PDF是我们极其常用的文件格式，但对如何生成PDF，个人一直觉得很神秘，其实利用一些公开的PDF库，我们就可以直接生成PDF文件，而不用关注PDF文件的内部细节。我知道的PDF库有如CARIO和HARU。
HARU是一款免费的，跨平台的，开源的生成PDF的库。支持嵌入PNG、JPEG图片，支持CJK字体编码。用C语言编写，因此可以在C/C++中调用。HARU也提供了Ruby，Delphhi，和C#的捆绑（binding）。项目主页见http://libharu.sourceforge.net/index.html和http://libharu.org/wiki/Main_Page。
项目主页上有详尽的文档来说明如何安装和使用。在Mac OX下，不喜欢折腾的人可以用macports来安装(当然，必须先安装macports，google之):
sudo port install libharu
下面是从项目主页上摘下来的例子text_demo.c
下面是代码，可以从主页上下载：text_demo.c, grid_sheet.c, grid_sheet.h
text_demo.c
text_demo.c
/*
* << Haru Free PDF Library 2.0.0 >> -- text_demo.c
*
* Copyright (c) 1999-2006 Takeshi Kanno <takeshi_kanno@est.hi-ho.ne.jp>
*
* Permission to use, copy, modify, distribute and sell this software
* and its documentation for any purpose is hereby granted without fee,
* provided that the above copyright notice appear in all copies and
* that both that copyright notice and this permission notice appear
* in supporting documentation.
* It is provided "as is" without express or implied warranty.
*
*/
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <math.h>
#include <setjmp.h>
#include "hpdf.h"
#include "grid_sheet.h"
jmp_buf env;
#ifdef HPDF_DLL
void __stdcall
#else
void
#endif
error_handler (HPDF_STATUS error_no,
HPDF_STATUS detail_no,
void *user_data)
{
printf ("ERROR: error_no=%04X, detail_no=%u\n", (HPDF_UINT)error_no,
(HPDF_UINT)detail_no);
longjmp(env, 1);
}
void
show_stripe_pattern (HPDF_Page page,
HPDF_REAL x,
HPDF_REAL y)
{
HPDF_UINT iy = 0;
while (iy < 50) {
HPDF_Page_SetRGBStroke (page, 0.0, 0.0, 0.5);
HPDF_Page_SetLineWidth (page, 1);
HPDF_Page_MoveTo (page, x, y + iy);
HPDF_Page_LineTo (page, x + HPDF_Page_TextWidth (page, "ABCabc123"),
y + iy);
HPDF_Page_Stroke (page);
iy += 3;
}
HPDF_Page_SetLineWidth (page, 2.5);
}
void
show_description (HPDF_Page page,
HPDF_REAL x,
HPDF_REAL y,
const char *text)
{
float fsize = HPDF_Page_GetCurrentFontSize (page);
HPDF_Font font = HPDF_Page_GetCurrentFont (page);
HPDF_RGBColor c = HPDF_Page_GetRGBFill (page);
HPDF_Page_BeginText (page);
HPDF_Page_SetRGBFill (page, 0, 0, 0);
HPDF_Page_SetTextRenderingMode (page, HPDF_FILL);
HPDF_Page_SetFontAndSize (page, font, 10);
HPDF_Page_TextOut (page, x, y - 12, text);
HPDF_Page_EndText (page);
HPDF_Page_SetFontAndSize (page, font, fsize);
HPDF_Page_SetRGBFill (page, c.r, c.g, c.b);
}
int main (int argc, char **argv)
{
const char *page_title = "Text Demo";
HPDF_Doc pdf;
HPDF_Font font;
HPDF_Page page;
char fname[256];
const char* samp_text = "abcdefgABCDEFG123!#$%&+-@?";
const char* samp_text2 = "The quick brown fox jumps over the lazy dog.";
float tw;
float fsize;
int i;
int len;
float angle1;
float angle2;
float rad1;
float rad2;
float ypos;
strcpy (fname, argv[0]);
strcat (fname, ".pdf");
pdf = HPDF_New (error_handler, NULL);
if (!pdf) {
printf ("error: cannot create PdfDoc object\n");
return 1;
}
if (setjmp(env)) {
HPDF_Free (pdf);
return 1;
}
/* set compression mode */
HPDF_SetCompressionMode (pdf, HPDF_COMP_ALL);
/* create default-font */
font = HPDF_GetFont (pdf, "Helvetica", NULL);
/* add a new page object. */
page = HPDF_AddPage (pdf);
/* draw grid to the page */
print_grid (pdf, page);
/* print the lines of the page.
