/* Fills the specified buffer with the metrics for the currently selected font. */
internal static int GetTextMetrics(HandleRef hDC, ref NativeMethods.TEXTMETRIC lptm)
{
if (Marshal.SystemDefaultCharSize != 1)
{
// Handle Unicode
return(SafeNativeMethods.GetTextMetricsW(hDC, out lptm));
}
// Handle ANSI; call GetTextMetricsA and translate to Unicode struct
NativeMethods.TEXTMETRICA tEXTMETRICA = new NativeMethods.TEXTMETRICA();
int result = SafeNativeMethods.GetTextMetricsA(hDC, out tEXTMETRICA);
lptm.tmHeight = tEXTMETRICA.tmHeight;
lptm.tmAscent = tEXTMETRICA.tmAscent;
lptm.tmDescent = tEXTMETRICA.tmDescent;
lptm.tmInternalLeading = tEXTMETRICA.tmInternalLeading;
lptm.tmExternalLeading = tEXTMETRICA.tmExternalLeading;
lptm.tmAveCharWidth = tEXTMETRICA.tmAveCharWidth;
lptm.tmMaxCharWidth = tEXTMETRICA.tmMaxCharWidth;
lptm.tmWeight = tEXTMETRICA.tmWeight;
lptm.tmOverhang = tEXTMETRICA.tmOverhang;
lptm.tmDigitizedAspectX = tEXTMETRICA.tmDigitizedAspectX;
lptm.tmDigitizedAspectY = tEXTMETRICA.tmDigitizedAspectY;
lptm.tmFirstChar = Convert.ToChar(tEXTMETRICA.tmFirstChar);
lptm.tmLastChar = Convert.ToChar(tEXTMETRICA.tmLastChar);
lptm.tmDefaultChar = Convert.ToChar(tEXTMETRICA.tmDefaultChar);
lptm.tmBreakChar = Convert.ToChar(tEXTMETRICA.tmBreakChar);
lptm.tmItalic = tEXTMETRICA.tmItalic;
lptm.tmUnderlined = tEXTMETRICA.tmUnderlined;
lptm.tmStruckOut = tEXTMETRICA.tmStruckOut;
lptm.tmPitchAndFamily = tEXTMETRICA.tmPitchAndFamily;
lptm.tmCharSet = tEXTMETRICA.tmCharSet;
return(result);
}
private static int GetBaseline(Control ctrl, ContentAlignment alignment)
{
int textAscent = 0;
int textHeight = 0;
// Retrieve the ClientRect of the Control
Rectangle clientRect = ctrl.ClientRectangle;
// Create a Graphics object for the Control
using (Graphics graphics = ctrl.CreateGraphics())
{
// Retrieve the device context Handle
IntPtr hDC = graphics.GetHdc();
// Create a wrapper for the Font of the Control
Font controlFont = ctrl.Font;
HandleRef tempFontHandle = new HandleRef(controlFont, controlFont.ToHfont());
try
{
// Create a wrapper for the device context
HandleRef deviceContextHandle = new HandleRef(ctrl, hDC);
// Select the Font into the device context
IntPtr originalFont = SafeNativeMethods.SelectObject(deviceContextHandle, tempFontHandle);
// Create a TEXTMETRIC and calculate metrics for the selected Font
NativeMethods.TEXTMETRIC tEXTMETRIC = new NativeMethods.TEXTMETRIC();
if (SafeNativeMethods.GetTextMetrics(deviceContextHandle, ref tEXTMETRIC) != 0)
{
textAscent = (tEXTMETRIC.tmAscent + 1);
textHeight = tEXTMETRIC.tmHeight;
}
// Restore original Font
HandleRef originalFontHandle = new HandleRef(ctrl, originalFont);
SafeNativeMethods.SelectObject(deviceContextHandle, originalFontHandle);
}
finally
{
// Cleanup tempFont
SafeNativeMethods.DeleteObject(tempFontHandle);
// Release device context
graphics.ReleaseHdc(hDC);
}
}
// Calculate return value based on the specified alignment; first check top alignment
if ((alignment & (ContentAlignment.TopLeft | ContentAlignment.TopCenter | ContentAlignment.TopRight)) != 0)
{
return(clientRect.Top + textAscent);
}
// Check middle alignment
if ((alignment & (ContentAlignment.MiddleLeft | ContentAlignment.MiddleCenter | ContentAlignment.MiddleRight)) == 0)
{
return((clientRect.Bottom - textHeight) + textAscent);
}
// Assume bottom alignment
return((int)Math.Round((double)clientRect.Top + (double)clientRect.Height / 2 - (double)textHeight / 2 + (double)textAscent));
}
private static extern int GetTextMetricsW(HandleRef hDC, out NativeMethods.TEXTMETRIC lptm);
