DM36x IPNC OSD显示中文 --- 基本数据准备篇

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*;
     FILE *fp = fopen(filename,"wb");
     if(!fp)
     {
         perror("open file error");
         return -;
     }

     bmp_head.bfType=0x4d42;
     bmp_head.bfSize=size+sizeof(FileHead)+sizeof(Infohead);//24+head+info no quad
     bmp_head.bfReserved1=bmp_head.bfReserved2=;
     bmp_head.bfOffBits=bmp_head.bfSize-size;

     bmp_info.biSize=;
     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=;
     bmp_info.biBitCount = ;
     bmp_info.biCompress=;
     bmp_info.biSizeImage=size;
     bmp_info.biXPelsPerMeter=;
     bmp_info.biYPelsPerMeter=;
     bmp_info.biClrUsed=;
     bmp_info.biClrImportant=;

     fwrite(&bmp_head,,sizeof(FileHead),fp);
     fwrite(&bmp_info,,sizeof(Infohead),fp);
     fwrite(data,,size,fp);
     fclose(fp);
     return ;
 }

//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 = ;//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=;
     int area,location;
     char testfilename[];

     unsigned char *image = NULL, *pimage;//一个区转换为一张图片
     int temp;

     if(font_width <=  && font_height <= )
     {
         printf("invalidate font size.\n");
         return -;
     }
     if(font_width <= )
         font_width = font_height;
     if(font_height <= )
         font_height = font_width;
     if(font_width % )//4字节对齐,这里先保证宽度为4pixel对齐
     {
         printf("invalidate font size.\n");
         return -;
     }
     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, , &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 * );
         if(!bmpdata)
         {
             printf("outof memory.\n");
             break;
         }
         image = malloc( * font_width * font_height * );//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=;i<face->num_fixed_sizes;i++)
         {
             printf("supported size %d:width=%d,heigh=%d\n",i+,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 = ;area < ;area ++)//1- 87区
         {
             if( (area > && area < )/* 8 - 15区跳过*/
                 ||(area >  && area < )/* 87 - 94 区跳过*/
             )
             {
                 continue;
             }
             memset(image,, * font_width * font_height * );
             pimage = image;
             for(location = ;location < ;location++)//1 - 94位
             {
                 index = area *  + location;
                 if(Gb2312ToUnicode(gb2312_table[index],&unicode) < )
                 {
                     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/,face->glyph->metrics.height/,
                         face->glyph->metrics.vertBearingX/,face->glyph->metrics.vertBearingY/,face->glyph->metrics.horiAdvance/);
                 }
                 else
                 {
                     printf("HORI:(w:%ld h:%ld)(bearingX:%ld bearingY:%ld Advance:%ld)\n",face->glyph->metrics.width/,face->glyph->metrics.height/,
                         face->glyph->metrics.horiBearingX/,face->glyph->metrics.horiBearingY/,face->glyph->metrics.vertAdvance/);
                 }
                 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     = ;//字型顶部距离位图顶部空行数目
                             int leftblank     = ;//字型左边距离位图左边空列数目
                             int rightblank     = ;//字型右边距离位图右边空列数目
                             int pitch     = ;//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/;
                                 leftblank     = font_width/ + face->glyph->metrics.vertBearingX/;
                             }
                             else
                             {
                                 topblank    = font_height *  / - face->glyph->metrics.horiBearingY/;
                                 leftblank     = face->glyph->metrics.horiBearingX/;
                             }
                             if(topblank < )topblank     = ;
                             if(leftblank < )leftblank     = ;
                             rightblank = font_width - width - leftblank;
                             if(rightblank < )rightblank    = ;
                             pitch =  ft_bmp ->width / ;
                             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,,font_width * font_height * );
                             pdata = bmpdata;
                             pdata += topblank *font_width * ;//跳过上边距
                             for(i=;i<height;i++)
                             {
                                 pdata += leftblank * ;
                                 k = ;
                                 for(j=;j<width;j++)
                                 {
                                     if(ft_bmp_buff[j/] & ( << k) )
                                     {
                                         //pdata[0] = 255;//蓝
                                         pdata[] = ;//绿
                                         pdata[] = ;//红
                                     }
                                     k--;
                                     if(k<)k=;
                                     pdata += ;
                                 }
                                 ft_bmp_buff += pitch;
                                 pdata += rightblank * ;
                             }
                             /*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 * ;
                 for(temp=;temp<font_height;temp++)
                 {
                     memcpy(pimage,pdata,font_width * );
                     pdata += font_width * ;
                     pimage +=  * font_width *;
                 }
 #ifndef _WIN32
                 usleep();
 #else
                 Sleep();
 #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, * font_width,font_height,image))
             {
                 printf("save bmp file [%s] error.\n",testfilename);
             }
         }//for( 1 - 94 区)
         printf("\nConvert Done.\n");

     }while ();
 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 ;
 }

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***************************/

http://blog.csdn.net/sloan6/article/details/9231373