由于工作需要，时常需要将像素矩阵保存图片显示观看。为此，特地总结了三种使用纯C++代码生成bmp图片的方法。分别是使用自定义数据、从外界导入的txt和csv以及从图片中导入的数据。
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1.使用自定义数据保存为bmp图片
自定义数据可以是使用公式生成，或者是根据自己需求自己定义的数据，范围为0-255，分别对应从黑色到白色。代码生成过程如下：
1 #pragma warning(disable:4996) 2 #include<iostream> 3 #include<string> 4 using namespace std; 5 6 //#define FrameSize 960*960 //视频帧大小 7 int width = 120, height = 120; 8 #define FrameNum 300 //yuv帧数 9 static const double S_PI = 3.14159265358979323846; 10 #define scos(x) cos((double)(x)) 11 #define stan(x) tan((double)(x)) 12 #define ssqrt(x) sqrt((double)(x)) 13 #define ET_SIZE 300 14 char errorText[ET_SIZE]; 15 16 void errorMsg(const char *msg) 17 { 18 printf("error:%sn", msg); 19 #ifdef _WIN32 20 system("pause"); 21 #endif 22 exit(-1); 23 } 24 25 void readSequence(unsigned char *frames) 26 { 27 //Test start 28 for (int y = 0; y < height; y++) 29 { 30 for (int x = 0; x < width; x++) 31 { 32 //使用公式生成像素数据 33 float pu0 = (float)((2.0*(x + 0.5)) / width - 1.0); 34 float pv0 = (float)((2.0*(y + 0.5)) / height - 1.0); 35 36 double tu0 = stan(pu0*S_PI / 4.0); 37 double tv0 = stan(pv0*S_PI / 4.0); 38 double value= 1.0 / (scos(pu0*S_PI / 4.0)*scos(pu0*S_PI / 4.0)*scos(pv0*S_PI / 4.0)*scos(pv0*S_PI / 4.0) * (tu0*tu0 + tv0*tv0 + 1.0) * ssqrt(tu0*tu0 + tv0*tv0 + 1.0)); 39 40 //将值从(0，1)放大到(0，255) 41 value= 255.0*value; 42 //将值从(128，255)放大到(0，255),增加图像对比度 43 frames[y*width + x] = 2.0*value- 255.0; 44 } 45 } 46 } 47 48 void write_bmpheader(unsigned char *bitmap, int offset, int bytes, int value) 49 { 50 int i; 51 for (i = 0; i < bytes; i++) 52 bitmap[offset + i] = (value >> (i << 3)) & 0xFF; 53 } 54 55 unsigned char *convertToBmp(unsigned char *inputImg, int width, int height, int *ouputSize) 56 { 57 /*create a bmp format file*/ 58 int bitmap_x = (int)ceil((double)width * 3 / 4) * 4; 59 unsigned char *bitmap = (unsigned char*)malloc(sizeof(unsigned char)*height*bitmap_x + 54); 60 61 bitmap[0] = 'B'; 62 bitmap[1] = 'M'; 63 write_bmpheader(bitmap, 2, 4, height*bitmap_x + 54); //whole file size 64 write_bmpheader(bitmap, 0xA, 4, 54); //offset before bitmap raw data 65 write_bmpheader(bitmap, 0xE, 4, 40); //length of bitmap info header 66 write_bmpheader(bitmap, 0x12, 4, width); //width 67 write_bmpheader(bitmap, 0x16, 4, height); //height 68 write_bmpheader(bitmap, 0x1A, 2, 1); 69 write_bmpheader(bitmap, 0x1C, 2, 24); //bit per pixel 70 write_bmpheader(bitmap, 0x1E, 4, 0); //compression 71 write_bmpheader(bitmap, 0x22, 4, height*bitmap_x); //size of bitmap raw data 72 73 for (int i = 0x26; i < 0x36; i++) 74 bitmap[i] = 0; 75 int k = 54; 76 for (int i = height - 1; i >= 0; i--) { 77 int j; 78 for (j = 0; j < width; j++) { 79 int index = i*width + j; 80 for (int l = 0; l < 3; l++) 81 bitmap[k++] = inputImg[index]; 82 } 83 j *= 3; 84 while (j < bitmap_x) { 85 bitmap[k++] = 0; 86 j++; 87 } 88 } 89 *ouputSize = k; 90 return bitmap; 91 } 92 93 void saveToBmp(unsigned char *inputImg, int width, int height, char *outputFileName) 94 { 95 int size; 96 unsigned char *bmp = convertToBmp(inputImg, width, height, &size); 97 FILE *fp = fopen(outputFileName, "wb+"); 98 if (fp == NULL) { 99 sprintf(errorText, "Could not open file: %s", outputFileName);100 errorMsg(errorText);101 }102 fwrite(bmp, 1, size, fp);103 fclose(fp);104 free(bmp);105 }106 int main() 107 {108 unsigned char *oriFrames;109 oriFrames = (unsigned char*)malloc(sizeof(unsigned char) * width * height);110 readSequence(oriFrames);111 112 char imgName[30];113 sprintf(imgName, "F:\pictures\Bitmap_Weight_Map_Convex2.bmp");114 //矩阵oriFrames[i]可以是任何你想保存为图片的像素矩阵，这里是yuv视频图像每一帧的像素数据115 saveToBmp(oriFrames, width, height, imgName);116 //system("pause");117 }View Code
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2.从外界导入的txt和csv保存为bmp图片
将数据导入txt中：
1 #pragma warning(disable:4996) 2 #include <stdio.h> 3 #include <stdlib.h> 4 int main() 5 { 6 //文件写操作txt 7 FILE *fp;//文件指针 8 int i, d; 9 /*文件的打开*/10 fp = fopen("E:\VS_Test_Code\data.txt", "w");//fopen打开文件，这个文件可以是当前不存在的。“w”以写入的形式打开，“r”以读的形式打开 11 if (fp == NULL) //判断如果文件指针为空 12 {13 printf("File cannot open! ");14 exit(0);//在以0的形式退出，必须在文件开头有#include <stdlib.h>,stdlib 头文件即standard library标准库头文件 15 }16 //写入数据 17 for (i = 0; i < 10; i++)18 {19 scanf("%d", &d);//用户输入 20 fprintf(fp, "%d，", d);//写入指针fp，写入的东西就是刚才的用户输入的d,注意这里的fp和d没有引号 21 }22 //关闭文件 23 fclose(fp);24 }View Code
从txt中读取数据：
1 #pragma warning(disable:4996)
2 #include <stdio.h>
3 #include <stdlib.h>
4 int main()
5 {
6 //文件读操作txt
7 FILE *fp;//文件指针
8 int i, d;
9 /*文件的打开*/
10 fp = fopen("E:\VS_Test_Code\data.txt", "r");//fopen打开文件，这个文件可以是当前不存在的。“w”以写入的形式打开，“r”以读的形式打开
11 if (fp == NULL) //判断如果文件指针为空
12 {
13 printf("File cannot open! ");
14 exit(0);//在以0的形式退出，必须在文件开头有#include <stdlib.h>,stdlib 头文件即standard library标准库头文件
15 }
16 int *array = (int*)malloc(sizeof(int) * 10);
17 //读取数据
18 for (i = 0; i < 10; i++)
19 {
20 fscanf(fp, "%d，", &array[i]);//从文件输入
21 printf("%d ", array[i]);//写入指针fp，写入的东西就是刚才的用户输入的d,注意这里的fp和d没有引号
22 }
23 printf("n");
24 //关闭文件
25 fclose(fp);
26 system("pause");//使窗口保持不关闭
27 }
View Code
将数据导入csv中：
1 #pragma warning(disable:4996)
2 #include <stdio.h>
3 #include <stdlib.h>
4 int main()
5 {
6 //文件写操作csv
7 FILE *fp;//文件指针
8 int i, No;
9 double salary;
10 fp = fopen("E:\VS_Test_Code\data.csv", "w");//fopen打开文件，这个文件可以是当前不存在的。“w”以写入的形式打开，“r”以读的形式打开
11 if (fp == NULL) //判断如果文件指针为空
12 {
13 printf("File cannot open! ");
14 exit(0);//在以0的形式退出，必须在文件开头有#include <stdlib.h>,stdlib 头文件即standard library标准库头文件
15 }
16 //写入数据
17 for (i = 0; i < 5; i++)
18 {
19 scanf("%d %lf", &No, &salary);//用户输入，double一定要用%lf
20 fprintf(fp, "%d %.2fn", No, salary);//写入指针fp，写入的东西就是刚才的用户输入的d,注意这里的fp和d没有引号
21 }
22 //关闭文件
23 fclose(fp);
24 }
View Code
从csv中读取数据：
1 #pragma warning(disable:4996)
2 #include <stdio.h>
3 #include <stdlib.h>
4 int main()
5 {
6 //文件读操作csv
7 FILE *fp;//文件指针
8 int i, No;
9 double salary;
10 fp = fopen("E:\VS_Test_Code\data.csv", "r");//fopen打开文件，这个文件可以是当前不存在的。“w”以写入的形式打开，“r”以读的形式打开
11 if (fp == NULL) //判断如果文件指针为空
