C ++ reads the RGB value of the image (both methods have been tested)

1. Use magick ++ to read images. It is applicable to various image formats (supported by magick ++)

Related information:

Http://www.imagemagick.org/Magick++/Image.html

Http://www.imagemagick.org/Magick++/Documentation.html

Http://www.imagemagick.org/discourse-server/viewtopic.php? F = 2 & t = 16625

 

Int _ tmain (INT argc, _ tchar * argv []) {<br/> geometry g (800,533); <br/> image thei; <br/> file * FH; <br/> float * floatpixelmap; <br/> try {<br/> thei. read (G ,". /bluejay.jpg "); <br/> int Height = thei. rows (); <br/> int width = thei. columns (); <br/> int size = height * width * 4; <br/> pixelpacket * mymap = thei. getpixels (0, 0, width, height); <br/> floatpixelmap = new float [size]; <br/> for (INT counter = 0, K = 0; counter <size; counter ++, ++ K) {<br/> floatpixelmap [counter ++] = (float) mymap [K]. red/255.0f; <br/> floatpixelmap [counter ++] = (float) mymap [K]. green/255.0f; <br/> floatpixelmap [counter ++] = (float) mymap [K]. blue/255.0f; <br/> floatpixelmap [Counter] = (float) mymap [K]. opacity/255.0f; <br/>}// end for loop <br/> FH = fopen (". /bluejay32float. procd. rgba "," WB "); <br/> fwrite (void *) floatpixelmap, sizeof (float), size, FH ); <br/>}// end try block <br/> catch (exception & Ex) {<br/> cout <"imagicktstr, error," <ex. what () <Endl; <br/>}// end Catch Block <br/> return 0; <br/>}// end main 

2. parse the BMP file format directly and only read the BMP format.

