freetype实现电子书

      这个电子书的功能很简单，通过在控制台输入"u"/"n"来控制显示上一页，下一页，并且使用轮询方法实现，很占CPU资源，后面我会慢慢改进。源码下载地址：https://download.youkuaiyun.com/download/qq_22863733/10399962

      总共3个文件：main.c、function.c、function.h

function.h:

#include <stdio.h>
#include <string.h>
#include <math.h>
#include <sys/mman.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <unistd.h>
#include <linux/fb.h>
#include <fcntl.h>
#include <wchar.h>

#include <ft2build.h>
#include FT_FREETYPE_H

#define WIDTH   80
#define HEIGHT  80
#define FONTSIZE 30
#define iHeadLen 3
#define DBG_PRINTF(...)

typedef struct PageInfo{
	unsigned char * pucPagePos;
	struct PageInfo *pt_PrePageInfo;
	struct PageInfo *pt_NextPageInfo;
}T_PageInfo,*PT_PageInfo;

int lcd_init(void);
void lcd_put_pixel(int x, int y, unsigned int color);
             
void freetype_init(void);
void draw_bitmap( FT_Bitmap* bitmap, FT_Int x, FT_Int y);
void close_freetype(void);

int OpenTextFile(char *pcFileName);

unsigned int GetCodeFrmUTF8Buf(unsigned char * pucUTF8Buf);
int show_one_font(unsigned int);
unsigned char * show_line(unsigned char *pucLineFirsPostAtFile);
unsigned char* show_one_page(PT_PageInfo ptCurPageInfo);
static void RecordPage(PT_PageInfo ptPageNew);
unsigned char* Renew_pucLcdFirstPosAtFile(unsigned int code,unsigned char * pucCurPosAtFile);


int fd_fb;
struct fb_var_screeninfo var;	/* Current var */
struct fb_fix_screeninfo fix;	/* Current fix */
int screen_size;
unsigned char *fbmem;
unsigned int line_width;
unsigned int pixel_width;

FT_Library    library;
FT_Face       face;
FT_GlyphSlot  slot;
FT_Matrix     matrix;                 /* transformation matrix */
FT_Vector     pen;                    /* untransformed origin  */
FT_Error      error;
double        angle;
int           target_height;
int           n, num_chars;

int g_iFdTextFile;
unsigned char *g_pucTextFileMem;
unsigned char *g_pucLcdFirstPosAtFile;
unsigned char *g_pucTextFileMemEnd;
char *TextFileName;
char *FontFile;

T_PageInfo g_tPageInfoHeader;
PT_PageInfo g_ptPageInfoCur;
PT_PageInfo g_ptPages;

function.c:

#include"function.h"

int lcd_init(void)
{
	fd_fb = open("/dev/fb0", O_RDWR);
	if (fd_fb < 0)
	{
		printf("can't open /dev/fb0\n");
		return -1;
	}

	if (ioctl(fd_fb, FBIOGET_VSCREENINFO, &var))
	{
		printf("can't get var\n");
		return -1;
	}

	if (ioctl(fd_fb, FBIOGET_FSCREENINFO, &fix))
	{
		printf("can't get fix\n");
		return -1;
	}

	line_width  = var.xres * var.bits_per_pixel / 8;
	pixel_width = var.bits_per_pixel / 8;
	screen_size = var.xres * var.yres * var.bits_per_pixel / 8;
	fbmem = (unsigned char *)mmap(NULL , screen_size, PROT_READ | PROT_WRITE, MAP_SHARED, fd_fb, 0);
	if (fbmem == (unsigned char *)-1)
	{
		printf("can't mmap\n");
		return -1;

