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
1 int save_bmp24(char * filename,int width,int height,unsigned char *data)
2 {
3 FileHead bmp_head;
4 Infohead bmp_info;
5 int size = width*height*3;
6 FILE *fp = fopen(filename,"wb");
7 if(!fp)
8 {
9 perror("open file error");
10 return -1;
11 }
12
13 bmp_head.bfType=0x4d42;
14 bmp_head.bfSize=size+sizeof(FileHead)+sizeof(Infohead);//24+head+info no quad
15 bmp_head.bfReserved1=bmp_head.bfReserved2=0;
16 bmp_head.bfOffBits=bmp_head.bfSize-size;
17
18 bmp_info.biSize=40;
19 bmp_info.biWidth=width;
20 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
21 bmp_info.biPlanes=1;
22 bmp_info.biBitCount = 24;
23 bmp_info.biCompress=0;
24 bmp_info.biSizeImage=size;
25 bmp_info.biXPelsPerMeter=0;
26 bmp_info.biYPelsPerMeter=0;
27 bmp_info.biClrUsed=0;
28 bmp_info.biClrImportant=0;
29
30 fwrite(&bmp_head,1,sizeof(FileHead),fp);
31 fwrite(&bmp_info,1,sizeof(Infohead),fp);
32 fwrite(data,1,size,fp);
33 fclose(fp);
34 return 0;
35 }
//转换函数,这里是一个区转换为一个图片
1 int convert(const char * font_file,int font_width,int font_height)
2 {
3 FT_Library library = NULL;
4 FT_Face face = NULL;
5 int error;
6 int char_index;
7 int char_code;
8
9 unsigned char * bmpdata = NULL,*pdata;//保存一个字的图片数据
10 int isVert = 0;//是否垂直布局,中文为垂直布局
11 FT_Bitmap *ft_bmp;
12
13 unsigned short unicode;//用于存储unicode
14 int index=0;
15 int area,location;
16 char testfilename[100];
17
18 unsigned char *image = NULL, *pimage;//一个区转换为一张图片
19 int temp;
20
21 if(font_width <= 0 && font_height <= 0)
22 {
23 printf("invalidate font size.\n");
24 return -1;
25 }
26 if(font_width <= 0)
27 font_width = font_height;
28 if(font_height <= 0)
29 font_height = font_width;
30 if(font_width % 2)//4字节对齐,这里先保证宽度为4pixel对齐
31 {
32 printf("invalidate font size.\n");
33 return -1;
34 }
35 setlocale(LC_ALL,"zh_CN.UTF-8");
36
37 do
38 {
39 //下面开始初始化FT2库
40 error = FT_Init_FreeType(&library);
41 if (error)
42 {
43 printf("can not init free type library!\n");
44 break;
45 }
46
47 error = FT_New_Face(library, font_file, 0, &face);
48 if (error)
49 {
50 printf("create new face falied!\n");
51 break;
52 }
53 isVert = FT_HAS_VERTICAL(face);
54 error = FT_Set_Pixel_Sizes(face, font_width, font_height);//设置字体大小
55 if (error)
56 {
57 printf("set font size error!\n");
58 break;
59 }
60 bmpdata = malloc(font_width * font_height * 3);
61 if(!bmpdata)
62 {
63 printf("outof memory.\n");
64 break;
65 }
66 image = malloc(94 * font_width * font_height * 3);//这里要求font_size必须为偶数
67 if(!image)
68 {
69 printf("outof memory.\n");
70 break;
71 }
72
73 #if 0
74 //打印字体相关信息
75 printf("file has %d faces\n", face->num_faces);
76 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");
77 printf("file family name %s\n", face->family_name);
78 printf("file style name %s\n", face->style_name);
