From d890a03706282500c2129ae8ab7b399069038192 Mon Sep 17 00:00:00 2001
From: kramm <kramm>
Date: Thu, 7 Apr 2005 09:00:38 +0000
Subject: [PATCH] initial revision

---
 lib/png.c |  837 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 lib/png.h |   35 +++
 2 files changed, 872 insertions(+)
 create mode 100644 lib/png.c
 create mode 100644 lib/png.h

diff --git a/lib/png.c b/lib/png.c
new file mode 100644
index 0000000..8dd105b
--- /dev/null
+++ b/lib/png.c
@@ -0,0 +1,837 @@
+/*  png.c
+   
+   Copyright (c) 2003/2004/2005 Matthias Kramm <kramm@quiss.org>
+
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 2 of the License, or
+   (at your option) any later version.
+
+   This program 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 General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program; if not, write to the Free Software
+   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <math.h>
+#include <fcntl.h>
+#include <zlib.h>
+#include "png.h"
+
+typedef unsigned char U8;
+typedef unsigned long U32;
+typedef struct _COL {
+    U8 a,r,g,b;
+} COL;
+
+#define REVERSESWAP16(s) ((((s)>>8)&0x00ff)|(((s)<<8)&0xff00))
+#define REVERSESWAP32(s) (REVERSESWAP16(((s)>>16)&0x0000ffff)|((REVERSESWAP16(s)<<16)&0xffff0000))
+
+int png_read_chunk(char (*head)[4], int*destlen, U8**destdata, FILE*fi)
+{
+    unsigned int len;
+    if(destlen) *destlen=0;
+    if(destdata) *destdata=0;
+    if(!fread(&len, 4, 1, fi)) {
+	return 0;
+    }
+    if(!fread(head, 4, 1, fi)) {
+	return 0;
+    }
+    len = REVERSESWAP32(len);
+    if(destlen) *destlen = len;
+    if(destdata) {
+	if(!len) {
+	    *destdata = 0;
+	} else {
+	    *destdata = (U8*)malloc(len);
+	    if(!fread(*destdata, len, 1, fi)) {
+		*destdata = 0;
+		if(destlen) *destlen=0;
+		return 0;
+	    }
+	}
+	fseek(fi, 4, SEEK_CUR);
+
+    } else {
+	fseek(fi, len+4, SEEK_CUR);
+    }
+    return 1;
+}
+
+unsigned int png_get_dword(FILE*fi)
+{
+    unsigned int a;
+    fread(&a,4,1,fi);
+    return REVERSESWAP32(a);
+}
+
+struct png_header
+{
+    int width;
+    int height;
+    int bpp;
+    int mode;
+};
+
+int png_read_header(FILE*fi, struct png_header*header)
+{
+    char id[4];
+    int len;
+    int ok=0;
+    U8 head[8] = {137,80,78,71,13,10,26,10};
+    U8 head2[8];
+    U8*data;
+    fread(head2,8,1,fi);
+    if(strncmp((const char*)head,(const char*)head2,4))
+	return 0;
+    
+    while(png_read_chunk(&id, &len, &data, fi))
+    {
+	//printf("Chunk: %c%c%c%c (len:%d)\n", id[0],id[1],id[2],id[3], len);
+	if(!strncasecmp(id, "IHDR", 4)) {
+	    char a,b,c,f,i;
+	    if(len < 8) exit(1);
+	    header->width = REVERSESWAP32(*(U32*)&data[0]);
+	    header->height = REVERSESWAP32(*(U32*)&data[4]);
+	    a = data[8];      // should be 8
+	    b = data[9];      // should be 3(indexed) or 2(rgb)
+
+	    c = data[10];     // compression mode (0)
+	    f = data[11];     // filter mode (0)
+	    i = data[12];     // interlace mode (0)
+
+	    if(b!=0 && b!=2 && b!=3 && b!=6) {
