DM36x IPNC OSD显示中文 --- 基本数据准备篇

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经过上一篇的叙述,基本原理搞清楚后,便需要对我们在OSD上显示中文作数据准备,
首先是需要将gb2312关键区(也就是实际有文字存在的区)中的汉字转换为图片,在实际的转换中,并不像上一篇中GB2312编码转换为UNICODE描述一样,
使用libiconv库中的iconv函数将94x94的gb2312编码表直接传递给iconv函数会转换失败(错误提示不完整的多字节字符或宽字符).为了简化这其中的转换难度,目前使用的是查表的方法将GB2312编码转换为UNICODE编码,
这样就要求先准备好GB2312 UNICODE对照表,这个表网上有各种形式的,但是通过我花了很长时间查找也没有找到合适自己需求的,主要是网上的GB2312区位码不全,都会丢掉某些区中的某些编码,这样会有个问题,
就是我们转换后的数据需要记录我们中间丢失了哪些编码,对应的位置等等.会造成后续程序执行效率降低和设计难度加大.这里我是直接将94x94个GB2312编码都转换为对应的unicode编码,保存在一个数组中(很占篇幅,这里不贴实际数据了),通过查找下标的方式查找对应的UNICODE编码.
将对应的GB2312编码转换为UNICODE编码后,接下来就是使用Freetype2将该UNICODE码提取出对应的字符映像,并转换为位图,保存在磁盘上了,下面是其中的核心程序:
//linux下保存24位bmp图像,数据结构FileHead、Infohead见上一篇
int save_bmp24(char * filename,int width,int height,unsigned char *data){    FileHead bmp_head;    Infohead bmp_info;    int size = width*height*3;    FILE *fp = fopen(filename,"wb");    if(!fp)    {        perror("open file error");        return -1;    }    bmp_head.bfType=0x4d42;    bmp_head.bfSize=size+sizeof(FileHead)+sizeof(Infohead);//24+head+info no quad        bmp_head.bfReserved1=bmp_head.bfReserved2=0;    bmp_head.bfOffBits=bmp_head.bfSize-size;    bmp_info.biSize=40;    bmp_info.biWidth=width;    bmp_info.biHeight=-height;//如果为正数,转换出来的图片还需要进行垂直翻转    bmp_info.biPlanes=1;    bmp_info.biBitCount = 24;    bmp_info.biCompress=0;    bmp_info.biSizeImage=size;    bmp_info.biXPelsPerMeter=0;    bmp_info.biYPelsPerMeter=0;    bmp_info.biClrUsed=0;    bmp_info.biClrImportant=0;    fwrite(&bmp_head,1,sizeof(FileHead),fp);    fwrite(&bmp_info,1,sizeof(Infohead),fp);    fwrite(data,1,size,fp);    fclose(fp);    return 0;}

