From afd1e274fd0a21d50ae88dfe45cc0db18eedb97e Mon Sep 17 00:00:00 2001
From: Pavel Krajcevski <pavel@cs.unc.edu>
Date: Sun, 26 Aug 2012 20:31:41 -0400
Subject: [PATCH] Add support for cmake to look for libpng and then add the
 proper files if available.

---
 IO/CMakeLists.txt     |  9 +++++++++
 IO/ImageFile.cpp      |  6 +++++-
 IO/ImageLoader.h.in   |  2 ++
 IO/ImageLoaderPNG.cpp | 14 ++++++++++++++
 IO/ImageLoaderPNG.h   |  6 +++---
 5 files changed, 33 insertions(+), 4 deletions(-)
 create mode 100644 IO/ImageLoaderPNG.cpp

diff --git a/IO/CMakeLists.txt b/IO/CMakeLists.txt
index e62b223..89ced9d 100644
--- a/IO/CMakeLists.txt
+++ b/IO/CMakeLists.txt
@@ -8,6 +8,15 @@ SET( HEADERS
 	ImageFile.h
 )
 
+FIND_PACKAGE( PNG )
+IF( PNG_FOUND )
+	INCLUDE_DIRECTORIES( ${PNG_INCLUDE_DIR} )
+	TARGET_LINK_LIBRARIES( ${PNG_LIBRARY} )
+
+	SET( SOURCES ${SOURCES} ImageLoaderPNG.cpp )
+	SET( HEADERS ${HEADERS} ImageLoaderPNG.h )
+ENDIF()
+
 CONFIGURE_FILE(
 	"ImageLoader.h.in"
 	"ImageLoader.h"
diff --git a/IO/ImageFile.cpp b/IO/ImageFile.cpp
index 00ee9a4..19d9e75 100644
--- a/IO/ImageFile.cpp
+++ b/IO/ImageFile.cpp
@@ -1,5 +1,9 @@
-#include "ImageFile.h"
 #include <string.h>
+#include "ImageFile.h"
+
+#ifdef PNG_FOUND
+#  include "ImageLoaderPNG.h"
+#endif
 
 ImageFile::ImageFile(const char *filename) : 
   m_PixelData(0),
diff --git a/IO/ImageLoader.h.in b/IO/ImageLoader.h.in
index 4ce6473..9b54d9b 100644
--- a/IO/ImageLoader.h.in
+++ b/IO/ImageLoader.h.in
@@ -43,4 +43,6 @@ class ImageLoader {
   unsigned char * GetAlphaPixelData() const { return m_AlphaData; }
 };
 
+#cmakedefine PNG_FOUND
+
 #endif // _IMAGE_LOADER_H_
diff --git a/IO/ImageLoaderPNG.cpp b/IO/ImageLoaderPNG.cpp
new file mode 100644
index 0000000..9c8f8a6
--- /dev/null
+++ b/IO/ImageLoaderPNG.cpp
@@ -0,0 +1,14 @@
+#include "ImageLoaderPNG.h"
+
+#include <png.h>
+
+ImageLoaderPNG::ImageLoaderPNG(const unsigned char *rawData) 
+  : ImageLoader(rawData)
+{
+}
+
+ImageLoaderPNG::~ImageLoaderPNG() {
+}
+
+void ImageLoaderPNG::ReadData() {
+}
diff --git a/IO/ImageLoaderPNG.h b/IO/ImageLoaderPNG.h
index d2bf7cf..dfb80e0 100644
--- a/IO/ImageLoaderPNG.h
+++ b/IO/ImageLoaderPNG.h
@@ -5,10 +5,10 @@
 
 class ImageLoaderPNG : public ImageLoader {
  public:
-  ImageLoader(const unsigned char *rawData);
-  virtual ~ImageLoader();
+  ImageLoaderPNG(const unsigned char *rawData);
+  virtual ~ImageLoaderPNG();
 
-  void ReadData();
+  virtual void ReadData();
 };
 
 #endif // _IMAGE_LOADER_H_