79 printf("face index %d\n", face->face_index);
80 printf("number of char %d\n", face->num_glyphs);
81 printf("number of fixed bitmap %d\n", face->num_fixed_sizes);
82 printf("Char size %d\n", face->size);
83 printf("has %d fixed sizes\n",face->num_fixed_sizes);
84 for(i=0;i<face->num_fixed_sizes;i++)
85 {
86 printf("supported size %d:width=%d,heigh=%d\n",i+1,face->available_sizes[i].width,face->available_sizes[i].height);
87 }
88 #endif
89 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
90 if(error)
91 {
92 printf("select char map error.\n");
93 break;
94 }
95 //printf("code %x\n",face ->charmap ->encoding);
96 switch(face ->charmap ->encoding)
97 {
98 case FT_ENCODING_MS_GB2312: printf("USE GB2312 CODE\n");break;
99 case FT_ENCODING_MS_BIG5: printf("USE BIG5 CODE\n");break;
100 case FT_ENCODING_UNICODE: printf("USE UNICODE CODE\n");break;
101 default:
102 printf("UNKNOWN CODE\n");
103 goto done;
104 break;
105 }
106
107 //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
108 for(area = 0;area < 87;area ++)//1- 87区
109 {
110 if( (area >8 && area < 15)/* 8 - 15区跳过*/
111 ||(area > 86 && area < 94)/* 87 - 94 区跳过*/
112 )
113 {
114 continue;
115 }
116 memset(image,0,94 * font_width * font_height * 3);
117 pimage = image;
118 for(location = 0;location < 94;location++)//1 - 94位
119 {
120 index = area * 94 + location;
121 if(Gb2312ToUnicode(gb2312_table[index],&unicode) < 0)
122 {
123 printf("get unicode code error.gb2312 code 0x%04X\n",gb2312_table[index]);
124 continue;
125 }
126 char_code = unicode;
127 if(!char_code)
128 {
129 printf("\ninvalidate char code.\n");
130 continue;
131 }
132 char_index = FT_Get_Char_Index(face,char_code);
133 error = FT_Load_Glyph(face, char_index, FT_LOAD_DEFAULT | FT_LOAD_MONOCHROME);
134 if (error)
135 {
136 printf("\nload char error!\n");
137 goto done;
138 }
139 if (face->glyph->format != FT_GLYPH_FORMAT_BITMAP)
140 {
141 error = FT_Render_Glyph(face->glyph, FT_RENDER_MODE_MONO);
142 if (error)
143 {
144 printf("\nrender char failed!\n");
145 goto done;
146 }
147 }
148
149 /*
150 单色位图图像数据的表示方法:
151 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。
152 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）
153 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。
154 一行单色位图数据的存储格式规定：
155 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
156 以 720 × 450 的单色位图图像为例
157 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。
158 最终，长度为720的水平扫描行使用了 92 个字节来表示。
159 NOTE:非8位位图可用函数FT_Bitmap_Convert进行转换
160 */
161 //转换为4字节对齐
162 ft_bmp = &face->glyph->bitmap;
163 #if 0
164 //dump位图信息
165 printf("bit_map_left %d bit_map_top %d\n", face->glyph->bitmap_left,face->glyph->bitmap_top);
166 printf("int rows:%d\n",ft_bmp ->rows);
167 printf("int width:%d\n",ft_bmp ->width);