//转换函数,这里是一个区转换为一个图片
int convert(const char * font_file,int font_width,int font_height){    FT_Library library = NULL;    FT_Face face = NULL;    int error;    int char_index;    int char_code;        unsigned char * bmpdata = NULL,*pdata;//保存一个字的图片数据    int isVert = 0;//是否垂直布局,中文为垂直布局    FT_Bitmap *ft_bmp;        unsigned short  unicode;//用于存储unicode    int index=0;    int area,location;    char testfilename[100];        unsigned char *image = NULL, *pimage;//一个区转换为一张图片    int temp;        if(font_width <= 0 && font_height <= 0)    {        printf("invalidate font size.\n");        return -1;    }    if(font_width <= 0)        font_width = font_height;    if(font_height <= 0)        font_height = font_width;    if(font_width % 2)//4字节对齐,这里先保证宽度为4pixel对齐    {        printf("invalidate font size.\n");        return -1;    }    setlocale(LC_ALL,"zh_CN.UTF-8");    do    {        //下面开始初始化FT2库        error = FT_Init_FreeType(&library);        if (error)        {            printf("can not init free type library!\n");            break;        }        error = FT_New_Face(library, font_file, 0, &face);        if (error)        {            printf("create new face falied!\n");            break;        }        isVert = FT_HAS_VERTICAL(face);            error = FT_Set_Pixel_Sizes(face, font_width, font_height);//设置字体大小        if (error)        {            printf("set font size error!\n");            break;        }        bmpdata = malloc(font_width * font_height * 3);        if(!bmpdata)        {            printf("outof memory.\n");            break;        }        image = malloc(94 * font_width * font_height * 3);//这里要求font_size必须为偶数        if(!image)        {            printf("outof memory.\n");            break;        }#if 0        //打印字体相关信息        printf("file has %d faces\n", face->num_faces);        printf("%s  italic or oblique,%s bold\n", face->style_flags & FT_STYLE_FLAG_ITALIC ?"support":"not support",face->style_flags & FT_STYLE_FLAG_BOLD ?"support":"not support");        printf("file family name %s\n", face->family_name);        printf("file style name %s\n", face->style_name);        printf("face index %d\n", face->face_index);        printf("number of char %d\n", face->num_glyphs);        printf("number of fixed bitmap %d\n", face->num_fixed_sizes);        printf("Char size %d\n", face->size);        printf("has %d fixed sizes\n",face->num_fixed_sizes);        for(i=0;i<face->num_fixed_sizes;i++)        {            printf("supported size %d:width=%d,heigh=%d\n",i+1,face->available_sizes[i].width,face->available_sizes[i].height);        }#endif        error = FT_Select_Charmap(face,FT_ENCODING_UNICODE);//这里使用UNICODE映射表,便于使用UNICODE码(char code)来获取char index        if(error)        {            printf("select char map error.\n");            break;        }        //printf("code %x\n",face ->charmap ->encoding);        switch(face ->charmap ->encoding)        {            case FT_ENCODING_MS_GB2312:    printf("USE GB2312 CODE\n");break;            case FT_ENCODING_MS_BIG5:    printf("USE BIG5 CODE\n");break;            case FT_ENCODING_UNICODE:    printf("USE UNICODE CODE\n");break;            default:                printf("UNKNOWN CODE\n");                goto done;                break;        }                //实际有字体的区码为(0-8) (15-86)区(区号从0开始 ) = 9 + 72 = 81个区        for(area = 0;area < 87;area ++)//1- 87区        {            if( (area >8 && area < 15)/* 8 - 15区跳过*/                ||(area > 86 && area < 94)/* 87 - 94 区跳过*/            )            {                continue;            }            memset(image,0,94 * font_width * font_height * 3);            pimage = image;            for(location = 0;location < 94;location++)//1 - 94位            {                index = area * 94 + location;                if(Gb2312ToUnicode(gb2312_table[index],&unicode) < 0)                {                    printf("get unicode code error.gb2312 code 0x%04X\n",gb2312_table[index]);                    continue;                }                char_code = unicode;                if(!char_code)                {                    printf("\ninvalidate char code.\n");                    continue;                }                char_index = FT_Get_Char_Index(face,char_code);                error = FT_Load_Glyph(face, char_index,  FT_LOAD_DEFAULT | FT_LOAD_MONOCHROME);                if (error)                {                    printf("\nload char error!\n");                    goto done;                }                if (face->glyph->format != FT_GLYPH_FORMAT_BITMAP)                {                    error = FT_Render_Glyph(face->glyph, FT_RENDER_MODE_MONO);                    if (error)                    {                        printf("\nrender char failed!\n");                        goto done;                    }                }                /*                单色位图图像数据的表示方法:                在单色位图图像中,只有两种颜色,黑色或白色,每一个像素只需要一个比特就能够完成表示,为了清楚比特0或1具体表示哪一种颜色,可以通过查询调色板。                在单色位图图像中,调色板只包含两种颜色,每一种颜色用R G B 0 四个字节表示 (在实际的字节流中,顺序是 B G R 0)                所以,位图图像数据中的0 代表调色板中 第一种颜色的颜色值, 1 代表调色板中 第二种颜色的颜色值。                一行单色位图数据的存储格式规定:                每一扫描行的字节数必需是4的整倍数,当不够4的整数倍时,需要加0补齐                以 720 × 450 的单色位图图像为例                水平扫描行的长度为720,则需要720比特来表示一个扫描行,即需要 720/8=90字节来表示,但是 90不是 4 的整数倍,因此需要用0补齐,直至为4的整数倍,即需要额外的2个填充字节。                最终,长度为720的水平扫描行使用了 92 个字节来表示。                