C++ GDI+;闪烁
所以我想制作一个便宜的Gyazo(截屏工具) 问题是光标坐标在闪烁,我怎样才能防止呢?我已经尝试了C++ GDI+;闪烁,c++,winapi,gdi+,flicker,double-buffering,C++,Winapi,Gdi+,Flicker,Double Buffering,所以我想制作一个便宜的Gyazo(截屏工具) 问题是光标坐标在闪烁,我怎样才能防止呢?我已经尝试了WM_ERASEBKGND,但是没有任何帮助 我的代码还有其他问题吗?有什么不好的做法/技巧吗 #include <Windows.h> #include <string> #include <gdiplus.h> #pragma comment (lib, "Gdiplus.lib") // Store the "screenshot" when first
WM_ERASEBKGND
,但是没有任何帮助
我的代码还有其他问题吗?有什么不好的做法/技巧吗
#include <Windows.h>
#include <string>
#include <gdiplus.h>
#pragma comment (lib, "Gdiplus.lib")
// Store the "screenshot" when first launching the program
HBITMAP hbm;
// This draws the cursor coordinates close to the cursor
void DrawCursorCoords(Gdiplus::Graphics &graphics, Gdiplus::Bitmap &bitmap, Gdiplus::Color c)
{
POINT cursorPos;
GetCursorPos(&cursorPos);
std::wstring x = std::to_wstring(cursorPos.x);
std::wstring y = std::to_wstring(cursorPos.y);
graphics.DrawString(x.c_str(), x.length(), &Gdiplus::Font(L"Consolas", 16), Gdiplus::PointF(cursorPos.x, cursorPos.y), &Gdiplus::SolidBrush(c));
graphics.DrawString(y.c_str(), y.length(), &Gdiplus::Font(L"Consolas", 16), Gdiplus::PointF(cursorPos.x, cursorPos.y + 16), &Gdiplus::SolidBrush(c));
}
// Paint our stuff
void Paint(HDC &hdc)
{
Gdiplus::Graphics * gfx = new Gdiplus::Graphics(hdc);
Gdiplus::Bitmap * bmap = new Gdiplus::Bitmap(hbm, (HPALETTE)0);
gfx->DrawImage(bmap, 0, 0, GetSystemMetrics(SM_CXSCREEN), GetSystemMetrics(SM_CYSCREEN));
if (GetAsyncKeyState(VK_LBUTTON))
DrawCursorCoords(*gfx, *bmap, Gdiplus::Color::Red);
else
DrawCursorCoords(*gfx, *bmap, Gdiplus::Color::Green);
delete gfx;
delete bmap;
}
LRESULT APIENTRY WndProc(HWND hwnd, UINT message, WPARAM wParam, LPARAM lParam)
{
PAINTSTRUCT ps;
HDC hdc;
switch (message)
{
case WM_PAINT:
{
hdc = BeginPaint(hwnd, &ps);
Paint(hdc);
EndPaint(hwnd, &ps);
break;
}
case WM_TIMER:
{
InvalidateRect(hwnd, NULL, NULL);
break;
}
case WM_CLOSE:
{
DestroyWindow(hwnd);
break;
}
case WM_RBUTTONUP:
case WM_KEYDOWN:
case WM_DESTROY:
{
PostQuitMessage(0);
break;
}
case WM_ERASEBKGND: return TRUE;
default: return DefWindowProc(hwnd, message, wParam, lParam);
}
return 0L;
}
BOOL InitInstance(HINSTANCE hInstance, int nCmdShow)
{
char className[] = "_className";
HWND hwnd = NULL;
WNDCLASS wc;
