www.pudn.com > CXIMAGE_SRC.ZIP > ximabmp.cpp
/*
* File: ximabmp.cpp
* Purpose: Platform Independent BMP Image Class Loader and Writer
* 07/Aug/2001
* CxImage version 5.00 23/Aug/2002
*/
#include "ximabmp.h"
#if CXIMAGE_SUPPORT_BMP
#include "ximaiter.h"
const int RLE_COMMAND = 0;
const int RLE_ENDOFLINE = 0;
const int RLE_ENDOFBITMAP = 1;
const int RLE_DELTA = 2;
#if !defined(BI_RLE8)
#define BI_RLE8 1L
#endif
#if !defined(BI_RLE4)
#define BI_RLE4 2L
#endif
////////////////////////////////////////////////////////////////////////////////
#if CXIMAGE_SUPPORT_ENCODE
////////////////////////////////////////////////////////////////////////////////
bool CxImageBMP::Encode(CxFile * hFile)
{
if (hFile==NULL) return false;
BITMAPFILEHEADER hdr;
hdr.bfType = 0x4d42; // 'BM' WINDOWS_BITMAP_SIGNATURE
hdr.bfSize = GetSize() + sizeof(BITMAPFILEHEADER);
hdr.bfReserved1 = hdr.bfReserved2 = 0;
hdr.bfOffBits = (DWORD) sizeof(hdr) + head.biSize + GetPaletteSize();
//copy attributes
memcpy(pDib,&head,sizeof(BITMAPINFOHEADER));
// Write the file header
hFile->Write(&hdr,sizeof(BITMAPFILEHEADER),1);
// Write the DIB header and the pixels
hFile->Write(pDib,GetSize(),1);
return true;
}
////////////////////////////////////////////////////////////////////////////////
#endif //CXIMAGE_SUPPORT_ENCODE
////////////////////////////////////////////////////////////////////////////////
#if CXIMAGE_SUPPORT_DECODE
////////////////////////////////////////////////////////////////////////////////
bool CxImageBMP::Decode(CxFile * hFile)
{
if (hFile == NULL) return false;
BITMAPFILEHEADER bf;
DWORD off = hFile->Tell(); //
try {
if (hFile->Read(&bf,sizeof(bf),1)==0) throw "Not a BMP";
if (bf.bfType != BFT_BITMAP) { //do we have a RC HEADER?
bf.bfOffBits = 0L;
hFile->Seek(off,SEEK_SET);
}
if (!DibReadBitmapInfo(hFile,&head)) throw "Error reading BMP info";
DWORD dwCompression=head.biCompression;
DWORD dwBitCount=head.biBitCount; //preserve for BI_BITFIELDS compression
bool bIsOS2 = head.biSize == sizeof(BITMAPCOREHEADER);
head.biSize = sizeof(BITMAPINFOHEADER);
bool bTopDownDib = head.biHeight<0; // check if it's a top-down bitmap
if (bTopDownDib) head.biHeight=-head.biHeight;
if (!Create(head.biWidth,head.biHeight,head.biBitCount))
throw "Can't allocate memory";
info.xDPI = (long) floor(head.biXPelsPerMeter * 254.0 / 10000.0 + 0.5);
info.yDPI = (long) floor(head.biYPelsPerMeter * 254.0 / 10000.0 + 0.5);
if (info.nEscape) throw "Cancelled"; // - cancel decoding
RGBQUAD *pRgb = GetPalette();
if (pRgb){
if (bIsOS2){
// convert a old color table (3 byte entries) to a new
// color table (4 byte entries)
hFile->Read((void*)pRgb,DibNumColors(&head) * sizeof(RGBTRIPLE),1);
for (int i=DibNumColors(&head)-1; i>=0; i--){
pRgb[i].rgbRed = ((RGBTRIPLE *)pRgb)[i].rgbtRed;
pRgb[i].rgbBlue = ((RGBTRIPLE *)pRgb)[i].rgbtBlue;
