add SK_ENABLE_LIBPNG to force reference to PNG codec

git-svn-id: http://skia.googlecode.com/svn/trunk@550 2bbb7eff-a529-9590-31e7-b0007b416f81

3 files changed, 33 insertions, 7 deletions

diff --git a/src/images/SkImageDecoder_Factory.cpp b/src/images/SkImageDecoder_Factory.cpp
index bd81d1fc1d..e7c71e52c9 100644
--- a/src/images/SkImageDecoder_Factory.cpp
+++ b/src/images/SkImageDecoder_Factory.cpp
@@ -24,10 +24,15 @@ typedef SkTRegistry<SkImageDecoder*, SkStream*> DecodeReg;
 
 template DecodeReg* DecodeReg::gHead;
 
+#ifdef SK_ENABLE_LIBPNG
+    extern SkImageDecoder* sk_libpng_dfactory(SkStream*);
+#endif
+
 SkImageDecoder* SkImageDecoder::Factory(SkStream* stream) {
+    SkImageDecoder* codec = NULL;
     const DecodeReg* curr = DecodeReg::Head();
     while (curr) {
-        SkImageDecoder* codec = curr->factory()(stream);
+        codec = curr->factory()(stream);
         // we rewind here, because we promise later when we call "decode", that
         // the stream will be at its beginning.
         stream->rewind();
@@ -36,6 +41,13 @@ SkImageDecoder* SkImageDecoder::Factory(SkStream* stream) {
         }
         curr = curr->next();
     }
+#ifdef SK_ENABLE_LIBPNG
+    codec = sk_libpng_dfactory(stream);
+    stream->rewind();
+    if (codec) {
+        return codec;
+    }
+#endif
     return NULL;
 }
 
diff --git a/src/images/SkImageDecoder_libpng.cpp b/src/images/SkImageDecoder_libpng.cpp
index 3548fc8393..267c066a65 100644
--- a/src/images/SkImageDecoder_libpng.cpp
+++ b/src/images/SkImageDecoder_libpng.cpp
@@ -845,7 +845,12 @@ bool SkPNGImageEncoder::onEncode(SkWStream* stream, const SkBitmap& bitmap,
 
 #include "SkTRegistry.h"
 
-static SkImageDecoder* DFactory(SkStream* stream) {
+#ifdef SK_ENABLE_LIBPNG
+    SkImageDecoder* sk_libpng_dfactory(SkStream*);
+    SkImageEncoder* sk_libpng_efactory(SkImageEncoder::Type);
+#endif
+
+SkImageDecoder* sk_libpng_dfactory(SkStream* stream) {
     char buf[PNG_BYTES_TO_CHECK];
     if (stream->read(buf, PNG_BYTES_TO_CHECK) == PNG_BYTES_TO_CHECK &&
         !png_sig_cmp((png_bytep) buf, (png_size_t)0, PNG_BYTES_TO_CHECK)) {
@@ -854,9 +859,9 @@ static SkImageDecoder* DFactory(SkStream* stream) {
     return NULL;
 }
 
-static SkImageEncoder* EFactory(SkImageEncoder::Type t) {
+SkImageEncoder* sk_libpng_efactory(SkImageEncoder::Type t) {
     return (SkImageEncoder::kPNG_Type == t) ? SkNEW(SkPNGImageEncoder) : NULL;
 }
 
-static SkTRegistry<SkImageEncoder*, SkImageEncoder::Type> gEReg(EFactory);
-static SkTRegistry<SkImageDecoder*, SkStream*> gDReg(DFactory);
+static SkTRegistry<SkImageEncoder*, SkImageEncoder::Type> gEReg(sk_libpng_efactory);
+static SkTRegistry<SkImageDecoder*, SkStream*> gDReg(sk_libpng_dfactory);
diff --git a/src/images/SkImageEncoder_Factory.cpp b/src/images/SkImageEncoder_Factory.cpp
index d673167523..0bb4d1aed9 100644
--- a/src/images/SkImageEncoder_Factory.cpp
+++ b/src/images/SkImageEncoder_Factory.cpp
@@ -21,15 +21,24 @@ typedef SkTRegistry<SkImageEncoder*, SkImageEncoder::Type> EncodeReg;
 
 template EncodeReg* EncodeReg::gHead;
 
+#ifdef SK_ENABLE_LIBPNG
+    extern SkImageEncoder* sk_libpng_efactory(SkImageEncoder::Type);
+#endif
+
 SkImageEncoder* SkImageEncoder::Create(Type t) {
+    SkImageEncoder* codec = NULL;
     const EncodeReg* curr = EncodeReg::Head();
     while (curr) {
-        SkImageEncoder* codec = curr->factory()(t);
-        if (codec) {
+        if ((codec = curr->factory()(t)) != NULL) {
             return codec;
         }
         curr = curr->next();
     }
+#ifdef SK_ENABLE_LIBPNG
+    if ((codec = sk_libpng_efactory(t)) != NULL) {
+        return codec;
+    }
+#endif
     return NULL;
 }