# Include <string. h> <br/> # include <math. h> <br/> # include <stdio. h> <br/> # include <stdlib. h> <br/> # include <malloc. h> <br/> # define widthbytes (BITs) + 31)/32*4) <br/> typedef unsigned char byte; // struct type <br/> typedef unsigned short word; // short integer <br/> typedef unsigned long DWORD; // long integer <br/> typedef long; <br/> // structure definition of Bitmap File Header Information <br/> // It does not contain file type information (determined by the memory structure of the struct, if the file information is added, the file information cannot be correctly read. <br/> typedef struct tagbi Tmapfileheader {<br/> // word bftype; <br/> DWORD bfsize; // file size <br/> word bfreserved1; // reserved words, <br/> word bfreserved2; // reserved words, same as above <br/> DWORD bfoffbits; // The actual bitmap data offset bytes, that is, the sum of the length of the first three parts <br/>} bitmapfileheader; <br/> // The Information header bitmapinfoheader is also a structure, which is defined as follows: <br/> typedef struct tagbitmapinfoheader {<br/> // public: <br/> DWORD bisize; // specify the length of the struct, which is 40 <br/> long biwidth; // bitmap width <br/> long biheight; // bitmap height <br/> word biplan Es; // number of planes, 1 <br/> word bibitcount; // color digits, which can be 1, 2, 4, 8, 16, 24, the new one can be 32 <br/> DWORD bicompression; // compression mode, which can be, 2, where 0 indicates no compression <br/> DWORD bisizeimage; // number of bytes occupied by the actual bitmap data <br/> long bixpelspermeter; // X-direction resolution <br/> long biypelspermeter; // y-direction resolution <br/> DWORD biclrused; // The number of colors used. If it is 0, it indicates the default value (2 ^ number of colors) <br/> DWORD biclrimportant; // The number of important colors. If it is 0, it indicates that all colors are important <br/>} bitmapinfoheader; <br/> // palette. Of course, this is for bitmap files that require a palette.. A 24-bit or 32-bit color palette is not required. <Br/> // (it seems that the number of struct in the color palette is equal to the number of colors used .) <Br/> typedef struct tagrgbquad {<br/> // public: <br/> byte rgbblue; // The Blue weight of the color <br/> byte rgbgreen; // The green weight of the color <br/> byte rgbred; // The Red weight of the color <br/> byte rgbreserved; // reserved value <br/>} rgbquad; <br/> void showrgbquan (tagrgbquad * prgb) <br/> {<br/> printf ("(%-3D, %-3D, %-3d )", prgb-> rgbred, prgb-> rgbgreen, prgb-> rgbblue); <br/>}< br/> int main () {<br/> char CH, PD; <br/> int B, C, M, D, W, E, F; <br/> int X, Y; <br/> unsign Ed char * q; <br/> int I, j; <br/> unsigned char a [2]; <br/> char strfile [50]; <br/> bitmapfileheader bithead; <br/> bitmapinfoheader bitinfohead; <br/> tagrgbquad * prgb; <br/> file * FP; <br/> file * P; <br/> q = (unsigned char *) malloc (1 ); <br/> printf ("mkx ** uses C programming language to read data of a certain pixel in the BMP file **/n enter a BMP file:/N "); <br/> scanf ("% s", strfile); <br/> fp = fopen (strfile, "rb"); </P> <p> If (FP! = NULL) <br/>{< br/> printf ("file open success! /N "); <br/> word filetype; <br/> fread (& filetype, 1, sizeof (Word), FP); <br/> If (filetype! = 0x4d42) <br/>{< br/> printf ("file is not. BMP file! "); <Br/> system (" pause "); <br/> return 0; <br/>}< br/> else <br/> {<br/> printf ("file open fail! /N "); <br/> system (" pause "); <br/> return 0; <br/>}< br/> // read file header information, and print the values of the file header information <br/> fread (& bithead, 1, sizeof (tagbitmapfileheader), FP ); <br/> printf ("BMP file header information/n file size: % d/n reserved words: % d/n actual bitmap data offset Bytes: % d/n ", <br/> bithead. bfsize, bithead. bfreserved1, bithead. bfreserved2, bithead. bfoffbits); <br/> // read the file information header and print the values of each item in the file information header <br/> fread (& bitinfohead, 1, sizeof (tagbitmapinfoheader ), FP); <br/> printf ("BMP file information Header/length of N struct Degree: % d/n bitmap width: % d/n bitmap Height: % d/nbiplanes flat count: % d/nbibitcount adopts the color bits: % d/n compression mode: % d/nbisizeimage the number of bytes occupied by the actual bitmap data: % d/NX direction resolution: % d/NY direction resolution: % d/n the number of colors used: % d/n important colors: % d/N ", <br/> bitinfohead. bisize, bitinfohead. biwidth, bitinfohead. biheight, bitinfohead. biplanes, bitinfohead. bibitcount, bitinfohead. bicompression, bitinfohead. bisizeimage, bitinfohead. bixpelspermeter, bitinfohead. biypelspermeter, bitinfohead. biclrused, bitinfohead. biclrimp Ortant); <br/> If (bitinfohead. bibitcount <24) {<br/> printf ("the file has a color palette, that is, the bitmap is non-real color/n"); <br/> M = 1; <br/> If (bitinfohead. bibitcount = 8) {<br/> long nplantnum = long (POW (2, double (bitinfohead. bibitcount); // mix color plant number; <br/> prgb = (tagrgbquad *) malloc (nplantnum * sizeof (tagrgbquad); <br/> memset (prgb, 0, nplantnum * sizeof (tagrgbquad); <br/> int num = fread (prgb, 4, nplantnum, FP); <br/> printf ("col Or plate number: % d/N ", nplantnum); <br/> printf (" color palette information:/N "); <br/> for (INT I = 0; I <nplantnum; I ++) <br/>{< br/> if (I % 5 = 0) <br/>{< br/> printf ("/N"); <br/>}< br/> showrgbquan (& prgb [I]); <br/>}< br/> printf ("/N "); <br/>}< br/> else {<br/> printf ("the bitmap is a 24-bit real color/n "); <br/> M = 3; <br/>}</P> <p> fclose (FP); </P> <p> while (Ch! = 'N') {<br/> P = fopen (strfile, "rb"); <br/> CH = NULL; <br/> F = bitinfohead. biheight; <br/> E = bitinfohead. biwidth; <br/> B = bithead. bfoffbits; <br/> printf ("** enter the data of the specified pixel ** (row: 1 ~ % D column 1 ~ % D)/n ", F, E); <br/> printf (" Enter line I: "); <br/> scanf (" % d ", & X); <br/> printf ("Enter column J:"); <br/> scanf ("% d", & Y ); <br/> C = B + (x-1) * E * m + M * (Y-1); <br/> fseek (p, C, 0 ); <br/> // printf ("% d/N", m); <br/> If (M <2) {<br/> fread (& A [0], p); <br/> printf ("the data of the pixel point (hexadecimal) is: % x ", A [0]); <br/> printf ("in decimal format: % d/N", a [0]); <br/> d = A [0]; <br/> printf ("the corresponding RGB value is:"); <br/> showrgbquan (& prgb [d]); <br/> printf ("/N"); <br/>}< br/> el Se {<br/> for (I = 0; I <3; I ++) {<br/> fread (& A [I], 1, 1, P ); <br/> // printf ("% x/N", a [I]); <br/>}< br/> printf ("hexadecimal representation: /n Blue: % x/n Green: % x/n red: % x/N ", a [0], a [1], a [2]); <br/> printf ("in decimal format:/n Blue: % d/n Green: % d/n red: % d/N", a [0], A [1], a [2]); <br/>}< br/> rewind (p); <br/> // W = ftell (P ); <br/> // printf ("% d", W); <br/> fclose (p); <br/> printf ("** enter any character to continue, to exit, enter n/n "); <br/> getchar (); <br/> scanf (" % C ", & Ch ); <br/>}< br/> printf ("Thank you for using it ~ /N "); <br/> system (" pause "); <br/> return 0; <br/>}