RichMemo

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About

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 a cross-platform is the primary, most of windows RichEdit features are replaced, making RichMemo not compatible with Delphi's VCL or RX RichEdits.

Its main caracteristics are :

  • Text highlight
  • Import/Export RichText (not yet implemented)
  • 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.

Screenshot

RichMemo macosx screenshot. Thanks to Dominique Louis

Bug reporting

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

Author

Dmitry 'skalogryz' Boyarintsev

License

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.

Download

Releases can be found at Sourceforge Lazarus-CCR project

The latest trunk is available here: https://lazarus-ccr.svn.sourceforge.net/svnroot/lazarus-ccr/components/richmemo


note: Currently it's recommended to use the svn version. [1]

Change Log

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

Dependencies / System Requirements

  • Lazarus 1.0.0

Status: Released.

Issues:

Supported Widgetset

  • Win32
  • Gtk2
  • Carbon - support is limited due to inflexible Carbon APIs and deprecation of Carbon by Apple
  • Cocoa

Installation

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

RichMemoPalette.PNG

TRichMemo

methods

SetTextAttributes

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);

GetTextAttributes

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.

GetStyleRange

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 or some other error.

SetRangeColor

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

SetRangeParams

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.

GetParaAlignment

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.

Note:

  • 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.

SetParaAlignment

Sets paragraph alignent

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

Note:

  • 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

GetParaMetric

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

Note

  • 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;

SetParaMetric

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.

LoadRichText

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.

SaveRichText

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

properties

HideSelection

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.

TRichEditForMemo

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.

methods

FindText

Searches a given range in the text for a target string

properties

SelAttributes

Reads/Modifies character attributes of the current selection.

Paragraph

Reads/Modifies paragraph attributes of the current selection.

RichMemoUtilities

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

InsertImageFromFile

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

Installation

  • Download the package 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';

See Also

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

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