+		fprintf(stderr, "Image mode %d not supported!\n", b);
+		if(b == 4) {
+		    fprintf(stderr, "(This is a grayscale image with alpha channel-\n");
+		    fprintf(stderr, " try converting it into an RGB image with alpha channel)\n");
+		}
+		return 0;
+	    }
+	    if(a!=8 && (b==2 || b==6)) {
+		printf("Bpp %d in mode %d not supported!\n", a);
+		return 0;
+	    }
+	    if(c!=0) {
+		printf("Compression mode %d not supported!\n", c);
+		return 0;
+	    }
+	    if(f!=0) {
+		printf("Filter mode %d not supported!\n", f);
+		return 0;
+	    }
+	    if(i!=0) {
+		printf("Interlace mode %d not supported!\n", i);
+		return 0;
+	    }
+	    //printf("%dx%d bpp:%d mode:%d comp:%d filter:%d interlace:%d\n",header->width, header->height, a,b,c,f,i);
+	    header->bpp = a;
+	    header->mode = b;
+	    ok = 1;
+	} 
+	
+	free(data);
+    }
+    return ok;
+}
+
+typedef unsigned char byte;
+#define ABS(a) ((a)>0?(a):(-(a)))
+byte inline PaethPredictor (byte a,byte b,byte c)
+{
+        // a = left, b = above, c = upper left
+        int p = a + b - c;        // initial estimate
+        int pa = ABS(p - a);      // distances to a, b, c
+        int pb = ABS(p - b);
+        int pc = ABS(p - c);
+        // return nearest of a,b,c,
+        // breaking ties in order a,b,c.
+        if (pa <= pb && pa <= pc) 
+		return a;
+        else if (pb <= pc) 
+		return b;
+        else return c;
+}
+
+void applyfilter1(int mode, U8*src, U8*old, U8*dest, int width)
+{
+    int x;
+    unsigned char last=0;
+    unsigned char upperlast=0;
+
+    if(mode==0) {
+	for(x=0;x<width;x++) {
+	    *dest = *src;
+	    dest++;
+	    src++;
+	}
+    }
+    else if(mode==1) {
+	for(x=0;x<width;x++) {
+	    *dest = *src+last;
+	    last = *dest;
+	    dest++;
+	    src++;
+	}
+    }
+    else if(mode==2) {
+	for(x=0;x<width;x++) {
+	    *dest = *src+*old;
+	    dest++;
+	    old++;
+	    src++;
+	}
+    }
+    else if(mode==3) {
+	for(x=0;x<width;x++) {
+	    *dest = *src+(*old+last)/2;
+	    dest++;
+	    old++;
+	    src++;
+	}
+    }
+    else if(mode==4) {
+	for(x=0;x<width;x++) {
+	    *dest = *src+PaethPredictor(last,*old,upperlast);
+	    last = *dest;
+	    upperlast = *old;
+	    dest++;
+	    old++;
+	    src++;
+	}
+    }    
+
+}
+
+void applyfilter2(int mode, U8*src, U8*old, U8*dest, int width)
+{
+    int x;
+    unsigned char lasta=0;
+    unsigned char lastb=0;
+    unsigned char upperlasta=0;
+    unsigned char upperlastb=0;
+
+    if(mode==0) {
+	for(x=0;x<width;x++) {
+	    dest[0] = src[0];
+	    dest[1] = src[1];
+	    dest+=2;
+	    src+=2;
+	}
+    }
+    else if(mode==1) {
+	for(x=0;x<width;x++) {
+	    dest[0] = src[0]+lasta;
+	    dest[1] = src[1]+lastb;
+	    lasta = dest[0];
+	    lastb = dest[1];
+	    dest+=2;
+	    src+=2;
+	}
+    }
+    else if(mode==2) {
+	for(x=0;x<width;x++) {
+	    dest[0] = src[0]+old[0];
+	    dest[1] = src[1]+old[1];
+	    dest+=2;
+	    old+=2;
+	    src+=2;
+	}
+    }
+    else if(mode==3) {
