BMP 文件到 PNG 文件转换器
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【中文标题】BMP 文件到 PNG 文件转换器【英文标题】：BMP File to PNG File Converter 【发布时间】：2020-04-04 17:35:13 【问题描述】：我正在制作 BMP 到 PNG 转换器。 BMP 图像未压缩。
所以我的问题是当 BMP 文件转换为 PNG 文件时，PNG 文件是否被压缩，即图像数据是否被压缩。如果是这样，图像数据如何以 PNG 文件格式对齐？
如果PNG图像数据未压缩，那么BMP图像数据如何在PNG文件中对齐。
#include<stdio.h>
#include<stdlib.h>
#pragma pack(1)
typedef struct
unsigned short int st_m40_FileType;
unsigned int st_m40_ImgFileSize;
unsigned short int st_m40_RsvdBytes1;
unsigned short int st_m40_RsvdBytes2;
unsigned int st_m40_ImgDataOffset;
unsigned int st_m40_Info40HeaderSze;
int st_m40_PxWdth;
int st_m40_PxHeight;
unsigned short int st_m40_NumOfColrPlnes;
unsigned short int st_m40_BitsPerPixel;
unsigned int st_m40_CmprsnType;
unsigned int st_m40_AftrCmprsnImgDataSze;
int st_m40_xResolutn_ppm;
int st_m40_yResolutn_ppm;
unsigned int st_m40_NumOfColrTbleColrs;
unsigned int st_m40_NumOfImprtntColrs;
ST_BMP40HEADER_t;
typedef struct
ST_BMP40HEADER_t st_mBMP40MainHdrVar;
unsigned char * pst_mImgeData;
ST_IMAGE_40_HEADER_t;
typedef enum
BI_RGB = 0x00,
BI_RLE8,
BI_RLE4,
BI_BITFIELDS,
BI_JPEG,
BI_PNG,
BI_ALPHABITFIELDS,
BI_CMYK,
BI_CMYKRLE8,
BI_CMYKRLE4,
EN_BMP_COMPRESN_TYPE_t;
#pragma pack(1)
typedef struct
int st_mImgWdth;
int st_ImgHeight;
unsigned char st_mBitDepth;
unsigned char st_mColorType;
unsigned char st_mCmprsnMthd;
unsigned char st_mFltrMthd;
unsigned char st_mInterlaceMthd;
ST_IHDR_DATA_FIELDS_t;
#pragma pack(1)
typedef struct
unsigned int st_mChunkDataLngth;
unsigned char st_mChunkType[4];
ST_IHDR_DATA_FIELDS_t st_IHDR_DataFieldsVar;
unsigned int st_mCRC32CheckSum;
ST_IHDR_t;
#pragma pack(1)
typedef struct
unsigned int st_mPLTE_ChunkDataLngth;
unsigned char st_mPLTE_ChunkType[4];
unsigned char* st_mPLTE_ChunkDataPtr;
unsigned int st_mPLTE_CRC32CheckSum;
ST_PLTE_t;
#pragma pack(1)
typedef struct
unsigned int st_mIDAT_ChunkDataLngth;
unsigned char st_mIDAT_ChunkType[4];
unsigned char* st_mIDAT_ChunkDataPtr;
unsigned int st_mIDAT_CRC32CheckSum;
ST_IDAT_t;
#pragma pack(1)
typedef struct
unsigned int st_mIEND_ChunkDataLength;
unsigned char st_mIEND_ChunkType[4];
unsigned char * st_mIEND_ChunkDataPtr;
unsigned int st_mIEND_CRC32CheckSum;
ST_IEND_t;
/* Little Endian to Big-Endian API. */
unsigned int BMP2PNG_LitToBigEndian(unsigned int f_BigEndianVal)
return (((f_BigEndianVal>>24) & 0x000000ff) | ((f_BigEndianVal>>8) & 0x0000ff00) |\
((f_BigEndianVal<<8) & 0x00ff0000) | ((f_BigEndianVal<<24) & 0xff000000));
/* CRC32 API.*/
unsigned int BMP2PNG_CmputeCRC32(unsigned char *p_fIpVal, unsigned int f_IpSize)
int l_LoopVar;
unsigned int l_ByteVal, l_CRCVal, l_MaskVal;
unsigned int l_TmpIncVar = 0;
l_CRCVal = 0xFFFFFFFF;
while (l_TmpIncVar <= f_IpSize)
// Get next byte.
