我想使用 C++ 和 Win API 以编程方式创建 32 位颜色图标。为此,我使用了以下我发现的代码 here .
HICON CreateSolidColorIcon(COLORREF iconColor, int width, int height)
{
// Obtain a handle to the screen device context.
HDC hdcScreen = GetDC(NULL);
// Create a memory device context, which we will draw into.
HDC hdcMem = CreateCompatibleDC(hdcScreen);
// Create the bitmap, and select it into the device context for drawing.
HBITMAP hbmp = CreateCompatibleBitmap(hdcScreen, width, height);
HBITMAP hbmpOld = (HBITMAP)SelectObject(hdcMem, hbmp);
// Draw your icon.
//
// For this simple example, we're just drawing a solid color rectangle
// in the specified color with the specified dimensions.
HPEN hpen = CreatePen(PS_SOLID, 1, iconColor);
HPEN hpenOld = (HPEN)SelectObject(hdcMem, hpen);
HBRUSH hbrush = CreateSolidBrush(iconColor);
HBRUSH hbrushOld = (HBRUSH)SelectObject(hdcMem, hbrush);
Rectangle(hdcMem, 0, 0, width, height);
SelectObject(hdcMem, hbrushOld);
SelectObject(hdcMem, hpenOld);
DeleteObject(hbrush);
DeleteObject(hpen);
// Create an icon from the bitmap.
//
// Icons require masks to indicate transparent and opaque areas. Since this
// simple example has no transparent areas, we use a fully opaque mask.
HBITMAP hbmpMask = CreateCompatibleBitmap(hdcScreen, width, height);
ICONINFO ii;
ii.fIcon = TRUE;
ii.hbmMask = hbmpMask;
ii.hbmColor = hbmp;
HICON hIcon = CreateIconIndirect(&ii);
DeleteObject(hbmpMask);
// Clean-up.
SelectObject(hdcMem, hbmpOld);
DeleteObject(hbmp);
DeleteDC(hdcMem);
ReleaseDC(NULL, hdcScreen);
// Return the icon.
return hIcon;
}
原则上代码可以工作,我可以使用它在运行时使用 Win API 创建彩色图标。但是,我有一些关于该代码(以及一般创建图标)的问题和疑问,我想讨论一下。
- 使用此功能创建的图标似乎不是 32 位颜色深度。如果我使用像 RGB(218, 112, 214) 这样的颜色,我希望它是浅紫色。然而,实际显示的颜色是灰色的。如何更改代码,使颜色真正成为 32 位 RGB?
- 创建的图标完全充满了颜色,我想在它周围有一个薄薄的黑色边界......这怎么能实现?
- 在 MSDN documentation (向下一点)提到 “在关闭之前,您的应用程序必须使用 DestroyIcon 来销毁它使用 CreateIconIndirect 创建的任何图标。没有必要销毁由其他函数创建的图标。” 但是,在例如文档中CreateIcon在 MSDN 中说 “当您使用完图标后,使用 DestroyIcon 函数销毁它。” 这几乎是自相矛盾的。我什么时候必须真正销毁图标?
- 当我将图标添加到图像列表并将该列表添加到组合框时,这些规则是否也适用? IE。我必须清理图像列表和每个关联的图标吗?
非常感谢任何帮助。
最佳答案
When do I actually have to destroy the icon?
了解 DestroyIcon
It is only necessary to call
DestroyIcon
for icons and cursors created with the following functions:CreateIconFromResourceEx
(if called without theLR_SHARED
flag),CreateIconIndirect
, andCopyIcon
. Do not use this function to destroy a shared icon. A shared icon is valid as long as the module from which it was loaded remains in memory. The following functions obtain a shared icon.
LoadIcon
LoadImage
(if you use theLR_SHARED
flag)CopyImage
(if you use theLR_COPYRETURNORG
flag and thehImage
parameter is a shared icon)CreateIconFromResource
CreateIconFromResourceEx
(if you use theLR_SHARED
flag)
所以当你使用完未共享图标时,你需要调用DestroyIcon
ComboBoxEx
不会破坏您使用 CBEM_SETIMAGELIST
分配给它的图像列表 - 因此此图像列表必须有效直到 ComboBoxEx
有效并且您必须稍后自行销毁。
Because the system does not save hicon, you can destroy it after the macro returns
换句话说 ImageList_AddIcon
复制你的图标,你可以在宏返回后销毁你原来的图标
要创建 32 位颜色图标,请尝试这样的代码:
HICON CreateGradientColorIcon(COLORREF iconColor, int width, int height)
{
HICON hIcon = 0;
ICONINFO ii = { TRUE };
ULONG n = width * height;
if (PULONG lpBits = new ULONG[n])
{
PULONG p = lpBits;
ULONG x, y = height, t;
do
{
x = width, t = --y << 8;
do
{
*p++ = iconColor | ((t * --x) / n << 24);
} while (x);
} while (y);
if (ii.hbmColor = CreateBitmap(width, height, 1, 32, lpBits))
{
if (ii.hbmMask = CreateBitmap(width, height, 1, 1, 0))
{
hIcon = CreateIconIndirect(&ii);
DeleteObject(ii.hbmMask);
}
DeleteObject(ii.hbmColor);
}
delete [] lpBits;
}
return hIcon;
}
当我在绿色网格上绘制 (DrawIconEx(, DI_IMAGE|DI_MASK)
) 这个图标时,我接下来会看到:
关于c++ - 以编程方式创建 32 位颜色图标,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/41533158/