+	for(x=0;x<width;x++) {
+	    dest[0] = src[0]+(old[0]+lasta)/2;
+	    dest[1] = src[1]+(old[1]+lastb)/2;
+	    lasta = dest[0];
+	    lastb = dest[1];
+	    dest+=2;
+	    old+=2;
+	    src+=2;
+	}
+    }
+    else if(mode==4) {
+	for(x=0;x<width;x++) {
+	    dest[0] = src[0]+PaethPredictor(lasta,old[0],upperlasta);
+	    dest[1] = src[1]+PaethPredictor(lastb,old[1],upperlastb);
+	    lasta = dest[0];
+	    lastb = dest[1];
+	    upperlasta = old[0];
+	    upperlastb = old[1];
+	    dest+=2;
+	    old+=2;
+	    src+=2;
+	}
+    }    
+}
+
+
+/* also performs 24 bit conversion! */
+void applyfilter3(int mode, U8*src, U8*old, U8*dest, int width)
+{
+    int x;
+    unsigned char lastr=0;
+    unsigned char lastg=0;
+    unsigned char lastb=0;
+    unsigned char upperlastr=0;
+    unsigned char upperlastg=0;
+    unsigned char upperlastb=0;
+
+    if(mode==0) {
+	for(x=0;x<width;x++) {
+	    dest[0] = 255;
+	    dest[1] = src[0];
+	    dest[2] = src[1];
+	    dest[3] = src[2];
+	    dest+=4;
+	    src+=3;
+	}
+    }
+    else if(mode==1) {
+	for(x=0;x<width;x++) {
+	    dest[0] = 255;
+	    dest[1] = src[0]+lastr;
+	    dest[2] = src[1]+lastg;
+	    dest[3] = src[2]+lastb;
+	    lastr = dest[1];
+	    lastg = dest[2];
+	    lastb = dest[3];
+	    dest+=4;
+	    src+=3;
+	}
+    }
+    else if(mode==2) {
+	for(x=0;x<width;x++) {
+	    dest[0] = 255;
+	    dest[1] = src[0]+old[1];
+	    dest[2] = src[1]+old[2];
+	    dest[3] = src[2]+old[3];
+	    dest+=4;
+	    old+=4;
+	    src+=3;
+	}
+    }
+    else if(mode==3) {
+	for(x=0;x<width;x++) {
+	    dest[0] = 255;
+	    dest[1] = src[0]+(old[1]+lastr)/2;
+	    dest[2] = src[1]+(old[2]+lastg)/2;
+	    dest[3] = src[2]+(old[3]+lastb)/2;
+	    lastr = dest[1];
+	    lastg = dest[2];
+	    lastb = dest[3];
+	    dest+=4;
+	    old+=4;
+	    src+=3;
+	}
+    }
+    else if(mode==4) {
+	for(x=0;x<width;x++) {
+	    dest[0] = 255;
+	    dest[1] = src[0]+PaethPredictor(lastr,old[1],upperlastr);
+	    dest[2] = src[1]+PaethPredictor(lastg,old[2],upperlastg);
+	    dest[3] = src[2]+PaethPredictor(lastb,old[3],upperlastb);
+	    lastr = dest[1];
+	    lastg = dest[2];
+	    lastb = dest[3];
+	    upperlastr = old[1];
+	    upperlastg = old[2];
+	    upperlastb = old[3];
+	    dest+=4;
+	    old+=4;
+	    src+=3;
+	}
+    }    
+}
+
+void inline applyfilter4(int mode, U8*src, U8*old, U8*dest, int width)
+{
+    int x;
+    unsigned char lastr=0;
+    unsigned char lastg=0;
+    unsigned char lastb=0;
+    unsigned char lasta=0;
+    unsigned char upperlastr=0;
+    unsigned char upperlastg=0;
+    unsigned char upperlastb=0;
+    unsigned char upperlasta=0;
+
+    if(mode==0) {
+	for(x=0;x<width;x++) {
+	    dest[0] = src[3];
+	    dest[1] = src[0];
+	    dest[2] = src[1];
+	    dest[3] = src[2];
+	    dest+=4;
+	    src+=4;
+	}
+    }
+    else if(mode==1) {
+	for(x=0;x<width;x++) {
+	    dest[0] = src[3]+lasta;
+	    dest[1] = src[0]+lastr;
+	    dest[2] = src[1]+lastg;