l_ByteVal = p_fIpVal[l_TmpIncVar];
l_CRCVal = l_CRCVal ^ l_ByteVal;
for (l_LoopVar = 7; l_LoopVar >= 0; l_LoopVar--)
// Do eight times.
l_MaskVal = -(l_CRCVal & 1);
l_CRCVal = (l_CRCVal >> 1) ^ (0xEDB88320 & l_MaskVal);
l_TmpIncVar = l_TmpIncVar + 1;
return ~l_CRCVal;
/* API converts BMP-to-PNG format. */
char * Convert__40_BMP2PNG(ST_IMAGE_40_HEADER_t * pst_fBMP40ImgHdrVar, FILE * p_ImgFilePtr,\
unsigned char * p_fBMP_ColrTble)
FILE * l_BMP2PNGFilePtr;
ST_IHDR_t * pst_lIHDRChunkVar;
unsigned char l_PNGSignature[8]=137, 80, 78, 71, 13, 10, 26, 10;
unsigned int l_BigEndianVal;
unsigned int l_CRC32Val;
unsigned char * l_TempCRCBuff;
unsigned char * l_CRCBuffer;
unsigned int l_BuffLength = 0;
unsigned int l_TempIHDRChunkDataLngth;
pst_lIHDRChunkVar = (ST_IHDR_t *) malloc(sizeof(*pst_lIHDRChunkVar));
l_BMP2PNGFilePtr = fopen("BMP2PNG2.png","w");
/* Writing the 1st 8-bytes to the PNG File.*/
fwrite(l_PNGSignature,1,8,l_BMP2PNGFilePtr);
fseek(l_BMP2PNGFilePtr,8,SEEK_SET);
pst_lIHDRChunkVar->st_mChunkDataLngth = 13;
l_TempIHDRChunkDataLngth = BMP2PNG_LitToBigEndian(13);
/*Writing the IHDR Chunk Data-Length-Size value to the file.*/
fwrite(&l_TempIHDRChunkDataLngth,sizeof(unsigned int),1,l_BMP2PNGFilePtr);
pst_lIHDRChunkVar->st_mChunkType[0] = 'I';
pst_lIHDRChunkVar->st_mChunkType[1] = 'H';
pst_lIHDRChunkVar->st_mChunkType[2] = 'D';
pst_lIHDRChunkVar->st_mChunkType[3] = 'R';
/* Writing the IHDR-Chunk-Type value to the file.*/
fwrite( pst_lIHDRChunkVar->st_mChunkType ,sizeof(unsigned char),4,l_BMP2PNGFilePtr);
// pst_lIHDRChunkVar->st_IHDR_DataFieldsVar.st_mImgWdth = BMP2PNG_LitToBigEndian(pst_fBMP40ImgHdrVar->st_mBMP40MainHdrVar.st_m40_PxWdth);
pst_lIHDRChunkVar->st_IHDR_DataFieldsVar.st_mImgWdth = BMP2PNG_LitToBigEndian(3);
// pst_lIHDRChunkVar->st_IHDR_DataFieldsVar.st_ImgHeight = BMP2PNG_LitToBigEndian(pst_fBMP40ImgHdrVar->st_mBMP40MainHdrVar.st_m40_PxHeight);
pst_lIHDRChunkVar->st_IHDR_DataFieldsVar.st_ImgHeight = BMP2PNG_LitToBigEndian(3);
if(pst_fBMP40ImgHdrVar->st_mBMP40MainHdrVar.st_m40_BitsPerPixel <= 8)
pst_lIHDRChunkVar->st_IHDR_DataFieldsVar.st_mBitDepth = pst_fBMP40ImgHdrVar->st_mBMP40MainHdrVar.st_m40_BitsPerPixel;
else if( (pst_fBMP40ImgHdrVar->st_mBMP40MainHdrVar.st_m40_BitsPerPixel == 24) || \
(pst_fBMP40ImgHdrVar->st_mBMP40MainHdrVar.st_m40_BitsPerPixel == 32) )