	}
	
	fprintf ( stderr, "lcd init done!\n");
}

/* color : 0x00RRGGBB */
void lcd_put_pixel(int x, int y, unsigned int color)
{
	unsigned char *pen_8 = fbmem+y*line_width+x*pixel_width;
	unsigned short *pen_16;	
	unsigned int *pen_32;	
	unsigned int red, green, blue;	

	pen_16 = (unsigned short *)pen_8;
	pen_32 = (unsigned int *)pen_8;

	switch (var.bits_per_pixel)//不同的像素位数，颜色值格式不同。根据位数设置颜色值格式，并写值。
	{//像素的各位就代表着颜色分量值。
		case 8:
		{
			*pen_8 = color;//8位像素的话，颜色值直接赋给这个内存中即可。
			break;
		}
		case 16:
		{
			/* color : 0x00RRGGBB ，unsigned int 32位color的格式*/
			/* 565 */
			red   = (color >> 16) & 0xff;//右移16位后剩下高16位，再&0xff，又剩下低8位。即取出32位color的16-23位
			green = (color >> 8) & 0xff;//取出32color的8-15位
			blue  = (color >> 0) & 0xff;//取出32color的0-7位
			color = ((red >> 3) << 11) | ((green >> 2) << 5) | (blue >> 3);//取出对应的组成565
			*pen_16 = color;
			break;
		}
		case 32:
		{
			*pen_32 = color;//32位像素也直接写即可。
			break;
		}
		default:
		{
			printf("can't surport %dbpp\n", var.bits_per_pixel);
			break;
		}
	}
}


void freetype_init(void)
{
	angle         = ( 0.0 / 360 ) * 3.14159 * 2;      /* use 25 degrees     */
	target_height = var.yres;
	
	error = FT_Init_FreeType( &library );              /* initialize library */
	error = FT_New_Face( library, FontFile, 0, &face ); /* create face object */
#if 0
	/* use 50pt at 100dpi */
	error = FT_Set_Char_Size( face, 50 * 64, 0,
	                            100, 0 );                /* set character size */
	/* pixels = 50 /72 * 100 = 69  */
#else
	FT_Set_Pixel_Sizes(face, FONTSIZE, 0);
#endif
	
	slot = face->glyph;	//先使slot指向face->glyph,下面也是通过glyph来设置slot。
	/* set up matrix */
	matrix.xx = (FT_Fixed)( cos( angle ) * 0x10000L );
	matrix.xy = (FT_Fixed)(-sin( angle ) * 0x10000L );
	matrix.yx = (FT_Fixed)( sin( angle ) * 0x10000L );
	matrix.yy = (FT_Fixed)( cos( angle ) * 0x10000L );
	
	/* the pen position in 26.6 cartesian space coordinates; */
	/* start at (0,40) relative to the upper left corner  */
	pen.x = 0 * 64;
	pen.y = ( target_height - FONTSIZE ) * 64; 

	fprintf(stderr,"freetype init done!\n"); 	
}

void draw_bitmap(FT_Bitmap* bitmap, FT_Int x, FT_Int y)
{
  	FT_Int  i, j, p, q;
  	FT_Int  x_max = x + bitmap->width;
  	FT_Int  y_max = y + bitmap->rows;

  	for ( i = x, p = 0; i < x_max; i++, p++ )
  	{
    		for ( j = y, q = 0; j < y_max; j++, q++ )
    		{
      			if ( i < 0      || j < 0       ||
           			i >= var.xres || j >= var.yres )
        			continue;

      			lcd_put_pixel(i,j,bitmap->buffer[q * bitmap->width + p]);
      		}
  	}
}

void close_freetype(void)
{
	FT_Done_Face( face );
  	FT_Done_FreeType( library );	
}


int OpenTextFile(char *pcFileName)
{
	struct stat tStat;
	g_iFdTextFile = open(pcFileName, O_RDONLY);
	if (0 > g_iFdTextFile)
	{
		DBG_PRINTF("can't open text file %s\n", pcFileName);
		return -1;
	}
	if(fstat(g_iFdTextFile, &tStat))
	{
		DBG_PRINTF("can't get fstat\n");
		return -1;
	}
	g_pucTextFileMem = (unsigned char *)mmap(NULL , tStat.st_size, PROT_READ, MAP_SHARED, g_iFdTextFile, 0);
	if (g_pucTextFileMem == (unsigned char *)-1)
	{
		DBG_PRINTF("can't mmap for text file\n");
		return -1;
	}

	g_pucTextFileMemEnd = g_pucTextFileMem + tStat.st_size;
	g_tPageInfoHeader.pucPagePos  = g_pucTextFileMem + iHeadLen;
	 