+	    dest[3] = src[2]+lastb;
+	    lasta = dest[0];
+	    lastr = dest[1];
+	    lastg = dest[2];
+	    lastb = dest[3];
+	    dest+=4;
+	    src+=4;
+	}
+    }
+    else if(mode==2) {
+	for(x=0;x<width;x++) {
+	    dest[0] = src[3]+old[0];
+	    dest[1] = src[0]+old[1];
+	    dest[2] = src[1]+old[2];
+	    dest[3] = src[2]+old[3];
+	    dest+=4;
+	    old+=4;
+	    src+=4;
+	}
+    }
+    else if(mode==3) {
+	for(x=0;x<width;x++) {
+	    dest[0] = src[3]+(old[0]+lasta)/2;
+	    dest[1] = src[0]+(old[1]+lastr)/2;
+	    dest[2] = src[1]+(old[2]+lastg)/2;
+	    dest[3] = src[2]+(old[3]+lastb)/2;
+	    lasta = dest[0];
+	    lastr = dest[1];
+	    lastg = dest[2];
+	    lastb = dest[3];
+	    dest+=4;
+	    old+=4;
+	    src+=4;
+	}
+    }
+    else if(mode==4) {
+	for(x=0;x<width;x++) {
+	    dest[0] = src[3]+PaethPredictor(lasta,old[0],upperlasta);
+	    dest[1] = src[0]+PaethPredictor(lastr,old[1],upperlastr);
+	    dest[2] = src[1]+PaethPredictor(lastg,old[2],upperlastg);
+	    dest[3] = src[2]+PaethPredictor(lastb,old[3],upperlastb);
+	    lasta = dest[0];
+	    lastr = dest[1];
+	    lastg = dest[2];
+	    lastb = dest[3];
+	    upperlasta = old[0];
+	    upperlastr = old[1];
+	    upperlastg = old[2];
+	    upperlastb = old[3];
+	    dest+=4;
+	    old+=4;
+	    src+=4;
+	}
+    }    
+}
+
+
+int getPNGdimensions(char*sname, int*destwidth, int*destheight)
+{
+    FILE*fi;
+    struct png_header header;
+    if ((fi = fopen(sname, "rb")) == NULL) {
+	fprintf(stderr, "Couldn't open %s\n", sname);
+	return 0;
+    }
+    if(!png_read_header(fi, &header)) {
+	fprintf(stderr, "Error reading header from file %s\n", sname);
+	return 0;
+    }
+
+    *destwidth = header.width;
+    *destheight = header.height;
+    return 1;
+}
+
+int getPNG(char*sname, int*destwidth, int*destheight, unsigned char**destdata)
+{
+    char tagid[4];
+    int len;
+    U8*data;
+    U8*imagedata;
+    U8*zimagedata=0;
+    unsigned long int imagedatalen;
+    unsigned long int zimagedatalen=0;
+    U8*palette = 0;
+    int palettelen = 0;
+    U8*alphapalette = 0;
+    int alphapalettelen = 0;
+    struct png_header header;
+    int bypp;
+
+    FILE *fi;
+    U8 *scanline;
+
+    if ((fi = fopen(sname, "rb")) == NULL) {
+	printf("Couldn't open %s\n", sname);
+	return 0;
+    }
+
+    if(!png_read_header(fi, &header)) {
+	printf("Error reading header from file %s\n", sname);
+	return 0;
+    }
+
+    if(header.mode == 3 || header.mode == 0) bypp = 1;
+    else
+    if(header.mode == 2) bypp = 3;
+    else
+    if(header.mode == 6) bypp = 4;
+    else {
+	printf("ERROR: mode:%d\n", header.mode);
+	return 0;
+    }
+
+    imagedatalen = bypp * header.width * header.height + 65536;
+    imagedata = (U8*)malloc(imagedatalen);
+
+    fseek(fi,8,SEEK_SET);
+    while(!feof(fi))
+    {
+	if(!png_read_chunk(&tagid, &len, &data, fi))
+	    break;
+	if(!strncmp(tagid, "IEND", 4)) {
+	    break;
+	}
+	if(!strncmp(tagid, "PLTE", 4)) {
+	    palette = data;