pRgb[i].rgbGreen = ((RGBTRIPLE *)pRgb)[i].rgbtGreen;
pRgb[i].rgbReserved = (BYTE)0;
}
} else {
hFile->Read((void*)pRgb,DibNumColors(&head) * sizeof(RGBQUAD),1);
}
}
if (info.nEscape) throw "Cancelled"; // - cancel decoding
if (bf.bfOffBits != 0L) hFile->Seek(off + bf.bfOffBits,SEEK_SET);
switch (dwBitCount) {
case 32 :
if (dwCompression == BI_BITFIELDS || dwCompression == BI_RGB){
long imagesize=4*head.biHeight*head.biWidth;
BYTE* buff32=(BYTE*)malloc(imagesize);
if (buff32){
hFile->Read(buff32, imagesize,1); // read in the pixels
Bitfield2RGB(buff32,0,0,0,32);
free(buff32);
} else throw "can't allocate memory";
} else throw "unknown compression";
break;
case 24 :
if (dwCompression == BI_RGB){
hFile->Read(info.pImage, head.biSizeImage,1); // read in the pixels
} else throw "unknown compression";
break;
case 16 :
{
DWORD bf[3];
if (head.biCompression == BI_BITFIELDS) {
hFile->Read(bf, 12, 1);
} else {
bf[0]=0x7C00; bf[1]=0x3E0; bf[2]=0x1F; //RGB555
}
// read in the pixels
hFile->Read(info.pImage, head.biHeight*((head.biWidth+1)/2)*4,1);
// transform into RGB
Bitfield2RGB(info.pImage,(WORD)bf[0],(WORD)bf[1],(WORD)bf[2],16);
break;
}
case 8 :
case 4 :
case 1 :
switch (dwCompression) {
case BI_RGB :
hFile->Read(info.pImage, head.biSizeImage,1); // read in the pixels
break;
case BI_RLE4 :
{
BYTE status_byte = 0;
BYTE second_byte = 0;
int scanline = 0;
int bits = 0;
BOOL low_nibble = FALSE;
CImageIterator iter(this);
for (BOOL bContinue = TRUE; bContinue;) {
hFile->Read(&status_byte, sizeof(BYTE), 1);
switch (status_byte) {
case RLE_COMMAND :
hFile->Read(&status_byte, sizeof(BYTE), 1);
switch (status_byte) {
case RLE_ENDOFLINE :
bits = 0;
scanline++;
low_nibble = FALSE;
break;
case RLE_ENDOFBITMAP :
bContinue=FALSE;
break;
case RLE_DELTA :
{
// read the delta values
BYTE delta_x;
BYTE delta_y;
hFile->Read(&delta_x, sizeof(BYTE), 1);
hFile->Read(&delta_y, sizeof(BYTE), 1);
// apply them
bits += delta_x / 2;
scanline += delta_y;
break;
}
default :
hFile->Read(&second_byte, sizeof(BYTE), 1);
BYTE *sline = iter.GetRow(scanline);
for (int i = 0; i < status_byte; i++) {
if (low_nibble) {
if ((DWORD)(sline+bits) < (DWORD)(info.pImage+head.biSizeImage)){
*(sline + bits) |= second_byte & 0x0F;
}
if (i != status_byte - 1)
hFile->Read(&second_byte, sizeof(BYTE), 1);
bits++;
} else {
if ((DWORD)(sline+bits) < (DWORD)(info.pImage+head.biSizeImage)){
*(sline + bits) = (BYTE)(second_byte & 0xF0);
}
}
low_nibble = !low_nibble;
}
if (((status_byte / 2) & 1 )== 1)
hFile->Read(&second_byte, sizeof(BYTE), 1);
break;
};
break;
default :
{
BYTE *sline = iter.GetRow(scanline);
hFile->Read(&second_byte, sizeof(BYTE), 1);
for (unsigned i = 0; i < status_byte; i++) {
if (low_nibble) {
if ((DWORD)(sline+bits) < (DWORD)(info.pImage+head.biSizeImage)){
*(sline + bits) |= second_byte & 0x0F;
}
bits++;
} else {