wc.style = 0;
wc.lpfnWndProc = WndProc;
wc.cbClsExtra = 0;
wc.cbWndExtra = 0;
wc.hInstance = hInstance;
wc.hIcon = NULL;
wc.hCursor = LoadCursor(NULL, IDC_CROSS);
wc.hbrBackground = (HBRUSH)(0);
wc.lpszMenuName = NULL;
wc.lpszClassName = className;
if (RegisterClass(&wc))
{
hwnd = CreateWindowEx(
WS_EX_TRANSPARENT | WS_EX_TOPMOST,
className, NULL,
WS_POPUP | WS_VISIBLE,
0, 0, GetSystemMetrics(SM_CXSCREEN), GetSystemMetrics(SM_CYSCREEN),
NULL, NULL, hInstance, NULL);
}
if (!hwnd) return FALSE;
ShowWindow(hwnd, SW_SHOW);
UpdateWindow(hwnd);
SetTimer(hwnd, 1, 1, NULL);
return TRUE;
}
int APIENTRY WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance, LPSTR lpCmdLine, int nCmdShow)
{
// Take a screenshot and store it to 'hbm'
HWND hwndDesktop = GetDesktopWindow();
HDC hdcDesktop = GetDC(hwndDesktop);
HDC hdcCapture = CreateCompatibleDC(hdcDesktop);
hbm = CreateCompatibleBitmap(hdcDesktop, GetSystemMetrics(SM_CXSCREEN), GetSystemMetrics(SM_CYSCREEN));
SelectObject(hdcCapture, hbm);
BitBlt(hdcCapture, 0, 0, GetSystemMetrics(SM_CXSCREEN), GetSystemMetrics(SM_CYSCREEN),
hdcDesktop, 0, 0, SRCCOPY | CAPTUREBLT);
// Start GDI+
Gdiplus::GdiplusStartupInput gdiplusStartupInput;
ULONG_PTR gdiplusToken;
Gdiplus::GdiplusStartup(&gdiplusToken, &gdiplusStartupInput, NULL);
MSG msg;
InitInstance(hInstance, nCmdShow);
while (GetMessage(&msg, NULL, 0, 0) > 0)
{
TranslateMessage(&msg);
DispatchMessage(&msg);
}
Gdiplus::GdiplusShutdown(gdiplusToken);
DeleteObject(hbm);
ReleaseDC(hwndDesktop, hdcDesktop);
DeleteDC(hdcDesktop);
DeleteDC(hdcCapture);
return msg.wParam;
}
#包括
#包括
#包括
#pragma注释(lib,“Gdiplus.lib”)
//首次启动程序时存储“屏幕截图”
HBITMAP-hbm;
//这将在靠近光标的位置绘制光标坐标
void DrawCursorCoords(Gdiplus::Graphics&Graphics,Gdiplus::Bitmap&Bitmap,Gdiplus::Color c)
{
点游标;
GetCursorPos(&cursorPos);
std::wstring x=std::to_wstring(cursorPos.x);
std::wstring y=std::towstring(cursorPos.y);
graphics.DrawString(x.c_str(),x.length(),&Gdiplus::Font(L“Consolas”,16),Gdiplus::PointF(cursorPos.x,cursorPos.y),&Gdiplus::SolidBrush(c));
graphics.DrawString(y.c_str(),y.length(),&Gdiplus::Font(L“Consolas”,16),Gdiplus::PointF(cursorPos.x,cursorPos.y+16),&Gdiplus::SolidBrush(c));
}
//油漆我们的东西
空隙涂料(HDC和HDC)
{
Gdiplus::Graphics*gfx=新的Gdiplus::Graphics(hdc);