+	    palettelen = len/3;
+	    data = 0; //don't free data
+	    //printf("%d colors in palette\n", palettelen);
+	}
+	if(!strncmp(tagid, "tRNS", 4)) {
+	    if(header.mode == 3) {
+		alphapalette = data;
+		alphapalettelen = len;
+		data = 0; //don't free data
+		//printf("found %d alpha colors\n", alphapalettelen);
+	    }
+	}
+	if(!strncmp(tagid, "IDAT", 4)) {
+	    if(!zimagedata) {
+		zimagedatalen = len;
+		zimagedata = (U8*)malloc(len);
+		memcpy(zimagedata,data,len);
+	    } else {
+		zimagedata = (U8*)realloc(zimagedata, zimagedatalen+len);
+		memcpy(&zimagedata[zimagedatalen], data, len);
+		zimagedatalen += len;
+	    }
+	}
+	if(!strncmp(tagid, "tEXt", 4)) {
+	    /*int t;
+	    printf("Image Text: ");
+	    for(t=0;t<len;t++) {
+		if(data[t]>=32 && data[t]<128)
+		    printf("%c", data[t]);
+		else
+		    printf("?");
+	    }
+	    printf("\n");*/
+	}
+	if(data)
+	    free(data);
+    }
+    
+    if(!zimagedata || uncompress(imagedata, &imagedatalen, zimagedata, zimagedatalen) != Z_OK) {
+	printf("Couldn't uncompress %s!\n", sname);
+	if(zimagedata)
+	    free(zimagedata);
+	return 0;
+    }
+    free(zimagedata);
+    fclose(fi);
+
+    *destwidth = header.width;
+    *destheight = header.height;
+
+    if(header.mode == 6 || header.mode == 2)
+    {
+	U8*data2 = (U8*)malloc(header.width*header.height*4);
+	int i,s=0;
+	int x,y;
+	int pos=0;
+	*destdata = data2;
+	for(y=0;y<header.height;y++) {
+	    int mode = imagedata[pos++]; //filter mode
+	    U8*src;
+	    U8*dest;
+	    U8*old;
+	    dest = &data2[(y*header.width)*4];
+
+	    if(header.bpp == 8)
+	    {
+		/* one byte per pixel */
+		src = &imagedata[pos];
+		pos+=header.width*(header.mode==6?4:3);
+	    } else {
+		/* not implemented yet */
+		printf("ERROR: bpp:%d\n", header.bpp);
+		free(data2);
+		return 0;
+	    }
+
+	    if(!y) {
+		memset(data2,0,header.width*4);
+		old = &data2[y*header.width*4];
+	    } else {
+		old = &data2[(y-1)*header.width*4];
+	    }
+	    if(header.mode == 6)
+		applyfilter4(mode, src, old, dest, header.width);
+	    else // header.mode = 2
+		applyfilter3(mode, src, old, dest, header.width);
+	}
+    } else if(header.mode == 0 || header.mode == 3) {
+	COL*rgba = 0;
+	U8*data2 = (U8*)malloc(header.width*header.height*4);
+	U8*tmpline = (U8*)malloc(header.width+1);
+	U8*destline = (U8*)malloc(header.width+1);
+	int i,x,y;
+	int pos=0;
+	
+	*destdata = data2;
+	
+	if(header.mode == 0) { // grayscale palette
+            int mult = (0x1ff>>header.bpp);
+	    palettelen = 1<<header.bpp;
+	    rgba = (COL*)malloc(palettelen*sizeof(COL));
+	    for(i=0;i<palettelen;i++) {
+		rgba[i].a = 255;
+		rgba[i].r = i*mult;
+		rgba[i].g = i*mult;
+		rgba[i].b = i*mult;
+	    }
+	} else {
+	    if(!palette) {
+		fprintf(stderr, "Error: No palette found!\n");
+		exit(1);
+	    }
+	    rgba = (COL*)malloc(palettelen*4);
+	    /* 24->32 bit conversion */
+	    for(i=0;i<palettelen;i++) {
+		rgba[i].r = palette[i*3+0];
+		rgba[i].g = palette[i*3+1];
