[C++知识库]电子量产工具——4.文字系统

电子量产工具——4.文字系统

软件总框架

一、数据结构抽象

1.1 文字系统：数据结构抽象

1.2 能支持复杂的Freetype，就能支持其他字

1.3 文字系统：描述一个文字的位图

1.4 文字系统：描述一个字库操作

1.5 代码 font_manager.h

font_manager.h

#ifndef _FONT_MANAGER_H
#define _FONT_MANAGER_H

#include <common.h>

typedef struct FontBitMap {
	Region tRegion;
	int iCurOriginX;
	int iCurOriginY;
	int iNextOriginX;
	int iNextOriginY;
	unsigned char *pucBuffer;
}FontBitMap, *PFontBitMap;

typedef struct FontOpr {
	char *name;
	int (*FontInit)(char *aFineName);
	int (*SetFontSize)(int iFontSize);
	int (*GetFontBitMap)(unsigned int dwCode, PFontBitMap ptFontBitMap);
	struct FontOpr *ptNext;
}FontOpr, *PFontOpr;

void RegisterFont(PFontOpr ptFontOpr);

void FontsRegister(void);

int SelectAndInitFont(char *aFontOprName, char *aFontFileName);
int SetFontSize(int iFontSize);
int GetFontBitMap(unsigned int dwCode, PFontBitMap ptFontBitMap);


#endif

common.h

common.h
typedef struct Region {
	int iLeftUpX;
	int iLeftUpY;
	int iWidth;
	int iHeigh;
}Region, *PRegion;

二、实现freetype

1.框架

讲解：
ptFontBitMap->tRegion.iLeftUpY = ptFontBitMap->iCurOriginY*2 - slot-> bitmap_top;

2.代码freetype.c

freetype.c

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

#include <ft2build.h>
#include FT_FREETYPE_H
#include FT_GLYPH_H


static FT_Face g_tFace;
static int g_iDefaultFontSize = 12;

static int FreeTypeFontInit(char *aFineName)
{
    FT_Library    library;
    int error;

    error = FT_Init_FreeType( &library );                 /* initialize library */    
	if (error)
	{
		printf("FT_Init_FreeType err\n");
		return -1;
	}
	
    error = FT_New_Face(library, aFineName, 0, &g_tFace ); /* create face object */
	if (error)
	{
		printf("FT_New_Face err\n");
		return -1;
	}

    FT_Set_Pixel_Sizes(g_tFace, g_iDefaultFontSize, 0);

	return 0;
}

static int FreeTypeSetFontSize(int iFontSize)
{
    FT_Set_Pixel_Sizes(g_tFace, iFontSize, 0);
	return 0;
}

static int FreeTypeGetFontBitMap(unsigned int dwCode, PFontBitMap ptFontBitMap)
{
	int error;
    FT_Vector pen;
    FT_GlyphSlot slot = g_tFace->glyph;

    pen.x = ptFontBitMap->iCurOriginX * 64; /* 单位: 1/64像素 */
    pen.y = ptFontBitMap->iCurOriginY * 64; /* 单位: 1/64像素 */

	/* 转换：transformation */
	FT_Set_Transform(g_tFace, 0, &pen);

	/* 加载位图: load glyph image into the slot (erase previous one) */
	error = FT_Load_Char(g_tFace, dwCode, FT_LOAD_RENDER);
	if (error)
	{
		printf("FT_Load_Char error\n");
		return -1;
	}

	ptFontBitMap->pucBuffer = slot->bitmap.buffer;

	ptFontBitMap->tRegion.iLeftUpX = slot->bitmap_left;
	ptFontBitMap->tRegion.iLeftUpY = ptFontBitMap->iCurOriginY*2 - slot->bitmap_top;
	ptFontBitMap->tRegion.iWidth   = slot->bitmap.width;
	ptFontBitMap->tRegion.iHeigh   = slot->bitmap.rows;
	ptFontBitMap->iNextOriginX = ptFontBitMap->iCurOriginX + slot->advance.x / 64;
	ptFontBitMap->iNextOriginY = ptFontBitMap->iCurOriginY;

	return 0;
}


static FontOpr g_tFreetypeOpr = {
	.name          = "freetype",
	.FontInit      = FreeTypeFontInit,
	.SetFontSize   = FreeTypeSetFontSize,
	.GetFontBitMap = FreeTypeGetFontBitMap,
};

void FreetypeRegister(void)
{
	RegisterFont(&g_tFreetypeOpr);
}

三、文字管理

1. 框架

2.代码 font_manager.c

font_manager.c

#include <font_manager.h>

#include <string.h>

static PFontOpr g_ptFonts = NULL;
static PFontOpr g_ptDefaulFontOpr = NULL;


void RegisterFont(PFontOpr ptFontOpr)
{
	ptFontOpr->ptNext = g_ptFonts;
	g_ptFonts = ptFontOpr;
}

void FontsRegister(void)
{
	extern void FreetypeRegister(void);
	FreetypeRegister();
}

int SelectAndInitFont(char *aFontOprName, char *aFontFileName)
{
	PFontOpr ptTmp = g_ptFonts;
	while (ptTmp)
	{
		if (strcmp(ptTmp->name, aFontOprName) == 0)
			break;
		ptTmp = ptTmp->ptNext;
	}

	if (!ptTmp)
		return -1;

	g_ptDefaulFontOpr = ptTmp;
	return ptTmp->FontInit(aFontFileName);
}

int SetFontSize(int iFontSize)
{
	return g_ptDefaulFontOpr->SetFontSize(iFontSize);
}

int GetFontBitMap(unsigned int dwCode, PFontBitMap ptFontBitMap)
{
	return g_ptDefaulFontOpr->GetFontBitMap(dwCode, ptFontBitMap);
}

四、测试代码 font_test.c

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

#include <stdlib.h>

#include <disp_manager.h>
#include <font_manager.h>

#define FONTDATAMAX 4096

static const unsigned char fontdata_8x16[FONTDATAMAX] = {

	/* 0 0x00 '^@' */
	0x00, /* 00000000 */
	0x00, /* 00000000 */
	0x00, /* 00000000 */
	0x00, /* 00000000 */
	0x00, /* 00000000 */
	0x00, /* 00000000 */
	0x00, /* 00000000 */
	0x00, /* 00000000 */
	0x00, /* 00000000 */
	.................
	...............
	.....
	0x00, /* 00000000 */
	0x00, /* 00000000 */

};
void lcd_put_ascii(int x, int y, unsigned char c)
{
	unsigned char *dots = (unsigned char *)&fontdata_8x16[c*16];
	int i, b;
	unsigned char byte;

	for (i = 0; i < 16; i++)
	{
		byte = dots[i];
		for (b = 7; b >= 0; b--)
		{
			if (byte & (1<<b))
			{
				/* show */
				PutPixel(x+7-b, y+i, 0xffffff); /* 白 */
			}
			else
			{
				/* hide */
				PutPixel(x+7-b, y+i, 0); /* 黑 */
			}
		}
	}
}
int iLeftUpX;
	int iLeftUpY;
	int iWidth;
	int iRows;

int main(int argc, char **argv)
{
	PDispBuff ptBuffer;
	int error;
	
	FontBitMap tFontBitMap;
	char *str= "i am your gan bother";
	int i = 0;
	int lcd_x;
	int lcd_y;

	int font_size;

	if (argc != 5)
	{
		printf("Usage: %s <font_file> <lcd_x> <lcd_y> <font_size>\n",argv[0]);
		return -1;
	}

	lcd_x = strtol(argv[2], NULL, 0);
	lcd_y = strtol(argv[3], NULL, 0);
	
	font_size  = strtol(argv[4], NULL, 0);
	
	DisplayInit();

	SelectDefaultDisplay("fb");

	InitDefaultDisplay();

	ptBuffer = GetDisplayBuffer();

	FontsRegister();

	error = SelectAndInitFont("freetype",  argv[1]);
	if (error)
	{
		printf("SelectAndInitFont err\n");
		return -1;
	}
	
	SetFontSize(font_size);

	while (str[i])
	{
		/* get bitmap */
		tFontBitMap.iCurOriginX = lcd_x;
		tFontBitMap.iCurOriginY = lcd_y;
		error = GetFontBitMap(str[i], &tFontBitMap);
		if (error)
		{
			printf("SelectAndInitFont err\n");
			return -1;
		}
		
		/* draw on buffer */		
		DrawFontBitMap(&tFontBitMap, 0x0000ff);

		/* flush to lcd/web */		
		FlushDisplayRegion(&tFontBitMap.tRegion, ptBuffer);
		

		lcd_x = tFontBitMap.iNextOriginX;
		lcd_y = tFontBitMap.iNextOriginY;	
		i++;
	}
	
	return 0;	
}

总结

…待写