Gdiplus::Bitmap*bmap=新的Gdiplus::Bitmap(hbm,(HPALETTE)0);
gfx->DrawImage(bmap,0,0,GetSystemMetrics(SM_CXSCREEN),GetSystemMetrics(SM_CXSCREEN));
if(GetAsyncKeyState(VK_LBUTTON))
DrawCursorCoords(*gfx,*bmap,Gdiplus::颜色::红色);
其他的
DrawCursorCoords(*gfx,*bmap,Gdiplus::Color::Green);
删除gfx;
删除bmap;
}
LRESULT APIENTRY WndProc(HWND HWND,UINT消息,WPARAM WPARAM,LPARAM LPARAM)
{
PAINTSTRUCT-ps;
HDC-HDC;
开关(信息)
{
案例WM_油漆:
{
hdc=开始喷漆(hwnd和ps);
涂料(hdc);
端漆(hwnd和ps);
打破
}
案例WM_计时器:
{
无效(hwnd,NULL,NULL);
打破
}
案例WM_结束:
{
窗口(hwnd);
打破
}
案例WM_RBUTTONUP:
案例WM_键控:
案例WM_销毁:
{
PostQuitMessage(0);
打破
}
案例WM_ERASEBKGND:返回TRUE;
默认值:返回DefWindowProc(hwnd、message、wParam、lParam);
}
返回0升;
}
BOOL InitInstance(HINSTANCE HINSTANCE,int nCmdShow)
{
char className[]=“_className”;
HWND HWND=NULL;
WNDCLASS wc;
wc.style=0;
wc.lpfnWndProc=WndProc;
wc.cbClsExtra=0;
wc.cbWndExtra=0;
wc.hInstance=hInstance;
wc.hIcon=NULL;
wc.hCursor=LoadCursor(空,IDC_交叉);
wc.hbrBackground=(HBRUSH)(0);
wc.lpszMenuName=NULL;
wc.lpszClassName=className;
if(注册表类(&wc))
{
hwnd=CreateWindowEx(
WS_EX_透明| WS_EX_顶部,
类名,NULL,
WS|U弹出窗口| WS|U可见,
0,0,GetSystemMetrics(SM_CXSCREEN),GetSystemMetrics(SM_CYSCREEN),
NULL,NULL,hInstance,NULL);
}
如果(!hwnd)返回FALSE;
展示窗口(hwnd、SW_展示);
更新窗口(hwnd);
设置计时器(hwnd,1,1,NULL);
返回TRUE;
}
int APICENTRY WinMain(HINSTANCE HINSTANCE、HINSTANCE hPrevInstance、LPSTR lpCmdLine、int nCmdShow)
{
//拍摄屏幕截图并将其存储到“hbm”
HWND hwndDesktop=GetDesktopWindow();
HDC hdcDesktop=GetDC(hwndDesktop);
HDC hdcCapture=CreateCompatibleDC(hdcDesktop);
hbm=CreateCompatibleBitmap(hdcDesktop、GetSystemMetrics(SM_CXSCREEN)、GetSystemMetrics(SM_CYSCREEN));
选择对象(hdcCapture,hbm);
BitBlt(hdcCapture,0,0,GetSystemMetrics(SM_CXSCREEN),GetSystemMetrics(SM_CYSCREEN),
hdcDesktop,0,0,SRCCOPY | CAPTUREBLT);
//启动GDI+
Gdiplus::GdiplusStartupInput GdiplusStartupInput;
ULONG_PTR gdiplusToken;
Gdiplus::GdiplusStartup(&gdiplusToken,&gdiplusStartupInput,NULL);
味精;
InitInstance(hInstance、nCmdShow);
while(GetMessage(&msg,NULL,0,0)>0)
{
翻译信息(&msg);
发送消息(&msg);
}
Gdiplus::GdiplusShutdown(gdiplusToken);
删除对象(hbm);
ReleaseDC(hwndDesktop、hdcDesktop);
DeleteDC(hdcDesktop);
DeleteDC(hdcCapture);
返回msg.wParam;
}
您需要使用缓冲区进行绘制。您可以创建内存dc,或使用BeginBufferedPaint
:
#include <uxtheme.h>
#pragma comment (lib, "uxtheme.lib")
...
