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#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include "fmt_image.H"
fmtImage::fmtImage(const char *filename, int autocrop )
: Image(filename, autocrop)
{
LoadImageFile( filename );
if (autocrop) CropImage();
}
fmtImage::fmtImage() {
/*nothing*/
}
fmtImage::~fmtImage() {
/*nothing*/
}
/* This function may be omitted if the file format doesn't support it. Just
* delete the following line and the prototype in the corresponding .H file. */
const char *fmtImage::GetExtensionData( unsigned char code ) { return 0; }
/*
LoadImageFile must fill in the following fields:
int width, height; // image dimensions
byte *data; // image data
byte Red[256], Green[256], Blue[256]; // Colormap-Data
boolean HasColormap;
int ColorMapSize; // number of colors
int Background; // background color
The data is one byte per pixel, the bytes index the Red[], Green[], and
Blue[] arrays, so you have 24-bit color with an 8-bit palette. If the
image format contains more than 256 distinct colors, LoadImageFile must
quantize it down to 256. You must malloc the data, but don't worry about
freeing it. The superclass will take care of that.
If there are any errors opening the file or decoding the image, the best
that can be done is to print an error message to stderr and exit().
I'm not sure what the HasColormap field is for. In the GIF loader, it
might end up as 0 depending on the file headers. What kind of GIF doesn't
have a palette? Fortunately nothing outside the GIF loader uses it. I
decree that it shall be set to 1 by all loaders until I figure out what
it's good for.
The Background field isn't used either, but it's probably a good idea to
set it. If your image file doesn't have a "background" color, call
DefaultBackground() after you've filled in all the other fields and one
will be chosen for you.
The return value is also not used anywhere, but to be consistent with the
GIF loader you should return 0 to indicate success.
If you prefer to open and close the image file yourself, you can take a
const char *filename arg instead of FILE *fp. If you take the FILE *fp
arg, all you have to do is read from it.
Obviously, there is room for improvement in the interface.
*/
/*****************************/
int fmtImage::LoadImageFile(FILE *fp)
/*****************************/
{
fprintf(stderr, "This file format is just a stub!\n");
exit(1);
}
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