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24/32 bit pcx/bitmaps

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all i know about is bmp, so dont ask me about pcx
first of all, each bmp contains header information about the actually image, and the image''s palette. Now, I could sit here and explain the whole thing to you, or i could give you some code to handle the job. Choice 2, for me
BTW, the following code will convert the 24 bit image (if it is one) into 16-bit, since you probably don''t want to make anything in 24-bit:

int Load_Bitmap_File(BITMAP_FILE_PTR bitmap, char *filename)
{
// this function opens a bitmap file and loads the data into bitmap

int file_handle, // the file handle
index; // looping index

UCHAR *temp_buffer = NULL; // used to convert 24 bit images to 16 bit
OFSTRUCT file_data; // the file data information

// open the file if it exists
if ((file_handle = OpenFile(filename,&file_data,OF_READ))==-1)
return(0);

// now load the bitmap file header
_lread(file_handle, &bitmap->bitmapfileheader,sizeof(BITMAPFILEHEADER));

// test if this is a bitmap file
if (bitmap->bitmapfileheader.bfType!=BITMAP_ID)
{
// close the file
_lclose(file_handle);

// return error
return(0);
} // end if

// now we know this is a bitmap, so read in all the sections

// first the bitmap infoheader

// now load the bitmap file header
_lread(file_handle, &bitmap->bitmapinfoheader,sizeof(BITMAPINFOHEADER));

// now load the color palette if there is one
if (bitmap->bitmapinfoheader.biBitCount == 8)
{
_lread(file_handle, &bitmap->palette,MAX_COLORS_PALETTE*sizeof(PALETTEENTRY));

// now set all the flags in the palette correctly and fix the reversed
// BGR RGBQUAD data format
for (index=0; index < MAX_COLORS_PALETTE; index++)
{
// reverse the red and green fields
int temp_color = bitmap->palette[index].peRed;
bitmap->palette[index].peRed = bitmap->palette[index].peBlue;
bitmap->palette[index].peBlue = temp_color;

// always set the flags word to this
bitmap->palette[index].peFlags = PC_NOCOLLAPSE;
} // end for index

} // end if

// finally the image data itself
_lseek(file_handle,-(int)(bitmap->bitmapinfoheader.biSizeImage),SEEK_END);

// now read in the image
if (bitmap->bitmapinfoheader.biBitCount==8 // bitmap->bitmapinfoheader.biBitCount==16)
{
// delete the last image if there was one
if (bitmap->buffer)
free(bitmap->buffer);

// allocate the memory for the image
if (!(bitmap->buffer = (UCHAR *)malloc(bitmap->bitmapinfoheader.biSizeImage)))
{
// close the file
_lclose(file_handle);

// return error
return(0);
} // end if

// now read it in
_lread(file_handle,bitmap->buffer,bitmap->bitmapinfoheader.biSizeImage);

} // end if
else
if (bitmap->bitmapinfoheader.biBitCount==24)
{
// allocate temporary buffer to load 24 bit image
if (!(temp_buffer = (UCHAR *)malloc(bitmap->bitmapinfoheader.biSizeImage)))
{
// close the file
_lclose(file_handle);

// return error
return(0);
} // end if

// allocate final 16 bit storage buffer
if (!(bitmap->buffer=(UCHAR *)malloc(2*bitmap->bitmapinfoheader.biWidth*bitmap->bitmapinfoheader.biHeight)))
{
// close the file
_lclose(file_handle);

// release working buffer
free(temp_buffer);

// return error
return(0);
} // end if

// now read the file in
_lread(file_handle,temp_buffer,bitmap->bitmapinfoheader.biSizeImage);

// now convert each 24 bit RGB value into a 16 bit value
for (index=0; index < bitmap->bitmapinfoheader.biWidth*bitmap->bitmapinfoheader.biHeight; index++)
{
// build up 16 bit color word
USHORT color;

// build pixel based on format of directdraw surface
if (dd_pixel_format==DD_PIXEL_FORMAT555)
{
// extract RGB components (in BGR order), note the scaling
UCHAR blue = (temp_buffer[index*3 + 0] >> 3),
green = (temp_buffer[index*3 + 1] >> 3),
red = (temp_buffer[index*3 + 2] >> 3);
// use the 555 macro
color = _RGB16BIT555(red,green,blue);
} // end if 555
else
if (dd_pixel_format==DD_PIXEL_FORMAT565)
{
// extract RGB components (in BGR order), note the scaling
UCHAR blue = (temp_buffer[index*3 + 0] >> 3),
green = (temp_buffer[index*3 + 1] >> 3),
red = (temp_buffer[index*3 + 2] >> 3);

// use the 565 macro
color = _RGB16BIT565(red,green,blue);

} // end if 565

// write color to buffer
((USHORT *)bitmap->buffer)[index] = color;

} // end for index

// finally write out the correct number of bits
bitmap->bitmapinfoheader.biBitCount=16;

// release working buffer
free(temp_buffer);

} // end if 24 bit
else
{
// serious problem
return(0);

} // end else

#if 0
// write the file info out
printf("\nfilename:%s \nsize=%d \nwidth=%d \nheight=%d \nbitsperpixel=%d \ncolors=%d \nimpcolors=%d",
filename,
bitmap->bitmapinfoheader.biSizeImage,
bitmap->bitmapinfoheader.biWidth,
bitmap->bitmapinfoheader.biHeight,
bitmap->bitmapinfoheader.biBitCount,
bitmap->bitmapinfoheader.biClrUsed,
bitmap->bitmapinfoheader.biClrImportant);
#endif

// close the file
_lclose(file_handle);

// flip the bitmap
Flip_Bitmap(bitmap->buffer,
bitmap->bitmapinfoheader.biWidth*(bitmap->bitmapinfoheader.biBitCount/8),
bitmap->bitmapinfoheader.biHeight);

// return success
return(1);

} // end Load_Bitmap_File




int Flip_Bitmap(UCHAR *image, int bytes_per_line, int height)
{
// this function is used to flip bottom-up .BMP images

UCHAR *buffer; // used to perform the image processing
int index; // looping index

// allocate the temporary buffer
if (!(buffer = (UCHAR *)malloc(bytes_per_line*height)))
return(0);

// copy image to work area
memcpy(buffer,image,bytes_per_line*height);

// flip vertically
for (index=0; index < height; index++)
memcpy(&image[((height-1) - index)*bytes_per_line],
&buffer[index*bytes_per_line], bytes_per_line);

// release the memory
free(buffer);

// return success
return(1);

} // end Flip_Bitmap



Im sorry if the margins are screwed up, since i don''t know the "code block" thingy. Just copy and paste.

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yes I''ve seen it done before... I don''t have code(never bothered with bmp... rather use bmp or my own format) for it but look around it is posable....

Great Milenko

Words Of Wisdom:
"Never Stick A Pretzel In Your Butt It Might Break Off In There."


http://www.crosswinds.net/~milenko
http://www.crosswinds.net/~pirotech

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