Added libpng based png loading

meson.build

@@ -33,6 +33,10 @@ if get_option('log') == true
     message('Enable Log')
 endif
 
+if get_option('png') == true
+    config_h.set10('THORVG_PNG_LOADER_SUPPORT', true)
+endif
+
 configure_file(
     output: 'config.h',
     configuration: config_h

meson_options.txt

@@ -33,6 +33,11 @@ option('examples',
     value: false,
     description: 'Enable building examples')
 
+option('png',
+   type: 'boolean',
+   value: false,
+   description: 'Enable libpng based png loading')
+
 option('test',
    type: 'boolean',
    value: false,

src/lib/tvgLoaderMgr.cpp

@@ -24,6 +24,11 @@
 #ifdef THORVG_SVG_LOADER_SUPPORT
     #include "tvgSvgLoader.h"
 #endif
+
+#ifdef THORVG_PNG_LOADER_SUPPORT
+    #include "tvgPngLoader.h"
+#endif
+
 #include "tvgRawLoader.h"
 
 /************************************************************************/
@@ -39,6 +44,12 @@ static Loader* _find(FileType type)
         case FileType::Svg: {
 #ifdef THORVG_SVG_LOADER_SUPPORT
             return new SvgLoader;
+#endif
+            break;
+        }
+        case FileType::Png: {
+#ifdef THORVG_PNG_LOADER_SUPPORT
+            return new PngLoader;
 #endif
             break;
         }
@@ -58,6 +69,7 @@ static Loader* _find(const string& path)
 {
     auto ext = path.substr(path.find_last_of(".") + 1);
     if (!ext.compare("svg")) return _find(FileType::Svg);
+    if (!ext.compare("png")) return _find(FileType::Png);
     return nullptr;
 }
 

src/lib/tvgLoaderMgr.h

@@ -24,7 +24,7 @@
 
 #include "tvgLoader.h"
 
-enum class FileType { Svg = 0, Raw, Unknown };
+enum class FileType { Svg = 0, Raw, Png, Unknown };
 
 struct LoaderMgr
 {

src/loaders/meson.build

@@ -5,6 +5,10 @@ if get_option('loaders').contains('svg') == true
     message('Enable SVG Loader')
 endif
 
+if get_option('png') == true
+    subdir('png')
+endif
+
 subdir('raw')
 
 loader_dep = declare_dependency(

src/loaders/png/meson.build

@@ -0,0 +1,9 @@
+source_file = [
+   'tvgPngLoader.h',
+   'tvgPngLoader.cpp',
+]
+
+subloader_dep += [declare_dependency(
+    include_directories : include_directories('.'),
+    sources : source_file
+)]

src/loaders/png/tvgPngLoader.cpp

@@ -0,0 +1,52 @@
+#include <fstream>
+#include <string>
+#include "tvgLoaderMgr.h"
+#include "tvgPngLoader.h"
+// #include "png.h"
+
+PngLoader::~PngLoader()
+{
+    if (content) {
+        free((void*)content);
+        content = nullptr;
+    }
+}
+
+bool PngLoader::open(const string& path)
+{
+    png_image image;
+    image.version = PNG_IMAGE_VERSION;
+    image.opaque = NULL;
+
+    if (!png_image_begin_read_from_file(&image, path.c_str())) return false;
+    w = image.width;
+    h = image.height;
+    vw = w;
+    vh = h;
+    png_bytep buffer;
+    image.format = PNG_FORMAT_BGRA;
+    buffer = static_cast<png_bytep>(malloc(PNG_IMAGE_SIZE(image)));
+    if (!buffer) {
+        // out of memory, only time when libpng doesnt free its data
+        png_image_free(&image);
+        return false;
+    }
+    if (!png_image_finish_read(&image, NULL, buffer, 0, NULL)) return false;
+    content = reinterpret_cast<uint32_t*>(buffer);
+    return true;
+}
+
+bool PngLoader::read()
+{
+    return true;
+}
+
+bool PngLoader::close()
+{
+    return true;
+}
+
+const uint32_t* PngLoader::pixels()
+{
+    return this->content;
+}

src/loaders/png/tvgPngLoader.h

@@ -0,0 +1,22 @@
+#ifndef _TVG_PNG_LOADER_H_
+#define _TVG_PNG_LOADER_H_
+
+#include <png.h>
+
+class PngLoader : public Loader
+{
+public:
+    const uint32_t* content = nullptr;
+
+    ~PngLoader();
+
+    using Loader::open;
+    bool open(const string& path) override;
+    bool read() override;
+    bool close() override;
+
+    const uint32_t* pixels() override;
+};
+
+
+#endif //_TVG_PNG_LOADER_H_

src/meson.build

@@ -19,6 +19,12 @@ subdir('bindings')
 thread_dep = meson.get_compiler('cpp').find_library('pthread')
 thorvg_lib_dep = [common_dep, loader_dep, binding_dep, thread_dep]
 
+if get_option('png') == true
+    message('Enable libpng based png loading')
+    png_dep = meson.get_compiler('cpp').find_library('libpng')
+    thorvg_lib_dep += png_dep
+endif
+
 thorvg_lib = library(
 	'thorvg',
 	include_directories    : headers,