12 {
13 printf("File cannot open! ");
14 exit(0);//在以0的形式退出，必须在文件开头有#include <stdlib.h>,stdlib 头文件即standard library标准库头文件
15 }
16 //读取数据
17 for (i = 0; i < 5; i++)
18 {
19 fscanf(fp, "%d %lf", &No, &salary);//用户输入,double要用%lf
20 printf("%dt%.2fn", No, salary);//写入指针fp，写入的东西就是刚才的用户输入的d,注意这里的fp和d没有引号
21 }
22 //关闭文件
23 fclose(fp);
24 system("pause");
25 }
View Code
将txt中的数据保存为bmp图片
1 #pragma warning(disable:4996)
2 #include<iostream>
3 #include<string>
4 using namespace std;
5
6 #define FrameSize 100*100 //视频帧大小
7 #define FrameNum 10 //yuv帧数
8 #define ET_SIZE 300
9 char errorText[ET_SIZE];
10
11 void errorMsg(const char *msg) {
12
13 printf("error:%sn", msg);
14
15 #ifdef _WIN32
16
17 system("pause");
18
19 #endif
20
21 exit(-1);
22
23 }
24
25 void readSequence(char *fileName, unsigned char **frames)
26 {
27 FILE *fp = fopen(fileName, "rb");
28 if (fp == NULL)
29 {
30 sprintf(errorText, "File %s doesn't existn", fileName);
31 errorMsg(errorText);
32 }
33
34 int uvSize = FrameSize / 2; //H.264编解码获得的关键帧都是彩色序列，这里主要是提取亮度分量Y。
35 unsigned char *buf = (unsigned char *)malloc(sizeof(unsigned char) * uvSize);
36 for (int i = 0; i < FrameNum; i++) {
37 //read y
38 if (fread(frames[i], 1, FrameSize, fp) != FrameSize) { //每一个keyFrames[i]分配的是 (unsigned char) * FrameSize的大小，所以fread要读的每个数据项的字节数为1，可以表示每个像素点亮度范围0~255
39 sprintf(errorText, "Input sequence %s is not enough", fileName);
40 errorMsg(errorText);
41 }
42
43 //read u,v
44 fread(buf, 1, uvSize, fp);
45 }
46 free(buf);
47 fclose(fp);
48 }
49
50 void write_bmpheader(unsigned char *bitmap, int offset, int bytes, int value) {
51 int i;
52 for (i = 0; i < bytes; i++)
53 bitmap[offset + i] = (value >> (i << 3)) & 0xFF;
54 }
55
56 unsigned char *convertToBmp(unsigned char *inputImg, int width, int height, int *ouputSize) {
57
58 /*create a bmp format file*/
59 int bitmap_x = (int)ceil((double)width * 3 / 4) * 4;
60 unsigned char *bitmap = (unsigned char*)malloc(sizeof(unsigned char)*height*bitmap_x + 54);
61
62 bitmap[0] = 'B';
63 bitmap[1] = 'M';
64 write_bmpheader(bitmap, 2, 4, height*bitmap_x + 54); //whole file size
65 write_bmpheader(bitmap, 0xA, 4, 54); //offset before bitmap raw data
66 write_bmpheader(bitmap, 0xE, 4, 40); //length of bitmap info header
67 write_bmpheader(bitmap, 0x12, 4, width); //width
68 write_bmpheader(bitmap, 0x16, 4, height); //height
69 write_bmpheader(bitmap, 0x1A, 2, 1);
70 write_bmpheader(bitmap, 0x1C, 2, 24); //bit per pixel
71 write_bmpheader(bitmap, 0x1E, 4, 0); //compression
72 write_bmpheader(bitmap, 0x22, 4, height*bitmap_x); //size of bitmap raw data
73
74 for (int i = 0x26; i < 0x36; i++)
75 bitmap[i] = 0;
76
77 int k = 54;
78 for (int i = height - 1; i >= 0; i--) {
79 int j;
80 for (j = 0; j < width; j++) {
81 int index = i*width + j;
82 for (int l = 0; l < 3; l++)
83 bitmap[k++] = inputImg[index];
84 }
85 j *= 3;
86 while (j < bitmap_x) {
87 bitmap[k++] = 0;
88 j++;
89 }
90 }
91
92 *ouputSize = k;
93 return bitmap;
94 }
95
