我有一个子类化的按钮,我希望它显示具有透明背景的位图。在互联网上搜索后,我发现您必须使用功能AlphaBlend(我尝试过此操作,但这也不起作用)。我也看到了这个bitmap transparency in Visual Studio 2013 C++线程,我尝试了这些步骤,但是我做不到。只要我可以使用带有透明背景图像的按钮,就可以使用GDI或GDI +。示例:
这是我的代码-我知道它很乱,但是请尝试一下,因为我正在尝试很多事情来使其正常工作(有很多复制和粘贴)
更新:这是代码再次出现,但没有所有赘肉地被修剪,是的,我确实在两个窗口上都尝试了WS_EX_LAYERED。
// CustomButton2.cpp : Defines the entry point for the application.
//
#include "framework.h"
#include "CustomButton2.h"
#include <commctrl.h>
#include <gdiplus.h>
#include <system_error>
#include "SkinClass/skin.h"
#define MAX_LOADSTRING 100
#define CRAPPY 567
#pragma comment(linker,"/manifestdependency:\"type='win32' name='Microsoft.Windows.Common-Controls' " "version='6.0.0.0' processorArchitecture='*' publicKeyToken='6595b64144ccf1df' language='*'\"")
// Global Variables:
HINSTANCE hInst; // current instance
WCHAR szTitle[MAX_LOADSTRING]; // The title bar text
WCHAR szWindowClass[MAX_LOADSTRING]; // the main window class name
const char g_szClassName[] = "MyClassName";
// Forward declarations of functions included in this code module:
ATOM MyRegisterClass(HINSTANCE hInstance);
void RegisterClass1(HINSTANCE);
LRESULT CALLBACK WndProc(HWND, UINT, WPARAM, LPARAM);
/// Turn given window into a layered window and load a bitmap from given resource ID
/// into it.
/// The window will be resized to fit the bitmap.
/// Bitmap must be 32bpp, top-down row order, premultiplied alpha.
///
/// \note For child windows, this requires Win 8 or newer OS
/// (and "supportedOS" element for Win 8 in application manifest)
///
/// \exception Throws std::system_error in case of any error.
void SetLayeredWindowFromBitmapResource(
HWND hwnd, UINT bitmapResourceId, HINSTANCE hInstance = nullptr)
{
// Enable "layered" mode for the child window. This enables full alpha channel
// transparency.
// GetWindowLong() won't reset the last error in case of success.
// As we can't judge from the return value of GetWindowLong() alone if
// the function was successful (0 may be returned even in case of
// success), we must reset the last error to reliably detect errors.
::SetLastError(0);
DWORD exStyle = ::GetWindowLong(hwnd, GWL_EXSTYLE);
if (!exStyle)
{
// NOTE: Call GetLastError() IMMEDIATELY when a function's return value
// indicates failure and it is documented that said function supports
// GetLastError().
// ANY other code (be it your own or library code) before the next line
// must be avoided as it may invalidate the last error value.
if (DWORD err = ::GetLastError())
throw std::system_error(static_cast<int>(err),
std::system_category(),
"SetLayeredWindowFromBitmapResource: Could not get extended window style");
}
// SetWindowLong() won't reset the last error in case of success.
// As we can't judge from the return value of GetWindowLong() alone if
// the function was successful (0 may be returned even in case of
// success), we must reset the last error to reliably detect errors.
::SetLastError(0);
if (!::SetWindowLong(hwnd, GWL_EXSTYLE, exStyle | WS_EX_LAYERED))
{
if (DWORD err = ::GetLastError())
throw std::system_error(static_cast<int>(err),
std::system_category(),
"SetLayeredWindowFromBitmapResource: Could not set extended window style");
}
// Use RAII ( https://en.wikipedia.org/wiki/Resource_acquisition_is_initialization )
// to cleanup resources even in case of exceptions.
// This greatly simplifies the code because now we don't have to manually cleanup the
// resources at every location in the code where we throw an exception.
struct Resources {
HBITMAP hImage = nullptr;
HGDIOBJ hOldImage = nullptr;
HDC hMemDC = nullptr;
// This destructor will be automatically called before the function
// SetLayeredWindowFromBitmapResource() returns aswell as any locations
// in the code where the "throw" keyword is used to throw an exception.
