public Size MeasureText(string text, WindowsFont font, Size proposedSize, IntTextFormatFlags flags)
{
if (string.IsNullOrEmpty(text))
{
return(Size.Empty);
}
IntNativeMethods.DRAWTEXTPARAMS lpDTParams = null;
if (MeasurementDCInfo.IsMeasurementDC(this.DeviceContext))
{
lpDTParams = MeasurementDCInfo.GetTextMargins(this, font);
}
if (lpDTParams == null)
{
lpDTParams = this.GetTextMargins(font);
}
int num = (1 + lpDTParams.iLeftMargin) + lpDTParams.iRightMargin;
if (proposedSize.Width <= num)
{
proposedSize.Width = num;
}
if (proposedSize.Height <= 0)
{
proposedSize.Height = 1;
}
IntNativeMethods.RECT lpRect = IntNativeMethods.RECT.FromXYWH(0, 0, proposedSize.Width, proposedSize.Height);
HandleRef hDC = new HandleRef(null, this.dc.Hdc);
if (font != null)
{
this.dc.SelectFont(font);
}
if ((proposedSize.Height >= MaxSize.Height) && ((flags & IntTextFormatFlags.SingleLine) != IntTextFormatFlags.Default))
{
flags &= ~(IntTextFormatFlags.Bottom | IntTextFormatFlags.VerticalCenter);
}
if (proposedSize.Width == MaxSize.Width)
{
flags &= ~IntTextFormatFlags.WordBreak;
}
flags |= IntTextFormatFlags.CalculateRectangle;
IntUnsafeNativeMethods.DrawTextEx(hDC, text, ref lpRect, (int)flags, lpDTParams);
return(lpRect.Size);
}
/// <summary>
/// Returns the Size in logical units of the given text using the given Font, and according to the formatting flags.
/// The proposed size is used to create a bounding rectangle as follows:
/// - If there are multiple lines of text, DrawText uses the width of the rectangle pointed to by
/// the lpRect parameter and extends the base of the rectangle to bound the last line of text.
/// - If the largest word is wider than the rectangle, the width is expanded.
/// - If the text is less than the width of the rectangle, the width is reduced.
/// - If there is only one line of text, DrawText modifies the right side of the rectangle so that
/// it bounds the last character in the line.
/// If the font is null, the hdc's current font will be used.
///
/// Note for vertical fonts (if ever supported): DrawTextEx uses GetTextExtentPoint32 for measuring the text and this
/// function has the following limitation (from MSDN):
/// - This function assumes that the text is horizontal, that is, that the escapement is always 0. This is true for both
/// the horizontal and vertical measurements of the text. The application must convert it explicitly.
/// </summary>
public Size MeasureText(string text, WindowsFont font, Size proposedSize, User32.DT flags)
{
Debug.Assert(((uint)flags & GdiUnsupportedFlagMask) == 0, "Some custom flags were left over and are not GDI compliant!");
if (string.IsNullOrEmpty(text))
{
return(Size.Empty);
}
// DrawText returns a rectangle useful for aligning, but not guaranteed to encompass all
// pixels (its not a FitBlackBox, if the text is italicized, it will overhang on the right.)
// So we need to account for this.
#if OPTIMIZED_MEASUREMENTDC
User32.DRAWTEXTPARAMS dtparams;
// use the cache if we've got it
if (MeasurementDCInfo.IsMeasurementDC(DeviceContext))
{
dtparams = MeasurementDCInfo.GetTextMargins(this, font);
}
else
{
dtparams = GetTextMargins(font);
}
#else
User32.DRAWTEXTPARAMS dtparams = GetTextMargins(font);
#endif
// If Width / Height are < 0, we need to make them larger or DrawText will return
// an unbounded measurement when we actually trying to make it very narrow.
int minWidth = 1 + dtparams.iLeftMargin + dtparams.iRightMargin;
if (proposedSize.Width <= minWidth)
{
proposedSize.Width = minWidth;
}
if (proposedSize.Height <= 0)
{
proposedSize.Height = 1;
}
var rect = new RECT(0, 0, proposedSize.Width, proposedSize.Height);
if (font != null)
{
DeviceContext.SelectFont(font);
}
// If proposedSize.Height >= MaxSize.Height it is assumed bounds needed. If flags contain SINGLELINE and
// VCENTER or BOTTOM options, DrawTextEx does not bind the rectangle to the actual text height since
// it assumes the text is to be vertically aligned; we need to clear the VCENTER and BOTTOM flags to
// get the actual text bounds.
if (proposedSize.Height >= MaxSize.Height && (flags & User32.DT.SINGLELINE) != 0)
{
// Clear vertical-alignment flags.
flags &= ~(User32.DT.BOTTOM | User32.DT.VCENTER);
}
if (proposedSize.Width == MaxSize.Width)
{
// PERF: No constraining width means no word break.
// in this case, we dont care about word wrapping - there should be enough room to fit it all
flags &= ~(User32.DT.WORDBREAK);
}
flags |= User32.DT.CALCRECT;
User32.DrawTextExW(DeviceContext.Hdc, text, text.Length, ref rect, flags, ref dtparams);
return(rect.Size);
}
/// <summary>
/// Returns the Size in logical units of the given text using the given Font, and according to the formatting flags.
/// The proposed size is used to create a bounding rectangle as follows:
/// - If there are multiple lines of text, DrawText uses the width of the rectangle pointed to by
/// the lpRect parameter and extends the base of the rectangle to bound the last line of text.
/// - If the largest word is wider than the rectangle, the width is expanded.
/// - If the text is less than the width of the rectangle, the width is reduced.
/// - If there is only one line of text, DrawText modifies the right side of the rectangle so that
/// it bounds the last character in the line.
/// If the font is null, the hdc's current font will be used.
///
/// Note for vertical fonts (if ever supported): DrawTextEx uses GetTextExtentPoint32 for measuring the text and this
/// function has the following limitation (from MSDN):
/// - This function assumes that the text is horizontal, that is, that the escapement is always 0. This is true for both
/// the horizontal and vertical measurements of the text. The application must convert it explicitly.
/// </summary>
public Size MeasureText(string text, WindowsFont font, Size proposedSize, IntTextFormatFlags flags)
{
Debug.Assert(((uint)flags & GdiUnsupportedFlagMask) == 0, "Some custom flags were left over and are not GDI compliant!");
if (string.IsNullOrEmpty(text))
{
return(Size.Empty);
}
//
// DrawText returns a rectangle useful for aligning, but not guaranteed to encompass all
// pixels (its not a FitBlackBox, if the text is italicized, it will overhang on the right.)
// So we need to account for this.
//
IntNativeMethods.DRAWTEXTPARAMS dtparams = null;
#if OPTIMIZED_MEASUREMENTDC
// use the cache if we've got it
if (MeasurementDCInfo.IsMeasurementDC(DeviceContext))
{
dtparams = MeasurementDCInfo.GetTextMargins(this, font);
}
#endif
if (dtparams == null)
{
dtparams = GetTextMargins(font);
}
//
// If Width / Height are < 0, we need to make them larger or DrawText will return
// an unbounded measurement when we actually trying to make it very narrow.
//
int minWidth = 1 + dtparams.iLeftMargin + dtparams.iRightMargin;
if (proposedSize.Width <= minWidth)
{
proposedSize.Width = minWidth;
}
if (proposedSize.Height <= 0)
{
proposedSize.Height = 1;
}
IntNativeMethods.RECT rect = IntNativeMethods.RECT.FromXYWH(0, 0, proposedSize.Width, proposedSize.Height);
HandleRef hdc = new HandleRef(null, dc.Hdc);
if (font != null)
{
dc.SelectFont(font);
}
// If proposedSize.Height >= MaxSize.Height it is assumed bounds needed. If flags contain SingleLine and
// VerticalCenter or Bottom options, DrawTextEx does not bind the rectangle to the actual text height since
// it assumes the text is to be vertically aligned; we need to clear the VerticalCenter and Bottom flags to
// get the actual text bounds.
if (proposedSize.Height >= MaxSize.Height && (flags & IntTextFormatFlags.SingleLine) != 0)
{
// Clear vertical-alignment flags.
flags &= ~(IntTextFormatFlags.Bottom | IntTextFormatFlags.VerticalCenter);
}
if (proposedSize.Width == MaxSize.Width)
{
// PERF: No constraining width means no word break.
// in this case, we dont care about word wrapping - there should be enough room to fit it all
flags &= ~(IntTextFormatFlags.WordBreak);
}
flags |= IntTextFormatFlags.CalculateRectangle;
IntUnsafeNativeMethods.DrawTextEx(hdc, text, ref rect, (int)flags, dtparams);
/* No need to restore previous objects into the dc (see comments on top of the class).
*
* if( hOldFont != IntPtr.Zero )
* {
* this.dc.SelectObject(hOldFont);
* }
*/
return(rect.Size);
}
