/// <summary>
/// Creates the font handle.
/// </summary>
private unsafe WindowsFont(User32.LOGFONTW logFont, FontStyle style, bool createHandle)
{
Debug.Assert(Hfont == IntPtr.Zero, "hFont is not null, this will generate a handle leak.");
_logFont = logFont;
if (_logFont.FaceName.Length == 0)
{
_logFont.FaceName = DefaultFaceName;
}
Style = style;
if (createHandle)
{
Hfont = Gdi32.CreateFontIndirectW(ref _logFont);
if (Hfont == IntPtr.Zero)
{
_logFont.FaceName = DefaultFaceName;
_logFont.lfOutPrecision = Gdi32.OUT_PRECIS.TT_ONLY; // TrueType only.
Hfont = Gdi32.CreateFontIndirectW(ref _logFont);
}
// Update logFont height and other adjusted parameters.
Gdi32.GetObjectW(new HandleRef(this, Hfont), out _logFont);
// We created the hFont, we will delete it on dispose.
_ownHandle = true;
}
}
public unsafe void CreateFontIndirect()
{
User32.LOGFONTW logFont = default;
IntPtr handle = Gdi32.CreateFontIndirectW(ref logFont);
Assert.NotEqual(IntPtr.Zero, handle);
Assert.True(Gdi32.DeleteObject(handle).IsTrue());
}
public unsafe void CreateFontIndirect()
{
LOGFONTW logFont = default;
Gdi32.HFONT handle = Gdi32.CreateFontIndirectW(ref logFont);
Assert.False(handle.IsNull);
Assert.True(Gdi32.DeleteObject(handle).IsTrue());
}
/// <summary>
/// Constructs a WindowsFont object from an existing System.Drawing.Font object (GDI+), based on the screen dc
/// MapMode and resolution (normally: MM_TEXT and 96 dpi).
/// </summary>
private static Gdi32.HFONT FromFont(Font font, Gdi32.QUALITY quality = Gdi32.QUALITY.DEFAULT)
{
string familyName = font.FontFamily.Name;
// Strip vertical-font mark from the name if needed.
if (familyName != null && familyName.Length > 1 && familyName[0] == '@')
{
familyName = familyName.Substring(1);
}
// Now, creating it using the Font.SizeInPoints makes it GraphicsUnit-independent.
Debug.Assert(font.SizeInPoints > 0.0f, "size has a negative value.");
// Get the font height from the specified size. The size is in point units and height in logical units
// (pixels when using MM_TEXT) so we need to make the conversion using the number of pixels per logical
// inch along the screen height. (1 point = 1/72 inch.)
int pixelsY = (int)Math.Ceiling(DpiHelper.DeviceDpi * font.SizeInPoints / 72);
// The lfHeight represents the font cell height (line spacing) which includes the internal leading; we
// specify a negative size value (in pixels) for the height so the font mapper provides the closest match
// for the character height rather than the cell height.
User32.LOGFONTW logFont = new User32.LOGFONTW
{
lfHeight = -pixelsY,
lfCharSet = font.GdiCharSet,
lfOutPrecision = Gdi32.OUT_PRECIS.TT,
lfQuality = quality,
lfWeight = (font.Style & FontStyle.Bold) == FontStyle.Bold ? Gdi32.FW.BOLD : Gdi32.FW.NORMAL,
lfItalic = (font.Style & FontStyle.Italic) == FontStyle.Italic ? True : False,
lfUnderline = (font.Style & FontStyle.Underline) == FontStyle.Underline ? True : False,
lfStrikeOut = (font.Style & FontStyle.Strikeout) == FontStyle.Strikeout ? True : False,
FaceName = familyName
};
if (logFont.FaceName.IsEmpty)
{
logFont.FaceName = DefaultFaceName;
}
Gdi32.HFONT hfont = Gdi32.CreateFontIndirectW(ref logFont);
if (hfont.IsNull)
{
// Get the default font if we couldn't get what we requested.
logFont.FaceName = DefaultFaceName;
logFont.lfOutPrecision = Gdi32.OUT_PRECIS.TT_ONLY;
hfont = Gdi32.CreateFontIndirectW(ref logFont);
Debug.Assert(!hfont.IsNull);
}
return(hfont);
}