pst_lIHDRChunkVar->st_IHDR_DataFieldsVar.st_mBitDepth = 8;
else
/*No Action.*/
if( pst_fBMP40ImgHdrVar->st_mBMP40MainHdrVar.st_m40_BitsPerPixel <=8 )
pst_lIHDRChunkVar->st_IHDR_DataFieldsVar.st_mColorType = 3;
else if (pst_fBMP40ImgHdrVar->st_mBMP40MainHdrVar.st_m40_BitsPerPixel == 24)
pst_lIHDRChunkVar->st_IHDR_DataFieldsVar.st_mColorType = 2;
else if (pst_fBMP40ImgHdrVar->st_mBMP40MainHdrVar.st_m40_BitsPerPixel == 32)
pst_lIHDRChunkVar->st_IHDR_DataFieldsVar.st_mColorType = 6;
else
/*No Action.*/
pst_lIHDRChunkVar->st_IHDR_DataFieldsVar.st_mCmprsnMthd = 0;
pst_lIHDRChunkVar->st_IHDR_DataFieldsVar.st_mFltrMthd = 0;
pst_lIHDRChunkVar->st_IHDR_DataFieldsVar.st_mInterlaceMthd = 0;
fseek(l_BMP2PNGFilePtr,16,SEEK_SET);
fwrite(&pst_lIHDRChunkVar->st_IHDR_DataFieldsVar,sizeof(ST_IHDR_DATA_FIELDS_t),1,l_BMP2PNGFilePtr);
/* Framing the data for calculating the 32-bit CRC Checksum.*/
l_BuffLength = 4+(pst_lIHDRChunkVar->st_mChunkDataLngth);
l_CRCBuffer = (unsigned char*)malloc(l_BuffLength);
l_TempCRCBuff = l_CRCBuffer;
*l_TempCRCBuff++ = pst_lIHDRChunkVar->st_mChunkType[0];
*l_TempCRCBuff++ = pst_lIHDRChunkVar->st_mChunkType[1];
*l_TempCRCBuff++ = pst_lIHDRChunkVar->st_mChunkType[2];
*l_TempCRCBuff++ = pst_lIHDRChunkVar->st_mChunkType[3];
*l_TempCRCBuff++ = (unsigned char)pst_lIHDRChunkVar->st_IHDR_DataFieldsVar.st_mImgWdth;
*l_TempCRCBuff++ = (unsigned char)(pst_lIHDRChunkVar->st_IHDR_DataFieldsVar.st_mImgWdth << 8);
*l_TempCRCBuff++ = (unsigned char)(pst_lIHDRChunkVar->st_IHDR_DataFieldsVar.st_mImgWdth << 16);
*l_TempCRCBuff++ = (unsigned char)(pst_lIHDRChunkVar->st_IHDR_DataFieldsVar.st_mImgWdth << 24);
*l_TempCRCBuff++ = (unsigned char)pst_lIHDRChunkVar->st_IHDR_DataFieldsVar.st_ImgHeight;
*l_TempCRCBuff++ = (unsigned char)(pst_lIHDRChunkVar->st_IHDR_DataFieldsVar.st_ImgHeight << 8);
*l_TempCRCBuff++ = (unsigned char)(pst_lIHDRChunkVar->st_IHDR_DataFieldsVar.st_ImgHeight << 16);
*l_TempCRCBuff++ = (unsigned char)(pst_lIHDRChunkVar->st_IHDR_DataFieldsVar.st_ImgHeight << 24);
*l_TempCRCBuff++ = (unsigned char)(pst_lIHDRChunkVar->st_IHDR_DataFieldsVar.st_mBitDepth);
*l_TempCRCBuff++ = (unsigned char)(pst_lIHDRChunkVar->st_IHDR_DataFieldsVar.st_mColorType);
*l_TempCRCBuff++ = (unsigned char)(pst_lIHDRChunkVar->st_IHDR_DataFieldsVar.st_mCmprsnMthd);
