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RichMemo macosx screenshot. Thanks to Dominique Louis

TRichMemo is a component to replace Delphi TRichEdit component. It's designed in cross-platform way, so implementation is possible for the following platforms: Win32, MacOSX, Linux. Since, being cross-platform is the primary target. The native RichMemo API can be extended to make it Delphi's RichEdit compatible.

Its main caracteristics are :

  • Text highlight
  • System based Unicode edit support

Planned: (patches are welcomed)

  • Adding images into text
  • Embedding LCL Controls?

The download contains the component, an installation package and a demo application, that illustrates the features of the component along with some instrumentation for evaluating the chart on a given system.

Please add your Bugreports/Feature requests in Lazarus CCR project of the Lazarus bug tracker.



Author: Dmitry 'skalogryz' Boyarintsev

modified LGPL (same as the FPC RTL and the Lazarus LCL). You can contact the author if the modified LGPL doesn't work with your project licensing.


The latest trunk is available here:

Trunk snapshot can be downloaded from here: . The snapshot is updated nightly.

Change Log

  • Version 1.0.0 22th Jun 2009
  • Version 0.8.0 Jun 2009

Dependencies / System Requirements

  • Lazarus 1.0.0

Status: Released.


  • Download the package
  • Open the package, and install it, rebuilding the IDE
  • TRichMemo is added to 'Common Controls' component page.



Font Parameters

Font parameters are generally represtened by TFontParams record. The type is used to describe rich attributes of the font. Some attributes goes beyond the scope of TFont class, thus an extra type was necessary. However, most of the TFont related data types are reused (i.e. TFontStyles).

  • Name - name of the font (family).
  • Size - size of the font in points. (passing a negative value might produce unexpected results)
  • Color - color of the font.
  • Style - font styles, including Bold, italic, strike-through, underline.
  • HasBkClr - boolean flag, if the text for the should have background color. (if true, BkColor field is used, otherwise BkColor is ignored). Transparency for is not supported.
  • BkColor - background (aka highlight) color for the text.
  • VScriptPos - vertical adjustement for the text
    richmemo Subsuper.png
    • vpNormal - no special position
    • vpSubscript - the text is subscript
    • vpSuperscript - the text is superscript.
The actual vertical offset of super/sub scripts depends on OS implementation and currently cannot be controlled.

You can assign FontParams from TFont structure. For that you'll need to use GetFontParams(afont: TFont) function. Note, most of LCL controls have TFont set to "default" values. These are not actual values, but rather an indication that control's default font should be used (similar to crDefault for TColor).

GetFontParams function resolves "Default" font name and returns the actual font family name.



procedure SetTextAttributes(TextStart, TextLen: Integer; AFont: TFont);
  • TextStart : Integer - the first character to be modified
  • TextLen : Integer - number of characters to be modified
  • AFont : TFont - a font that should be applied to the part of the text

procedure SetTextAttributes(TextStart, TextLen: Integer; const TextParams: TFontParams);
  • TextStart : Integer - the first character to be modified
  • TextLen : Integer - number of characters to be modified
  • TextParams : TFontParams - font parameters to be set

SetTextureAttributes methods are changing specified text range style. Font parameters is passed in both methods, by AFont parameter (LCL TFont object) or by TFontParams (declared at RichMemo).

Setting text attributes does not change current selection. If it's necessary to modify the style of currently selected text, you should SelStart and SelLength as a text range values:

RichMemo1.SetTextAttributes(RichMemo1.SelStart, RichMemo1.SelLength, FontDialog1.Font);


function GetTextAttributes(TextStart: Integer; var TextParams: TFontParams): Boolean; virtual;
  • TextStart : Integer - the character position to be queried for font parameters
  • var TextParams : TFontParams - output value, filled with charachter's font attributes. If the method fails and returns false, record's field values is undefined.

Fill font params of the character, at TextStart position. Method returns True if textstart is valid character position, and False overwise.


function GetStyleRange(CharPos: Integer; var RangeStart, RangeLen: Integer): Boolean; virtual;

Returns a range of characters that share the same font parameters, i.e. all characters in the range has the same font name, size, color and styles.

  • CharPos : Integer - a character that belongs to the style range. It's not necessary for this position to be at the begining on the style range. It can be in the middle on in the end of the style range. The first character position is returned by RangeStart parameter.
  • var RangeStart : Integer - the first character in the range
  • var RangeLen : Integer - number of characthers in the range

The method returns true if successed. the method returns false, if CharPos is incorrect value - more than available characters or some other error.


function CharAtPos(x,y: Integer): Integer; virtual;

Returns zero-based character offset (not UTF8 position). Returns -1 if fails.

