implemented type 3 transparency.

diff --git a/src/png2swf.c b/src/png2swf.c
index 8a10871..4736939 100644 (file)
--- a/src/png2swf.c
+++ b/src/png2swf.c
@@ -343,6 +343,8 @@ TAG *MovieAddFrame(SWF * swf, TAG * t, char *sname, int id)
     unsigned long int zimagedatalen=0;
     U8*palette = 0;
     int palettelen = 0;
+    U8*alphapalette = 0;
+    int alphapalettelen = 0;
     struct png_header header;
     int bypp;
 
@@ -377,10 +379,19 @@ TAG *MovieAddFrame(SWF * swf, TAG * t, char *sname, int id)
        if(!strncmp(tagid, "PLTE", 4)) {
            palette = data;
            palettelen = len/3;
-           data = 0;
+           data = 0; //don't free data
            if(VERBOSE(2))
                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
+               if(VERBOSE(2))
+                   printf("found %d alpha colors\n", alphapalettelen);
+           }
+       }
        if(!strncmp(tagid, "IDAT", 4)) {
            if(!zimagedata) {
                zimagedatalen = len;
@@ -404,7 +415,11 @@ TAG *MovieAddFrame(SWF * swf, TAG * t, char *sname, int id)
     }
     free(zimagedata);
 
-    t = swf_InsertTag(t, ST_DEFINEBITSLOSSLESS);
+    if(alphapalette)
+       t = swf_InsertTag(t, ST_DEFINEBITSLOSSLESS2);
+    else
+       t = swf_InsertTag(t, ST_DEFINEBITSLOSSLESS);
+
     swf_SetU16(t, id);         // id
     if(header.mode == 2) {
        U8*data2 = malloc(header.width*header.height*4);
@@ -456,8 +471,20 @@ TAG *MovieAddFrame(SWF * swf, TAG * t, char *sname, int id)
            rgba[i].r = palette[i*3+0];
            rgba[i].g = palette[i*3+1];
            rgba[i].b = palette[i*3+2];
-           rgba[i].a = 255;
+           if(alphapalette && i<alphapalettelen) {
+               rgba[i].a = alphapalette[i];
+               if(alphapalette[i] == 0) {
+                   /* if the color is fully transparent, it doesn't matter
+                      what it's rgb values are. furthermore, all Flash 
+                      players up to Flash 5 can't deal with anything beyond
+                      one transparent color with value (00,00,00,00). */
+                   rgba[i].r = rgba[i].g = rgba[i].b = 0;
+               }
+           } else {
+               rgba[i].a = 255;
+           }
        }
+
        for(y=0;y<header.height;y++) {
            int mode = imagedata[pos++]; //filter mode
            U8*old;