168 printf("int pitch:%d\n",ft_bmp ->pitch);
169 printf("short num_grays:%d\n",ft_bmp ->num_grays);
170 printf("char pixel_mode:%d\n",ft_bmp ->pixel_mode);
171 if(isVert)
172 {
173 printf("VERT:(w:%ld h:%ld)(bearingX:%ld bearingY:%ld Advance:%ld)\n",face->glyph->metrics.width/64,face->glyph->metrics.height/64,
174 face->glyph->metrics.vertBearingX/64,face->glyph->metrics.vertBearingY/64,face->glyph->metrics.horiAdvance/64);
175 }
176 else
177 {
178 printf("HORI:(w:%ld h:%ld)(bearingX:%ld bearingY:%ld Advance:%ld)\n",face->glyph->metrics.width/64,face->glyph->metrics.height/64,
179 face->glyph->metrics.horiBearingX/64,face->glyph->metrics.horiBearingY/64,face->glyph->metrics.vertAdvance/64);
180 }
181 printf("xMin=%ld, yMin=%ld, xMax=%ld, yMax=%ld\n",face ->bbox.xMin,face ->bbox.yMin,face ->bbox.xMax,face ->bbox.yMax);
182 #endif
183
184 switch(ft_bmp ->pixel_mode)
185 {
186 case FT_PIXEL_MODE_MONO://单色位图
187 {
188 //将数据转换到24位
189 int topblank = 0;//字型顶部距离位图顶部空行数目
190 int leftblank = 0;//字型左边距离位图左边空列数目
191 int rightblank = 0;//字型右边距离位图右边空列数目
192 int pitch = 0;//每个扫描行占用几个字节
193 int width = ft_bmp ->width;//实际字型宽度
194 int height = ft_bmp ->rows; //实际字型高度
195 unsigned char * ft_bmp_buff = ft_bmp ->buffer;
196 int i,j,k;
197 if(isVert)
198 {
199 topblank = face->glyph->metrics.vertBearingY/64;
200 leftblank = font_width/2 + face->glyph->metrics.vertBearingX/64;
201 }
202 else
203 {
204 topblank = font_height * 2 /3 - face->glyph->metrics.horiBearingY/64;
205 leftblank = face->glyph->metrics.horiBearingX/64;
206 }
207 if(topblank < 0)topblank = 0;
208 if(leftblank < 0)leftblank = 0;
209 rightblank = font_width - width - leftblank;
210 if(rightblank < 0)rightblank = 0;
211 pitch = ft_bmp ->width / 8;
212 if(pitch% ft_bmp ->pitch)
213 pitch = pitch + (ft_bmp ->pitch - pitch %ft_bmp ->pitch);
214 //printf("PITCH=%d\n",pitch);
215
216 //转换1bit位图数据到24bit位图数据
217 printf("begin convert.area %d ----> %d\r",area,location);
218 memset(bmpdata,0,font_width * font_height * 3);
219 pdata = bmpdata;
220 pdata += topblank *font_width * 3;//跳过上边距
221 for(i=0;i<height;i++)
222 {
223 pdata += leftblank * 3;
224 k = 7;
225 for(j=0;j<width;j++)
226 {
227 if(ft_bmp_buff[j/8] & (1 << k) )
228 {
229 //pdata[0] = 255;//蓝
230 pdata[1] = 255;//绿
231 pdata[2] = 255;//红
232 }
233 k--;
234 if(k<0)k=7;
235 pdata += 3;
236 }
237 ft_bmp_buff += pitch;
238 pdata += rightblank * 3;
239 }
240 /*if(!(font_width %4))
241 {
242 sprintf(testfilename,"./testbmp/%d_%d.bmp",area,location );
243 printf("\nsave bmp file [%s]\n",testfilename);
244 if(save_bmp24(testfilename,font_width ,font_height,bmpdata))
245 {
246 printf("save bmp file [%s] error.\n",testfilename);
247 }
248 }*/
249
250 }
251 break;
252 default:
253 printf("位图为非单色图片.\n");
254 goto done;
255 break;
256 }//switch
257 pdata = bmpdata;
258 pimage = image + location * font_width * 3;
259 for(temp=0;temp<font_height;temp++)
260 {
261 memcpy(pimage,pdata,font_width * 3);
262 pdata += font_width * 3;
263 pimage += 94 * font_width *3;
264 }
265 #ifndef _WIN32
266 usleep(10);
267 #else
268 Sleep(10);
269 #endif
270 }//for( 1 - 94 位 )
271 //保存图片
272 sprintf(testfilename,"./testbmp/area%d_%dx%d.bmp",area,font_width,font_height);
273 //printf("\nsave bmp file [%s]\n",testfilename);
274 if(save_bmp24(testfilename,94 * font_width,font_height,image))
275 {
276 printf("save bmp file [%s] error.\n",testfilename);
277 }
278 }//for( 1 - 94 区)
279 printf("\nConvert Done.\n");
280
281 }while (0);
282 done:
283 #if 0 //出现莫名其妙的错误,注释了
284 fprintf(stderr,"begin cleanup.\n");
285 if(bmpdata)
286 {
287 free(bmpdata);
288 bmpdata = NULL;
289 }
290 if(image)
291 {
292 free(image);
293 image = NULL;
294 }
295 if(face)
296 {
297 FT_Done_Face(face);
298 face = NULL;
299 }
300 if(library)
301 {
302 FT_Done_FreeType(library);
303 library = NULL;
304 }
305 #endif
306 return 0;
307 }
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
1 /*********************Y***************************/
2 unsigned char data_Y[]={
3 0x10,0x10,0x10,0x10,0x10,0x10,0x10,0x10,0x10,0x10,0x10,0x10,0x10,0x10,0x10,0x10
4 ,0x10,0x10,0x10,0x10,0x10,0x10,0x10,0x10,0x10,0x10,0x10,0x10,0x10,0x10,0x10,0x10
5 ,0x10,0x10,0x10,0x10,0x10,0x10,0x10,0x10,0x10,0x10,0x10,0x10,0x10,0x10,0x10,0x10
6 ,0x10,0x10,0x10,0x10,0x10,0x10,0x10,0x10,0x10,0x10,0x10,0x10,0x10,0x10,0x10,0x10
7 ......
8 ,0x10,0x10,0x10,0x10,0x10,0x10,0x10,0x10,0x10,0x10,0x10,0x10,0x10,0x10,0x10,0x10
9 ,0x10,0x10,0x10,0x10,0x10,0x10,0x10,0x10,0x10,0x10,0x10,0x10,0x10,0x10,0x10,0x10
10 ,0x10,0x10,0x10,0x10,0x10,0x10,0x10,0x10,0x10,0x10,0x10,0x10,0x10,0x10,0x10,0x10
11 ,0x10,0x10,0x10,0x10,0x10,0x10,0x10,0x10
12 };
13 //37224 bytes
14 /**************end of Y***************************/
15
16 /********************UV***************************/
17 unsigned char data_UV[]={
18 0x80,0x80,0x80,0x80,0x80,0x80,0x80,0x80,0x80,0x80,0x80,0x80,0x80,0x80,0x80,0x80
19 ,0x80,0x80,0x80,0x80,0x80,0x80,0x80,0x80,0x80,0x80,0x80,0x80,0x80,0x80,0x80,0x80
20 ,0x80,0x80,0x80,0x80,0x80,0x80,0x80,0x80,0x80,0x80,0x80,0x80,0x80,0x80,0x80,0x80
21 ,0x80,0x80,0x80,0x80,0x80,0x80,0x80,0x80,0x80,0x80,0x80,0x80,0x80,0x80,0x80,0x80
22 ......
23 ,0x80,0x80,0x80,0x80,0x80,0x80,0x80,0x80,0x80,0x80,0x80,0x80,0x80,0x80,0x80,0x80
24 ,0x80,0x80,0x80,0x80,0x80,0x80,0x80,0x80,0x80,0x80,0x80,0x80,0x80,0x80,0x80,0x80
25 ,0x80,0x80,0x80,0x80,0x80,0x80,0x80,0x80,0x80,0x80,0x12,0x92,0x80,0x80,0x80,0x80
26 ,0x80,0x80,0x80,0x80
27 };
28 //18612 bytes
29 /*************end of UV***************************/
http://blog.csdn.net/sloan6/article/details/9231373
时间： 2024-10-09 23:22:57