  • x, y - is a point in the client area of the RichMemo control.

The method is aware of scrolling state of the control. Thus two calls to CharAtPos(0,0) might return different values if scroll positions is changed between calls. See "examples/hittest" for the sample of usage.

If specified x,y would be out of the content of RichMemo the return value is undefined. It is left up to widgetset to either return -1 or closes character available.


procedure SetRangeColor(TextStart, TextLength: Integer; FontColor: TColor);

The method sets color of characters in the specified range to the FontColor. Other font parameters (name, size, styles) are left unchanged.

  • TextStart: Integer - the first character in the range
  • TextLength: Integer - number of characters in the range
  • FontColor: TColor - color that should be set


procedure SetRangeParams(TextStart, TextLength: Integer;
    ModifyMask: TTextModifyMask; const FontName: String; 
    FontSize: Integer; FontColor: TColor; 
    AddFontStyle, RemoveFontStyle: TFontStyles);

The method changes font parameters in the specified range.


Gets paragraph alignment

function GetParaAlignment(TextStart: Integer; var AAlign: TParaAlignment): Boolean;
  • TextStart - the position of the character that's belongs to the paragraph
  • AAlign - gets alignment of a paragraph.


  • Win32 - full-width Justification doesn't work on Windows XP and earlier.
  • OSX - due to Carbon limitation, this is not working in Carbon, but works for Cocoa widgetset.


Sets paragraph alignent

procedure SetParaAlignment(TextStart, TextLen: Integer; AAlign: TParaAlignment);


  • Win32 - full-width Justification doesn't work on Windows XP and earlier.
  • OSX - due to Carbon limitation, this is not working in Carbon, but works for Cocoa widgetset. It's also need to loaded that the correct alignment would be loaded from RTF file


Returns paragraph metrics for a given paragraph

richmemo parametric.PNG
  • FirstLine - an offset for the first line (in points), of the paragraph from the beginning of control
  • TailIndent - an offset for each line (in points), except for the first line, of the paragraph from the end of the control
  • HeadIndent - an offset for each line (in points) of the paragraph from the end of the control
  • SpaceBefore - additional space before paragraph (in points)
  • SpaceAfter - additional space after paragraph (in points)
  • LineSpacing - a factor used to calculate line spacing between lines in the paragraph. The factor is applied to Font size (tallest in the line), not the line height. Thus it's matching CSS's line-height property. Note that normal line-spacing is 1.2. I.e. font of 12 pt size, an actual lines spacing set to 1.2, would result in 14pt line height.
    • not supported in WinXP or earlier
    • most of the system would not allow if linespacing is set to less than 1.2. The value would be ignored and they'd default to 1.2


  • RichEdit paragraph settings are specified in pixels, not points, so you'll need to either convert these sizes yourself or use RichMemoHelper methods
  • the notation of "Left"/"Right" offsets is avoided to prevent confusion for RTL.
function GetParaMetric(TextStart: Integer; var AMetric: TParaMetric): Boolean;


Sets paragraph metrics

procedure SetParaMetric(TextStart, TextLen: Integer; const AMetric: TParaMetric);

It's recommended to use InitParaMetric function in order to initialize TParaMetric structure. Otherwise zeroing structure out is by it size (i.e. FillChar(m, sizeof(TParaMetric), 0) is sufficient. If TParaMetric values are received from GetParaMetric call, then the structure is considered to be initialized properly.


Returns character range for a paragraph. The paragraph is identified by a character.

  function GetParaRange(CharOfs: Integer; var ParaRange: TParaRange): Boolean; 
  function GetParaRange(CharOfs: Integer; var TextStart, TextLength: Integer): Boolean;

CharOfs - is a character that belongs to a paragraph which range is returned. TParaRange - is a structure that returns 3 fields

  • start - the first character in the paragraph
  • lengthNoBr - the length of the paragraph, excluding the line break character
  • length - the length of the paragrpah, including the line break, if present the last line in the control doesn't contain a line break character, thus length = lengthNoBr value.


Sets the set of tab stops to paragraphs in the specified length.

  procedure SetParaTabs(TextStart, TextLen: Integer; const AStopList: TTabStopList);
  • TextStart
  • TextLen
  • AStopList - the structure that contains an array of tab stops.
    • Count - specifies the number of initialized elements.
    • Tabs - array contains the description of each tab stop, consisting of an Offset and Alignment.
      • Offset - the tab point offset in points (from the left side of the control)
      • Align - the alignment of the tab stop (tabLeft - default one, tabCenter, tabRight, tabDecimal).