HPDF_Page_SetLineWidth (page, 1);
HPDF_Page_Rectangle (page, 50, 50, HPDF_Page_GetWidth(page) - 100,
HPDF_Page_GetHeight (page) - 110);
HPDF_Page_Stroke (page);
*/
/* print the title of the page (with positioning center). */
HPDF_Page_SetFontAndSize (page, font, 24);
tw = HPDF_Page_TextWidth (page, page_title);
HPDF_Page_BeginText (page);
HPDF_Page_TextOut (page, (HPDF_Page_GetWidth(page) - tw) / 2,
HPDF_Page_GetHeight (page) - 50, page_title);
HPDF_Page_EndText (page);
HPDF_Page_BeginText (page);
HPDF_Page_MoveTextPos (page, 60, HPDF_Page_GetHeight(page) - 60);
/*
* font size
*/
fsize = 8;
while (fsize < 60) {
char buf[50];
int len;
/* set style and size of font. */
HPDF_Page_SetFontAndSize(page, font, fsize);
/* set the position of the text. */
HPDF_Page_MoveTextPos (page, 0, -5 - fsize);
/* measure the number of characters which included in the page. */
strcpy(buf, samp_text);
len = HPDF_Page_MeasureText (page, samp_text,
HPDF_Page_GetWidth(page) - 120, HPDF_FALSE, NULL);
/* truncate the text. */
buf[len] = 0x00;
HPDF_Page_ShowText (page, buf);
/* print the description. */
HPDF_Page_MoveTextPos (page, 0, -10);
HPDF_Page_SetFontAndSize(page, font, 8);
#ifdef __WIN32__
_snprintf(buf, 50, "Fontsize=%.0f", fsize);
#else
snprintf(buf, 50, "Fontsize=%.0f", fsize);
#endif
HPDF_Page_ShowText (page, buf);
fsize *= 1.5;
}
/*
* font color
*/
HPDF_Page_SetFontAndSize(page, font, 8);
HPDF_Page_MoveTextPos (page, 0, -30);
HPDF_Page_ShowText (page, "Font color");
HPDF_Page_SetFontAndSize (page, font, 18);
HPDF_Page_MoveTextPos (page, 0, -20);
len = strlen (samp_text);
for (i = 0; i < len; i++) {
char buf[2];
float r = (float)i / (float)len;
float g = 1 - ((float)i / (float)len);
buf[0] = samp_text[i];
buf[1] = 0x00;
HPDF_Page_SetRGBFill (page, r, g, 0.0);
HPDF_Page_ShowText (page, buf);
}
HPDF_Page_MoveTextPos (page, 0, -25);
for (i = 0; i < len; i++) {
char buf[2];
float r = (float)i / (float)len;
float b = 1 - ((float)i / (float)len);
buf[0] = samp_text[i];
buf[1] = 0x00;
HPDF_Page_SetRGBFill (page, r, 0.0, b);
HPDF_Page_ShowText (page, buf);
}
HPDF_Page_MoveTextPos (page, 0, -25);
for (i = 0; i < len; i++) {
char buf[2];
float b = (float)i / (float)len;
float g = 1 - ((float)i / (float)len);
buf[0] = samp_text[i];
buf[1] = 0x00;
HPDF_Page_SetRGBFill (page, 0.0, g, b);
HPDF_Page_ShowText (page, buf);
}
HPDF_Page_EndText (page);
ypos = 450;
/*
* Font rendering mode
*/
HPDF_Page_SetFontAndSize(page, font, 32);
HPDF_Page_SetRGBFill (page, 0.5, 0.5, 0.0);