+		rgba[i].b = palette[i*3+2];
+		if(alphapalette && i<alphapalettelen) {
+		    rgba[i].a = alphapalette[i];
+		    /*rgba[i].r = ((int)rgba[i].r*rgba[i].a)/255;
+		    rgba[i].g = ((int)rgba[i].g*rgba[i].a)/255;
+		    rgba[i].b = ((int)rgba[i].b*rgba[i].a)/255;*/
+		} else {
+		    rgba[i].a = 255;
+		}
+	    }
+	}
+
+	for(y=0;y<header.height;y++) {
+	    int mode = imagedata[pos++]; //filter mode
+	    int x;
+	    U8*old;
+	    U8*src;
+	    src = &imagedata[pos];
+	    if(header.bpp == 8) {
+		pos+=header.width;
+	    } else {
+		int x,s=0;
+		int bitpos = 0;
+		U32 v = (1<<header.bpp)-1;
+		for(x=0;x<header.width;x++) {
+		    U32 r = src[s/8]<<8 | 
+			    src[s/8+1];
+		    int t;
+		    tmpline[x] = (r>>(16-header.bpp-(s&7)))&v;
+		    s+=header.bpp;
+		}
+		src = tmpline;
+		pos+=(header.width*header.bpp+7)/8;
+	    }
+
+	    if(!y) {
+		memset(destline,0,header.width);
+		old = &destline[y*header.width];
+	    } else {
+		old = tmpline;
+	    }
+	    applyfilter1(mode, src, old, destline, header.width);
+	    memcpy(tmpline,destline,header.width);
+	    for(x=0;x<header.width;x++) {
+		*(COL*)&data2[y*header.width*4+x*4+0] = rgba[destline[x]];
+	    }
+	}
+	free(tmpline);
+	free(destline);
+	free(rgba);
+    } else {
+	printf("expected PNG mode to be 2, 3 or 6 (is:%d)\n", header.mode);
+	return 0;
+    }
+
+    return 1;
+}
+
+static U32 mycrc32;
+
+static U32*crc32_table = 0;
+static void make_crc32_table(void)
+{
+  int t;
+  if(crc32_table) 
+      return;
+  crc32_table = (U32*)malloc(1024);
+
+  for (t = 0; t < 256; t++) {
+    U32 c = t;
+    int s;
+    for (s = 0; s < 8; s++) {
+      c = (0xedb88320L*(c&1)) ^ (c >> 1);
+    }
+    crc32_table[t] = c;
+  }
+}
+static inline void png_write_byte(FILE*fi, U8 byte)
+{
+    fwrite(&byte,1,1,fi);
+    mycrc32 = crc32_table[(mycrc32 ^ byte) & 0xff] ^ (mycrc32 >> 8);
+}
+static void png_start_chunk(FILE*fi, char*type, int len)
+{
+    U8 mytype[4]={0,0,0,0};
+    U32 mylen = REVERSESWAP32(len);
+    memcpy(mytype,type,strlen(type));
+    fwrite(&mylen, 4, 1, fi);
+    mycrc32=0xffffffff;
+    png_write_byte(fi,mytype[0]);
+    png_write_byte(fi,mytype[1]);
+    png_write_byte(fi,mytype[2]);
+    png_write_byte(fi,mytype[3]);
+}
+static void png_write_bytes(FILE*fi, U8*bytes, int len)
+{
+    int t;
+    for(t=0;t<len;t++)
+	png_write_byte(fi,bytes[t]);
+}
+static void png_write_dword(FILE*fi, U32 dword)
+{
+    png_write_byte(fi,dword>>24);
+    png_write_byte(fi,dword>>16);
+    png_write_byte(fi,dword>>8);
+    png_write_byte(fi,dword);
+}
+static void png_end_chunk(FILE*fi)
+{
+    U32 tmp = REVERSESWAP32((mycrc32^0xffffffff));
+    fwrite(&tmp,4,1,fi);
+}
+
+void writePNG(char*filename, unsigned char*data, int width, int height)
+{
+    FILE*fi;
+    int crc;
+    int t;
+    U8 format;
+    U8 tmp;
+    U8* data2=0;
+    U8* data3=0;
+    U32 datalen;
+    U32 datalen2;
+    U32 datalen3;
+    U8 head[] = {137,80,78,71,13,10,26,10}; // PNG header
+    int cols;
