将HBITMAP绘制到分层窗口上.怎么了? [英] Draw HBITMAP onto layered window. What's wrong?
问题描述
大家好，祝你美好！
我的最终目标是在屏幕上绘制一个包含Alpha的PNG文件-这意味着不进入自己的窗口，而只是在桌面上的某个位置. 将PNG加载到HBITMAP中的部分现在可以正常工作(以不同的方式进行了测试)，但是我无法绘制包括Alpha在内的图片.
my final target is to draw a PNG file including alpha onto the screen - that means not into an own window but just somewhere on the desktop. The part to load PNG's into a HBITMAP works now (tested that in a diffrent way) but I don't manage to draw it including alpha.
据我所知，最好的方法是使用独立的窗户.因此，我花了很多精力来重做一些示例和小型教程.
As far as I've heard the best way to do this would be using alyered windows. So I wroked a lot to redo a couple of examples and tiny tutorials.
下面的代码编译没有问题，并且不提示任何消息(这意味着从不调用showError(#")函数).
The following code compiles without problems and there do not prompt any messages (that means the showError("#") function is never called).
但是在屏幕上没有可见的 :/
Yet there is nothing visible on the screen :/
很抱歉，时间太长了……希望有人希望至少快点看看.
Sorry that it is so long... Hope someone would like to look at it at least quickly..
LRESULT CALLBACK WndProc(HWND hWindow, UINT msg, WPARAM wParam, LPARAM lParam);
int main(HINSTANCE hInstance)
{
WNDCLASSEX WndClass;
char sClassName[] = "mainClass";
WndClass.cbSize = sizeof(WNDCLASSEX);
WndClass.style = NULL;
WndClass.lpfnWndProc = WndProc;//WndProc;
WndClass.cbClsExtra = 0;
WndClass.cbWndExtra = 0;
WndClass.hInstance = hInstance;
WndClass.hIcon = NULL;
WndClass.hCursor = LoadCursor(NULL, IDC_ARROW);
WndClass.hbrBackground = (HBRUSH)(COLOR_WINDOW+1);
WndClass.lpszMenuName = NULL;
WndClass.lpszClassName = sClassName;
WndClass.hIconSm = LoadIcon(NULL, IDI_APPLICATION);
if (RegisterClassEx(&WndClass) == 0) showError("-1");
HWND screen = CreateWindowEx(WS_EX_LAYERED,//WS_EX_LEFT
"mainClass",
"UpdateLayeredWind",
WS_DISABLED | WS_VISIBLE,
200,200,260,260,
NULL /*eventuelly, GM window*/,
NULL,
hInstance,
NULL);
if (screen == NULL) showError("0");
HBITMAP img = LoadImageResource("D://ThreadDraw/ThreadDraw-test/ThreadDraw/test.png");
if (img == NULL) showError("1");
BLENDFUNCTION blend = {0};
blend.AlphaFormat = AC_SRC_ALPHA;
blend.SourceConstantAlpha = 155;
POINT ptPos = {200,300};
SIZE sizeWnd = {260,260};
POINT ptPos2 = {200,300};
ShowWindow(screen, SW_SHOW);
while (1)
{
PAINTSTRUCT ps;
HDC hdc;
BITMAP bitmap;
HDC hdcMem;
HGDIOBJ oldBitmap;
hdc = BeginPaint(screen, &ps);
hdcMem = CreateCompatibleDC(hdc);
oldBitmap = SelectObject(hdcMem, img);
GetObject(img, sizeof(bitmap), &bitmap);
if (SetLayout(hdc,LAYOUT_RTL) == GDI_ERROR)
showError("5");
if (!BitBlt(hdc, 0, 0, 64, 64, hdcMem, 0, 0, SRCCOPY))
showError("4");
if (!UpdateLayeredWindow(screen,hdcMem,&ptPos,&sizeWnd,hdc,&ptPos2,RGB(255,255,255),&blend,ULW_ALPHA))//ULW_OPAQUE))
showError("2");
EndPaint(screen, &ps);
SelectObject(hdcMem, oldBitmap);
DeleteDC(hdcMem);
Sleep(10);
}
return 0;
}
LRESULT CALLBACK WndProc(HWND hwnd, UINT Message, WPARAM wParam, LPARAM lParam)
{
switch(Message)
{
case WM_CLOSE:
DestroyWindow(hwnd);
break;
case WM_DESTROY:
PostQuitMessage(0);
break;
default:
return DefWindowProc(hwnd, Message, wParam, lParam);
}
return 0;
}
顺便说一句，如果我在UpdateLayeredWindow中使用ULW_OPAQUE而不是ULW_ALPHA，则会出现一个尺寸正确的黑色窗口，因此认为问题必须与PAINTSTRUKT或BitBlt函数无关.没有任何改变.
By the way, if I use ULW_OPAQUE instead of ULW_ALPHA in UpdateLayeredWindow, then a right sized, black window appears so think the issue has to be something minimal related to the PAINTSTRUKT or BitBlt function.. Yet I tried a lot of ways without any change.
希望有人可以提供帮助.提前非常感谢您！
Hope someone can help. Thank you very much in advance!
推荐答案
这主要是错误的.您的代码应:
This is mostly wrong. Your code should:
- 使用
CreateWindowEx创建分层窗口. - 使用
UpdateLayeredWindow将位图附加到其上. - 使用
ShowWindow显示窗口. Windows将负责绘制分层窗口，因此您无需处理WM_PAINT或调用BeginPaint. - 进入消息循环.
- Create the layered window with
CreateWindowEx. - Attach the bitmap to it with
UpdateLayeredWindow. - Show the window with
ShowWindow. Windows will take care of painting the layered window, so you don't need to handleWM_PAINTor callBeginPaint. - Enter a message loop.
就是这样.
如果您使用的是Visual Studio，请创建一个新的Win32项目，它将为您创建一个带有消息循环的新项目.
If you're using Visual Studio, create a new Win32 Project and it will create a new project with a message loop for you.
更新
这是一个示例程序，可创建一个透明的分层窗口.它需要一个函数来将PNG加载为透明位图.而且没有错误检查.
Here's a sample program that creates a transparent layered window. It needs a function to load a PNG as a transparent bitmap. And it has no error checking.
int APIENTRY _tWinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance, LPTSTR lpCmdLine, int nCmdShow)
{
LPCTSTR szWindowClass = _T("TransparentClass");
// Register class
WNDCLASSEX wcex = {0};
wcex.cbSize = sizeof(WNDCLASSEX);
wcex.lpfnWndProc = DefWindowProc;
wcex.hInstance = hInstance;
wcex.lpszClassName = szWindowClass;
RegisterClassEx(&wcex);
HWND hWnd = CreateWindowEx(WS_EX_LAYERED, szWindowClass, 0, WS_OVERLAPPEDWINDOW,
CW_USEDEFAULT, 0, CW_USEDEFAULT, 0, NULL, NULL, hInstance, NULL);
int width;
int height;
HBITMAP hbmp = LoadPng(L"sample.png", &width, &height);
HDC hdcScreen = GetDC(0);
HDC hdc = CreateCompatibleDC(hdcScreen);
ReleaseDC(0, hdcScreen);
HBITMAP hbmpold = (HBITMAP)SelectObject(hdc, hbmp);
POINT dcOffset = {0, 0};
SIZE size = {width, height};
BLENDFUNCTION bf;
bf.BlendOp = AC_SRC_OVER;
bf.BlendFlags = 0;
bf.SourceConstantAlpha = 255;
bf.AlphaFormat = AC_SRC_ALPHA;
UpdateLayeredWindow(hWnd, 0, 0, &size, hdc, &dcOffset, 0, &bf, ULW_ALPHA);
SelectObject(hdc, hbmpold);
DeleteDC(hdc);
DeleteObject(hbmp);
ShowWindow(hWnd, SW_SHOW);
MSG msg;
// Main message loop:
while (GetMessage(&msg, NULL, 0, 0))
{
TranslateMessage(&msg);
DispatchMessage(&msg);
}
return (int)msg.wParam;
}
另一个更新
这里有一些代码将红色，绿色和蓝色值乘以alpha.假定splash_image指向大小为width*height的32bpp ARGB数据.
Here's some code to premultiply the red, green and blue values by alpha. It assumes that splash_image points to 32bpp ARGB data of size width*height.
LPBYTE bits = (LPBYTE)splash_image;
int size = width * height;
for (int pixel = 0; pixel != size; ++pixel)
{
bits[0] = bits[0] * bits[3] / 255;
bits[1] = bits[1] * bits[3] / 255;
bits[2] = bits[2] * bits[3] / 255;
bits += 4;
}
这篇关于将HBITMAP绘制到分层窗口上.怎么了?的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！
