MFC 用 Direct2D 显示图像到 Picture Control 中
2016年第一天，新年快乐！！！
由于一直跟视频这块打交道，对于图像编解码和显示等方面都有所研究。最近遇到一个性能要求比较高的应用，原本的GDI绘图导致到线程负荷比较重，造成整个系统不稳定，因而生了要用Direct2D来取代的念头。经过一番研究后发现，Direct2D原来是这么的简单方便，而效率也比GDI有了显著的提升。废话不多说，下面还是直接上代码吧。
本人一开始是在网上搜的一份代码，后来改了很多才将代码调好，并修复了一些内存泄露的bug，所以如有雷同绝非偶然，但不雷同之处便是其中要紧之处。
主要的代码都封装成了BaseFactory类，其代码如下：
BaseFactory.h
// THIS CODE AND INFORMATION IS PROVIDED "AS IS" WITHOUT WARRANTY OF
// ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING BUT NOT LIMITED TO
// THE IMPLIED WARRANTIES OF MERCHANTABILITY AND/OR FITNESS FOR A
// PARTICULAR PURPOSE.
//
// Copyright (c) Microsoft Corporation. All rights reserved
//
#pragma once
// Modify the following defines if you have to target a platform prior to the ones specified below.
// Refer to MSDN for the latest info on corresponding values for different platforms.
#ifndef WINVER // Allow use of features specific to Windows 7 or later.
#define WINVER 0x0700 // Change this to the appropriate value to target other versions of Windows.
#endif
#ifndef _WIN32_WINNT // Allow use of features specific to Windows 7 or later.
#define _WIN32_WINNT 0x0700 // Change this to the appropriate value to target other versions of Windows.
#endif
#ifndef UNICODE
#define UNICODE
#endif
// Exclude rarely-used items from Windows headers.
#include <d2d1.h>
//#include <d2d1helper.h>
/******************************************************************
* *
* Macros *
* *
******************************************************************/
template<class Interface>
inline void SafeRelease(
Interface **ppInterfaceToRelease
)
{
if (*ppInterfaceToRelease != NULL)
{
(*ppInterfaceToRelease)->Release();
(*ppInterfaceToRelease) = NULL;
}
}
#ifndef Assert
#if defined( DEBUG ) || defined( _DEBUG )
#define Assert(b) do {if (!(b)) {OutputDebugStringA("Assert: " #b "\n");}} while(0)
#else
#define Assert(b)
#endif //DEBUG || _DEBUG
#endif
#ifndef HINST_THISCOMPONENT
EXTERN_C IMAGE_DOS_HEADER __ImageBase;
#define HINST_THISCOMPONENT ((HINSTANCE)&__ImageBase)
#endif
class BaseFactory
{
public:
BaseFactory(void);
~BaseFactory(void);
bool Initialize(HWND hwnd,int width,int height);
private:
// Initialize device-dependent resources.
HRESULT CreateDeviceResources();
// Release device-dependent resource.
public:
//绘图
void OnRender(char *data);
void DiscardDeviceResources();
//图片信息
int imgwidth;
int imgheight;
D2D1_RECT_U imgrect;
char *imgdata;
private:
RECT rc;
HWND m_hwnd;
ID2D1Factory* m_pDirect2dFactory;
ID2D1HwndRenderTarget* m_pRenderTarget;
ID2D1Bitmap* m_pBitmap;
};
BaseFactory.cpp
#include "stdafx.h"
#include "BaseFactory.h"
BaseFactory::BaseFactory(void)
{
}
bool BaseFactory::Initialize(HWND hwnd, int width, int height)
{
imgheight = height;
imgwidth = width;
m_hwnd = hwnd;
m_pRenderTarget = nullptr;
m_pBitmap = nullptr;
CreateDeviceResources();
return true;
}
BaseFactory::~BaseFactory(void)
{
}
HRESULT BaseFactory::CreateDeviceResources()
{
D2D1CreateFactory(D2D1_FACTORY_TYPE_SINGLE_THREADED, &m_pDirect2dFactory);
HRESULT hr = S_OK;
if (!m_pRenderTarget)
{
GetClientRect(m_hwnd, &rc);
D2D1_SIZE_U size = D2D1::SizeU
(
rc.right-rc.left,
rc.bottom-rc.top
);
// Create a Direct2D render target.
