Swap red / blue and output twicebgra2x

1 files changed, 19 insertions, 0 deletions

diff --git a/decodepng.c b/decodepng.c
index 907be9a..5d75bc3 100644
--- a/decodepng.c
+++ b/decodepng.c
@@ -2,6 +2,23 @@
 #include <stdint.h>
 #include "lodepng/lodepng.h"
 
+static inline void rgbSwap(unsigned char*buf)
+{
+  unsigned char t;
+  t=buf[0];
+  buf[0]=buf[2];
+  buf[2]=t;
+  buf[3]=0;
+}
+
+static void rgbSwapImage(unsigned char*buf,unsigned len)
+{
+  for(unsigned i=0;i<len;i+=4)
+  {
+    rgbSwap(buf+i);
+  }
+}
+
 int main(int argc, char *argv[])
 {
   if(argc < 2)
@@ -28,6 +45,8 @@ int main(int argc, char *argv[])
     return 1;
   }
   
+  rgbSwapImage(image,imageLength);
+  fwrite(image, 1, imageLength, stdout);
   fwrite(image, 1, imageLength, stdout);
   fflush(stdout);