Prior to r4140 TTabAlignment enum values were taLeft, taCenter, taRight, taDecimal,but it did collide with Classes.TAlignment declarations. Thus the suffix was changed.
allows no more that 32 tabs
only tabLeft align is supported
not implemented


Gets the tab stops array. If no specific tabs were specified (widget default tab stops) AStopList count would be set to 0.

 function GetParaTabs(CharOfs: Integer; var AStopList: TTabStopList): Boolean;


Sets paragraph metrics selectively

 procedure SetRangeParaParams(TextStart, TextLength: Integer; ModifyMask: TParaModifyMask; const ParaMetric: TParaMetric);
  • TextStart - the character of the the first paragraph to apply the style too
  • TextLength - the number of characters that paragraph properties should be modified
  • ModifyMask - masks the identifies what para metric should be set for each paragraph within TextStart..TextLength block. Other characters will be left unmodified. Members of the set are
    • pmm_FirstLine - changes the first line indentation. FirstLine field of ParaMetric must be initialized
    • pmm_HeadIndent - changes the heading paragraph indentation. HeadIndent field of ParaMetric must be initialized
    • pmm_TailIndent - changes the trail paragraph indentation. TailIndent field of ParaMetric must be initialized
    • pmm_SpaceBefore - changes the space preceding . SpaceBefore field of ParaMetric must be initialized
    • pmm_SpaceAfter - changes the space after (below) the paragraph. SpaceAfter field of ParaMetric must be initialized
    • pmm_LineSpacing - line spacing within paragraph. LineSpace field of ParaMetric must be initialized
  • ParaMetric - the structure containing the values to be set. Only fields specified by ModifyMask should be initialized


function LoadRichText(Source: TStream): Boolean; virtual;
  • Source: TStream - a stream to read richtext data from

The method loads RTF enocded data from the specified stream. Returns true if success, and false otherwise. If source is nil, the method returns false

The content of TRichMemo is completely replaced by the content on the source stream. Current text selection is reset.


function SaveRichText(Dest: TStream): Boolean; virtual;
  • Source: TStream - a stream to read richtext data from

The method saves RTF enocded data to the specified stream. Returns true if success, and false otherwise. If source is nil, the method returns false

Current state of TRichMemo is unchanged after the method returns



property ZoomFactor: double

Read/Write property. Controls zooming of the RichMemo content. 1.0 - is no-zoom. Less than < 1.0 - decrease zoom, more than 1.0 - increasing zooming. If 0 is set - value defaults to 1.0 zoom factor (no zoom).


property HideSelection: Boolean default false

Read/Write property. If True RichMemo selection is hidden if the control is not focused. If False, the selection is shown all the time.


property Rtf: String

Read/Write property that allows to read or write Rich-Text Formatted (RTF) text to the whole control. The intent of the property is to have an ability to set Rich-Text in design time, however the property would work in run-time as well.

If then property value is an empty string then Lines property is used as a plain text to initialize control value in load-time.

Note: The property is available in TRichMemo class only, it's not available (or even implemented in anyway) in TCustomRichMemo class. It is recommended to use LoadRichText/SaveRichText in order to modify the content of the page, just because they could consume less memory, than copying the whole rich-text into the memory.

Cross-platform and Forward Compatibility Note: - currently the property is implemented based on the widgetset providede Rich-text read/write routines. It is very likely that in near future it would be changed to used RichMemo read/write RTF stream code only. The issue is with older systems might not support the latest version of RTF.

So right now, you might run into an issue, If you create a project in Gtk2 and save the richmemo is design time containing Unicode characters. Then if you try to load it on the XP machine and would use widgetset native loader, you might see characters missing or rendered improperly. Changing to the usage of RichMemo RTF loader/saver will prevent this issue from happening. Currently you can also avoid it by registering RichMemo loaders (call RegisterRTFLoader, RegisterRTFSaver procedures in project initialization, before any RichMemo is loaded)



property OnSelectionChange: TNotifyEvent
TNotifyEvent = procedure (Sender: TObject) of object;

The event is fired whenever, selection is changed within RichMemo, either programmatically or due to the user action.


The class helper that implements RichEdit programmatic interface. The helper is declared at RichEditHelpers unit, so you have to add it to the uses section. Helpers are available in FPC 2.6.0 or later.



Searches a given range in the text for a target string



Reads/Modifies character attributes of the current selection.


Reads/Modifies paragraph attributes of the current selection.