NOTE:非8位位图可用函数FT_Bitmap_Convert进行转换                */                //转换为4字节对齐                ft_bmp = &face->glyph->bitmap;#if 0                //dump位图信息                printf("bit_map_left %d bit_map_top %d\n", face->glyph->bitmap_left,face->glyph->bitmap_top);                printf("int rows:%d\n",ft_bmp ->rows);                printf("int width:%d\n",ft_bmp ->width);                printf("int pitch:%d\n",ft_bmp ->pitch);                printf("short num_grays:%d\n",ft_bmp ->num_grays);                printf("char pixel_mode:%d\n",ft_bmp ->pixel_mode);                if(isVert)                {                    printf("VERT:(w:%ld h:%ld)(bearingX:%ld bearingY:%ld Advance:%ld)\n",face->glyph->metrics.width/64,face->glyph->metrics.height/64,                        face->glyph->metrics.vertBearingX/64,face->glyph->metrics.vertBearingY/64,face->glyph->metrics.horiAdvance/64);                }                else                {                    printf("HORI:(w:%ld h:%ld)(bearingX:%ld bearingY:%ld Advance:%ld)\n",face->glyph->metrics.width/64,face->glyph->metrics.height/64,                        face->glyph->metrics.horiBearingX/64,face->glyph->metrics.horiBearingY/64,face->glyph->metrics.vertAdvance/64);                }                printf("xMin=%ld, yMin=%ld, xMax=%ld, yMax=%ld\n",face ->bbox.xMin,face ->bbox.yMin,face ->bbox.xMax,face ->bbox.yMax);#endif                        switch(ft_bmp ->pixel_mode)                {                    case FT_PIXEL_MODE_MONO://单色位图                        {                            //将数据转换到24位                            int topblank     = 0;//字型顶部距离位图顶部空行数目                            int leftblank     = 0;//字型左边距离位图左边空列数目                            int rightblank     = 0;//字型右边距离位图右边空列数目                            int pitch     = 0;//每个扫描行占用几个字节                            int width    = ft_bmp ->width;//实际字型宽度                            int height    = ft_bmp ->rows; //实际字型高度                            unsigned char * ft_bmp_buff = ft_bmp ->buffer;                            int i,j,k;                            if(isVert)                            {                                topblank     = face->glyph->metrics.vertBearingY/64;                                leftblank     = font_width/2 + face->glyph->metrics.vertBearingX/64;                            }                            else                            {                                topblank    = font_height * 2 /3 - face->glyph->metrics.horiBearingY/64;                                leftblank     = face->glyph->metrics.horiBearingX/64;                            }                            if(topblank < 0)topblank     = 0;                            if(leftblank < 0)leftblank     = 0;                            rightblank = font_width - width - leftblank;                            if(rightblank < 0)rightblank    = 0;                            pitch =  ft_bmp ->width / 8;                            if(pitch% ft_bmp ->pitch)                                pitch = pitch + (ft_bmp ->pitch - pitch %ft_bmp ->pitch);                            //printf("PITCH=%d\n",pitch);                                            //转换1bit位图数据到24bit位图数据                            printf("begin convert.area %d ----> %d\r",area,location);                            memset(bmpdata,0,font_width * font_height * 3);                            pdata = bmpdata;                            pdata += topblank *font_width * 3;//跳过上边距                            for(i=0;i<height;i++)                            {                                pdata += leftblank * 3;                                k = 7;                                for(j=0;j<width;j++)                                {                                    if(ft_bmp_buff[j/8] & (1 << k) )                                    {                                        //pdata[0] = 255;//蓝                                        pdata[1] = 255;//绿                                        pdata[2] = 255;//红                                    }                                    k--;                                    if(k<0)k=7;                                    pdata += 3;                                }                                ft_bmp_buff += pitch;                                pdata += rightblank * 3;                            }                            /*if(!(font_width %4))                            {                                sprintf(testfilename,"./testbmp/%d_%d.bmp",area,location );                                printf("\nsave bmp file [%s]\n",testfilename);                                if(save_bmp24(testfilename,font_width ,font_height,bmpdata))                                {                                    printf("save bmp file [%s] error.\n",testfilename);                                }                            }*/                            }                        break;                    default:                        printf("位图为非单色图片.\n");                        goto done;                        break;                }//switch                pdata = bmpdata;                pimage = image + location * font_width * 3;                                for(temp=0;temp<font_height;temp++)                {                    memcpy(pimage,pdata,font_width * 3);                    pdata += font_width * 3;                    pimage += 94 * font_width *3;                }#ifndef _WIN32                usleep(10);#else                Sleep(10);#endif            }//for( 1 - 94 位 )            //保存图片            sprintf(testfilename,"./testbmp/area%d_%dx%d.bmp",area,font_width,font_height);            //printf("\nsave bmp file [%s]\n",testfilename);            if(save_bmp24(testfilename,94 * font_width,font_height,image))            {                printf("save bmp file [%s] error.\n",testfilename);            }        }//for( 1 - 94 区)        printf("\nConvert Done.\n");    }while (0);done:#if 0    //出现莫名其妙的错误,注释了    fprintf(stderr,"begin cleanup.\n");    if(bmpdata)    {        free(bmpdata);        bmpdata = NULL;    }    if(image)    {        free(image);        image = NULL;    }    if(face)    {        FT_Done_Face(face);        face = NULL;    }    if(library)    {        FT_Done_FreeType(library);        library = NULL;    }#endif    return 0;}

这里上传几个程序转换的图片:

14x16:

16x18:


20x24:

28x32:

将编码转换为图片后,需要将bmp24图片数据转换为yuv420p数据,利用libswscale库进行转换的核心代码已经在上一篇贴了,这里不再重贴.
下面是转换后的结果,当然也可以直接将数据保存为一个二进制文件,而不是一个C源程序文件
/*********************Y***************************/unsigned char data_Y[]={     0x10,0x10,0x10,0x10,0x10,0x10,0x10,0x10,0x10,0x10,0x10,0x10,0x10,0x10,0x10,0x10    ,0x10,0x10,0x10,0x10,0x10,0x10,0x10,0x10,0x10,0x10,0x10,0x10,0x10,0x10,0x10,0x10    ,0x10,0x10,0x10,0x10,0x10,0x10,0x10,0x10,0x10,0x10,0x10,0x10,0x10,0x10,0x10,0x10    ,0x10,0x10,0x10,0x10,0x10,0x10,0x10,0x10,0x10,0x10,0x10,0x10,0x10,0x10,0x10,0x10    ......    ,0x10,0x10,0x10,0x10,0x10,0x10,0x10,0x10,0x10,0x10,0x10,0x10,0x10,0x10,0x10,0x10    ,0x10,0x10,0x10,0x10,0x10,0x10,0x10,0x10,0x10,0x10,0x10,0x10,0x10,0x10,0x10,0x10    ,0x10,0x10,0x10,0x10,0x10,0x10,0x10,0x10,0x10,0x10,0x10,0x10,0x10,0x10,0x10,0x10    ,0x10,0x10,0x10,0x10,0x10,0x10,0x10,0x10};//37224 bytes/**************end of Y***************************//********************UV***************************/unsigned char data_UV[]={     0x80,0x80,0x80,0x80,0x80,0x80,0x80,0x80,0x80,0x80,0x80,0x80,0x80,0x80,0x80,0x80    ,0x80,0x80,0x80,0x80,0x80,0x80,0x80,0x80,0x80,0x80,0x80,0x80,0x80,0x80,0x80,0x80    ,0x80,0x80,0x80,0x80,0x80,0x80,0x80,0x80,0x80,0x80,0x80,0x80,0x80,0x80,0x80,0x80    ,0x80,0x80,0x80,0x80,0x80,0x80,0x80,0x80,0x80,0x80,0x80,0x80,0x80,0x80,0x80,0x80    ......    ,0x80,0x80,0x80,0x80,0x80,0x80,0x80,0x80,0x80,0x80,0x80,0x80,0x80,0x80,0x80,0x80    ,0x80,0x80,0x80,0x80,0x80,0x80,0x80,0x80,0x80,0x80,0x80,0x80,0x80,0x80,0x80,0x80    ,0x80,0x80,0x80,0x80,0x80,0x80,0x80,0x80,0x80,0x80,0x12,0x92,0x80,0x80,0x80,0x80    ,0x80,0x80,0x80,0x80};//18612 bytes/*************end of UV***************************/

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