~Resources()
{
if (hMemDC)
{
if (hOldImage)
::SelectObject(hMemDC, hOldImage);
::DeleteDC(hMemDC);
}
if (hImage)
::DeleteObject(hImage);
}
} res;
// Make it possible to use nullptr as an argument for the hInstance parameter of
// this function. This means we will load the resources from the current executable
// (instead of another DLL).
if (!hInstance)
hInstance = ::GetModuleHandle(nullptr);
// Load bitmap with alpha channel from resource.
// Flag LR_CREATEDIBSECTION is required to create a device-independent bitmap that
// preserves the alpha channel.
res.hImage = reinterpret_cast<HBITMAP>(::LoadImage(
hInstance, MAKEINTRESOURCE(bitmapResourceId), IMAGE_BITMAP,
0, 0, LR_CREATEDIBSECTION));
if (!res.hImage)
{
DWORD err = ::GetLastError();
throw std::system_error(static_cast<int>(err),
std::system_category(),
"SetLayeredWindowFromBitmapResource: Could not load bitmap resource");
}
// Get bitmap information (width, height, etc.)
BITMAP imgInfo{ 0 };
if (!::GetObject(res.hImage, sizeof(imgInfo), &imgInfo))
{
DWORD err = ::GetLastError();
throw std::system_error(static_cast<int>(err),
std::system_category(),
"SetLayeredWindowFromBitmapResource: Could not get bitmap information");
}
if (imgInfo.bmBitsPixel != 32 || imgInfo.bmPlanes != 1)
{
// Use a constant error value here because this is our own error condition.
// Of course GetLastError() wouldn't return anything useful in this case.
DWORD err = ERROR_INVALID_DATA;
throw std::system_error(err, std::system_category(),
"SetLayeredWindowFromBitmapResource: bitmap must be 32 bpp, single plane");
}
// Create a memory DC that will be associated with the image.
// UpdateLayeredWindow() can't use image directly, it must be in a memory DC.
res.hMemDC = ::CreateCompatibleDC(nullptr);
if (!res.hMemDC)
{
DWORD err = ::GetLastError();
throw std::system_error(static_cast<int>(err),
std::system_category(),
"SetLayeredWindowFromBitmapResource: Could not create memory DC");
}
res.hOldImage = ::SelectObject(res.hMemDC, res.hImage);
if (!res.hOldImage)
{
DWORD err = ::GetLastError();
throw std::system_error(static_cast<int>(err),
std::system_category(),
"SetLayeredWindowFromBitmapResource: Could not select bitmap into memory DC");
}
// Assign the image to the child window, making it transparent.
SIZE size{ imgInfo.bmWidth, imgInfo.bmHeight };
POINT ptSrc{ 0, 0 };
BLENDFUNCTION blend{ AC_SRC_OVER, 0, 255, AC_SRC_ALPHA };
if (!::UpdateLayeredWindow(hwnd, nullptr, nullptr, &size, res.hMemDC, &ptSrc,
0, &blend, ULW_ALPHA))
{
DWORD err = ::GetLastError();
throw std::system_error(static_cast<int>(err),
std::system_category(),
"SetLayeredWindowFromBitmapResource: Could not update layered window");
}
// Destructor of res object will cleanup resources here!
}
int APIENTRY wWinMain(_In_ HINSTANCE hInstance,
_In_opt_ HINSTANCE hPrevInstance,
_In_ LPWSTR lpCmdLine,
_In_ int nCmdShow)
{
UNREFERENCED_PARAMETER(hPrevInstance);
UNREFERENCED_PARAMETER(lpCmdLine);
// TODO: Place code here.
RegisterClass1(hInstance);
HWND hWnd = CreateWindowExA(WS_EX_LAYERED, g_szClassName, "Scenes", WS_OVERLAPPEDWINDOW | WS_EX_LAYERED, CW_USEDEFAULT, CW_USEDEFAULT, CW_USEDEFAULT, CW_USEDEFAULT, NULL, NULL,
hInstance, NULL);
HWND hButton = CreateWindow(TEXT("BUTTON"), TEXT("START EDITING!"), WS_CHILD | WS_VISIBLE | BS_OWNERDRAW | WS_EX_LAYERED, 1, 1,228, 228,
hWnd, (HMENU)CRAPPY, NULL, NULL);
//SetLayeredWindowFromBitmapResource(hButton, ID_THECIRCLE, hInstance);
SetLayeredWindowAttributes(hWnd, 0, 249, LWA_ALPHA);
ShowWindow(hWnd, nCmdShow);
UpdateWindow(hWnd);
SetLayeredWindowFromBitmapResource(hButton, ID_THECIRCLE);
MSG msg;
// Main message loop:
while (GetMessage(&msg, nullptr, 0, 0))
{
TranslateMessage(&msg);
DispatchMessage(&msg);
}
return (int) msg.wParam;
}
//
// FUNCTION: RegisterClass1()
//
// PURPOSE: Registers the class
//
// COMMENTS:
//
//
//
//
void RegisterClass1(HINSTANCE hInstance) {
WNDCLASSEXA wc;
wc.cbSize = sizeof(WNDCLASSEX);
wc.cbClsExtra = 0;
wc.cbWndExtra = 0;
//wc.hbrBackground = (HBRUSH)(COLOR_WINDOW + 1);
wc.hbrBackground = CreateSolidBrush(RGB(255, 0, 0));
wc.hCursor = LoadCursor(NULL, IDC_ARROW);
wc.hIcon = LoadIcon(NULL, IDI_APPLICATION);
wc.hIconSm = LoadIcon(NULL, IDI_APPLICATION);
wc.hInstance = hInstance;
wc.lpfnWndProc = WndProc;
wc.lpszClassName = g_szClassName;
wc.lpszMenuName = "MENU";
wc.style = CS_HREDRAW | CS_VREDRAW;
if (!RegisterClassEx(&wc))
{
MessageBox(NULL, "Window Registration Failed!", "Error!",
MB_ICONEXCLAMATION | MB_OK);
}
}
//
// FUNCTION: WndProc(HWND, UINT, WPARAM, LPARAM)
//
// PURPOSE: Processes messages for the main window.
//
// WM_COMMAND - process the application menu
// WM_PAINT - Paint the main window
// WM_DESTROY - post a quit message and return
//
//
LRESULT CALLBACK WndProc(HWND hWnd, UINT message, WPARAM wParam, LPARAM lParam)
{
switch (message)
{
case WM_COMMAND:
{
int wmId = LOWORD(wParam);
// Parse the menu selections:
switch (wmId)
{
case IDM_ABOUT:
break;
case IDM_EXIT:
DestroyWindow(hWnd);
break;
default:
return DefWindowProc(hWnd, message, wParam, lParam);
}
}
break;
case WM_PAINT:
{
PAINTSTRUCT ps;
HDC hdc = BeginPaint(hWnd, &ps);
// TODO: Add any drawing code that uses hdc here...
