/// <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 static Size MeasureText( this Gdi32.HDC hdc, ReadOnlySpan <char> text, FontCache.Scope font, Size proposedSize, TextFormatFlags flags) { (User32.DT dt, TextPaddingOptions padding) = SplitTextFormatFlags(flags); if (text.IsEmpty) { 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. User32.DRAWTEXTPARAMS dtparams = GetTextMargins(font, padding); // 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); using var fontSelection = new Gdi32.SelectObjectScope(hdc, font.Object); // 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 >= TextRenderer.MaxSize.Height && (dt & User32.DT.SINGLELINE) != 0) { // Clear vertical-alignment flags. dt &= ~(User32.DT.BOTTOM | User32.DT.VCENTER); } if (proposedSize.Width == TextRenderer.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 dt &= ~(User32.DT.WORDBREAK); } dt |= User32.DT.CALCRECT; User32.DrawTextExW(hdc, text, ref rect, dt, ref dtparams); return(rect.Size); }
/// GetTextMargins - checks to see if we have cached information about the current font, /// returns info about it. /// An MRU of Font margins was considered, but seems like overhead. internal static User32.DRAWTEXTPARAMS GetTextMargins(WindowsGraphics wg, WindowsFont font) { // PERF: operate on a local reference rather than party directly on the thread static one. CachedInfo currentCachedInfo = cachedMeasurementDCInfo; if (currentCachedInfo != null && currentCachedInfo.LeftTextMargin > 0 && currentCachedInfo.RightTextMargin > 0 && font == currentCachedInfo.LastUsedFont) { // we have to return clones as DrawTextEx will modify this struct return(new User32.DRAWTEXTPARAMS { iLeftMargin = currentCachedInfo.LeftTextMargin, iRightMargin = currentCachedInfo.RightTextMargin }); } else if (currentCachedInfo == null) { currentCachedInfo = new CachedInfo(); cachedMeasurementDCInfo = currentCachedInfo; } User32.DRAWTEXTPARAMS drawTextParams = wg.GetTextMargins(font); currentCachedInfo.LeftTextMargin = drawTextParams.iLeftMargin; currentCachedInfo.RightTextMargin = drawTextParams.iRightMargin; // returning a copy here to be consistent with the return value from the cache. return(new User32.DRAWTEXTPARAMS { iLeftMargin = currentCachedInfo.LeftTextMargin, iRightMargin = currentCachedInfo.RightTextMargin }); }
public static void DrawString(Control context, Font font, string text, Rectangle textBounds, bool useMnemonics, GdiTextDrawMode textMode) { IntPtr hdc = User32.GetDC(context.Handle); try { Gdi32.SetBkColor(hdc, Gdi32.ToColorRef(context.BackColor)); Gdi32.SetTextColor(hdc, Gdi32.ToColorRef(context.ForeColor)); try { IntPtr hFont = font.ToHfont(); try { IntPtr hPrevFont = Gdi32.SelectObject(hdc, hFont); try { StringBuilder sb = new StringBuilder(text); RECT rect = textBounds; User32.DRAWTEXTPARAMS dtparams = new User32.DRAWTEXTPARAMS(); dtparams.cbSize = (uint)Marshal.SizeOf(typeof(User32.DRAWTEXTPARAMS)); User32.DT flags = textMode == GdiTextDrawMode.EndEllipsis ? User32.DT.END_ELLIPSIS : textMode == GdiTextDrawMode.WordBreak ? User32.DT.WORDBREAK | User32.DT.END_ELLIPSIS : User32.DT.WORDBREAK; if (useMnemonics) { flags |= User32.DT.NOPREFIX; } if (0 == User32.DrawTextEx(hdc, sb, sb.Length, ref rect, flags, ref dtparams)) { throw new Win32Exception(Marshal.GetLastWin32Error()); } } finally { Gdi32.SelectObject(hdc, hPrevFont); } } finally { Gdi32.DeleteObject(hFont); } } finally { } } finally { User32.ReleaseDC(context.Handle, hdc); } }
