我要评论本文使用c++双缓存进行指定窗口截图。createdibsection创建应用程序可以直接写入的、与设备无关的位图(dib)，它提供内存中位图的指针，外部程序可以直接使用。
需要注意的是，printwindow方法能够抓取使用d3d渲染的窗口（例如excel、win10自带视频播放器），如果抓取普通窗口则会附带窗口阴影，可见窗口阴影是windows使用d3d渲染出来的。
1、printcapturehelper.h
#pragma once
#include <windows.h>
#include <string>
using std::string;
class printcapturehelper
{
public:
printcapturehelper();
virtual ~printcapturehelper();
bool init(const string& windowname);
bool init(hwnd hwnd);
void cleanup();
bool refreshwindow();
bool changewindowhandle(const string& windowname);
bool changewindowhandle(hwnd hwnd);
bool capture() const;
const rect& getwindowrect() const { return windowrect_; }
const rect& getclientrect() const { return clientrect_; }
int getbitmapdatasize() const { return bmpdatasize_; }
hbitmap getbitmap() const { return bitmap_; }
void* getbitmapaddress() const { return bitsptr_; }
private:
hwnd hwnd_;
hdc scrdc_;
hdc memdc_;
hbitmap bitmap_;
hbitmap oldbitmap_;
void* bitsptr_;
rect windowrect_;
rect clientrect_;
int bmpdatasize_;
};
2、printcapturehelper.cpp
#include "stdafx.h"
#include "printcapturehelper.h"
printcapturehelper::printcapturehelper()
: hwnd_(nullptr)
, scrdc_(nullptr)
, memdc_(nullptr)
, bitmap_(nullptr)
, oldbitmap_(nullptr)
, bitsptr_(nullptr)
, windowrect_{ 0, 0, 0, 0 }
, clientrect_{ 0, 0, 0, 0 }
, bmpdatasize_(0)
{
}
printcapturehelper::~printcapturehelper()
{
cleanup();
}
bool printcapturehelper::init(const string& windowname)
{
const auto handle = ::findwindowa(nullptr, windowname.c_str());
if (handle == nullptr)
{
return false;
}
return init(handle);
}
bool printcapturehelper::init(hwnd hwnd)
{
hwnd_ = hwnd;
//获取窗口大小
if (!::getwindowrect(hwnd_, &windowrect_) || !::getclientrect(hwnd_, &clientrect_))
{
return false;
}
const auto clientrectwidth = clientrect_.right - clientrect_.left;
const auto clientrectheight = clientrect_.bottom - clientrect_.top;
bmpdatasize_ = clientrectwidth * clientrectheight * 4;
//位图信息
bitmapinfo bitmapinfo;
bitmapinfo.bmiheader.bisize = sizeof(bitmapinfo);
bitmapinfo.bmiheader.biwidth = clientrectwidth;
bitmapinfo.bmiheader.biheight = clientrectheight;
bitmapinfo.bmiheader.biplanes = 1;
bitmapinfo.bmiheader.bibitcount = 32;
bitmapinfo.bmiheader.bisizeimage = clientrectwidth * clientrectheight;
bitmapinfo.bmiheader.bicompression = bi_rgb;
scrdc_ = ::getwindowdc(hwnd_);
memdc_ = ::createcompatibledc(scrdc_);
bitmap_ = ::createdibsection(scrdc_, &bitmapinfo, dib_rgb_colors, &bitsptr_, nullptr, 0);
if (bitmap_ == nullptr)
{
::deletedc(memdc_);
::releasedc(hwnd_, scrdc_);
return false;
}
oldbitmap_ = static_cast<hbitmap>(::selectobject(memdc_, bitmap_));
return true;
}
void printcapturehelper::cleanup()
{
if (bitmap_ == nullptr)
{
return;
}
//删除用过的对象
::selectobject(memdc_, oldbitmap_);
::deleteobject(bitmap_);
::deletedc(memdc_);
::releasedc(hwnd_, scrdc_);
hwnd_ = nullptr;
scrdc_ = nullptr;
memdc_ = nullptr;
bitmap_ = nullptr;
oldbitmap_ = nullptr;
}
bool printcapturehelper::refreshwindow()
{
const auto hwnd = hwnd_;
cleanup();
return init(hwnd);
}
bool printcapturehelper::changewindowhandle(const string& windowname)
{
cleanup();
return init(windowname);
}
bool printcapturehelper::changewindowhandle(hwnd hwnd)
{
cleanup();
return init(hwnd);
}
bool printcapturehelper::capture() const
{
if (bitmap_ == nullptr || memdc_ == nullptr || scrdc_ == nullptr)
{
return false;
}
const auto ret = ::printwindow(hwnd_, memdc_, pw_clientonly | pw_renderfullcontent);
return ret != 0;
}
以上就是c++ 使用printwindow实现窗口截图功能的详细内容，更多关于c++ 窗口截图的资料请关注移动技术网其它相关文章！
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