EndPaint(hWnd, &ps);
}
break;
case WM_DESTROY:
PostQuitMessage(0);
break;
default:
return DefWindowProc(hWnd, message, wParam, lParam);
}
return 0;
}
从窗口8开始,WS_EX_LAYERED
可用于子控件。
方法:清单文件至少需要指定Windows 8兼容性(仅Windows 8支持子层。)。>
参考:Targeting your application for Windows
代码示例:(错误检查已删除)
// Test_CustomButton.cpp : Defines the entry point for the application. // #include "framework.h" #include "Test_CustomButton.h" #include <commctrl.h> #include <system_error> #pragma comment (lib,"Comctl32.lib") #define MAX_LOADSTRING 100 #define IDC_OWNERDRAWBUTTON 101 #define CRAPPY 567 // Global Variables: HINSTANCE hInst; // current instance WCHAR szTitle[MAX_LOADSTRING]; // The title bar text WCHAR szWindowClass[MAX_LOADSTRING]; // the main window class name // Forward declarations of functions included in this code module: ATOM MyRegisterClass(HINSTANCE hInstance); BOOL InitInstance(HINSTANCE, int); LRESULT CALLBACK WndProc(HWND, UINT, WPARAM, LPARAM); INT_PTR CALLBACK About(HWND, UINT, WPARAM, LPARAM); LRESULT CALLBACK OwnerDrawButtonProc(HWND hWnd, UINT uMsg, WPARAM wParam, LPARAM lParam, UINT_PTR uIdSubclass, DWORD_PTR dwRefData); void SetLayeredWindowFromBitmapResource( HWND hwnd, UINT bitmapResourceId, HINSTANCE hInstance = nullptr) { DWORD exStyle = ::GetWindowLong(hwnd, GWL_EXSTYLE); SetWindowLong(hwnd, GWL_EXSTYLE, exStyle | WS_EX_LAYERED); struct Resources { HBITMAP hImage = nullptr; HGDIOBJ hOldImage = nullptr; HDC hMemDC = nullptr; ~Resources() { if (hMemDC) { if (hOldImage) ::SelectObject(hMemDC, hOldImage); ::DeleteDC(hMemDC); } if (hImage) ::DeleteObject(hImage); } } res; if (!hInstance) hInstance = ::GetModuleHandle(nullptr); res.hImage = reinterpret_cast<HBITMAP>(::LoadImage( hInstance, MAKEINTRESOURCE(bitmapResourceId), IMAGE_BITMAP, 0, 0, LR_CREATEDIBSECTION)); BITMAP imgInfo{ 0 }; GetObject(res.hImage, sizeof(imgInfo), &imgInfo); res.hMemDC = ::CreateCompatibleDC(nullptr); res.hOldImage = ::SelectObject(res.hMemDC, res.hImage); // Assign the image to the child window, making it transparent. SIZE size{ imgInfo.bmWidth, imgInfo.bmHeight }; POINT ptSrc{ 0, 0 }; BLENDFUNCTION blend{ AC_SRC_OVER, 0, 200, AC_SRC_ALPHA }; UpdateLayeredWindow(hwnd, nullptr, nullptr, &size, res.hMemDC, &ptSrc, 0, &blend, ULW_ALPHA); // Destructor of res object will cleanup resources here! } int APIENTRY wWinMain(_In_ HINSTANCE hInstance, _In_opt_ HINSTANCE hPrevInstance, _In_ LPWSTR lpCmdLine, _In_ int nCmdShow) { UNREFERENCED_PARAMETER(hPrevInstance); UNREFERENCED_PARAMETER(lpCmdLine); LoadStringW(hInstance, IDS_APP_TITLE, szTitle, MAX_LOADSTRING); LoadStringW(hInstance, IDC_TESTCUSTOMBUTTON, szWindowClass, MAX_LOADSTRING); MyRegisterClass(hInstance); if (!InitInstance (hInstance, nCmdShow)) { return FALSE; } HACCEL hAccelTable = LoadAccelerators(hInstance, MAKEINTRESOURCE(IDC_TESTCUSTOMBUTTON)); MSG msg; while (GetMessage(&msg, nullptr, 0, 0)) { if (!TranslateAccelerator(msg.hwnd, hAccelTable, &msg)) { TranslateMessage(&msg); DispatchMessage(&msg); } } return (int) msg.wParam; } ATOM MyRegisterClass(HINSTANCE hInstance) { WNDCLASSEXW