add support of JPEG by using libjpeg

include/nana/config.hpp

@@ -87,6 +87,14 @@
 	#define NANA_LIBPNG	//Comment it to use libpng from operating system.
 #endif
 
+///////////////////
+//Support for JPEG
+//	Define the NANA_ENABLE_JPEG to enable the support of JPEG.
+//
+//#define NANA_ENABLE_JPEG	//!
+#if defined(NANA_ENABLE_JPEG)
+	#define NANA_LIBJPEG	//Comment this whole line to use libjpeg from operating system.
+#endif
 
 
 #endif	//NANA_CONFIG_HPP

source/paint/detail/image_jpeg.hpp

@@ -0,0 +1,95 @@
+#ifndef NANA_PAINT_DETAIL_IMAGE_JPEG_HPP
+#define NANA_PAINT_DETAIL_IMAGE_JPEG_HPP
+
+#include "image_pixbuf.hpp"
+
+//Separate the libpng from the package that system provides.
+#if defined(NANA_LIBJPEG)
+	#include <nana_extrlib/jpeglib.h>
+#else
+	#include <jpeglib.h>
+#endif
+
+#include <stdio.h>
+
+namespace nana
+{
+	namespace paint{	namespace detail{
+
+		class image_jpeg
+			: public basic_image_pixbuf
+		{
+			struct error_mgr
+			{
+				struct ::jpeg_error_mgr pub;
+				jmp_buf	setjmp_buf;
+			};
+		public:
+			bool open(const nana::char_t* jpeg_file) override
+			{
+#ifdef NANA_UNICODE
+				FILE * fp = ::fopen(static_cast<std::string>(nana::charset(jpeg_file)).c_str(), "rb");
+#else
+				FILE* fp = ::fopen(jpeg_file, "rb");
+#endif
+				if(nullptr == fp) return false;
+
+				bool is_opened = false;
+
+				struct ::jpeg_decompress_struct jdstru;
+				error_mgr	jerr;
+
+				jdstru.err = ::jpeg_std_error(&jerr.pub);
+				jerr.pub.error_exit = _m_error_handler;
+
+				if (!setjmp(jerr.setjmp_buf))
+				{
+					::jpeg_create_decompress(&jdstru);
+
+					::jpeg_stdio_src(&jdstru, fp);
+
+					::jpeg_read_header(&jdstru, true);	//Reject a tables-only JPEG file as an error
+
+					::jpeg_start_decompress(&jdstru);
+
+					//JSAMPLEs per row in output buffer
+					auto row_stride = jdstru.output_width * jdstru.output_components;
+
+					pixbuf_.open(jdstru.output_width, jdstru.output_height);
+
+					auto row_buf = jdstru.mem->alloc_sarray(reinterpret_cast<j_common_ptr>(&jdstru), JPOOL_IMAGE, row_stride, 1);
+
+					while (jdstru.output_scanline < jdstru.output_height)
+					{
+						::jpeg_read_scanlines(&jdstru, row_buf, 1);
+
+						pixbuf_.fill_row(jdstru.output_scanline - 1, reinterpret_cast<unsigned char*>(*row_buf), row_stride, jdstru.output_components * 8);
+					}
+
+					jpeg_finish_decompress(&jdstru);
+				}
+
+				::jpeg_destroy_decompress(&jdstru);
+				::fclose(fp);
+				return is_opened;
+			}
+
+			bool open(const void* data, std::size_t bytes) override
+			{
+				throw std::logic_error("JPEG is not supported for raw data buffer");
+				return false;
+			}
+		private:
+			static void _m_error_handler(::j_common_ptr jdstru)
+			{
+				auto err_ptr = reinterpret_cast<error_mgr*>(jdstru->err);
+
+				err_ptr->pub.output_message(jdstru);
+				longjmp(err_ptr->setjmp_buf, 1);
+			}
+		};
+	}//end namespace detail
+	}//end namespace paint
+}//end namespace nana
+
+#endif

source/paint/image.cpp

@@ -21,6 +21,9 @@
 #include <nana/paint/detail/image_impl_interface.hpp>
 #include <nana/paint/pixel_buffer.hpp>
 
+#if defined(NANA_ENABLE_JPEG)
+#include "detail/image_jpeg.hpp"
+#endif
 
 #if defined(NANA_ENABLE_PNG)
 	#include "detail/image_png.hpp"