	return 0;
}


unsigned int GetCodeFrmUTF8Buf(unsigned char * pucUTF8Buf)
{
	unsigned int cFirst;
	unsigned int cSecond;
	unsigned int cThird;
	unsigned int cForth;
	unsigned int code=0;

	if((cFirst=(pucUTF8Buf[0]>>7) == 0))//ASCII
	{
		code = (unsigned int)pucUTF8Buf[0];
		return code;	
	}	

	if((cFirst=(pucUTF8Buf[0]>>5) == 6))//110xxxxx 10xxxxxx
	{
		cFirst=pucUTF8Buf[0]&0x1f;
		cSecond=pucUTF8Buf[1]&0x3f;
		code = (cFirst<<6)|cSecond;
		return code;	
	}	

	if((cFirst=(pucUTF8Buf[0]>>4) == 14))//1110xxxx 10xxxxxx 10xxxxxx
	{
		cFirst=pucUTF8Buf[0]&0xf;
		cSecond=pucUTF8Buf[1]&0x3f;
		cThird=pucUTF8Buf[2]&0x3f;
		code = (cFirst<<12)|(cSecond<<6)|cThird;
		return code;	
	}	

	if((cFirst=(pucUTF8Buf[0]>>3) == 30))//11110xxx 10xxxxxx 10xxxxxx 10xxxxxx
	{
		cFirst=pucUTF8Buf[0]&0x7;
		cSecond=pucUTF8Buf[1]&0x3f;
		cThird=pucUTF8Buf[2]&0x3f;
		cForth=pucUTF8Buf[3] &0x3f;
		code = (cFirst<<18)|(cSecond<<12)|(cThird<<6)|cForth;
		return code;		
	}	
	else
	{
		return -1;
	}
}

// Show a font for a Unicode.And will renew pen.x after draw_bitmap()
int show_one_font(unsigned int code)
{
	FT_Set_Transform( face, &matrix, &pen );
   
    	/* load glyph image into the slot (erase previous one) */
    	FT_Load_Char( face, code, FT_LOAD_RENDER );//就会设置face->glyph,或slot,转换的位图又保存在哪里？
    							   //位图点阵应该是保存在face->glyph.bitmap或slot->bitmap中。
    	
    	/* now, draw to our target surface (convert position) */
    	draw_bitmap( &slot->bitmap,slot->bitmap_left,target_height - slot->bitmap_top ); 

    	/* increment pen position */
   	pen.x += slot->advance.x;
   	    
    	return 0;		
}

//will renew pen.x and pen.y after show one line.
unsigned char * show_line(unsigned char *pucLineFirsPostAtFile)
{
	unsigned int code = GetCodeFrmUTF8Buf(pucLineFirsPostAtFile);

	while(((pen.x/64 +FONTSIZE) <= var.xres) &&(code != '\0'))
	{	
		
		if (code == '\n')
		{
			pen.y = pen.y -FONTSIZE*64;
			pen.x = FONTSIZE*2*64;
			pucLineFirsPostAtFile=Renew_pucLcdFirstPosAtFile(code,pucLineFirsPostAtFile);
			code = GetCodeFrmUTF8Buf(pucLineFirsPostAtFile);
			return pucLineFirsPostAtFile;
		}
		else if (code == '\r')
		{
			pucLineFirsPostAtFile=Renew_pucLcdFirstPosAtFile(code,pucLineFirsPostAtFile);
			code = GetCodeFrmUTF8Buf(pucLineFirsPostAtFile);
			return pucLineFirsPostAtFile;
		}
		else if (code == '\t')
		{
			/* TAB键用一个空格代替 */
			code = ' ';
		}
		
		show_one_font(code);
		pucLineFirsPostAtFile=Renew_pucLcdFirstPosAtFile(code,pucLineFirsPostAtFile);
		code = GetCodeFrmUTF8Buf(pucLineFirsPostAtFile);

	}
	
	if((pen.x/64 + FONTSIZE) > var.xres || (code == '\0'))
	{
		pen.x=0;
		pen.y = pen.y - FONTSIZE*64;
		
