implemented filter bytes.

diff --git a/src/png2swf.c b/src/png2swf.c
index 52a442f..0e584e3 100644 (file)
--- a/src/png2swf.c
+++ b/src/png2swf.c
@@ -147,7 +147,19 @@ int png_read_header(FILE*fi, struct png_header*header)
            c = data[10];     // compression mode (0)
            f = data[11];     // filter mode (0)
            i = data[12];     // interlace mode (0)
-           printf("%08xx%08x %d %d %d %d %d\n",header->width, header->height, a,b,c,f,i);
+           if(c!=0) {
+               fprintf(stderr, "Compression mode %d not supported!\n", c);
+               exit(1);
+           }
+           if(f!=0) {
+               fprintf(stderr, "Filter mode %d not supported!\n", f);
+               exit(1);
+           }
+           if(i!=0) {
+               fprintf(stderr, "Interlace mode %d not supported!\n", i);
+               exit(1);
+           }
+           printf("%dx%d %d %d %d %d %d\n",header->width, header->height, a,b,c,f,i);
            header->bpp = a;
            header->mode = b;
            return 1;
@@ -159,6 +171,102 @@ int png_read_header(FILE*fi, struct png_header*header)
     return 0;
 }
 
+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 applyfilter(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;
+       }
+    }    
+
+}
+
 TAG *MovieAddFrame(SWF * swf, TAG * t, char *sname, int id)
 {
     SHAPE *s;
@@ -230,16 +338,19 @@ TAG *MovieAddFrame(SWF * swf, TAG * t, char *sname, int id)
        int pos=0;
        /* 24->32 bit conversion */
        for(y=0;y<header.height;y++) {
-           pos++; // filter mode
-           for(x=0;x<header.width;x++) {
-               U8*src  = &imagedata[pos];
-               U8*dest = &data2[(y*header.width+x)*4];
-               dest[0] = 255;
-               dest[1] = src[0];
-               dest[2] = src[1];
-               dest[3] = src[2];
-               pos+=3;
+           int mode = imagedata[pos++]; //filter mode
+
+           U8*src = &imagedata[pos];
+           U8*dest = &data2[(y*header.width)*4];
+           U8*old;
+           if(!y) {
+               memset(data2,0,header.width*4);
+               old = &data2[y*header.width*4];
+           } else {
+               old = &data2[(y-1)*header.width*4];
            }
+           applyfilter(mode, src, old, dest, header.width);
+           pos+=header.width*3;
        }
        swf_SetLosslessBits(t, header.width, header.height, data2, BMF_32BIT);
        free(data2);
@@ -261,6 +372,10 @@ TAG *MovieAddFrame(SWF * swf, TAG * t, char *sname, int id)
            rgba[i].a = 255;
        }
        for(y=0;y<header.height;y++) {
+           int mode = imagedata[pos];
+           if(mode!=0) {
+               fprintf(stderr, "Warning: Filter mode %d\n", mode);
+           }
            pos++; //filter mode
            for(x=0;x<header.width;x++) {
                data2[y*header.width+x] =