/// <summary> /// Draws the text in the given bounds, using the given Font, foreColor and backColor, and according to the specified /// TextFormatFlags flags. /// /// If font is null, the font currently selected in the hdc is used. /// /// If foreColor and/or backColor are Color.Empty, the hdc current text and/or background color are used. /// </summary> public static void DrawText( this Gdi32.HDC hdc, ReadOnlySpan <char> text, FontCache.Scope font, Rectangle bounds, Color foreColor, User32.DT flags, Color backColor = default, TextPaddingOptions padding = default) { if (text.IsEmpty || foreColor == Color.Transparent) { return; } ValidateFlags(flags); // DrawText requires default text alignment. using var alignment = new Gdi32.SetTextAlignmentScope(hdc, default); // Color empty means use the one currently selected in the dc. using var textColor = foreColor.IsEmpty ? default : new Gdi32.SetTextColorScope(hdc, foreColor); using var fontSelection = new Gdi32.SelectObjectScope(hdc, (Gdi32.HFONT)font); Gdi32.BKMODE newBackGroundMode = (backColor.IsEmpty || backColor == Color.Transparent) ? Gdi32.BKMODE.TRANSPARENT : Gdi32.BKMODE.OPAQUE; using var backgroundMode = new Gdi32.SetBkModeScope(hdc, newBackGroundMode); using var backgroundColor = newBackGroundMode != Gdi32.BKMODE.TRANSPARENT ? new Gdi32.SetBackgroundColorScope(hdc, backColor) : default; User32.DRAWTEXTPARAMS dtparams = GetTextMargins(font, padding); bounds = AdjustForVerticalAlignment(hdc, text, bounds, flags, ref dtparams); // Adjust unbounded rect to avoid overflow since Rectangle ctr does not do param validation. if (bounds.Width == TextRenderer.MaxSize.Width) { bounds.Width -= bounds.X; } if (bounds.Height == TextRenderer.MaxSize.Height) { bounds.Height -= bounds.Y; } RECT rect = bounds; User32.DrawTextExW(hdc, text, ref rect, flags, ref dtparams); }
public void Font_GetTextMargins(string family, float size, int left, int right) { using Font font = new Font(family, size); if (font.Name != family) { // Not installed on this machine return; } using var hfont = GdiCache.GetHFONT(font, Gdi32.QUALITY.CLEARTYPE); User32.DRAWTEXTPARAMS margins = hfont.GetTextMargins(); Assert.Equal(left, margins.iLeftMargin); Assert.Equal(right, margins.iRightMargin); }
public void Font_GetTextMargins(string family, float size, int left, int right) { using Font font = new Font(family, size); if (font.Name != family) { // Not installed on this machine return; } using WindowsFont windowsFont = WindowsFont.FromFont(font, Gdi32.QUALITY.CLEARTYPE); WindowsGraphics graphics = WindowsGraphicsCacheManager.MeasurementGraphics; User32.DRAWTEXTPARAMS margins = graphics.GetTextMargins(windowsFont); Assert.Equal(left, margins.iLeftMargin); Assert.Equal(right, margins.iRightMargin); }
/// <summary> /// The GDI DrawText does not do multiline alignment when User32.DT.SINGLELINE is not set. This /// adjustment is to workaround that limitation. We don't want to duplicate SelectObject calls here, /// so put your Font in the dc before calling this. /// /// AdjustForVerticalAlignment is only used when the text is multiline and it fits inside the bounds passed in. /// In that case we want the horizontal center of the multiline text to be at the horizontal center of the bounds. /// /// If the text is multiline and it does not fit inside the bounds passed in, then return the bounds that were passed in. /// This way we paint the top of the text at the top of the bounds passed in. /// </summary> public static Rectangle AdjustForVerticalAlignment( this Gdi32.HDC hdc, ReadOnlySpan <char> text, Rectangle bounds, User32.DT flags, ref