*l_TempCRCBuff++ = (unsigned char)(pst_lIHDRChunkVar->st_IHDR_DataFieldsVar.st_mFltrMthd);
*l_TempCRCBuff = (unsigned char)(pst_lIHDRChunkVar->st_IHDR_DataFieldsVar.st_mInterlaceMthd);
// Compute and output CRC
l_CRC32Val = BMP2PNG_CmputeCRC32(l_CRCBuffer, l_BuffLength);
l_CRC32Val = BMP2PNG_LitToBigEndian( l_CRC32Val);
fseek(l_BMP2PNGFilePtr,29,SEEK_SET);
unsigned int returnVal = fwrite(&l_CRC32Val,sizeof(unsigned int),1,l_BMP2PNGFilePtr);
unsigned char * p_lBMPImgData = pst_fBMP40ImgHdrVar->pst_mImgeData;
// unsigned int l_BMPImgeDataSze = ( (pst_fBMP40ImgHdrVar->st_mBMP40MainHdrVar.st_m40_PxWdth) * \
(pst_fBMP40ImgHdrVar->st_mBMP40MainHdrVar.st_m40_PxHeight) );
unsigned int l_BMPImgeDataSze = (3*3)*3;
ST_IDAT_t * pst_lIDAT_ChunkVar;
pst_lIDAT_ChunkVar = (ST_IDAT_t *) malloc(sizeof(*pst_lIDAT_ChunkVar));
unsigned int l_ImgDataSzeIncVar = 0;
unsigned char * p_IDATBuf;
unsigned char * p_TempIDATBuf;
unsigned int l_IDATBufSze;
if(pst_fBMP40ImgHdrVar->st_mBMP40MainHdrVar.st_m40_BitsPerPixel == 24)
fseek(l_BMP2PNGFilePtr,33,SEEK_SET);
l_BMPImgeDataSze *= 3;
l_IDATBufSze = 4 + l_BMPImgeDataSze;
p_IDATBuf = (unsigned char*)malloc(l_IDATBufSze);
p_TempIDATBuf = p_IDATBuf;
pst_lIDAT_ChunkVar->st_mIDAT_ChunkDataLngth = BMP2PNG_LitToBigEndian(l_BMPImgeDataSze);
fwrite(&pst_lIDAT_ChunkVar->st_mIDAT_ChunkDataLngth,sizeof(unsigned int),1,l_BMP2PNGFilePtr);
pst_lIDAT_ChunkVar->st_mIDAT_ChunkType[0] = 'I';
pst_lIDAT_ChunkVar->st_mIDAT_ChunkType[1] = 'D';
pst_lIDAT_ChunkVar->st_mIDAT_ChunkType[2] = 'A';
pst_lIDAT_ChunkVar->st_mIDAT_ChunkType[3] = 'T';
fwrite( pst_lIDAT_ChunkVar->st_mIDAT_ChunkType ,sizeof(unsigned char),4,l_BMP2PNGFilePtr);
fseek(l_BMP2PNGFilePtr,41,SEEK_SET);
unsigned char ImgeData[27] = 0,255,0,0,255,0,0,255,0,0,255,0,0,255,0,0,255,0,0,255,0,0,255,0,0,255,0,;
while(l_ImgDataSzeIncVar <= l_BMPImgeDataSze )
fwrite(ImgeData,sizeof(unsigned char),1,l_BMP2PNGFilePtr);
/*
fwrite( (p_lBMPImgData+2),sizeof(unsigned char),1,l_BMP2PNGFilePtr);
*p_TempIDATBuf++ = *(p_lBMPImgData+2);
fwrite( (p_lBMPImgData+1),sizeof(unsigned char),1,l_BMP2PNGFilePtr);
*p_TempIDATBuf++ = *(p_lBMPImgData+1);
fwrite( (p_lBMPImgData),sizeof(unsigned char),1,l_BMP2PNGFilePtr);
*p_TempIDATBuf++ = *(p_lBMPImgData);
p_lBMPImgData += 3;
l_ImgDataSzeIncVar += 3;
*/
// Compute and output CRC
unsigned int crc32 = BMP2PNG_CmputeCRC32(p_IDATBuf, l_IDATBufSze);