HPDF_Page_SetLineWidth (page, 1.5);
/* PDF_FILL */
show_description (page, 60, ypos,
"RenderingMode=PDF_FILL");
HPDF_Page_SetTextRenderingMode (page, HPDF_FILL);
HPDF_Page_BeginText (page);
HPDF_Page_TextOut (page, 60, ypos, "ABCabc123");
HPDF_Page_EndText (page);
/* PDF_STROKE */
show_description (page, 60, ypos - 50,
"RenderingMode=PDF_STROKE");
HPDF_Page_SetTextRenderingMode (page, HPDF_STROKE);
HPDF_Page_BeginText (page);
HPDF_Page_TextOut (page, 60, ypos - 50, "ABCabc123");
HPDF_Page_EndText (page);
/* PDF_FILL_THEN_STROKE */
show_description (page, 60, ypos - 100,
"RenderingMode=PDF_FILL_THEN_STROKE");
HPDF_Page_SetTextRenderingMode (page, HPDF_FILL_THEN_STROKE);
HPDF_Page_BeginText (page);
HPDF_Page_TextOut (page, 60, ypos - 100, "ABCabc123");
HPDF_Page_EndText (page);
/* PDF_FILL_CLIPPING */
show_description (page, 60, ypos - 150,
"RenderingMode=PDF_FILL_CLIPPING");
HPDF_Page_GSave (page);
HPDF_Page_SetTextRenderingMode (page, HPDF_FILL_CLIPPING);
HPDF_Page_BeginText (page);
HPDF_Page_TextOut (page, 60, ypos - 150, "ABCabc123");
HPDF_Page_EndText (page);
show_stripe_pattern (page, 60, ypos - 150);
HPDF_Page_GRestore (page);
/* PDF_STROKE_CLIPPING */
show_description (page, 60, ypos - 200,
"RenderingMode=PDF_STROKE_CLIPPING");
HPDF_Page_GSave (page);
HPDF_Page_SetTextRenderingMode (page, HPDF_STROKE_CLIPPING);
HPDF_Page_BeginText (page);
HPDF_Page_TextOut (page, 60, ypos - 200, "ABCabc123");
HPDF_Page_EndText (page);
show_stripe_pattern (page, 60, ypos - 200);
HPDF_Page_GRestore (page);
/* PDF_FILL_STROKE_CLIPPING */
show_description (page, 60, ypos - 250,
"RenderingMode=PDF_FILL_STROKE_CLIPPING");
HPDF_Page_GSave (page);
HPDF_Page_SetTextRenderingMode (page, HPDF_FILL_STROKE_CLIPPING);
HPDF_Page_BeginText (page);
HPDF_Page_TextOut (page, 60, ypos - 250, "ABCabc123");
HPDF_Page_EndText (page);
show_stripe_pattern (page, 60, ypos - 250);
HPDF_Page_GRestore (page);
/* Reset text attributes */
HPDF_Page_SetTextRenderingMode (page, HPDF_FILL);
HPDF_Page_SetRGBFill (page, 0, 0, 0);
HPDF_Page_SetFontAndSize(page, font, 30);
/*
* Rotating text
*/
angle1 = 30; /* A rotation of 30 degrees. */
rad1 = angle1 / 180 * 3.141592; /* Calcurate the radian value. */
show_description (page, 320, ypos - 60, "Rotating text");
HPDF_Page_BeginText (page);
HPDF_Page_SetTextMatrix (page, cos(rad1), sin(rad1), -sin(rad1), cos(rad1),
330, ypos - 60);
HPDF_Page_ShowText (page, "ABCabc123");
HPDF_Page_EndText (page);
/*
* Skewing text.
