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fltk/src/Fl_BMP_Image.cxx
Michael R Sweet f79c2375da Tag image data as allocated so that we don't waste memory. 
git-svn-id: file:///fltk/svn/fltk/branches/branch-1.1@2257 ea41ed52-d2ee-0310-a9c1-e6b18d33e121
2002-05-25 02:56:59 +00:00

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//
// "$Id: Fl_BMP_Image.cxx,v 1.1.2.4 2002/05/25 02:56:59 easysw Exp $"
//
// Fl_BMP_Image routines.
//
// Copyright 1997-2002 by Easy Software Products.
// Image support donated by Matthias Melcher, Copyright 2000.
//
// This library is free software; you can redistribute it and/or
// modify it under the terms of the GNU Library General Public
// License as published by the Free Software Foundation; either
// version 2 of the License, or (at your option) any later version.
//
// This library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
// Library General Public License for more details.
//
// You should have received a copy of the GNU Library General Public
// License along with this library; if not, write to the Free Software
// Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
// USA.
//
// Please report all bugs and problems to "fltk-bugs@fltk.org".
//
// Contents:
//
// Fl_BMP_Image::Fl_BMP_Image() - Load a BMP image file.
//
//
// Include necessary header files...
//
#include <FL/Fl_BMP_Image.H>
#include <config.h>
#include <stdio.h>
#include <stdlib.h>
//
// BMP definitions...
//
#ifndef BI_RGB
# define BI_RGB 0 // No compression - straight BGR data
# define BI_RLE8 1 // 8-bit run-length compression
# define BI_RLE4 2 // 4-bit run-length compression
# define BI_BITFIELDS 3 // RGB bitmap with RGB masks
#endif // !BI_RGB
//
// Local functions...
//
static int read_long(FILE *fp);
static unsigned short read_word(FILE *fp);
static unsigned int read_dword(FILE *fp);
//
// 'Fl_BMP_Image::Fl_BMP_Image()' - Load a BMP image file.
//
Fl_BMP_Image::Fl_BMP_Image(const char *bmp) // I - File to read
: Fl_RGB_Image(0,0,0) {
FILE *fp; // File pointer
int info_size, // Size of info header
depth, // Depth of image (bits)
compression, // Type of compression
colors_used, // Number of colors used
x, y, // Looping vars
color, // Color of RLE pixel
count, // Number of times to repeat
temp, // Temporary color
align; // Alignment bytes
unsigned long offbits; // Offset to image data
uchar bit, // Bit in image
byte; // Byte in image
uchar *ptr; // Pointer into pixels
uchar colormap[256][3];// Colormap
// Open the file...
if ((fp = fopen(bmp, "rb")) == NULL) return;
// Get the header...
getc(fp); // Skip "BM" sync chars
getc(fp);
read_dword(fp); // Skip size
read_word(fp); // Skip reserved stuff
read_word(fp);
offbits = read_dword(fp); // Read offset to image data
// Then the bitmap information...
info_size = read_dword(fp);
w(read_long(fp));
h(read_long(fp));
read_word(fp);
depth = read_word(fp);
if (info_size < 40) {
// Old Windows/OS2 BMP header...
compression = BI_RGB;
colors_used = 0;
count = info_size - 12;
} else {
// New BMP header...
compression = read_dword(fp);
read_dword(fp);
read_long(fp);
read_long(fp);
colors_used = read_dword(fp);
read_dword(fp);
count = info_size - 40;
}
// Skip remaining header bytes...
while (count > 0) {
getc(fp);
count --;
}
// Get colormap...
if (colors_used == 0 && depth <= 8)
colors_used = 1 << depth;
for (count = 0; count < colors_used; count ++) {
// Read BGR color...
fread(colormap, colors_used, 3, fp);
// Skip pad byte for new BMP files...
if (info_size > 12) getc(fp);
}
// Setup image and buffers...
d(3);
fseek(fp, offbits, SEEK_SET);
array = new uchar[w() * h() * d()];
alloc_array = 1;
// Read the image data...
color = 0;
count = 0;
align = 0;
byte = 0;
temp = 0;
for (y = h() - 1; y >= 0; y --) {
ptr = (uchar *)array + y * w() * d();
switch (depth)
{
case 1 : // Bitmap
for (x = w(), bit = 128; x > 0; x --) {
if (bit == 128) byte = getc(fp);
if (byte & bit) {
*ptr++ = colormap[1][2];
*ptr++ = colormap[1][1];
*ptr++ = colormap[1][0];
} else {
*ptr++ = colormap[0][2];
*ptr++ = colormap[0][1];
*ptr++ = colormap[0][0];
}
if (bit > 1)
bit >>= 1;
else
bit = 128;
}
// Read remaining bytes to align to 32 bits...