if ((DWORD)(sline+bits) < (DWORD)(info.pImage+head.biSizeImage)){
*(sline + bits) = (BYTE)(second_byte & 0xF0);
}
}
low_nibble = !low_nibble;
}
}
break;
};
}
break;
}
case BI_RLE8 :
{
BYTE status_byte = 0;
BYTE second_byte = 0;
int scanline = 0;
int bits = 0;
CImageIterator iter(this);
for (BOOL bContinue = TRUE; bContinue; ) {
hFile->Read(&status_byte, sizeof(BYTE), 1);
switch (status_byte) {
case RLE_COMMAND :
hFile->Read(&status_byte, sizeof(BYTE), 1);
switch (status_byte) {
case RLE_ENDOFLINE :
bits = 0;
scanline++;
break;
case RLE_ENDOFBITMAP :
bContinue=FALSE;
break;
case RLE_DELTA :
{
// read the delta values
BYTE delta_x;
BYTE delta_y;
hFile->Read(&delta_x, sizeof(BYTE), 1);
hFile->Read(&delta_y, sizeof(BYTE), 1);
// apply them
bits += delta_x;
scanline += delta_y;
break;
}
default :
hFile->Read((void *)(iter.GetRow(scanline) + bits), sizeof(BYTE) * status_byte, 1);
// align run length to even number of bytes
if ((status_byte & 1) == 1)
hFile->Read(&second_byte, sizeof(BYTE), 1);
bits += status_byte;
break;
};
break;
default :
BYTE *sline = iter.GetRow(scanline);
hFile->Read(&second_byte, sizeof(BYTE), 1);
for (unsigned i = 0; i < status_byte; i++) {
*(sline + bits) = second_byte;
bits++;
}
break;
};
}
break;
}
default :
throw "compression type not supported";
}
}
if (bTopDownDib) Flip(); //
} catch (char *message) {
strncpy(info.szLastError,message,255);
return false;
}
return true;
}
////////////////////////////////////////////////////////////////////////////////
/* ReadDibBitmapInfo()
*
* Will read a file in DIB format and return a global HANDLE to its
* BITMAPINFO. This function will work with both "old" and "new"
* bitmap formats, but will always return a "new" BITMAPINFO.
*/
bool CxImageBMP::DibReadBitmapInfo(CxFile* fh, BITMAPINFOHEADER *pdib)
{
if ((fh==NULL)||(pdib==NULL)) return false;
if (fh->Read(pdib,sizeof(BITMAPINFOHEADER),1)==0) return false;
BITMAPCOREHEADER bc;
switch (pdib->biSize) // what type of bitmap info is this?
{
default:
case sizeof(BITMAPINFOHEADER):
break;
case sizeof(BITMAPCOREHEADER):
bc = *(BITMAPCOREHEADER*)pdib;
pdib->biSize = bc.bcSize;
pdib->biWidth = (DWORD)bc.bcWidth;
pdib->biHeight = (DWORD)bc.bcHeight;
pdib->biPlanes = bc.bcPlanes;
pdib->biBitCount = bc.bcBitCount;
pdib->biCompression = BI_RGB;
pdib->biSizeImage = 0;
pdib->biXPelsPerMeter = 0;
pdib->biYPelsPerMeter = 0;
pdib->biClrUsed = 0;
pdib->biClrImportant = 0;
fh->Seek((LONG)sizeof(BITMAPCOREHEADER)-sizeof(BITMAPINFOHEADER),SEEK_CUR);
break;
}
FixBitmapInfo(pdib);
return true;
}
////////////////////////////////////////////////////////////////////////////////
#endif //CXIMAGE_SUPPORT_DECODE
////////////////////////////////////////////////////////////////////////////////
#endif // CXIMAGE_SUPPORT_BMP
////////////////////////////////////////////////////////////////////////////////