fwrite(&crc32,sizeof(unsigned int),1,l_BMP2PNGFilePtr);
ST_IMAGE_40_HEADER_t * ReadBMP40HdrImage(ST_IMAGE_40_HEADER_t * pst_fBMP40ImgHdrVar, \
FILE * p_ImgFilePtr)
unsigned short int l_ColorTbleSze;
unsigned char * l_ColorTbleVal;
unsigned int l_ImageDataOffset;
unsigned int l_ImageDataSize;
unsigned int l_ImageDataSzeIncVar = 1;
unsigned char * l_ImageDataPtr;
unsigned int l_PixelCount = 1;
int l_NumOfReadBlks = fread(pst_fBMP40ImgHdrVar,sizeof(pst_fBMP40ImgHdrVar->st_mBMP40MainHdrVar),1,p_ImgFilePtr);
printf("\n********************************************************************\n");
printf("\nPrinting the BMP Image Parameters:\n");
printf("\nBMP File Header Parameters.\n");
printf("File Type:\t'BM'\n");
printf("Total Size of the image:\t%u\n",pst_fBMP40ImgHdrVar->st_mBMP40MainHdrVar.st_m40_ImgFileSize);
printf("Image Data Offset:\t%u\n",pst_fBMP40ImgHdrVar->st_mBMP40MainHdrVar.st_m40_ImgDataOffset);
printf("\nBMP Info Header Parameters.\n");
printf("Size of the Info-Header:\t'%u-Bytes'.\n",pst_fBMP40ImgHdrVar->st_mBMP40MainHdrVar.st_m40_Info40HeaderSze);
printf("Width of the BMP Image:\t'%d-Pixels'.\n",pst_fBMP40ImgHdrVar->st_mBMP40MainHdrVar.st_m40_PxWdth);
printf("Height of the BMP Image:\t'%d-Pixels'.\n",pst_fBMP40ImgHdrVar->st_mBMP40MainHdrVar.st_m40_PxHeight);
printf("Number of Color Planes:\t'%d'.\n",pst_fBMP40ImgHdrVar->st_mBMP40MainHdrVar.st_m40_NumOfColrPlnes);
printf("Number of Bits-Per-Pixel:\t'%d'.\n",pst_fBMP40ImgHdrVar->st_mBMP40MainHdrVar.st_m40_BitsPerPixel);
printf("Compression Type used for compressing the BMP Raw Image:\t'%d'.\n",\
pst_fBMP40ImgHdrVar->st_mBMP40MainHdrVar.st_m40_CmprsnType);
printf("Horizontal Resolution:\t'%d-Pixels Per Meter'.\n,",\
pst_fBMP40ImgHdrVar->st_mBMP40MainHdrVar.st_m40_xResolutn_ppm);
printf("Vertical Resolution:\t'%d-Pixels Per Meter'.\n,",\
pst_fBMP40ImgHdrVar->st_mBMP40MainHdrVar.st_m40_yResolutn_ppm);
if(pst_fBMP40ImgHdrVar->st_mBMP40MainHdrVar.st_m40_NumOfColrTbleColrs !=0 )
printf("Number of Colors in the color table:\t'%u'.\n",\
pst_fBMP40ImgHdrVar->st_mBMP40MainHdrVar.st_m40_NumOfColrTbleColrs);
if( (pst_fBMP40ImgHdrVar->st_mBMP40MainHdrVar.st_m40_BitsPerPixel <= 8) && \
(pst_fBMP40ImgHdrVar->st_mBMP40MainHdrVar.st_m40_NumOfColrTbleColrs !=0) )
rewind(p_ImgFilePtr);
fseek(p_ImgFilePtr,55,SEEK_SET);