for (temp = (w() + 7) / 8; temp & 3; temp ++) {
getc(fp);
}
break;
case 4 : // 16-color
for (x = w(), bit = 0xf0; x > 0; x --) {
// Get a new count as needed...
if (compression != BI_RLE4 && count == 0) {
count = 2;
color = -1;
}
if (count == 0) {
while (align > 0) {
align --;
getc(fp);
}
if ((count = getc(fp)) == 0) {
if ((count = getc(fp)) == 0) {
// End of line...
x ++;
continue;
} else if (count == 1) {
// End of image...
break;
} else if (count == 2) {
// Delta...
count = getc(fp) * getc(fp) * w();
color = 0;
} else {
// Absolute...
color = -1;
align = ((4 - (count & 3)) / 2) & 1;
}
} else {
color = getc(fp);
}
}
// Get a new color as needed...
count --;
if (bit == 0xf0) {
if (color < 0) temp = getc(fp);
else temp = color;
// Copy the color value...
*ptr++ = colormap[temp >> 4][2];
*ptr++ = colormap[temp >> 4][1];
*ptr++ = colormap[temp >> 4][0];
bit = 0x0f;
} else {
// Copy the color value...
*ptr++ = colormap[temp & 15][2];
*ptr++ = colormap[temp & 15][1];
*ptr++ = colormap[temp & 15][0];
bit = 0xf0;
}
}
if (!compression) {
// Read remaining bytes to align to 32 bits...
for (temp = (w() + 1) / 2; temp & 3; temp ++) {
getc(fp);
}
}
break;
case 8 : // 256-color
for (x = w(); x > 0; x --) {
// Get a new count as needed...
if (compression != BI_RLE8) {
count = 1;
color = -1;
}
if (count == 0) {
while (align > 0) {
align --;
getc(fp);
}
if ((count = getc(fp)) == 0) {
if ((count = getc(fp)) == 0) {
// End of line...
x ++;
continue;
} else if (count == 1) {
// End of image...
break;
} else if (count == 2) {
// Delta...
count = getc(fp) * getc(fp) * w();
color = 0;
} else {
// Absolute...
color = -1;
align = (2 - (count & 1)) & 1;
}
} else {
color = getc(fp);
}
}
// Get a new color as needed...
if (color < 0) temp = getc(fp);
else temp = color;
count --;
// Copy the color value...
*ptr++ = colormap[temp][2];
*ptr++ = colormap[temp][1];
*ptr++ = colormap[temp][0];
}
if (!compression) {
// Read remaining bytes to align to 32 bits...
for (temp = w(); temp & 3; temp ++) {
getc(fp);
}
}
break;
case 24 : // 24-bit RGB
for (x = w(); x > 0; x --, ptr += 3) {
ptr[2] = getc(fp);
ptr[1] = getc(fp);
ptr[0] = getc(fp);
}
// Read remaining bytes to align to 32 bits...
for (temp = w() * 3; temp & 3; temp ++) {
getc(fp);
}
break;
}
}
// Close the file and return...
fclose(fp);
}
//
// 'read_word()' - Read a 16-bit unsigned integer.
//
static unsigned short // O - 16-bit unsigned integer
read_word(FILE *fp) { // I - File to read from
unsigned char b0, b1; // Bytes from file
b0 = getc(fp);
b1 = getc(fp);
return ((b1 << 8) | b0);
}
//
// 'read_dword()' - Read a 32-bit unsigned integer.
//
static unsigned int // O - 32-bit unsigned integer
read_dword(FILE *fp) { // I - File to read from
unsigned char b0, b1, b2, b3; // Bytes from file
b0 = getc(fp);
b1 = getc(fp);
b2 = getc(fp);
b3 = getc(fp);
return ((((((b3 << 8) | b2) << 8) | b1) << 8) | b0);
}
//
// 'read_long()' - Read a 32-bit signed integer.
//
static int // O - 32-bit signed integer
read_long(FILE *fp) { // I - File to read from
unsigned char b0, b1, b2, b3; // Bytes from file
b0 = getc(fp);
b1 = getc(fp);
b2 = getc(fp);
b3 = getc(fp);
return ((int)(((((b3 << 8) | b2) << 8) | b1) << 8) | b0);
}
//
// End of "$Id: Fl_BMP_Image.cxx,v 1.1.2.4 2002/05/25 02:56:59 easysw Exp $".
//
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