Make libpng optional

CMakeLists.txt

@@ -2,6 +2,8 @@ cmake_minimum_required (VERSION 2.6)
 
 project(mcpelauncher-client LANGUAGES CXX ASM)
 
+find_package(PNG)
+
 git_commit_hash(${CMAKE_CURRENT_SOURCE_DIR} CLIENT_GIT_COMMIT_HASH)
 configure_file(src/build_info.h.in ${CMAKE_CURRENT_BINARY_DIR}/build_info/build_info.h)
 
@@ -20,5 +22,11 @@ else()
     target_sources(mcpelauncher-client PRIVATE src/cpuid.cpp src/cpuid.h src/xbox_shutdown_patch.cpp src/xbox_shutdown_patch.h src/xbox_shutdown_patch.s src/texel_aa_patch.cpp src/texel_aa_patch.h)
 endif()
 
+if (PNG_FOUND)
+    target_compile_definitions(mcpelauncher-client PRIVATE HAS_LIBPNG)
+    target_include_directories(mcpelauncher-client PRIVATE ${PNG_INCLUDE_DIRS})
+    target_link_libraries(mcpelauncher-client ${PNG_LIBRARIES})
+endif()
+
 install(TARGETS mcpelauncher-client RUNTIME COMPONENT mcpelauncher-client DESTINATION bin)
 include(CPackSettings.cmake)

src/JNIBinding.cpp

@@ -10,7 +10,9 @@
 #include "client_app_platform.h"
 #include "xbox_live_game_interface.h"
 #include "xbox_live_helper.h"
+#ifdef HAS_LIBPNG
 #include <png.h>
+#endif
 #include <file_picker_factory.h>
 #include <hybris/dlfcn.h>
 
@@ -362,6 +364,7 @@ void com::mojang::minecraftpe::MainActivity::postScreenshotToFacebook(JNIEnv *en
 }
 
 jnivm::Array<jint>* com::mojang::minecraftpe::MainActivity::getImageData(JNIEnv *env, jnivm::Object<java::lang::String>* arg0) {
+#ifdef HAS_LIBPNG
     uint8_t header[8];
     FILE *fp = fopen(arg0->value->str.data(), "rb");
     if(fp) {
@@ -399,6 +402,13 @@ jnivm::Array<jint>* com::mojang::minecraftpe::MainActivity::getImageData(JNIEnv
         ret->length = 2;
         return ret;
     }
+#else
+    auto ret = new jnivm::Array<jint>();
+    ret->cl = 0;
+    ret->value = new jint[20] { 0 };
+    ret->length = 2;
+    return ret;
+#endif
 }
 
 jnivm::Array<jbyte>* com::mojang::minecraftpe::MainActivity::getFileDataBytes(JNIEnv *env, jnivm::Object<java::lang::String>* arg0) {