l_ColorTbleSze = (pst_fBMP40ImgHdrVar->st_mBMP40MainHdrVar.st_m40_NumOfColrTbleColrs) * 4 ;
l_ColorTbleVal = (unsigned char*) malloc( l_ColorTbleSze );
l_NumOfReadBlks = fread(l_ColorTbleVal, l_ColorTbleSze, 1, p_ImgFilePtr);
if(l_NumOfReadBlks <1)
printf("Couldn't read the Color-Table values from the BMP File.\n");
return NULL;
else if(l_NumOfReadBlks == 1)
unsigned short int l_ClrTbleIncVar = 0;
unsigned char * l_TempColorTbleVal = l_ColorTbleVal;
unsigned short int l_IndexVal = 0;
printf("\n*****************************************************************************\n");
printf("Printing the color Table.\n");
while (l_ClrTbleIncVar <= (l_ColorTbleSze-4) )
printf("Index '%d' : ", l_IndexVal);
printf("Blue -> '%d'\t",*l_TempColorTbleVal);
l_TempColorTbleVal++;
printf("Green -> '%d'\t",*l_TempColorTbleVal);
l_TempColorTbleVal++;
printf("Red -> '%d'\t\n",*l_TempColorTbleVal);
l_TempColorTbleVal+=2;
l_ClrTbleIncVar += 4;
l_IndexVal++;
rewind(p_ImgFilePtr);
l_ImageDataOffset = pst_fBMP40ImgHdrVar->st_mBMP40MainHdrVar.st_m40_ImgDataOffset;
fseek(p_ImgFilePtr,l_ImageDataOffset,SEEK_SET);
if(pst_fBMP40ImgHdrVar->st_mBMP40MainHdrVar.st_m40_BitsPerPixel == 4)
l_ImageDataSize = ( (pst_fBMP40ImgHdrVar->st_mBMP40MainHdrVar.st_m40_PxWdth) * \
(pst_fBMP40ImgHdrVar->st_mBMP40MainHdrVar.st_m40_PxHeight) )/2;
pst_fBMP40ImgHdrVar->pst_mImgeData = (unsigned char*)malloc(l_ImageDataSize);
l_ImageDataPtr = pst_fBMP40ImgHdrVar->pst_mImgeData;
l_NumOfReadBlks = fread(l_ImageDataPtr,1,l_ImageDataSize,p_ImgFilePtr);
if(l_NumOfReadBlks < 1)
printf("Couldn't read the image data from the file.\n");
return NULL;
else if(pst_fBMP40ImgHdrVar->st_mBMP40MainHdrVar.st_m40_BitsPerPixel == 8)
l_ImageDataSize = ( (pst_fBMP40ImgHdrVar->st_mBMP40MainHdrVar.st_m40_PxWdth) * \
(pst_fBMP40ImgHdrVar->st_mBMP40MainHdrVar.st_m40_PxHeight) );
pst_fBMP40ImgHdrVar->pst_mImgeData = (unsigned char*)malloc(l_ImageDataSize);
l_ImageDataPtr = pst_fBMP40ImgHdrVar->pst_mImgeData;
l_NumOfReadBlks = fread(l_ImageDataPtr,l_ImageDataSize,1,p_ImgFilePtr);
if(l_NumOfReadBlks < 1)
printf("Couldn't read the image data from the file.\n");
return NULL;
else if(pst_fBMP40ImgHdrVar->st_mBMP40MainHdrVar.st_m40_BitsPerPixel == 24)
l_ImageDataSize = ( (pst_fBMP40ImgHdrVar->st_mBMP40MainHdrVar.st_m40_PxWdth) * \
(pst_fBMP40ImgHdrVar->st_mBMP40MainHdrVar.st_m40_PxHeight) * 3 );