+    char alpha = 1;
+    int pos = 0;
+    int error;
+    U32 tmp32;
+    int bpp;
+    int ret;
+
+    make_crc32_table();
+
+    bpp = 32;
+    cols = 0;
+    format = 5;
+
+    datalen = (width*height*bpp/8+cols*8);
+    
+    fi = fopen(filename, "wb");
+    if(!fi) {
+	perror("open");
+	return;
+    }
+    fwrite(head,sizeof(head),1,fi);     
+
+    png_start_chunk(fi, "IHDR", 13);
+     png_write_dword(fi,width);
+     png_write_dword(fi,height);
+     png_write_byte(fi,8);
+     if(format == 3)
+     png_write_byte(fi,3); //indexed
+     else if(format == 5 && alpha==0)
+     png_write_byte(fi,2); //rgb
+     else if(format == 5 && alpha==1)
+     png_write_byte(fi,6); //rgba
+     else return;
+
+     png_write_byte(fi,0); //compression mode
+     png_write_byte(fi,0); //filter mode
+     png_write_byte(fi,0); //interlace mode
+    png_end_chunk(fi);
+   
+/*    if(format == 3) {
+	png_start_chunk(fi, "PLTE", 768);
+	 
+	 for(t=0;t<256;t++) {
+	     png_write_byte(fi,palette[t].r);
+	     png_write_byte(fi,palette[t].g);
+	     png_write_byte(fi,palette[t].b);
+	 }
+	png_end_chunk(fi);
+    }*/
+    {
+	int pos2 = 0;
+	int x,y;
+	int srcwidth = width * (bpp/8);
+	datalen3 = (width*4+5)*height;
+	data3 = (U8*)malloc(datalen3);
+	for(y=0;y<height;y++)
+	{
+	   data3[pos2++]=0; //filter type
+	   for(x=0;x<width;x++) {
+	       data3[pos2++]=data[pos+1];
+	       data3[pos2++]=data[pos+2];
+	       data3[pos2++]=data[pos+3];
+	       data3[pos2++]=data[pos+0]; //alpha
+	       pos+=4;
+	   }
+	   pos+=((srcwidth+3)&~3)-srcwidth; //align
+	}
+	datalen3=pos2;
+    }
+
+    datalen2 = datalen3;
+    data2 = malloc(datalen2);
+
+    if((ret = compress (data2, &datalen2, data3, datalen3)) != Z_OK) {
+	fprintf(stderr, "zlib error in pic %d\n", ret);
+	return;
+    }
+    png_start_chunk(fi, "IDAT", datalen2);
+    png_write_bytes(fi,data2,datalen2);
+    png_end_chunk(fi);
+    png_start_chunk(fi, "IEND", 0);
+    png_end_chunk(fi);
+
+    free(data);
+    free(data2);
+    free(data3);
+}
diff --git a/lib/png.h b/lib/png.h
new file mode 100644
index 0000000..95ababb
--- /dev/null
+++ b/lib/png.h
@@ -0,0 +1,35 @@
+/* png.h
+
+   Copyright (c) 2003/2004/2005 Matthias Kramm <kramm@quiss.org>
+
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 2 of the License, or
+   (at your option) any later version.
+
+   This program 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 General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program; if not, write to the Free Software
+   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA */
+
+#ifndef __png_h__
+#define __png_h__
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+int getPNG(char*sname, int*destwidth, int*destheight, unsigned char**destdata);
+int getPNGdimensions(char*sname, int*destwidth, int*destheight);
+void writePNG(char*filename, unsigned char*data, int width, int height);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif
+
-- 
1.7.10.4