*/
show_description (page, 320, ypos - 120, "Skewing text");
HPDF_Page_BeginText (page);
angle1 = 10;
angle2 = 20;
rad1 = angle1 / 180 * 3.141592;
rad2 = angle2 / 180 * 3.141592;
HPDF_Page_SetTextMatrix (page, 1, tan(rad1), tan(rad2), 1, 320, ypos - 120);
HPDF_Page_ShowText (page, "ABCabc123");
HPDF_Page_EndText (page);
/*
* scaling text (X direction)
*/
show_description (page, 320, ypos - 175, "Scaling text (X direction)");
HPDF_Page_BeginText (page);
HPDF_Page_SetTextMatrix (page, 1.5, 0, 0, 1, 320, ypos - 175);
HPDF_Page_ShowText (page, "ABCabc12");
HPDF_Page_EndText (page);
/*
* scaling text (Y direction)
*/
show_description (page, 320, ypos - 250, "Scaling text (Y direction)");
HPDF_Page_BeginText (page);
HPDF_Page_SetTextMatrix (page, 1, 0, 0, 2, 320, ypos - 250);
HPDF_Page_ShowText (page, "ABCabc123");
HPDF_Page_EndText (page);
/*
* char spacing, word spacing
*/
show_description (page, 60, 140, "char-spacing 0");
show_description (page, 60, 100, "char-spacing 1.5");
show_description (page, 60, 60, "char-spacing 1.5, word-spacing 2.5");
HPDF_Page_SetFontAndSize (page, font, 20);
HPDF_Page_SetRGBFill (page, 0.1, 0.3, 0.1);
/* char-spacing 0 */
HPDF_Page_BeginText (page);
HPDF_Page_TextOut (page, 60, 140, samp_text2);
HPDF_Page_EndText (page);
/* char-spacing 1.5 */
HPDF_Page_SetCharSpace (page, 1.5);
HPDF_Page_BeginText (page);
HPDF_Page_TextOut (page, 60, 100, samp_text2);
HPDF_Page_EndText (page);
/* char-spacing 1.5, word-spacing 3.5 */
HPDF_Page_SetWordSpace (page, 2.5);
HPDF_Page_BeginText (page);
HPDF_Page_TextOut (page, 60, 60, samp_text2);
HPDF_Page_EndText (page);
/* save the document to a file */
HPDF_SaveToFile (pdf, fname);
/* clean up */
HPDF_Free (pdf);
return 0;
}
grid_sheet.c
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <setjmp.h>
#include "hpdf.h"
#include "grid_sheet.h"
#ifdef STAND_ALONE
jmp_buf env;
#ifdef HPDF_DLL
void __stdcall
#else
void
#endif
error_handler (HPDF_STATUS error_no,
HPDF_STATUS detail_no,
void *user_data)
{
printf ("ERROR: error_no=%04X, detail_no=%u\n", (HPDF_UINT)error_no,
(HPDF_UINT)detail_no);
longjmp(env, 1);
}
#endif /* STAND_ALONE */
void
print_grid (HPDF_Doc pdf,
HPDF_Page page)
{
HPDF_REAL height = HPDF_Page_GetHeight (page);
HPDF_REAL width = HPDF_Page_GetWidth (page);
HPDF_Font font = HPDF_GetFont (pdf, "Helvetica", NULL);
HPDF_UINT x, y;
HPDF_Page_SetFontAndSize (page, font, 5);
HPDF_Page_SetGrayFill (page, 0.5);
HPDF_Page_SetGrayStroke (page, 0.8);
/* Draw horizontal lines */
y = 0;
while (y < height) {
if (y % 10 == 0)
HPDF_Page_SetLineWidth (page, 0.5);