hr = m_pDirect2dFactory->CreateHwndRenderTarget(
D2D1::RenderTargetProperties(),
D2D1::HwndRenderTargetProperties(m_hwnd, size, D2D1_PRESENT_OPTIONS_IMMEDIATELY),//第三个参数设置不等待垂直同步，默认垂直同步时最高刷新频率为显卡刷新频率，一般60FPS
&m_pRenderTarget
);
//创建位图
D2D1_SIZE_U imgsize= D2D1::SizeU(imgwidth, imgheight);
D2D1_PIXEL_FORMAT pixelFormat = //位图像素格式描述
{
DXGI_FORMAT_B8G8R8A8_UNORM, //该参数设置图像数据区的像素格式，现为RGBA，可根据需要改为别的格式，只是后面的数据拷贝要做相应的调整
D2D1_ALPHA_MODE_IGNORE
};
D2D1_BITMAP_PROPERTIES prop = //位图具体信息描述
{
pixelFormat,
imgsize.width,
imgsize.height
};
long pitch = imgsize.width*4;
imgdata = new char[imgsize.width * imgsize.height * 4];
memset(imgdata, 0, imgsize.width * imgsize.height * 4);
m_pRenderTarget->SetAntialiasMode(D2D1_ANTIALIAS_MODE_PER_PRIMITIVE);//设置图像为抗锯齿模式
m_pRenderTarget->CreateBitmap(imgsize, imgdata, pitch, &prop, &m_pBitmap);
imgrect.left = 0;
imgrect.right = imgwidth;
imgrect.top = 0;
imgrect.bottom = imgheight;
}
return hr;
}
void BaseFactory::DiscardDeviceResources()
{
delete[] imgdata;
SafeRelease(&m_pRenderTarget);
m_pDirect2dFactory->Release();
m_pBitmap->Release();
}
void BaseFactory::OnRender(char *data)//绘制图形到指定控件中
{
m_pRenderTarget->BeginDraw();//跟显示刷新频率有关系
m_pBitmap->CopyFromMemory(&imgrect, data, imgwidth * 4);
m_pRenderTarget->DrawBitmap(m_pBitmap, D2D1::RectF(0, 0, rc.right - rc.left, rc.bottom - rc.top));//该矩形大小会受到"更改文本、应用和其他项目的大小:xxx%"的影响
m_pRenderTarget->EndDraw();
}
将两个文件添加到工程，在需要的时候将 BaseFactory.h 包含进去即可。对了，由于用到了Diretc2D，所以需要将d2d1.lib给链接上去。
完成了上面的工作，在需要用到的地方加上下面代码即可，代码中调用了OpenCV库来读取并解码图片，所以给Direct2D的只是指向图像RGBA数据区的指针而已，假设不想如此，也可自作修改。
char *filename = "1.jpg";//图像路径
IplImage* img = cvLoadImage(filename);
BaseFactory* m_BaseFactory = new BaseFactory();//创建Direct2D工厂对象
HWND m_hWnd = GetDlgItem(IDC_STATIC_SHOW)->GetSafeHwnd();//IDC_STATIC_SHOW为Picture Control的ID
m_BaseFactory->Initialize(m_hWnd, img->width, img->height);//初始化
//将rgb转为rgba
char *data = new char[img->width*img->height * 4];
for (size_t row = 0; row < img->height; row++)
for (size_t col = 0; col < img->width; col++)
{
int point = col * 3 + row*img->width * 3;
int pointrbga = col * 4 + row*img->width * 4;
data[pointrbga + 0] = img->imageData[point + 0];
data[pointrbga + 1] = img->imageData[point + 1];
data[pointrbga + 2] = img->imageData[point + 2];
}
int i = 480;
long time = clock();
while (i--)
{
//将图像绘制到控件中
m_BaseFactory->OnRender(data);
}
printf("D2D花费时间%dms\n", clock() - time);
printf("刷新频率%lf张/s\n", 480 / (double(clock() - time) / 1000));
//释放对象，回收内存
if (m_BaseFactory != NULL)
{
m_BaseFactory->DiscardDeviceResources();
delete m_BaseFactory;
m_BaseFactory = NULL;
}
cvReleaseImage(&img);
delete[]data;