96 void saveToBmp(unsigned char *inputImg, int width, int height, char *outputFileName) {
97 int size;
98 unsigned char *bmp = convertToBmp(inputImg, width, height, &size);
99 FILE *fp = fopen(outputFileName, "wb+");
100 if (fp == NULL) {
101 sprintf(errorText, "Could not open file: %s", outputFileName);
102 errorMsg(errorText);
103
104 }
105 fwrite(bmp, 1, size, fp);
106 fclose(fp);
107 free(bmp);
108 }
109
110 int main() {
111 int width = 120, height = 120;
112
113 unsigned char **oriFrames;
114 oriFrames = (unsigned char**)malloc(sizeof(unsigned char*) * FrameNum);
115 for (int i = 0; i < FrameNum; i++) {
116 oriFrames[i] = (unsigned char*)malloc(sizeof(unsigned char) * FrameSize);
117 }
118
119 ////Test写入
120 //readSequence("E:\Research\YUV_Sequences\2D\BasketballPass_416x240_50\BasketballPass_416x240_50.yuv", oriFrames);
121 //FILE *fp;
122 //fp = fopen("E:\VS_Test_Code\cnblogData.txt", "w");
123 //if (fp == NULL)
124 //{
125 // exit(0);
126 //}
127 //for (int i = 0; i < FrameNum; i++)
128 //{
129 // for (int j = 0; j < FrameSize; j++)
130 // {
131 // fprintf(fp, "%d,", oriFrames[i][j]);
132 // }
133 // fprintf(fp, "n");
134 //}
135 ////Test写入
136
137 //Test读取
138 FILE *fp;
139 fp = fopen("E:\VS_Test_Code\cnblogData.txt", "r");
140 if (fp == NULL)
141 {
142 exit(0);
143 }
144 for (int i = 0; i < FrameNum; i++)
145 {
146 for (int j = 0; j < FrameSize; j++)
147 {
148 fscanf(fp, "%d,", &oriFrames[i][j]);//必须和fprintf格式保持一致
149 }
150 }
151 for (int i = 0; i < FrameNum; i++)
152 {
153 for (int j = 0; j < FrameSize; j++)
154 {
155 printf("%d ", oriFrames[i][j]);
156 }
157 printf("n");
158 }
159 //Test读取
160
161 char imgName[30];
162 for (int i = 0; i < FrameNum; i++) {
163 sprintf(imgName, "F:\pictures\ReconsFrame%d.bmp", i);
164 //矩阵oriFrames[i]可以是任何你想保存为图片的像素矩阵，这里是yuv视频图像每一帧的像素数据
165 saveToBmp(oriFrames[i], width, height, imgName);
166 }
167 system("pause");
168 }
View Code
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3.从图片中导入的数据保存为bmp图片
从图片中导入图像数据，将其存储为像素矩阵，像素值的范围是0-255，分别对应从黑色到白色，并将像素矩阵保存为bmp图片。代码如下所示：
1 #pragma warning(disable:4996) 2 #include<iostream> 3 #include<string> 4 using namespace std; 5 6 #define FrameSize 416*240 //视频帧大小 7 #define FrameNum 300 //yuv帧数 8 #define ET_SIZE 300 9 char errorText[ET_SIZE]; 10 11 void errorMsg(const char *msg) 12 { 13 printf("error:%sn", msg); 14 #ifdef _WIN32 15 system("pause"); 16 #endif 17 exit(-1); 18 19 } 20 21 void readSequence(char *fileName, unsigned char **frames) 22 { 23 FILE *fp = fopen(fileName, "rb"); 24 if (fp == NULL) 25 { 26 sprintf(errorText, "File %s doesn't existn", fileName); 27 errorMsg(errorText); 28 } 29 int uvSize = FrameSize / 2; //H.264编解码获得的关键帧都是彩色序列，这里主要是提取亮度分量Y。 