateObj(dd->pdf, dict);
pdfioObjClose(aobj);
aobj = pdfioFileCreateObj(dd->pdf, dict);
pdfioObjClose(aobj);
}

// Create the annotation object pointing to the action...
dict = pdfioDictCreate(dd->pdf);
Expand All @@ -436,10 +437,31 @@ add_links(docdata_t *dd) // I - Document data
pdfioArrayAppendNumber(border, 0.0);
pdfioArrayAppendNumber(border, 0.0);
pdfioDictSetArray(dict, "Border", border);
pdfioDictSetObj(dict, "A", aobj);

lobj = pdfioFileCreateObj(dd->pdf, dict);
pdfioObjClose(lobj);

if (l->url[0] == '#' && dd->num_actions < DOCACTION_MAX)
{
// Save this link action for later...
docaction_t *a = dd->actions + dd->num_actions;
// New action

a->target = l->url + 1;
a->obj = lobj;

dd->num_actions ++;
}
else if (aobj)
{
// Close out this link since we have a remote URL...
pdfioDictSetObj(dict, "A", aobj);
pdfioObjClose(lobj);
}
else
{
// Nothing that can be done for this one...
pdfioObjClose(lobj);
}

pdfioArrayAppendObj(dd->annots_array, lobj);
}
Expand All @@ -454,6 +476,38 @@ add_links(docdata_t *dd) // I - Document data
}


//
// 'find_image()' - Find an image in the document.
//

static pdfio_obj_t * // O - Image object or `NULL` if none
find_image(docdata_t *dd, // I - Document data
const char *url, // I - Image URL
size_t *imagenum) // O - Image number
{
size_t i; // Looping var


// Look for a matching URL...
for (i = 0; i < dd->num_images; i ++)
{
if (!strcmp(dd->images[i].url, url))
{
if (imagenum)
*imagenum = i;

return (dd->images[i].obj);
}
}

// Not found, return NULL...
if (imagenum)
*imagenum = 0;

return (NULL);
}


//
// 'format_block()' - Format a block of text
//
Expand Down Expand Up @@ -804,6 +858,18 @@ format_doc(docdata_t *dd, // I - Document data
dd->heading = mmdCopyAllText(current);

format_block(dd, current, DOCFONT_BOLD, heading_sizes[curtype - MMD_TYPE_HEADING_1], left, right, /*leader*/NULL);

if (dd->num_targets < DOCTARGET_MAX)
{
doctarget_t *t = dd->targets + dd->num_targets;
// New target

make_target_name(t->name, dd->heading, sizeof(t->name));
t->page = pdfioFileGetNumPages(dd->pdf) - 1;
t->y = dd->y + heading_sizes[curtype - MMD_TYPE_HEADING_1] * LINE_HEIGHT;

dd->num_targets ++;
}
break;

case MMD_TYPE_PARAGRAPH :
Expand Down Expand Up @@ -956,6 +1022,33 @@ format_table(docdata_t *dd, // I - Document data
}


//
// 'make_target_name()' - Convert text to a target name.
//

static void
make_target_name(char *dst, // I - Destination buffer
const char *src, // I - Source text
size_t dstsize) // I - Size of destination buffer
{
char *dstptr = dst, // Pointer into destination
*dstend = dst + dstsize - 1; // End of destination


while (*src && dstptr < dstend)
{
if (isalnum(*src) || *src == '.' || *src == '-')
*dstptr++ = tolower(*src);
else if (*src == ' ')
*dstptr++ = '-';

src ++;
}

*dstptr = '\0';
}


//
// 'measure_cell()' - Measure the dimensions of a table cell.
//
Expand Down Expand Up @@ -1261,7 +1354,10 @@ render_line(docdata_t *dd, // I - Document data


if (!dd->st)
{
new_page(dd);
margin_top = 0.0;
}

dd->y -= margin_top + lineheight;
if (dd->y < dd->art_box.y1)
Expand Down Expand Up @@ -1318,12 +1414,32 @@ render_line(docdata_t *dd, // I - Document data
else
pdfioContentTextShow(dd->st, UNICODE_VALUE, frag->text);

if (frag->type == MMD_TYPE_LINKED_TEXT && frag->url && dd->num_links < DOCLINK_MAX && (!strncmp(frag->url, "http://", 7) || !strncmp(frag->url, "https://", 8)))
if (frag->type == MMD_TYPE_LINKED_TEXT && frag->url && dd->num_links < DOCLINK_MAX)
{
doclink_t *l = dd->links + dd->num_links;
// Pointer to this link record

l->url = frag->url;
if (!strcmp(frag->url, "@"))
{
// Use mapped text as link target...
char targetlink[129]; // Targeted link

targetlink[0] = '#';
make_target_name(targetlink + 1, frag->text, sizeof(targetlink) - 1);

l->url = pdfioStringCreate(dd->pdf, targetlink);
}
else if (!strcmp(frag->url, "@@"))
{
// Use literal text as anchor...
l->url = pdfioStringCreatef(dd->pdf, "#%s", frag->text);
}
else
{
// Use URL as-is...
l->url = frag->url;
}

l->box.x1 = frag->x;
l->box.y1 = dd->y;
l->box.x2 = frag->x + frag->width;
Expand Down Expand Up @@ -1474,3 +1590,42 @@ set_font(docdata_t *dd, // I - Document data
dd->font = font;
dd->fsize = fsize;
}


//
// 'write_actions()' - Write remaining actions to the PDF file.
//

static void
write_actions(docdata_t *dd) // I - Document data
{
size_t i, j; // Looping vars
docaction_t *a; // Current action
doctarget_t *t; // Current target


for (i = 0, a = dd->actions; i < dd->num_actions; i ++, a ++)
{
for (j = 0, t = dd->targets; j < dd->num_targets; j ++, t ++)
{
if (!strcmp(a->target, t->name))
break;
}

if (j < dd->num_targets)
{
pdfio_array_t *dest = pdfioArrayCreate(dd->pdf);
// Destination array

pdfioArrayAppendObj(dest, pdfioFileGetPage(dd->pdf, t->page));
pdfioArrayAppendName(dest, "XYZ");
pdfioArrayAppendNumber(dest, PAGE_LEFT);
pdfioArrayAppendNumber(dest, t->y);
pdfioArrayAppendNumber(dest, 0.0);

pdfioDictSetArray(pdfioObjGetDict(a->obj), "Dest", dest);
}

pdfioObjClose(a->obj);
}
}
2 changes: 1 addition & 1 deletion examples/md2pdf.md
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Original file line number Diff line number Diff line change
Expand Up @@ -12,7 +12,7 @@ pages in a PDF file. It demonstrates how to:
- Format text,
- Embed JPEG and PNG images,
- Add headers and footers, and
- (Future) Add hyperlinks.
- Add hyperlinks.


Source Files
Expand Down
2 changes: 1 addition & 1 deletion examples/mmd.c
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Original file line number Diff line number Diff line change
Expand Up @@ -544,7 +544,7 @@ mmdLoadIO(mmd_t *root, // I - Root node for document or `NULL` for a new d
block = NULL;
continue;
}
else if (*lineptr == '>' && (lineptr - linestart) < 4)
else if (stackptr->parent->type != MMD_TYPE_CODE_BLOCK && *lineptr == '>' && (lineptr - linestart) < 4)
{
// Block quote. See if there is an existing blockquote...
DEBUG_printf(" BLOCKQUOTE (stackptr=%ld)\n", stackptr - stack);
Expand Down

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