case WM_PAINT:
{
hdc = BeginPaint(hwnd, &ps);
RECT rc;
GetClientRect(hwnd, &rc);
HDC memdc;
auto hbuff = BeginBufferedPaint(hdc, &rc, BPBF_COMPATIBLEBITMAP, NULL, &memdc);
Paint(memdc);
EndBufferedPaint(hbuff, TRUE);
EndPaint(hwnd, &ps);
break;
}
您可能还想使用SetLayeredWindowAttributes
浏览WS_EX_LAYERED
标志,这将创建一个透明窗口,显示其下方的桌面。对于简单的文本绘制,它实际上不需要GDI+
此外,Gdiplus的大多数类都有不同的构造函数,这样可以避免使用new
/delete
。例如:
void DrawCursorCoords(Gdiplus::Graphics &graphics, Gdiplus::Bitmap&, Gdiplus::Color c)
{
POINT cursorPos;
GetCursorPos(&cursorPos);
std::wstring x = std::to_wstring(cursorPos.x);
std::wstring y = std::to_wstring(cursorPos.y);
Gdiplus::Font font(L"Consolas", (Gdiplus::REAL)16);
Gdiplus::SolidBrush brush(c);
graphics.DrawString(x.c_str(), (int)x.length(), &font,
Gdiplus::PointF((Gdiplus::REAL)cursorPos.x, (Gdiplus::REAL)cursorPos.y),
&brush);
graphics.DrawString(y.c_str(), (int)y.length(), &font,
Gdiplus::PointF((Gdiplus::REAL)cursorPos.x, (Gdiplus::REAL)(cursorPos.y + 16)),
&brush);
}
void Paint(HDC &hdc)
{
Gdiplus::Graphics gfx(hdc);
Gdiplus::Bitmap bmap(hbm, (HPALETTE)0);
gfx.DrawImage(&bmap, 0, 0,
GetSystemMetrics(SM_CXSCREEN), GetSystemMetrics(SM_CYSCREEN));
if(GetAsyncKeyState(VK_LBUTTON))
DrawCursorCoords(gfx, bmap, (Gdiplus::Color)Gdiplus::Color::Red);
else
DrawCursorCoords(gfx, bmap, (Gdiplus::Color)Gdiplus::Color::Green);
}
或者您可以声明Gdiplus::Bitmap*bmap=new-Gdiplus::Bitmap(hbm,NULL)
这将创建一个hbm
的副本,因此您可以通过将bmap
声明为全局,并仅创建/销毁一次,从而使此操作更加高效
还应按如下方式还原旧位图:
hbm = CreateCompatibleBitmap(...)
auto oldbitmap = SelectObject(hdcCapture, hbm);
...
//cleanup
SelectObject(hdcCapture, oldbitmap);
DeleteObject(hbm);
尽管如果不还原旧位图,windows仍将尝试修复错误,因此大多数情况下不会出现任何问题。导致闪烁的是DrawImage()调用。它覆盖先前绘制的文本,然后DrawCursorCoords()将其放回原处。需要双缓冲来消除它,谷歌“c++gdi+双缓冲”才能获得好的点击率。@JesperJuhl:所以。。。您建议使用哪种C++设备来实现一个平台无关的GUI?如果你不能说出其中一个,那么是什么让你选择正确的工具成为“坏习惯”@IInspectable我的第一选择是Qt、SFML和SDL。很可能是Qt。希望这算是“命名一个”。@JesperJuhl:因此,与其为只针对Windows的工具编写特定于Windows的代码,不如建议添加另一个依赖项,现在将其设置为特定于Windows和特定于库?最近有没有将过度工程推广到最佳实践中?此外,Qt是一个玩具,它永远不会是专业的
ReleaseDC(hwndDesktop, hdcDesktop);
DeleteDC(hdcDesktop); //<- not required
hbm = CreateCompatibleBitmap(...)
SelectObject(hdcCapture, hbm);
...
DeleteObject(hbm);
hbm = CreateCompatibleBitmap(...)
auto oldbitmap = SelectObject(hdcCapture, hbm);
...
//cleanup
SelectObject(hdcCapture, oldbitmap);
DeleteObject(hbm);