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); }