pst_fBMP40ImgHdrVar->pst_mImgeData = (unsigned char*)malloc(l_ImageDataSize);
l_ImageDataPtr = pst_fBMP40ImgHdrVar->pst_mImgeData;
l_NumOfReadBlks = fread(l_ImageDataPtr,l_ImageDataSize,1,p_ImgFilePtr);
if(l_NumOfReadBlks < 1)
printf("Couldn't read the image data from the file.\n");
return NULL;
else if(pst_fBMP40ImgHdrVar->st_mBMP40MainHdrVar.st_m40_BitsPerPixel == 32)
l_ImageDataSize = ( (pst_fBMP40ImgHdrVar->st_mBMP40MainHdrVar.st_m40_PxWdth) * \
(pst_fBMP40ImgHdrVar->st_mBMP40MainHdrVar.st_m40_PxHeight) * 4 );
pst_fBMP40ImgHdrVar->pst_mImgeData = (unsigned char*)malloc(l_ImageDataSize);
l_ImageDataPtr = pst_fBMP40ImgHdrVar->pst_mImgeData;
l_NumOfReadBlks = fread(l_ImageDataPtr,l_ImageDataSize,1,p_ImgFilePtr);
if(l_NumOfReadBlks < 1)
printf("Couldn't read the image data from the file.\n");
return NULL;
rewind(p_ImgFilePtr);
Convert__40_BMP2PNG(pst_fBMP40ImgHdrVar,p_ImgFilePtr,l_ColorTbleVal);
int main()
FILE * l_ImgeFilePtr;
l_ImgeFilePtr = fopen("FLAG_B24.BMP","r");
unsigned short int l_ImgeFileType;
unsigned int l_InfoHdrSze;
int l_NumofReadBlocks;
l_NumofReadBlocks = fread(&l_ImgeFileType,2,1,l_ImgeFilePtr);
if(l_NumofReadBlocks <1)
printf("Couldn't read the bytes from the file.\n");
return 0;
if(l_ImgeFileType != 19778)
printf("Image Passed is not a BMP file.\n");
return 0;
fseek(l_ImgeFilePtr,14,SEEK_SET);
l_NumofReadBlocks = fread(&l_InfoHdrSze, 4, 1, l_ImgeFilePtr);
if(l_NumofReadBlocks <1)
printf("Couldn't read the bytes from the file.\n");
return 0;
rewind(l_ImgeFilePtr);
if( l_InfoHdrSze == 40 )
ST_IMAGE_40_HEADER_t * pst_Img40HdrVar;
pst_Img40HdrVar = malloc(sizeof(*pst_Img40HdrVar));
if(pst_Img40HdrVar == NULL)
printf("There isn't enough memory to allocate for the Image header variable.\n");
return 0;
ST_IMAGE_40_HEADER_t * pst_l40_ReadAPIReturnVal = ReadBMP40HdrImage(pst_Img40HdrVar, l_ImgeFilePtr);
【问题讨论】：
【参考方案1】：是压缩的PNG文件
是的。
PNG 文件格式中的图像数据如何对齐？
它没有对齐。来自spec，“块数据长度可以是最大字节数；因此，实现者不能假设块在大于字节的任何边界上对齐。”
虽然存在大量图像处理库，但您不必担心这些细节。除非您的目标是专门了解图像文件格式，否则我建议您不要使用自己的转换器。
【讨论】：
我有一个连接到相机的same51微控制器，当点击图片时，它会以BMP文件格式存储它，而在另一边我有一个显示单元，它显示PNG文件格式的图像.所以我必须在不使用 libpng 等库的情况下编写代码。为此，我创建了一个代码来读取 bmp 文件，将图像参数和图像分配给 PNG 块，我已经完成了。但最终的输出结果不会是 PNG 图像。我已附上包含代码的文件。以上是关于BMP 文件到 PNG 文件转换器的主要内容，如果未能解决你的问题，请参考以下文章
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