The unit is introduced to add some useful OS-specific features for handling working with RichMemo


function InsertImageFromFile (const ARichMemo: TCustomRichMemo; APos: Integer;
    const FileNameUTF8: string;
    const AImgSize: TSize
): Boolean = nil;

Disclaimer: the function would insert an image file into RichMemo (if implemented by the widgetset) But in a very inefficient way. The image would be read again and the memory would be re-allocated for the image every time. So please, don't use it for smileys in your chat instant messaging. A better API (with data caching) is considered. (That's why this method is not part of TCustomRichMemo class).

  • APos - position in the text
  • AImgSize - size to be inserted in POINTS, not pixels!. If both cx and cy are 0, the image would not be resized at all. If only one cx, cy is zero results are undefined


The set of functions that simplify appending and replacing of styled text. The specified style of the text is applied on the insertion. The common rule for all functions, if InsPos (insertion position) is negative - the text is appended to the end. In order to insert the text in the beginning of the test InsPos should set to 0.

The inserted text is not forced to be on a new line or add a new line. You might want to add LineFeed character to TestUTF8 parameter, if you want the inserted text to cause a new line to be started.

procedure InsertStyledText(
  const ARichMemo: TCustomRichMemo; 
  const TextUTF8: String; 
  AStyle: TFontStyles;
  InsPos : Integer = -1 )

InsertStyledText inserts the styled text at the specified position.

procedure InsertColorStyledText(
  const ARichMemo: TCustomRichMemo; 
  const TextUTF8: String; 
  AColor: TColor; 
  AStyle: TFontStyles;
  InsPos : Integer = -1 )

InsertColorStyledText inserts the text with specified style and color at the specified position. to the end of the RichMemo

procedure InsertFontText(
  const ARichMemo: TCustomRichMemo; 
  const TextUTF8: String; 
  const prms: TFontParams;     
  InsPos : Integer = -1 )

InsertFontText inserts the text and applies specified FontParams to it.

You might want to create a class helper to implement these functions as methods for RichMemo. Beware, if you're using Delphi-compatibility helper - you might right into a conflict.


  • Get the latest version from SVN
  • Open the package, and install it, rebuilding the IDE
  • TRichMemo is added to 'Common Controls' component page.

Frequently Asked Questions

Using RichMemo in Shared Libraries

Issue #17412 If you need to use the component in a shared library, you might need to add -fPIC key to the compiler option of "the package" and the "project".

(Delphi) RichEdit like interface

Issue #14632 A typical problem is porting an existing code that's using RichEdit from Delphi. RichMemo interface doesn't match RichEdit in many ways. But there're two ways to handle that:

  • you can either create a sub-class from TCustomRichMemo (or RichMemo) and implement Delphi RichEdit methods;
  • you can use RichMemoHelpers unit (fpc 2.6.0 or later required) and use methods provided by class Helpers that should; Currently SelAttributes and Paragraph properties are implemented.
uses ... RichMemo, RichMemoHelpers;

TForm = class
  RichMemo1 : TRichMemo;

// SelAttributes property is not available in the base class
// but added by a helper defined at RichMemoHelpers unit
RichMemo1.SelAttributes.Name := 'Courier New';

Append mixed color text at the end of the RichMemo

If you just need simple coloring then here is an example that will each time add a new line with random color (tested on Windows):

  procedure TForm1.Button1Click(Sender: TObject);
    i, j: integer;
    str: string;
    with Richmemo1 do
      str := 'Newline text';
      i := Length(Lines.Text) - Lines.Count; // cr as #10#13 is counted only once so subtract it once
      j := Length(str) + 1;                  // +1 to make the cr the same format
      SetRangeColor(i, j, Round(random * $FFFFFF));
 Newline text
 NewLine text
 NewLine text

Alternative example for simple coloring (tested on Windows):

  procedure TForm1.Button2Click(Sender: TObject);
    with RichMemo1 do
      Lines.Add('Line in red');
      SetRangeColor(Length(Lines.Text) - Length(Lines[Lines.Count - 1]) - Lines.Count - 1, Length(Lines[Lines.Count - 1]), clRed);
      Lines.Add('Line in blue');
      SetRangeColor(Length(Lines.Text) - Length(Lines[Lines.Count - 1]) - Lines.Count - 1, Length(Lines[Lines.Count - 1]), clBlue);
      Lines.Add('Normal line.');
      Lines.Add('Normal line.');
      Lines.Add('Line in green ');
      SetRangeColor(Length(Lines.Text) - Length(Lines[Lines.Count - 1]) - Lines.Count - 1, Length(Lines[Lines.Count - 1]), clGreen);
 Line in red
 Line in blue
 Normal line.
 Normal line.
 Line in green

