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2008-10-13 16:48:35
浅谈PDFlib中文输出（三）
-- PDFlib 的几种文本输出函数
作者:Michelle Yi
1．PDF_show
void PDF_show(PDF *p, const char *text)
void PDF_show2(PDF *p, const char *text, int len)
在当前坐标用当前字体及字体大小输出文本。
PDF_show将认为字符串是以空字符结尾（NULL）；若字符串有可能含有空字符（如多字节字符串），用PDF_show2。
2．PDF_show_xy
void PDF_show_xy(PDF *p, const char *text, double x, double y)
void PDF_show_xy2(PDF *p, const char *text, int len, double x, double
y)
在给出的坐标用当前字体及字体大小输出文本。
PDF_show_xy将认为字符串是以空字符结尾（NULL）；若字符串有可能含有空字符（如多字节字符串），用PDF_show_xy2。
3．PDF_continue_text
void PDF_continue_text(PDF *p, const char *text)
void PDF_continue_text2(PDF *p, const char *text, int len)
在下一行用当前字体及字体大小输出文本。
PDF_continue_xy将认为字符串是以空字符结尾（NULL）；若字符串有可能含有空字符（如多字节字符串），用PDF_continue_xy2。
4．PDF_fit_textline
void PDF_fit_textline(PDF*p, const char *text, int len, double x, double
y, const char *optlist)
在给出的坐标根据选择项输出一行文本。
若字符串是以空字符结尾（NULL），len为0；否则，给出具体字节数。
5．PDF_fit_textflow
int PDF_create_textflow(PDF *p, const char *text, int len, const char
*optlist)
建立文本流对象,并预处理文本为下面的文本格式化做准备。
若字符串是以空字符结尾（NULL），len为0；否则，给出具体字节数。
const char *PDF_fit_textflow(PDF *p, int textflow, double llx, double
lly, double urx, double ury, const char *optlist)
将文本输出到相应的矩形块中。
lly, llx, ury, urx, 分别是矩形块左下角及右上角的纵横坐标。
void PDF_delete_textflow(PDF *p, int textflow)
删除文本流对象及相关数据结构。
小结
1，2， 3 组函数简洁，直观，易用。4，5组函数可通过对选择项的控制而输出更灵活的文本格式。尤其是第5组函数，是专门为多行文本设计的，可通过选项控制对齐，字间距，边框显示，旋转等。但4，5组函数有个局限，在字符串是多字节时，它们只能处理Unicode类编码。换而言之，他们不支持cp936编码。
下面是一个相关的例子--C 源程序(下载源代码中包含了生成的pdf文件 –PDFlib_cs3.pdf)。
/*******************************************************************/ /* This example demostrates different ways to output Chinese Simplified text /* under Chinese Simplifed Windows. /*******************************************************************/ #include相关链接:#include #include #include "pdflib.h" int main(void) { PDF *p = NULL; int i = 0, j = 0, Left = 50, Top = 800, Right = 545; int Font_E = 0, Font_CS = 0, Font_CS2 = 0, TextFlow = 0; char TextUnicode[] = "\x80\x7B\x53\x4F\x2D\x4E\x87\x65"; char TextCp936[] = "\xBC\xF2\xCC\xE5\xD6\xD0\xCE\xC4"; /* create a new PDFlib object */ if ((p = PDF_new()) == (PDF *) 0) { printf("Couldn''t create PDFlib object (out of memory)!\n"); return(2); } PDF_TRY(p) { if (PDF_begin_document(p, "pdflib_cs3.pdf", 0, "") == -1) { printf("Error: %s\n", PDF_get_errmsg(p)); return(2); } PDF_set_info(p, "Creator", "pdflib_cs3.c"); PDF_set_info(p, "Author", "myi@pdflib.com"); PDF_set_info(p, "Title", "Different Ways To Output Chinese Simplify"); /* Start a new page. */ PDF_begin_page_ext(p, a4_width, a4_height, ""); Font_E = PDF_load_font(p, "Helvetica-Bold", 0, "winansi", ""); Font_CS = PDF_load_font(p, "STSong-Light", 0, "UniGB-UCS2-H", ""); Font_CS2 = PDF_load_font(p, "STSong-Light", 0, "GB-EUC-H", ""); /* Using PDF_set_text_pos and PDF_show functions. */ PDF_setfont(p, Font_E, 20); PDF_set_text_pos(p, Left, Top); PDF_show(p, "Using PDF_set_text_pos and PDF_show to output text:"); Top-=30; PDF_set_text_pos(p, Left+20, Top); PDF_show(p, "UniGB-UCS2-H encoding:"); PDF_setfont(p, Font_CS, 24); Top-=30; PDF_set_text_pos(p, Left+20, Top); PDF_show2(p, TextUnicode, 8); Top-=30; PDF_setfont(p, Font_E, 20); PDF_set_text_pos(p, Left+20, Top); PDF_show(p, "GB-EUC-H encoding:"); PDF_setfont(p, Font_CS2, 24); Top-=30; PDF_set_text_pos(p, Left+20, Top); PDF_show2(p, TextCp936, 8); /* Using PDF_show_xy function. */ Top-=50; PDF_setfont(p, Font_E, 20); PDF_show_xy(p, "Using PDF_show_xy to output text:" , Left, Top); Top-=30; PDF_show_xy(p, "UniGB-UCS2-H encoding:" , Left+20, Top); PDF_setfont(p, Font_CS, 24); Top-=30; PDF_show_xy2(p, TextUnicode, 8, Left+20, Top); Top-=30; PDF_setfont(p, Font_E, 20); PDF_show_xy(p, "GB-EUC-H encoding:", Left+20, Top); Top-=30; PDF_setfont(p, Font_CS2, 24); PDF_show_xy2(p, TextCp936, 8, Left+20, Top); /* Using PDF_continue_text function. */ Top-=30; PDF_setfont(p, Font_E, 20); PDF_set_text_pos(p, Left, Top); PDF_continue_text(p, "Using PDF_continue_text to output text:"); Top-=30; PDF_set_text_pos(p, Left+20, Top); PDF_continue_text(p, "UniGB-UCS2-H encoding:"); PDF_setfont(p, Font_CS, 24); PDF_continue_text2(p, TextUnicode, 8); PDF_setfont(p, Font_E, 20); PDF_continue_text(p, "GB-EUC-H encoding:"); PDF_setfont(p, Font_CS2, 24); PDF_continue_text2(p, TextCp936, 8); /* Using PDF_fit_textline function. */ Top-=140; PDF_setfont(p, Font_E, 20); PDF_fit_textline(p, "Using PDF_fit_textline to output text:", 0, Left, Top, ""); Top-=30; PDF_fit_textline(p, "UniGB-UCS2-H encoding:", 0, Left+20, Top, ""); PDF_setfont(p, Font_CS, 24); Top-=30; PDF_fit_textline(p, TextUnicode, 8, Left+20, Top, ""); /* Using PDF_create_textflow, PDF_fit_textflow and PDF_delete_textflow function. */ Top-=30; PDF_setfont(p, Font_E, 20); TextFlow = PDF_create_textflow(p, "Using PDF_create_textflow, PDF_fit_textflow and PDF_delete_textflow to output text:", 0, "fontname=Helvetica-Bold fontsize=20 encoding=winansi"); PDF_fit_textflow(p, TextFlow, Left, Top, Right, Top-60, ""); Top-=60; TextFlow = PDF_create_textflow(p, "UniGB-UCS2-H encoding:", 0, "fontname=Helvetica-Bold fontsize=20 encoding=winansi"); PDF_fit_textflow(p, TextFlow, Left+20, Top, Right, Top-30, ""); Top-=30; TextFlow = PDF_create_textflow(p, TextUnicode, 8, "fontname=STSong-Light fontsize=24 encoding=UniGB-UCS2-H textlen=8"); PDF_fit_textflow(p, TextFlow, Left+20, Top, Right, Top-30, ""); PDF_delete_textflow(p, TextFlow); /* End of page. */ PDF_end_page_ext(p, ""); PDF_end_document(p, ""); } PDF_CATCH(p) { printf("PDFlib exception occurred in pdflib_cs3 sample:\n"); printf("[%d] %s: %s\n", PDF_get_errnum(p), PDF_get_apiname(p), PDF_get_errmsg(p)); PDF_delete(p); return(2); } PDF_delete(p); return 0; }