wcex; wcex.cbSize = sizeof(WNDCLASSEX); wcex.style = CS_HREDRAW | CS_VREDRAW; wcex.lpfnWndProc = WndProc; wcex.cbClsExtra = 0; wcex.cbWndExtra = 0; wcex.hInstance = hInstance; wcex.hIcon = LoadIcon(hInstance, MAKEINTRESOURCE(IDI_TESTCUSTOMBUTTON)); wcex.hCursor = LoadCursor(nullptr, IDC_ARROW); wcex.hbrBackground = (HBRUSH)(COLOR_WINDOW+1); wcex.lpszMenuName = MAKEINTRESOURCEW(IDC_TESTCUSTOMBUTTON); wcex.lpszClassName = szWindowClass; wcex.hIconSm = LoadIcon(wcex.hInstance, MAKEINTRESOURCE(IDI_SMALL)); return RegisterClassExW(&wcex); } BOOL InitInstance(HINSTANCE hInstance, int nCmdShow) { hInst = hInstance; // Store instance handle in our global variable HWND hWnd = CreateWindowW(szWindowClass, szTitle, WS_OVERLAPPEDWINDOW, CW_USEDEFAULT, 0, CW_USEDEFAULT, 0, nullptr, nullptr, hInstance, nullptr); ShowWindow(hWnd, nCmdShow); UpdateWindow(hWnd); if (!hWnd) { return FALSE; } ShowWindow(hWnd, nCmdShow); UpdateWindow(hWnd); return TRUE; } LRESULT CALLBACK WndProc(HWND hWnd, UINT message, WPARAM wParam, LPARAM lParam) { switch (message) { case WM_CREATE: { HWND hButton = CreateWindowEx(0, L"button", NULL, WS_CHILD | WS_VISIBLE | BS_OWNERDRAW, 150, 50, 80, 80, hWnd, (HMENU)IDC_OWNERDRAWBUTTON, hInst, NULL); SetWindowSubclass(hButton, &OwnerDrawButtonProc, IDC_OWNERDRAWBUTTON, 0); } break; case WM_COMMAND: { int wmId = LOWORD(wParam); // Parse the menu selections: switch (wmId) { case IDM_ABOUT: DialogBox(hInst, MAKEINTRESOURCE(IDD_ABOUTBOX), hWnd, About); break; case IDM_EXIT: DestroyWindow(hWnd); break; default: return DefWindowProc(hWnd, message, wParam, lParam); } } break; case WM_PAINT: { PAINTSTRUCT ps; HDC hdc = BeginPaint(hWnd, &ps); // Used be test HPEN hPen = CreatePen(PS_SOLID, 2, RGB(255, 0, 0)); SelectObject(hdc, hPen); MoveToEx(hdc, 150, 150, NULL); LineTo(hdc, 200, 60); LineTo(hdc, 250, 150); LineTo(hdc, 150, 150); EndPaint(hWnd, &ps); } break; case WM_DESTROY: PostQuitMessage(0); break; default: return DefWindowProc(hWnd, message, wParam, lParam); } return 0; } // Message handler for about box. INT_PTR CALLBACK About(HWND hDlg, UINT message, WPARAM wParam, LPARAM lParam) { UNREFERENCED_PARAMETER(lParam); switch (message) { case WM_INITDIALOG: return (INT_PTR)TRUE; case WM_COMMAND: if (LOWORD(wParam) == IDOK || LOWORD(wParam) == IDCANCEL) { EndDialog(hDlg, LOWORD(wParam)); return (INT_PTR)TRUE; } break; } return (INT_PTR)FALSE; } LRESULT CALLBACK OwnerDrawButtonProc(HWND hWnd, UINT uMsg, WPARAM wParam, LPARAM lParam, UINT_PTR uIdSubclass, DWORD_PTR dwRefData) { switch (uMsg) { case WM_PAINT: { RECT rc; PAINTSTRUCT ps; HDC hdc = BeginPaint(hWnd, &ps); SetLayeredWindowFromBitmapResource(hWnd, IDB_BITMAP1); EndPaint(hWnd, &ps); return 0; } case WM_NCDESTROY: RemoveWindowSubclass(hWnd, &OwnerDrawButtonProc, 1); break; } return DefSubclassProc(hWnd, uMsg, wParam, lParam); }
调试:
注意:
当我测试时,我发现需要满足以下条件:
要加载的图像必须是32 bpp,自上而下的位图,预乘的Alpha通道。
这是我的32 bpp image供您测试。
正如我在开始时所说,您需要添加清单文件,您可以自己创建一个.manifest文件。然后将其添加到编译器中。
您只需要将WS_EX_LAYERED
样式添加到子控件中,因为您的要求是使按钮透明。
在我的情况下,所提供的代码不起作用,因为它引发了异常,并且我没有正确添加清单文件。我想指出一些事情: