FontDialog.cs source code in C# .NET

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                         / DotNET / DotNET / 8.0 / untmp / whidbey / REDBITS / ndp / fx / src / WinForms / Managed / System / WinForms / FontDialog.cs / 1 / FontDialog.cs
                        

                        
                            //------------------------------------------------------------------------------ 
// 
//     Copyright (c) Microsoft Corporation.  All rights reserved.
// 
//----------------------------------------------------------------------------- 

namespace System.Windows.Forms { 
 
    using System.Diagnostics;
    using System.Diagnostics.CodeAnalysis; 

    using System;
    using System.Drawing;
    using System.Runtime.InteropServices; 
    using System.ComponentModel;
    using System.Windows.Forms; 
    using System.Security; 
    using System.Security.Permissions;
 
    using Microsoft.Win32;

    /// 
    ///  
    ///    
    ///       Represents 
    ///       a common dialog box that displays a list of fonts that are currently installed 
    ///       on
    ///       the system. 
    ///    
    /// 
    [
    DefaultEvent("Apply"), 
    DefaultProperty("Font"),
    SRDescription(SR.DescriptionFontDialog) 
    ] 
    public class FontDialog : CommonDialog {
        ///  
        /// 
        ///    [To be supplied.]
        /// 
        protected static readonly object EventApply = new object(); 

        private const int defaultMinSize = 0; 
        private const int defaultMaxSize = 0; 

        private int options; 
        private Font font;
        private Color color;
        private int minSize = defaultMinSize;
        private int maxSize = defaultMaxSize; 
        private bool showColor = false;
 
        ///  
        /// 
        ///     
        ///       Initializes a new instance of the 
        ///       class.
        ///    
        ///  
        [
            SuppressMessage("Microsoft.Usage", "CA2214:DoNotCallOverridableMethodsInConstructors")  // If the constructor does not call Reset 
                                                                                                    // it would be a breaking change. 
        ]
        public FontDialog() { 
            Reset();
        }

        ///  
        /// 
        ///     
        ///       Gets or sets a value indicating whether the dialog box allows graphics device interface 
        ///       (GDI) font simulations.
        ///     
        /// 
        [
        SRCategory(SR.CatBehavior),
        DefaultValue(true), 
        SRDescription(SR.FnDallowSimulationsDescr)
        ] 
        public bool AllowSimulations { 
            get {
                return !GetOption(NativeMethods.CF_NOSIMULATIONS); 
            }

            set {
                SetOption(NativeMethods.CF_NOSIMULATIONS, !value); 
            }
        } 
 
        /// 
        ///  
        ///    
        ///       Gets or sets a value indicating whether the dialog box allows vector font selections.
        ///    
        ///  
        [
        SRCategory(SR.CatBehavior), 
        DefaultValue(true), 
        SRDescription(SR.FnDallowVectorFontsDescr)
        ] 
        public bool AllowVectorFonts {
            get {
                return !GetOption(NativeMethods.CF_NOVECTORFONTS);
            } 

            set { 
                SetOption(NativeMethods.CF_NOVECTORFONTS, !value); 
            }
        } 

        /// 
        /// 
        ///     
        ///       Gets or sets a value indicating whether
        ///       the dialog box displays both vertical and horizontal fonts or only 
        ///       horizontal fonts. 
        ///    
        ///  
        [
        SRCategory(SR.CatBehavior),
        DefaultValue(true),
        SRDescription(SR.FnDallowVerticalFontsDescr) 
        ]
        public bool AllowVerticalFonts { 
            get { 
                return !GetOption(NativeMethods.CF_NOVERTFONTS);
            } 

            set {
                SetOption(NativeMethods.CF_NOVERTFONTS, !value);
            } 
        }
 
        ///  
        /// 
        ///     
        ///       Gets
        ///       or sets a value indicating whether the user can change the character set specified
        ///       in the Script combo box to display a character set other than the one
        ///       currently displayed. 
        ///    
        ///  
        [ 
        SRCategory(SR.CatBehavior),
        DefaultValue(true), 
        SRDescription(SR.FnDallowScriptChangeDescr)
        ]
        public bool AllowScriptChange {
            get { 
                return !GetOption(NativeMethods.CF_SELECTSCRIPT);
            } 
 
            set {
                SetOption(NativeMethods.CF_SELECTSCRIPT, !value); 
            }
        }