else {
if (HPDF_Page_GetLineWidth (page) != 0.25)
HPDF_Page_SetLineWidth (page, 0.25);
}
HPDF_Page_MoveTo (page, 0, y);
HPDF_Page_LineTo (page, width, y);
HPDF_Page_Stroke (page);
if (y % 10 == 0 && y > 0) {
HPDF_Page_SetGrayStroke (page, 0.5);
HPDF_Page_MoveTo (page, 0, y);
HPDF_Page_LineTo (page, 5, y);
HPDF_Page_Stroke (page);
HPDF_Page_SetGrayStroke (page, 0.8);
}
y += 5;
}
/* Draw virtical lines */
x = 0;
while (x < width) {
if (x % 10 == 0)
HPDF_Page_SetLineWidth (page, 0.5);
else {
if (HPDF_Page_GetLineWidth (page) != 0.25)
HPDF_Page_SetLineWidth (page, 0.25);
}
HPDF_Page_MoveTo (page, x, 0);
HPDF_Page_LineTo (page, x, height);
HPDF_Page_Stroke (page);
if (x % 50 == 0 && x > 0) {
HPDF_Page_SetGrayStroke (page, 0.5);
HPDF_Page_MoveTo (page, x, 0);
HPDF_Page_LineTo (page, x, 5);
HPDF_Page_Stroke (page);
HPDF_Page_MoveTo (page, x, height);
HPDF_Page_LineTo (page, x, height - 5);
HPDF_Page_Stroke (page);
HPDF_Page_SetGrayStroke (page, 0.8);
}
x += 5;
}
/* Draw horizontal text */
y = 0;
while (y < height) {
if (y % 10 == 0 && y > 0) {
char buf[12];
HPDF_Page_BeginText (page);
HPDF_Page_MoveTextPos (page, 5, y - 2);
#ifdef __WIN32__
_snprintf (buf, 12, "%u", y);
#else
snprintf (buf, 12, "%u", y);
#endif
HPDF_Page_ShowText (page, buf);
HPDF_Page_EndText (page);
}
y += 5;
}
/* Draw virtical text */
x = 0;
while (x < width) {
if (x % 50 == 0 && x > 0) {
char buf[12];
HPDF_Page_BeginText (page);
HPDF_Page_MoveTextPos (page, x, 5);
#ifdef __WIN32__
_snprintf (buf, 12, "%u", x);
#else
snprintf (buf, 12, "%u", x);
#endif
HPDF_Page_ShowText (page, buf);
HPDF_Page_EndText (page);
HPDF_Page_BeginText (page);
HPDF_Page_MoveTextPos (page, x, height - 10);
HPDF_Page_ShowText (page, buf);
HPDF_Page_EndText (page);
}
x += 5;
}
HPDF_Page_SetGrayFill (page, 0);
HPDF_Page_SetGrayStroke (page, 0);
}
#ifdef STAND_ALONE
int
main (int argc, char **argv)
{
HPDF_Doc pdf;
HPDF_Page page;
char fname[256];
strcpy (fname, argv[0]);
strcat (fname, ".pdf");
pdf = HPDF_New (error_handler, NULL);
if (!pdf) {
printf ("error: cannot create PdfDoc object\n");
return 1;
}
if (setjmp(env)) {
HPDF_Free (pdf);
return 1;
}
/* add a new page object. */
page = HPDF_AddPage (pdf);
HPDF_Page_SetHeight (page, 600);
HPDF_Page_SetWidth (page, 400);
print_grid (pdf, page);
/* save the document to a file */
HPDF_SaveToFile (pdf, fname);
/* clean up */
HPDF_Free (pdf);
return 0;
}
#endif /* STAND_ALONE */
grid_sheet.h
#ifndef __GRID_SHEET_H #define __GRID_SHEET_H #include "hpdf.h" void print_grid (HPDF_Doc pdf, HPDF_Page page); #endif /* __GRID_SHEET_H */