X-Git-Url: http://git.asbjorn.biz/?a=blobdiff_plain;f=lib%2Fpng.c;h=f51715117343d024e6b36a4cabc8507abbc1e2ca;hb=5956b76b28e80a49abd7409520282edc5e11dfc0;hp=9669f89db27923a84eda9fa76a5122e8dc5d6713;hpb=61a17d8fd634fda91865af922cb5ca241408d0c3;p=swftools.git

diff --git a/lib/png.c b/lib/png.c
index 9669f89..f517151 100644
--- a/lib/png.c
+++ b/lib/png.c
@@ -30,21 +30,19 @@ 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;
+    unsigned char blen[4];
     if(destlen) *destlen=0;
     if(destdata) *destdata=0;
-    if(!fread(&len, 4, 1, fi)) {
+    if(!fread(&blen, 4, 1, fi)) {
 	return 0;
     }
     if(!fread(head, 4, 1, fi)) {
 	return 0;
     }
-    len = REVERSESWAP32(len);
+    len = blen[0]<<24|blen[1]<<16|blen[2]<<8|blen[3];
     if(destlen) *destlen = len;
     if(destdata) {
 	if(!len) {
@@ -68,8 +66,9 @@ int png_read_chunk(char (*head)[4], int*destlen, U8**destdata, FILE*fi)
 unsigned int png_get_dword(FILE*fi)
 {
     unsigned int a;
-    fread(&a,4,1,fi);
-    return REVERSESWAP32(a);
+    unsigned char b[4];
+    fread(&b,4,1,fi);
+    return b[0]<<24|b[1]<<16|b[2]<<8|b[3];
 }
 
 struct png_header
@@ -98,8 +97,8 @@ int png_read_header(FILE*fi, struct png_header*header)
 	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]);
+	    header->width = data[0]<<24|data[1]<<16|data[2]<<8|data[3];
+	    header->height = data[4]<<24|data[5]<<16|data[6]<<8|data[7];
 	    a = data[8];      // should be 8
 	    b = data[9];      // should be 3(indexed) or 2(rgb)
 
@@ -464,6 +463,8 @@ int getPNG(char*sname, int*destwidth, int*destheight, unsigned char**destdata)
     struct png_header header;
     int bypp;
     U8*data2 = 0;
+    U8 alphacolor[3];
+    int hasalphacolor=0;
 
     FILE *fi;
     U8 *scanline;
@@ -510,6 +511,16 @@ int getPNG(char*sname, int*destwidth, int*destheight, unsigned char**destdata)
 		alphapalettelen = len;
 		data = 0; //don't free data
 		//printf("found %d alpha colors\n", alphapalettelen);
+	    } else if(header.mode == 0 || header.mode == 2) {
+		int t;
+		if(header.mode == 2) {
+		    alphacolor[0] = data[1];
+		    alphacolor[1] = data[3];
+		    alphacolor[2] = data[5];
+		} else {
+		    alphacolor[0] = alphacolor[1] = alphacolor[2] = data[1];
+		}
+		hasalphacolor = 1;
 	    }
 	}
 	if(!strncmp(tagid, "IDAT", 4)) {
@@ -644,6 +655,10 @@ int getPNG(char*sname, int*destwidth, int*destheight, unsigned char**destdata)
 		rgba[i].r = i*mult;
 		rgba[i].g = i*mult;
 		rgba[i].b = i*mult;
+		if(hasalphacolor) {
+		    if(rgba[i].r == alphacolor[0])
+			rgba[i].a = 0;
+		}
 	    }
 	} else {
 	    if(!palette) {
@@ -664,6 +679,12 @@ int getPNG(char*sname, int*destwidth, int*destheight, unsigned char**destdata)
 		} else {
 		    rgba[i].a = 255;
 		}
+		if(hasalphacolor) {
+		    if(rgba[i].r == alphacolor[0] &&
+		       rgba[i].g == alphacolor[1] &&
+		       rgba[i].b == alphacolor[2])
+			rgba[i].a = 0;
+		}
 	    }
 	}
 
@@ -740,7 +761,11 @@ static inline void png_write_byte(FILE*fi, U8 byte)
 static void png_start_chunk(FILE*fi, char*type, int len)
 {
     U8 mytype[4]={0,0,0,0};
-    U32 mylen = REVERSESWAP32(len);
+    U8 mylen[4];
+    mylen[0] = len>>24;
+    mylen[1] = len>>16;
+    mylen[2] = len>>8;
+    mylen[3] = len;
     memcpy(mytype,type,strlen(type));
     fwrite(&mylen, 4, 1, fi);
     mycrc32=0xffffffff;
@@ -764,8 +789,13 @@ static void png_write_dword(FILE*fi, U32 dword)
 }
 static void png_end_chunk(FILE*fi)
 {
-    U32 tmp = REVERSESWAP32((mycrc32^0xffffffff));
-    fwrite(&tmp,4,1,fi);
+    U32 tmp = mycrc32^0xffffffff;
+    U8 tmp2[4];
+    tmp2[0] = tmp>>24;
+    tmp2[1] = tmp>>16;
+    tmp2[2] = tmp>>8;
+    tmp2[3] = tmp;
+    fwrite(&tmp2,4,1,fi);
 }
 
 void writePNG(char*filename, unsigned char*data, int width, int height)
@@ -853,7 +883,7 @@ void writePNG(char*filename, unsigned char*data, int width, int height)
     }
 
     datalen2 = datalen3;
-    data2 = malloc(datalen2);
+    data2 = (U8*)malloc(datalen2);
 
     if((ret = compress (data2, &datalen2, data3, datalen3)) != Z_OK) {
 	fprintf(stderr, "zlib error in pic %d\n", ret);