If you need mixed coloring then this is an example that will add a new line with several different colored words (tested on Windows):

procedure TForm1.Button3Click(Sender: TObject);
    procedure AddColorStr(s: string; const col: TColor = clBlack; const NewLine: boolean = true);
      with RichMemo1 do
        if NewLine then
          Lines.Delete(Lines.Count - 1); // avoid double line spacing
        SelStart  := Length(Text);
        SelText   := s;
        SelLength := Length(s);
        SetRangeColor(SelStart, SelLength, col);
        // deselect inserted string and position cursor at the end of the text
        SelStart  := Length(Text);
        SelText   := '';
    AddColorStr('Black, ');
    AddColorStr('Green, ', clGReen, false);
    AddColorStr('Blue, ', clBlue, false);
    AddColorStr('Red', clRed, false);
 Black, Green, Blue, Red
 Black, Green, Blue, Red
 Black, Green, Blue, Red


Platform Support Matrix

Values in the matrix are not expected to be static (except for "carbon" column), each system is planned to support all features declared by RichMemo.

Note that the table contains more features than published above. That means that the APIs are already available in RichMemo, but since they're unstable (on some platforms) it's considered "experimental" rather than promised.

Feature Win32 Gtk2 Qt Cocoa Carbon
Font color and style selection Yes Yes Yes Yes Yes
Font background color Yes Yes Yes Yes No
Subscript,Superscript Yes Yes No No No
GetStyleRange Yes Yes No Yes Yes
Paragraph Alignment Yes Yes Yes Yes Almost Impossible
Paragraph Metrics Yes Yes No Yes Almost Impossible
Paragraph Tabs Yes Yes No Yes No
Zoom Yes Incomplete No Yes No
Printing Yes No No No No
RTF Load/Save OS RichMemo No OS OS
Insertables Yes Yes No No No


RichMemo without Theme patch
RichMemo with Theme
  • RichEdit is used as system widgetset. The latest known .dll is loaded and initialized on start. Please note that RichEdit 1.0 would not support most of the features.
  • The internal wrapper of RichEditManager is provided in order to be compatible with Win 9x. However, it was never tried or tested. It's also expected that TOM object could be wrapped as one of the RichEditManager implementation. However, having the "manager" in place could be removed completely.
  • According to the internet, RichEdit control was not updated by Microsoft to support Theme drawing (since XP and up to Windows 8.1). Thus, RichEdit might always look like an old Win9x 3d-framed control. Based on the patch provided at the issue a way to override WM_NCPAINT method was introduced in r4153.

Win32RichMemo provides a global variable NCPaint. It's a handler of non-client area drawing. By default, it attempts to draw themed border (see Win32RichMemo.ThemedNCPaint for implementation). It provides good results on Windows XP themes, but later themes (where animations are used), the results are not so great and should be updated.

In order to let system do NCPaint only (i.e. LCL implementation is causing issues or new windows updated RichEdit to draw borders properly), you can change NCPaint value at runtime, resetting it to nil

  RichMemo, ..{$ifdef WINDOWS}Win32RichMemo{$endif}

  {$ifdef WINDOWS}

You can also provide your own implementation of NCPaint. However, if you implement proper animated theme drawing, please provide patch.

The behavior is Windows implementation specific and should not (and will not be) part of RichMemo interface.


  • GtkTextView is used as system widgetset
  • Sub and Superscript are not supported natively, an extra code is implemented in gtk2richmemo in order to implement them.
  • Bulletin and numbered lists are emulated.


The APIs between Gtk2 and Gtk3 are not really different. The major difference is in painting. For Gtk3 Cairo canvas is heavily used. The only area it affects is "Internals". IF any one wants to contribute Gtk2 implementation - please create separate gtk3richmemoXXX units. No {$ifdefs} should be created in gtk2 units.


  • NSTextView is used for Cocoa as system widgetset
  • Not every font-family provides italic font. Thus even if you pass fsItalic as part of Style for a font, it might be ignored.


  • QTextEdit widget is used. Current C-mappings for Qt are missing a lot of RichText APIs, thus full implementation is currently impossible.
  • The following classes need to be mapped to C-functions:
    • QTextBlockFormatH needed for paragraphs alignments (such as paragraph indents, line spacing and tabs). QTextEdit only exposes paragraph alignment.
    • QTextCharFormatH needed for additional character formatting (i.e. vertical alignment, links support). QTextEdit only exposes font styles.

See Also

MyNotex application which uses modified by Massimo Nardello RichMemo package on Linux-Gtk2

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