        ///  
        /// 
        ///     
        ///       Gets or sets a value indicating the selected font color. 
        ///    
        ///  
        [
        SRCategory(SR.CatData),
        SRDescription(SR.FnDcolorDescr),
        DefaultValue(typeof(Color), "Black") 
        ]
        public Color Color { 
            get { 
                return color;
            } 
            set {
                if (!value.IsEmpty) {
                    color = value;
                } 
                else {
                    color = Color.Black; 
                } 
            }
        } 

        /// 
        /// 
        ///     
        ///       Gets or sets
        ///       a value indicating whether the dialog box allows only the selection of fixed-pitch fonts. 
        ///     
        /// 
        [ 
        SRCategory(SR.CatBehavior),
        DefaultValue(false),
        SRDescription(SR.FnDfixedPitchOnlyDescr)
        ] 
        public bool FixedPitchOnly {
            get { 
                return GetOption(NativeMethods.CF_FIXEDPITCHONLY); 
            }
 
            set {
                SetOption(NativeMethods.CF_FIXEDPITCHONLY, value);
            }
        } 

        ///  
        ///  
        ///    
        ///       Gets or sets a value indicating the selected font. 
        ///    
        /// 
        [
        SRCategory(SR.CatData), 
        SRDescription(SR.FnDfontDescr)
        ] 
        public Font Font { 
            get {
                Font result = font; 
                if (result == null)
                    result = Control.DefaultFont;

                float actualSize =  result.SizeInPoints; 
                if (minSize != defaultMinSize && actualSize < MinSize)
                    result = new Font(result.FontFamily, MinSize, result.Style, GraphicsUnit.Point); 
                if (maxSize != defaultMaxSize && actualSize > MaxSize) 
                    result = new Font(result.FontFamily, MaxSize, result.Style, GraphicsUnit.Point);
 
                return result;
            }
            set {
                font = value; 
            }
        } 
 
        /// 
        ///  
        ///    
        ///       Gets or sets a value indicating whether the dialog box specifies an error condition if the
        ///       user attempts to select a font or style that does not exist.
        ///     
        /// 
        [ 
        SRCategory(SR.CatBehavior), 
        DefaultValue(false),
        SRDescription(SR.FnDfontMustExistDescr) 
        ]
        public bool FontMustExist {
            get {
                return GetOption(NativeMethods.CF_FORCEFONTEXIST); 
            }
 
            set { 
                SetOption(NativeMethods.CF_FORCEFONTEXIST, value);
            } 
        }

        /// 
        ///  
        ///    
        ///       Gets or sets the maximum 
        ///       point size a user can select. 
        ///    
        ///  
        [
        SRCategory(SR.CatData),
        DefaultValue(defaultMaxSize),
        SRDescription(SR.FnDmaxSizeDescr) 
        ]
        public int MaxSize { 
            get { 
                return maxSize;
            } 
            set {
                if (value < 0) {
                    value = 0;
                } 
                maxSize = value;
 
                if (maxSize > 0 && maxSize < minSize) { 
                    minSize = maxSize;
                } 
            }
        }

        ///  
        /// 
        ///     
        ///       Gets or sets a value indicating the minimum point size a user can select. 
        ///    
        ///  
        [
        SRCategory(SR.CatData),
        DefaultValue(defaultMinSize),
        SRDescription(SR.FnDminSizeDescr) 
        ]
        public int MinSize { 
            get { 
                return minSize;
            } 
            set {
                if (value < 0) {
                    value = 0;
                } 
                minSize = value;
 
                if (maxSize > 0 && maxSize < minSize) { 
                    maxSize = minSize;
                } 
            }
        }

        ///  
        /// 
        ///  
        ///     
        ///       Gets the value passed to CHOOSEFONT.Flags.
        ///     
        /// 
        protected int Options {
            get {
                return options; 
            }
        } 
 
        /// 
        ///  
        ///    
        ///       Gets or sets a
        ///       value indicating whether the dialog box allows selection of fonts for all non-OEM and Symbol character
        ///       sets, as well as the American National Standards Institute (ANSI) character set. 
        ///    
        ///  
        [ 
        SRCategory(SR.CatBehavior),
        DefaultValue(false), 
        SRDescription(SR.FnDscriptsOnlyDescr)
        ]
        public bool ScriptsOnly {
            get { 
                return GetOption(NativeMethods.CF_SCRIPTSONLY);
            } 
            set { 
                SetOption(NativeMethods.CF_SCRIPTSONLY, value);
            } 
        }

        /// 
        ///  
        ///    
        ///       Gets or sets a value indicating whether the dialog box contains an Apply button. 
        ///     
        /// 
        [ 
        SRCategory(SR.CatBehavior),
        DefaultValue(false),
        SRDescription(SR.FnDshowApplyDescr)
        ] 
        public bool ShowApply {
            get { 
                return GetOption(NativeMethods.CF_APPLY); 
            }
            set { 
                SetOption(NativeMethods.CF_APPLY, value);
            }
        }
 
        /// 
        ///  
        ///     
        ///       Gets or sets a value indicating whether the dialog box displays the color choice.
        ///     
        /// 
        [
        SRCategory(SR.CatBehavior),
        DefaultValue(false), 
        SRDescription(SR.FnDshowColorDescr)
        ] 
        public bool ShowColor { 
            get {
                return showColor; 
            }
            set {
                this.showColor = value;
            } 
        }
 
        ///  
        /// 
        ///     
        ///       Gets or sets a value indicating whether the dialog box contains controls that allow the
        ///       user to specify strikethrough, underline, and text color options.
        ///    
        ///  
        [
        SRCategory(SR.CatBehavior), 
        DefaultValue(true), 
        SRDescription(SR.FnDshowEffectsDescr)
        ] 
        public bool ShowEffects {
            get {
                return GetOption(NativeMethods.CF_EFFECTS);
            } 
            set {
                SetOption(NativeMethods.CF_EFFECTS, value); 
            } 
        }
 
        /// 
        /// 
        ///    
        ///       Gets or sets a value indicating whether the dialog box displays a Help button. 
        ///    
        ///  
        [ 
        SRCategory(SR.CatBehavior),
        DefaultValue(false), 
        SRDescription(SR.FnDshowHelpDescr)
        ]
        public bool ShowHelp {
            get { 
                return GetOption(NativeMethods.CF_SHOWHELP);
            } 
            set { 
                SetOption(NativeMethods.CF_SHOWHELP, value);
            } 
        }

        /// 
        ///  
        ///    
        ///       Occurs when the user clicks the Apply button in the font 
        ///       dialog box. 
        ///    
        ///  
        [SRDescription(SR.FnDapplyDescr)]
        public event EventHandler Apply {
            add {
                Events.AddHandler(EventApply, value); 
            }
            remove { 
                Events.RemoveHandler(EventApply, value); 
            }
        } 

        /// 
        /// 
        ///     Returns the state of the given option flag. 
        /// 
        ///  
        internal bool GetOption(int option) { 
            return(options & option) != 0;
        } 

        /// 
        /// 
        ///     
        ///       Specifies the common dialog box hook procedure that is overridden to add
        ///       specific functionality to a common dialog box. 
        ///     
        /// 
        [SecurityPermission(SecurityAction.LinkDemand, Flags=SecurityPermissionFlag.UnmanagedCode)] 
        protected override IntPtr HookProc(IntPtr hWnd, int msg, IntPtr wparam, IntPtr lparam) {

            switch (msg) {
                case NativeMethods.WM_COMMAND: 
                    if ((int)wparam == 0x402) {
                        NativeMethods.LOGFONT lf = new NativeMethods.LOGFONT(); 
                        UnsafeNativeMethods.SendMessage(new HandleRef(null, hWnd), NativeMethods.WM_CHOOSEFONT_GETLOGFONT, 0, lf); 
                        UpdateFont(lf);
                        int index = (int)UnsafeNativeMethods.SendDlgItemMessage(new HandleRef(null, hWnd), 0x473, NativeMethods.CB_GETCURSEL, IntPtr.Zero, IntPtr.Zero); 
                        if (index != NativeMethods.CB_ERR) {
                            UpdateColor((int)UnsafeNativeMethods.SendDlgItemMessage(new HandleRef(null, hWnd), 0x473,
                                                                         NativeMethods.CB_GETITEMDATA, (IntPtr) index, IntPtr.Zero));
                        } 
                        if (NativeWindow.WndProcShouldBeDebuggable) {
                            OnApply(EventArgs.Empty); 
                        } 
                        else {
                            try 
                            {
                                OnApply(EventArgs.Empty);
                            }
                            catch (Exception e) 
                            {
                                Application.OnThreadException(e); 
                            } 
                        }
                    } 
                    break;
                case NativeMethods.WM_INITDIALOG:
                    if (!showColor) {
                        IntPtr hWndCtl = UnsafeNativeMethods.GetDlgItem(new HandleRef(null, hWnd), NativeMethods.cmb4); 
                        SafeNativeMethods.ShowWindow(new HandleRef(null, hWndCtl), NativeMethods.SW_HIDE);
                        hWndCtl = UnsafeNativeMethods.GetDlgItem(new HandleRef(null, hWnd), NativeMethods.stc4); 
                        SafeNativeMethods.ShowWindow(new HandleRef(null, hWndCtl), NativeMethods.SW_HIDE); 
                    }
                    break; 
            }

            return base.HookProc(hWnd, msg, wparam, lparam);
        } 

        ///  
        ///  
        ///    
        ///       Raises the  event. 
        ///    
        /// 
        protected virtual void OnApply(EventArgs e) {
            EventHandler handler = (EventHandler)Events[EventApply]; 
            if (handler != null) handler(this, e);
        } 
 
        /// 
        ///  
        ///    
        ///       Resets all dialog box options to their default values.
        ///    
        ///  
        public override void Reset() {
            options = NativeMethods.CF_SCREENFONTS | NativeMethods.CF_EFFECTS; 
            font = null; 
            color = Color.Black;
            showColor = false; 
            minSize = defaultMinSize;
            maxSize = defaultMaxSize;
            SetOption(NativeMethods.CF_TTONLY, true);
        } 

        private void ResetFont() { 
            font = null; 
        }
 
        /// 
        /// 
        /// 
        ///     
        ///       The actual implementation of running the dialog. Inheriting classes
        ///       should override this if they want to add more functionality, and call 
        ///       base.runDialog() if necessary 
        ///
        ///     
        /// 
        protected override bool RunDialog(IntPtr hWndOwner) {
            NativeMethods.WndProc hookProcPtr = new NativeMethods.WndProc(this.HookProc);
            NativeMethods.CHOOSEFONT cf = new NativeMethods.CHOOSEFONT(); 
            IntPtr screenDC = UnsafeNativeMethods.GetDC(NativeMethods.NullHandleRef);
            NativeMethods.LOGFONT lf = new NativeMethods.LOGFONT(); 
 
            Graphics graphics = Graphics.FromHdcInternal(screenDC);
 
            // SECREVIEW : The Font.ToLogFont method is marked with the 'unsafe' modifier cause it needs to write bytes into the logFont struct,
            //             here we are passing that struct so the assert is safe.
            //
            IntSecurity.ObjectFromWin32Handle.Assert(); 
            try {
                Font.ToLogFont(lf, graphics); 
            } 
            finally {
                CodeAccessPermission.RevertAssert(); 
                graphics.Dispose();
            }
            UnsafeNativeMethods.ReleaseDC(NativeMethods.NullHandleRef, new HandleRef(null, screenDC));
 
            IntPtr logFontPtr = IntPtr.Zero;
            try { 
                logFontPtr = Marshal.AllocCoTaskMem(Marshal.SizeOf(typeof(NativeMethods.LOGFONT))); 
                Marshal.StructureToPtr(lf, logFontPtr, false);
 
                cf.lStructSize = Marshal.SizeOf(typeof(NativeMethods.CHOOSEFONT));
                cf.hwndOwner = hWndOwner;
                cf.hDC = IntPtr.Zero;
                cf.lpLogFont = logFontPtr; 
                cf.Flags = Options | NativeMethods.CF_INITTOLOGFONTSTRUCT | NativeMethods.CF_ENABLEHOOK;
                if (minSize > 0 || maxSize > 0) { 
                    cf.Flags |= NativeMethods.CF_LIMITSIZE; 
                }
 
                //if ShowColor=true then try to draw the sample text in color,
                //if ShowEffects=false then we will draw the sample text in black regardless.
                //(limitation of windows control)
                // 
                if (ShowColor || ShowEffects) {
                    cf.rgbColors = ColorTranslator.ToWin32(color); 
                } 
                else {
                    cf.rgbColors = ColorTranslator.ToWin32(Color.Black); 
                }

                cf.lpfnHook = hookProcPtr;
                cf.hInstance = UnsafeNativeMethods.GetModuleHandle(null); 
                cf.nSizeMin = minSize;
                if (maxSize == 0) { 
                    cf.nSizeMax = Int32.MaxValue; 
                }
                else { 
                    cf.nSizeMax = maxSize;
                }
                Debug.Assert(cf.nSizeMin <= cf.nSizeMax, "min and max font sizes are the wrong way around");
                if (!SafeNativeMethods.ChooseFont(cf)) return false; 

 
                NativeMethods.LOGFONT lfReturned = null; 
                lfReturned = (NativeMethods.LOGFONT)UnsafeNativeMethods.PtrToStructure(logFontPtr, typeof(NativeMethods.LOGFONT));
 
                if (lfReturned.lfFaceName != null && lfReturned.lfFaceName.Length > 0) {
                    lf = lfReturned;
                    UpdateFont(lf);
                    UpdateColor(cf.rgbColors); 
                }
 
                return true; 
            }
            finally { 
                if (logFontPtr != IntPtr.Zero)
                    Marshal.FreeCoTaskMem(logFontPtr);
            }
        } 

        ///  
        ///  
        ///     Sets the given option to the given boolean value.
        ///  
        /// 
        internal void SetOption(int option, bool value) {
            if (value) {
                options |= option; 
            }
            else { 
                options &= ~option; 
            }
        } 

        /// 
        /// 
        ///     
        ///       Indicates whether the  property should be
        ///       persisted. 
        ///     
        /// 
        private bool ShouldSerializeFont() { 
            return !Font.Equals(Control.DefaultFont);
        }

        ///  
        /// 
        ///  
        ///     
        ///       Retrieves a string that includes the name of the current font selected in
        ///       the dialog box. 
        ///
        ///    
        /// 
        public override string ToString() { 
            string s = base.ToString();
            return s + ",  Font: " + Font.ToString(); 
        } 

        ///  
        /// 
        /// 
        /// 
        private void UpdateColor(int rgb) { 
            if (ColorTranslator.ToWin32(color) != rgb) {
                color = ColorTranslator.FromOle(rgb); 
            } 
        }
 
        /// 
        /// 
        /// 
        ///  
        private void UpdateFont(NativeMethods.LOGFONT lf) {
            IntPtr screenDC = UnsafeNativeMethods.GetDC(NativeMethods.NullHandleRef); 
            try { 
                Font fontInWorldUnits = null;
                try { 
                    IntSecurity.UnmanagedCode.Assert();
                    try {
                        fontInWorldUnits = Font.FromLogFont(lf, screenDC);
                    } 
                    finally {
                        CodeAccessPermission.RevertAssert(); 
                    } 

                    // The dialog claims its working in points (a device-independent unit), 
                    // but actually gives us something in world units (device-dependent).
                    font = ControlPaint.FontInPoints(fontInWorldUnits);
                }
                finally { 
                    if (fontInWorldUnits != null) {
                        fontInWorldUnits.Dispose(); 
                    } 
                }
            } 
            finally {
                UnsafeNativeMethods.ReleaseDC(NativeMethods.NullHandleRef, new HandleRef(null, screenDC));
            }
        } 

    } 
} 

// File provided for Reference Use Only by Microsoft Corporation (c) 2007.
// Copyright (c) Microsoft Corporation. All rights reserved.

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