	}
	return pucLineFirsPostAtFile;
}

unsigned char* show_one_page(PT_PageInfo ptCurPageInfo)
{
	PT_PageInfo ptPageToRecord = malloc(sizeof(T_PageInfo));
	unsigned char * puctmp=ptCurPageInfo->pucPagePos;
	
	while(pen.y-64*FONTSIZE >=0)
	{
		 puctmp = show_line(puctmp);	
	}
	
	if(ptCurPageInfo->pt_NextPageInfo == NULL)
	{
		ptPageToRecord->pucPagePos=puctmp;
		RecordPage(ptPageToRecord);	
	}
		
	pen.y = ( target_height - FONTSIZE ) * 64; 
	
	return puctmp;
}

static void RecordPage(PT_PageInfo ptPageNew)
{
	PT_PageInfo ptPage;
		
	if (!g_ptPages)
	{
		g_ptPages = ptPageNew;
	}
	else
	{
		ptPage = g_ptPages;
		while (ptPage->pt_NextPageInfo)
		{
			ptPage = ptPage->pt_NextPageInfo;
		}
		ptPage->pt_NextPageInfo   = ptPageNew;
		ptPageNew->pt_PrePageInfo = ptPage;
		ptPageNew->pt_NextPageInfo = NULL;
	}
}

unsigned char* Renew_pucLcdFirstPosAtFile(unsigned int code,unsigned char *pucCurPosAtFile)
{
	int pitch;
	
	if( 0<=code &&code<=127 )
	{
		pitch = 1;
	}
	else if( 128<=code &&code<=2047 )
	{
		pitch = 2;
	}
	else if( 2048<=code &&code<=65535 )
	{
		pitch = 3;
	}
	else if( 65536<=code &&code<=1114111 )
	{
		pitch = 4;
	}
	else
	{
		fprintf(stderr,"renew err\n");	
		return pucCurPosAtFile;
	}
	
	pucCurPosAtFile=&pucCurPosAtFile[pitch];	

	return pucCurPosAtFile;
}

main.c:

#include "function.h"
   
int main(int argc,char** argv)
{
  	char cOpr;
	
	if ( argc != 3 )
	{
	    	fprintf ( stderr, "usage: %s FontFile TextFileName\n", argv[0] );
	    	exit( 1 );
	}
	
	lcd_init();
	memset(fbmem, 0, screen_size);
	FontFile = argv[1];
	freetype_init();
	  
	TextFileName = argv[2];         
	OpenTextFile(TextFileName);
	g_ptPageInfoCur = &g_tPageInfoHeader;
	g_ptPages = &g_tPageInfoHeader;
  	show_one_page(g_ptPageInfoCur);
  	
  	
 	while (1)
	{
		printf("Enter 'n' to show next page, 'u' to show previous page, 'q' to exit: ");

		do {
			cOpr = getchar();			
		} while ((cOpr != 'n') && (cOpr != 'u') && (cOpr != 'q'));

		if (cOpr == 'n')
		{
			
			if(g_ptPageInfoCur->pt_NextPageInfo->pucPagePos==g_pucTextFileMemEnd)
			{
				printf("is the end!\n");
				continue;
			}
			memset(fbmem, 0, screen_size);
			show_one_page(g_ptPageInfoCur->pt_NextPageInfo);
			g_ptPageInfoCur=g_ptPageInfoCur->pt_NextPageInfo;
			
		}
		
		else if (cOpr == 'u')
		{
			if(g_ptPageInfoCur->pt_PrePageInfo == NULL)
			{
				printf("this is first page!\n");	
			}
			else
			{
				memset(fbmem, 0, screen_size);
				show_one_page((g_ptPageInfoCur->pt_PrePageInfo));
				g_ptPageInfoCur=g_ptPageInfoCur->pt_PrePageInfo;
			}
		}
		
		else 
		{
			break;
		}			
	}
	 
	close_freetype();
	close(fd_fb);
	
	return 0;
}

电子书效果(为方便观察，我把字体调大了点，可在function.h文件中修改字体大小：#define FONTSIZE 30)：