D2D引擎与GDI\GDI+绘制效果对比

本例主要是对比D2D和GDI在绘制文字、线条的区别，以及D2D与GDI+在绘制图片时的区别。

D2D是基于COM组件开发的，使用前的CoInitialize(NULL)是必须的；另外，GDI+的初始化GdiplusStartup（）也别忘了。

废话少说，完整代码如下：

// D2DDemo.cpp : 定义应用程序的入口点。
//

#include "stdafx.h"
#include "D2DDemo.h"
#include <D2D1.h>
#include <DWrite.h>
#pragma comment(lib, "D2D1")
#pragma comment(lib, "DWrite")
#include <atlbase.h>
#include <atlcom.h>
#include <wincodec.h>
#pragma comment(lib, "windowscodecs")
#include <GdiPlus.h>
#pragma comment(lib, "GdiPlus")
using namespace Gdiplus;


#define MAX_LOADSTRING 100
// 全局变量:
HINSTANCE hInst;								// 当前实例
TCHAR szTitle[MAX_LOADSTRING];					// 标题栏文本
TCHAR szWindowClass[MAX_LOADSTRING];			// 主窗口类名

// 此代码模块中包含的函数的前向声明:
ATOM				MyRegisterClass(HINSTANCE hInstance);
BOOL				InitInstance(HINSTANCE, int);
LRESULT CALLBACK	WndProc(HWND, UINT, WPARAM, LPARAM);
INT_PTR CALLBACK	About(HWND, UINT, WPARAM, LPARAM);
BOOL				InitD2DResource();
BOOL				InitDeviceResource(HWND hWnd);
void				D2DDraw();
BOOL				OnCreate(HWND hWnd);
HRESULT				LoadBitmapFromFile(
						   ID2D1RenderTarget *pRenderTarget,
						   IWICImagingFactory *pIWICFactory,
						   PCWSTR uri,
						   UINT destinationWidth,
						   UINT destinationHeight,
						   ID2D1Bitmap **ppBitmap
						   );
//这里来定义全局变量
CComPtr<ID2D1Factory>			g_pD2d1Factory;
CComPtr<IDWriteFactory>			g_pDWriteFactory;
CComPtr<IDWriteTextFormat>		g_pDWriteFormat;
CComPtr<ID2D1HwndRenderTarget>	g_pD2D1HwndRender;
CComPtr<ID2D1GdiInteropRenderTarget>	g_pD2DGdiRender;
CComPtr<IWICImagingFactory>		g_pWicImageFactory;
CComPtr<ID2D1Bitmap>			g_pBkImage;
LOGFONT g_logFont;
HFONT	g_hTextFont	= NULL;
#define FREE_COM_PTR(x)	{ if (x) { x->Release(); x = NULL; } }

int APIENTRY _tWinMain(HINSTANCE hInstance,
                     HINSTANCE hPrevInstance,
                     LPTSTR    lpCmdLine,
                     int       nCmdShow)
{
	UNREFERENCED_PARAMETER(hPrevInstance);
	UNREFERENCED_PARAMETER(lpCmdLine);
	HRESULT hr = CoInitialize(NULL);
	ULONG_PTR ptr;
	GdiplusStartupInput	input;
	GdiplusStartup(&ptr, &input, NULL);
 	// TODO: 在此放置代码。
	MSG msg;
	HACCEL hAccelTable;
	memset(&g_logFont, 0, sizeof(LOGFONT));
	g_logFont.lfHeight	= 40;
	g_logFont.lfWidth	= 0;
	g_logFont.lfWeight	= FW_NORMAL;
	g_logFont.lfCharSet	= DEFAULT_CHARSET;
	g_logFont.lfOutPrecision	= OUT_DEFAULT_PRECIS;
	g_logFont.lfClipPrecision	= CLIP_DEFAULT_PRECIS;
	g_logFont.lfQuality			= DEFAULT_QUALITY;
	g_logFont.lfPitchAndFamily	= DEFAULT_PITCH|FF_SWISS;
	wcscpy(g_logFont.lfFaceName, L"微软雅黑");