User32.DRAWTEXTPARAMS dtparams) { ValidateFlags(flags); // Ok if any Top (Cannot test User32.DT.Top because it is 0), single line text or measuring text. bool isTop = (flags & User32.DT.BOTTOM) == 0 && (flags & User32.DT.VCENTER) == 0; if (isTop || ((flags & User32.DT.SINGLELINE) != 0) || ((flags & User32.DT.CALCRECT) != 0)) { return(bounds); } RECT rect = new RECT(bounds); // Get the text bounds. flags |= User32.DT.CALCRECT; int textHeight = User32.DrawTextExW(hdc, text, ref rect, flags, ref dtparams); // if the text does not fit inside the bounds then return the bounds that were passed in if (textHeight > bounds.Height) { return(bounds); } Rectangle adjustedBounds = bounds; if ((flags & User32.DT.VCENTER) != 0) { // Middle adjustedBounds.Y = adjustedBounds.Top + adjustedBounds.Height / 2 - textHeight / 2; } else { // Bottom adjustedBounds.Y = adjustedBounds.Bottom - textHeight; } return(adjustedBounds); }
/// <summary> /// The GDI DrawText does not do multiline alignment when User32.DT.SINGLELINE is not set. This /// adjustment is to workaround that limitation. We don't want to duplicate SelectObject calls here, /// so put your Font in the dc before calling this. /// /// AdjustForVerticalAlignment is only used when the text is multiline and it fits inside the bounds passed in. /// In that case we want the horizontal center of the multiline text to be at the horizontal center of the bounds. /// /// If the text is multiline and it does not fit inside the bounds passed in, then return the bounds that were passed in. /// This way we paint the top of the text at the top of the bounds passed in. /// </summary> public static Rectangle AdjustForVerticalAlignment( HandleRef hdc, string text, Rectangle bounds, User32.DT flags, ref User32.DRAWTEXTPARAMS dtparams) { Debug.Assert(((uint)flags & GdiUnsupportedFlagMask) == 0, "Some custom flags were left over and are not GDI compliant!"); // Ok if any Top (Cannot test User32.DT.Top because it is 0), single line text or measuring text. bool isTop = (flags & User32.DT.BOTTOM) == 0 && (flags & User32.DT.VCENTER) == 0; if (isTop || ((flags & User32.DT.SINGLELINE) != 0) || ((flags & User32.DT.CALCRECT) != 0)) { return(bounds); } RECT rect = new RECT(bounds); // Get the text bounds. flags |= User32.DT.CALCRECT; int textHeight = User32.DrawTextExW(hdc, text, text.Length, ref rect, flags, ref dtparams); // if the text does not fit inside the bounds then return the bounds that were passed in if (textHeight > bounds.Height) { return(bounds); } Rectangle adjustedBounds = bounds; if ((flags & User32.DT.VCENTER) != 0) // Middle { adjustedBounds.Y = adjustedBounds.Top + adjustedBounds.Height / 2 - textHeight / 2; } else // Bottom. { adjustedBounds.Y = adjustedBounds.Bottom - textHeight; } return(adjustedBounds); }
public void Font_AdjustForVerticalAlignment(string family, float size, Rectangle bounds, uint dt, Rectangle expected) { using Font font = new Font(family, size); if (font.Name != family) { // Not installed on this machine return; } using var hfont = GdiCache.GetHFONT(font, Gdi32.QUALITY.CLEARTYPE); using var screen = GdiCache.GetScreenHdc(); using var fontSelection = new Gdi32.SelectObjectScope(screen, hfont.Object); User32.DRAWTEXTPARAMS param = default; Rectangle result = screen.HDC.AdjustForVerticalAlignment( "Windows Foundation Classes", bounds, (User32.DT)dt, ref param); Assert.Equal(expected, result); }