30 unsigned char *buf = (unsigned char *)malloc(sizeof(unsigned char) * uvSize); 31 for (int i = 0; i < FrameNum; i++) { 32 //read y 33 if (fread(frames[i], 1, FrameSize, fp) != FrameSize) { //每一个keyFrames[i]分配的是 (unsigned char) * FrameSize的大小，所以fread要读的每个数据项的字节数为1，可以表示每个像素点亮度范围0~255 34 sprintf(errorText, "Input sequence %s is not enough", fileName); 35 errorMsg(errorText); 36 } 37 //read u,v 38 fread(buf, 1, uvSize, fp); 39 } 40 free(buf); 41 fclose(fp); 42 } 43 44 45 46 void write_bmpheader(unsigned char *bitmap, int offset, int bytes, int value) 47 { 48 int i; 49 for (i = 0; i < bytes; i++) 50 bitmap[offset + i] = (value >> (i << 3)) & 0xFF; 51 } 52 53 unsigned char *convertToBmp(unsigned char *inputImg, int width, int height, int *ouputSize) 54 { 55 /*create a bmp format file*/ 56 int bitmap_x = (int)ceil((double)width * 3 / 4) * 4; 57 unsigned char *bitmap = (unsigned char*)malloc(sizeof(unsigned char)*height*bitmap_x + 54); 58 59 bitmap[0] = 'B'; 60 bitmap[1] = 'M'; 61 write_bmpheader(bitmap, 2, 4, height*bitmap_x + 54); //whole file size 62 write_bmpheader(bitmap, 0xA, 4, 54); //offset before bitmap raw data 63 write_bmpheader(bitmap, 0xE, 4, 40); //length of bitmap info header 64 write_bmpheader(bitmap, 0x12, 4, width); //width 65 write_bmpheader(bitmap, 0x16, 4, height); //height 66 write_bmpheader(bitmap, 0x1A, 2, 1); 67 write_bmpheader(bitmap, 0x1C, 2, 24); //bit per pixel 68 write_bmpheader(bitmap, 0x1E, 4, 0); //compression 69 write_bmpheader(bitmap, 0x22, 4, height*bitmap_x); //size of bitmap raw data 70 71 for (int i = 0x26; i < 0x36; i++) 72 bitmap[i] = 0; 73 74 int k = 54; 75 for (int i = height - 1; i >= 0; i--) { 76 int j; 77 for (j = 0; j < width; j++) { 78 int index = i*width + j; 79 for (int l = 0; l < 3; l++) 80 bitmap[k++] = inputImg[index]; 81 } 82 j *= 3; 83 while (j < bitmap_x) { 84 bitmap[k++] = 0; 85 j++; 86 } 87 } 88 89 *ouputSize = k; 90 return bitmap; 91 } 92 93 void saveToBmp(unsigned char *inputImg, int width, int height, char *outputFileName) 94 { 95 int size; 96 unsigned char *bmp = convertToBmp(inputImg, width, height, &size); 97 FILE *fp = fopen(outputFileName, "wb+"); 98 if (fp == NULL) { 99 sprintf(errorText, "Could not open file: %s", outputFileName);100 errorMsg(errorText);101 102 }103 fwrite(bmp, 1, size, fp);104 fclose(fp);105 free(bmp);106 }107 108 int main() 109 {110 int width = 416, height = 240;111 112 unsigned char **oriFrames;113 oriFrames = (unsigned char**)malloc(sizeof(unsigned char*) * FrameNum);114 for (int i = 0; i < FrameNum; i++) {115 oriFrames[i] = (unsigned char*)malloc(sizeof(unsigned char) * FrameSize);116 }117 118 //获取图像的数据119 readSequence("E:\Research\YUV_Sequences\2D\BasketballPass_416x240_50\BasketballPass_416x240_50.yuv", oriFrames);120 121 char imgName[30];122 for (int i = 0; i < 10 /*FrameNum*/; i++) {123 sprintf(imgName, "F:\pictures\ReconsFrame%d.bmp", i);124 //矩阵oriFrames[i]可以是任何你想保存为图片的像素矩阵，这里是yuv视频图像每一帧的像素数据125 saveToBmp(oriFrames[i], width, height, imgName);126 }127 }View Code
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4.参考文献
https://blog.csdn.net/sinat_33718563/article/details/79424981
https://blog.csdn.net/zzwtyds/article/details/75095698
原文链接: https://www.cnblogs.com/ipersevere/p/12756048.html
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