How to call DrawThemeTextEx in .NET
I need to write a text with glow in a Vista/seven glass window, and I'm, trying to call the API to write some text there. I have checked out a great sample in CodeProject, but the problem is that I'm using .NET 1 (please, don't ask :-)
I need to translate the follwing .NET 2 code to PInvoke, .NET 1 code.
// using System.Windows.Forms.VisualStyles
VisualStyleRenderer开发者_C百科 renderer = new VisualStyleRenderer(
VisualStyleElement.Window.Caption.Active);
// call to UxTheme.dll
DrawThemeTextEx(renderer.Handle,
memoryHdc, 0, 0, text, -1, (int)flags,
ref textBounds, ref dttOpts);
The class VisualStyleRenderer
does not exist in .NET 1, so I need to get the renderer.Handle
in other way.
Define the OpenThemeData API and DrawThemeTextEx, as well as some required structs and constants:
[DllImport("uxtheme.dll", CharSet = CharSet.Unicode)]
private static extern IntPtr OpenThemeData(IntPtr hwnd, string pszClassList);
[DllImport("uxtheme.dll", CharSet = CharSet.Unicode)]
private extern static Int32 DrawThemeTextEx(IntPtr hTheme, IntPtr hdc, int iPartId, int iStateId, string pszText, int iCharCount, uint flags, ref RECT rect, ref DTTOPTS poptions);
[StructLayout(LayoutKind.Sequential)]
private struct RECT
{
public int left;
public int top;
public int right;
public int bottom;
}
[StructLayout(LayoutKind.Sequential)]
private struct DTTOPTS
{
public int dwSize;
public int dwFlags;
public int crText;
public int crBorder;
public int crShadow;
public int iTextShadowType;
public int ptShadowOffsetX;
public int ptShadowOffsetY;
public int iBorderSize;
public int iFontPropId;
public int iColorPropId;
public int iStateId;
public bool fApplyOverlay;
public int iGlowSize;
public IntPtr pfnDrawTextCallback;
public IntPtr lParam;
}
// taken from vsstyle.h
private const int WP_CAPTION = 1;
private const int CS_ACTIVE = 1;
And then, call it like this:
IntPtr handle = OpenThemeData(IntPtr.Zero, "WINDOW");
DrawThemeTextExt(handle, hdc, WS_CAPTION, CS_ACTIVE, ...)
The WS_CAPTION and CS_ACTIVE values match .NET 2's Caption and Active respectively. Values are described here officially: Parts and States
In short, you get what you want by calling OpenThemeData()
.
To work out all the details it would be much easier for you to write a sample app in C++ to get to know how to drive the theme API from the ground up. There are many tutorials and lots of sample code on the web. But do it in C++ where you will have all the functions readily available. The last thing you want to get doing is fighting with P/Invokes whilst you are also getting to grips with low-level theme API.
Once you get it cracked in C++, then move on to the P/Invokes and if you have trouble it will be easy to refer back to the C++ code that works.
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