public static Rectangle MeasureString(Control context, Font font, string text, Rectangle textBounds) { IntPtr hdc = User32.GetDC(context.Handle); try { IntPtr hFont = font.ToHfont(); try { IntPtr hPrevFont = Gdi32.SelectObject(hdc, hFont); try { StringBuilder sb = new StringBuilder(text); RECT rect = textBounds; rect.bottom = rect.top; // set height to 0 User32.DRAWTEXTPARAMS dtparams = new User32.DRAWTEXTPARAMS(); dtparams.cbSize = (uint)Marshal.SizeOf(typeof(User32.DRAWTEXTPARAMS)); if (0 == User32.DrawTextEx(hdc, sb, sb.Length, ref rect, User32.DT.CALCRECT | User32.DT.WORDBREAK | User32.DT.END_ELLIPSIS, ref dtparams)) { throw new Win32Exception(Marshal.GetLastWin32Error()); } return(rect); } finally { Gdi32.SelectObject(hdc, hPrevFont); } } finally { Gdi32.DeleteObject(hFont); } } finally { User32.ReleaseDC(context.Handle, hdc); } }
public void Font_AdjustForVerticalAlignment(string family, float size, Rectangle bounds, uint dt, Rectangle expected) { using Font font = new Font(family, size); if (font.Name != family) { // Not installed on this machine return; } using WindowsFont windowsFont = WindowsFont.FromFont(font, Gdi32.QUALITY.CLEARTYPE); WindowsGraphics graphics = WindowsGraphicsCacheManager.MeasurementGraphics; graphics.DeviceContext.SelectFont(windowsFont); User32.DRAWTEXTPARAMS param = default; Rectangle result = WindowsGraphics.AdjustForVerticalAlignment( graphics, "Windows Foundation Classes", bounds, (User32.DT)dt, ref param); Assert.Equal(expected, result); }
/// <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> /// Draws the text in the given bounds, using the given Font, foreColor and backColor, and according to the specified /// TextFormatFlags flags. /// /// If font is null, the font currently selected in the hdc is used. /// /// If foreColor and/or backColor are Color.Empty, the hdc current text and/or background color are used. /// </summary> public void DrawText(string text, WindowsFont font, Rectangle bounds, Color foreColor, Color backColor, User32.DT flags) { if (string.IsNullOrEmpty(text) || foreColor == Color.Transparent) { return; } Debug.Assert(((uint)flags & GdiUnsupportedFlagMask) == 0, "Some custom flags were left over and are not GDI compliant!"); Debug.Assert((flags & User32.DT.CALCRECT) == 0, "CALCRECT flag is set, text won't be drawn"); HandleRef hdc = new HandleRef(DeviceContext, DeviceContext.Hdc); // DrawText requires default text alignment. if (DeviceContext.TextAlignment != default) { DeviceContext.TextAlignment = default; } // color empty means use the one currently selected in the dc. if (!foreColor.IsEmpty && foreColor != DeviceContext.TextColor) { DeviceContext.TextColor = foreColor; } if (font != null) { DeviceContext.SelectFont(font); } Gdi32.BKMODE newBackGndMode = (backColor.IsEmpty || backColor == Color.Transparent) ? Gdi32.BKMODE.TRANSPARENT : Gdi32.BKMODE.OPAQUE; if (DeviceContext.BackgroundMode != newBackGndMode) { DeviceContext.SetBackgroundMode(newBackGndMode); } if (newBackGndMode != Gdi32.BKMODE.TRANSPARENT && backColor != DeviceContext.BackgroundColor) { DeviceContext.BackgroundColor = backColor; } User32.DRAWTEXTPARAMS dtparams = GetTextMargins(font); bounds = AdjustForVerticalAlignment(hdc, text, bounds, flags, ref dtparams); // Adjust unbounded rect to avoid overflow since Rectangle ctr does not do param validation. if (bounds.Width == MaxSize.Width) { bounds.Width -= bounds.X; } if (bounds.Height == MaxSize.Height) { bounds.Height -= bounds.Y; } var rect = new RECT(bounds); User32.DrawTextExW(hdc, text, text.Length, ref rect, flags, ref dtparams); // No need to restore previous objects into the dc (see comments on top of the class). }