Question

我尝试使用标准COLOR_BTNFACE纯色和FillRect()填充Windows上的屏幕外位图/设备上下文。但是，在葡萄酒上，我从下面的程序中得到this。 Windows 7显示this，Windows XP显示... this。我迷失了我做错的事，但我确定奇怪的模式是不对的，我知道黑色不是按钮面颜色，因为窗口看起来没有自定义颜料。

我尝试了以下所有方法;他们表现出同样的道理：

FillRect(rdc, &rrect, (HBRUSH) (COLOR_BTNFACE + 1));
FillRect(rdc, &rrect, GetSystemColorBrush(COLOR_BTNFACE));
FillRect(rdc, &rrect, GetSolidBrush(GetSysColor(COLOR_BTNFACE)));

对于GetDeviceCaps(BITSPIXEL)和屏幕外设备上下文，

BeginPaint()返回32; COLORRES返回24。

可能相关吗？我正在运行的实际程序中Here's the output，它会使用AlphaBlend()向此DC添加另一张图片;这导致其他人建议我不小心使用单色DC？因此，上一段中的信息

我在这里做错了什么？感谢。

程序：

// pietro gagliardi - 11-12 april 2014
#define _UNICODE
#define UNICODE
#include <stdio.h>
#include <windows.h>

// this test program doesn't check drawing errors; I have done so in the actual program and there are none
void paintwin(HWND hwnd)
{   
    PAINTSTRUCT ps;

    HDC hdc = BeginPaint(hwnd, &ps);
    RECT updaterect = ps.rcPaint;

    // this is the DC that will be drawn to hdc
    HDC rdc = CreateCompatibleDC(hdc);
    HBITMAP rbitmap = CreateCompatibleBitmap(rdc,
            updaterect.right - updaterect.left,
            updaterect.bottom - updaterect.top);
    HBITMAP prevrbitmap = SelectObject(rdc, rbitmap);
    RECT rrect = { 0, 0, updaterect.right - updaterect.left, updaterect.bottom - updaterect.top };
    FillRect(rdc, &rrect, (HBRUSH) (COLOR_BTNFACE + 1));

    BitBlt(hdc, updaterect.left, updaterect.top,
        updaterect.right - updaterect.left,
        updaterect.bottom - updaterect.top,
        rdc, 0, 0, SRCCOPY);

    SelectObject(rdc, prevrbitmap);
    DeleteObject(rbitmap);
    DeleteDC(rdc);

    EndPaint(hwnd, &ps);
}

LRESULT CALLBACK wndproc(HWND hwnd, UINT msg, WPARAM wparam, LPARAM lparam)
{
    switch (msg) {
    case WM_PAINT:
        paintwin(hwnd);
        return 0;
    case  WM_DESTROY:
        PostQuitMessage(0);
        return 0;
    }
    return DefWindowProc(hwnd, msg, wparam, lparam);
}

int getnCmdShow()
{
    STARTUPINFO si;

    GetStartupInfo(&si);
    if ((si.dwFlags & STARTF_USESHOWWINDOW) != 0)
        return si.wShowWindow;
    return SW_SHOWDEFAULT;
}

int main(int argc, char *argv[])
{
    WNDCLASS cls;
    MSG msg;
    HWND mainwin;

    HINSTANCE hInstance = GetModuleHandle(NULL);
    int nCmdShow = getnCmdShow();

    ZeroMemory(&cls, sizeof (WNDCLASS));
    cls.lpszClassName = L"mainwin";
    cls.lpfnWndProc = wndproc;
    cls.hInstance = hInstance;
    cls.hIcon = LoadIcon(NULL, IDI_APPLICATION);
    cls.hCursor = LoadCursor(NULL, IDC_ARROW);
    cls.hbrBackground = (HBRUSH) (COLOR_BTNFACE + 1);
    if (RegisterClass(&cls) == 0) {
        fprintf(stderr, "registering window class failed: %lu\n", GetLastError());
        return 1;
    }

    mainwin = CreateWindowEx(0,
        L"mainwin", L"mainwin",
        WS_OVERLAPPEDWINDOW,
        CW_USEDEFAULT, CW_USEDEFAULT,
        CW_USEDEFAULT, CW_USEDEFAULT,
        NULL, NULL, hInstance, NULL);
    if (mainwin == NULL) {
        fprintf(stderr, "opening main window failed: %lu", GetLastError());
        return 1;
    }
    ShowWindow(mainwin, nCmdShow);
    UpdateWindow(mainwin);

    while (GetMessage(&msg, NULL, 0, 0) > 0) {
        TranslateMessage(&msg);
        DispatchMessage(&msg);
    }
    return 0;
}

Answer 1

错误确实是您正在使用单色位图。

CreateCompatibleBitmap(rdc, ...);

问题是rdc选择了默认的1x1单色位图。相反，你需要

CreateCompatibleBitmap(hdc, ...);

winapi / gdi：FillRect（COLOR_BTNFACE）在Windows 7和wine上填充奇怪的网格状画笔; Windows XP上的纯黑色

1 个答案: