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ATSynEdit is the multi-line edit control, with fixed font.

(press "Download Zip" button at right)

Author: Alexey Torgashin



ATSynEdit files licensed under MPL 2.0. You can optionally use them under LGPL if your project needs it.

EControl files licensed under special license (readme.txt), usage allowed only in open-source projects.


Lazarus: 1.4+

One of the last versions was tested on:

  • Windows (x32)
  • Linux GTK2 (x32, x64)
  • Qt (Linux, Windows) (main problem was moving all painting code into Paint event, it's done)
  • macOS (10.8 and later)

Keyboard shortcuts

Run demo_editor and call menu item "Help - Commands'. You'll see all shortcuts in a dialog like this:

atsynedit keymap.png

Mouse shortcuts


  • Ctrl+click - add/delete caret
  • Ctrl+drag - add caret with selection
  • Ctrl+Shift+click - add carets column in several lines (from previous caret to clicked line)


  • Alt+drag - select column of text (Note: it may look weird if word-wrap on, because wrap is not considered here at all. Simple rectangle of coordinates [x1,y1]-[x2,y2] is always selected, even if this gives bad looking screen)
  • drag on gutter's line numbers - select by entire lines
  • double-click and immediately drag - select text by words


  • double-click - select clicked word
  • triple-click - select entire line (limited by end-of-lines)
  • middle-button click - start "Browser Scroll" mode: circle mark appears and mouse moving around this mark auto-scrolls text in 4 directions; speed of scrolling depends on distance of cursor from circle mark (any click to turn off)


Multi-carets are several carets at once. All carets work together for many editing commands: caret moving, text typing, deleting, selection with keyboard. See "Mouse shortcuts", how to add/remove carets.




If you add caret with Ctrl+click, caret has no selection. If you add caret with Ctrl+drag, caret will have selection. You can add selections to carets later, by Shift+arrows, Shift+Home, Shift+End etc.

Multi-selections are handled specially on copy/paste. If you copy selections, then move carets, then paste, paste will insert clipboard lines into carets: line-1 at caret-1, line-2 at caret-2 etc (only if carets count equals to lines count in clipboard, otherwise result is different).

Animation shows this:


Clipboard commands with selections

Clipboard-related commands work with carets, both with selections and without them. Some details about this:

Command Behaviour, when there're no selections Behaviour, when at last one selection present
Copy to clipboard Copies entire lines, containing carets. (Ignores multiple carets on same line.) Copies only selections text. (Ignores carets without selections.)
Cut to clipboard Similarly to "Copy" w/o selections. Similarly to "Copy" with selections.
Paste from clipboard First, selections are cleared (deleted). Then, command pastes text into each caret position. Special case is when clipboard lines count equals to carets count - in this case, first line is inserted at first caret, second line is inserted at 2nd caret, etc.
Delete char Deletes one char at each caret position. Deletes only selections text. (Ignores carets without selections.)

Help topics

What limitations it has?

  • Cannot set different fonts for different parts
  • All lines have the same height
  • Not supported RTL mode, limited support for Arabic text
  • Not supported Unicode code points >0xFFFF, caret pos incorrect

What features it has?

  • Fast editing of big texts (tested 10M log)
  • Syntax highliting using 'adapters'
  • Multi-carets from birth. All code carets aware.
  • Strings object is holder of text. 2+ editors can have 1 strings obj. (Split editor.)
  • Unicode (used UnicodeString in Strings obj)
  • Word-wrap (wrap at control edge, wrap at column)
  • Inter-line gaps (see #Gaps_object)
  • Undo/redo
  • Column blocks
  • Gutter (line numbers, folding, colored line states)
  • Bookmarks (with icons)
  • Supports Win/Unix/Mac line ends
  • Minimap like Sublime Text
  • Micromap (owner drawn)
  • Ruler (at top edge)
  • Renders wrapped indent (line contains some indent, wrapped parts contain the same indent)
  • Renders CJK chars with big width
  • Renders some Unicode chars as "AABB" hex code
  • Renders unprintable chars (space, tab, line end)
  • Can highlight URLs
  • Can set color attributes for ranges (to hilite brackets, words)

Difference from other components?

  • Adapters to support syntax hilight; possible to support syntax files from any app: Sublime Text, Atom, EmEditor etc.
  • Muti-carets, multi-selections
  • Gaps (I didn't see this in others)
  • Minimap, Micromap (rare in others)
  • Diff from SynEdit: simpler set of objects, no "markup objects"

Does it need to be installed?

It may be installed or not.

  • Use not installed: see below "Basic example how to use".
  • Use installed: in Lazarus IDE, open package file "atsynedit\atsynedit_package". Install it in Package dialog. You 'll have components installed in "Misc" page of component pallette: TATSynEdit, TATEdit (single line edit), etc.

What parts does it have?

Strings object

type TATStrings in unit atstrings. Holds text lines.

  • To add text lines, use procedures of Strings: LineAdd, LineInsert, LineDelete.
  • To get/set text lines, use properties:
    • Lines[i]: text, of type UnicodeString
    • LinesLen[i]: integer: same as getting Length of item (in WideChars), but faster
    • LinesEnds[i]: enum: kind of end-of-line chars
    • LinesHidden[i]: bool: true if line is fully hidden (inside folded block)
    • LinesFoldFrom[i]: byte: 0 if line is not folded, >0 if line is folded from this char-pos
    • LinesState[i]: enum: state normal/changed/saved, it's shown by color on gutter
    • LinesBm[i]: integer: bookmark kind (each kind has assigned color), or 0 if no bookmark
    • LinesHint[i]: string: hint which shows by moving mouse over bookmark icon (for items with bookmark only)

Carets object

type TATCarets in unit atsynedit_carets. Holds list of items of type TATCaretItem. Each caret item has properties:

  • PosY: index of line in Strings object, 0-based
  • PosX: offset of caret from line start, 0-based
  • EndY, EndX: position for selection edge for this caret, or -1/-1 if no selection for this caret
  • CoordY, CoordX: screen coordinates (usually you don't need these)

Note: for forward sel, pair (PosY, PosX) is after pair (EndY, EndX); for backward sel the order is reversed. So if you want to get pos of selection start (e.g. to delete this selection), get minimal pair.

Keymap object

type TATKeymap in unit atsynedit_keymap.

Holds list of keyboard actions of type TATKeymapItem. It's inited at start. And you can add more keymap items or change hotkeys for any keymap item. Each keymap item has 2 (yet) hotkeys, second is needed for Copy-to-clip (Ctrl-C and Ctrl-Ins), Paste-from-clip (Ctrl-V and Shift-Ins) etc.

When adding keymap item, you can set simple hotkeys (e.g. "Alt+Shift+F") or key combos (several simple hotkeys which must be pressed in order). Example adds commands with simple hotkey and combo:

    M: TATKeymap;
  M.Add(cmd_My1, 'cmd with simple hotkey', ['Ctrl+Shift+F'], []);
  M.Add(cmd_My2, 'cmd with 3 keys combo', ['Ctrl+B', 'Ctrl+B', 'Ctrl+M'], []);

WrapInfo object

type TATSynWrapInfo in unit atsynedit_wrapinfo. Holds list of wrap items, each is info about wrapped part of line or about entire line:

  • its original line index in Strings object (0-base)
  • its char offset in original line (0-base)
  • its length
  • its indent size (if feature "wrapped indent" is on)
  • its final-state: is it first/middle part of wrapped line, or final part

One wrap item renders on control as one short line. It is part of wrapped line or entire line. Also used for wrap-mode off, this is simple case - one wrap item per one line. Wrap items exist only for lines not hidden by folding feature (with Strings.LinesHidden[i]=true).

Undo object

Holds list of actions for Undo/Redo. You must not touch it. Filled auto by changing-adding-deleting of lines in Strings object (by any API). Also holds end-of-lines markers (changed ends-of-lines can undo too).

Items in Undo object have 'group marker'. This means that some editor commands set this marker, and items after marked item will undo as a group (if option "Group undo" on). You can set group marker (for next editor action) by method SetGroupMark of Strings object.

Gutter object

type TATGutter in unit atsynedit_gutter. Holds list of gutter items. Each gutter item has properties:

  • Visible: gutter band is shown on gutter
  • Size: width of gutter band
  • Left/Right: calculated auto from Visible and Size, coordinates of band on control

To know which band of gutter does what, use properties of ATSynEdit: GutterBandNum (index of band for line numbers), GutterBandFold (index of band for folding) etc. Example shows/hides gutter column:

  ed.Gutter[ed.GutterBandNum].Visible:= checkGutterNum.Checked;

Fold object

type TATSynRanges in unit atsynedit_ranges. Holds list of ranges which can be folded and show plus/minus on gutter. Each range is of type TATSynRange, it has properties:

  • Y: starting line of range (0-based)
  • Y2: ending line of range (if same as Y, plus/minus not shown on gutter)
  • X: char-offset in starting line (must be >0, 1 means fold from 1st char)
  • Folded: boolean, state: folded/unfolded
  • Staple: boolean, true if range has staple shown (vertical line on text area)
  • Hint: string, shown in rectangle when range is folded

Example adds few ranges to text:

  //nice to sort by 2nd param
  Edit1.Fold.Add(1, 4, 15, false, ''); //line 4 to 15, range1
  Edit1.Fold.Add(1, 5, 9, false, ''); //line 5 to 9, nested into range1
  Edit1.Fold.Add(1, 7, 8, false, ''); //line 7 to 8, nested into range2

To fold/unfold a range, don't change Folded field, use methods of ATSynEdit: DoRangeFold, DoRangeUnfold.

To fold/unfold all, use commands via DoCommand method: cCommand_FoldAll, cCommand_UnfoldAll.

Markers object

type TATMarkers in unit atsynedit_markers. Holds list of marker items. Each marker item has properties:

  • PosX, PosY: position of marker (like caret pos).
  • CoordX, CoordY: screen coordinates (don't change them).
  • Tag: integer field, useful for apps: e.g. CudaText holds here tabstop-index (several markers with the same index >0 give multi-carets, when user jumps to one of markers).
  • SelLen: integer field, useful for apps: e.g. CudaText holds here selection length for marker (caret will have this selection when user jumps to this marker).
  • Ptr: object field (to store app specific objects, TObject). Object is freed automatically when marker item freed.

Markers are painted as red triangles below their positions (PosX, PosY). They are needed e.g. for making snippets, where user needs to jump over snippet's insert points and wants to see these points. Also it's good for IDE to have commands like "drop marker here", "remove last marker", "swap caret and last marker" etc (like CodeRush).

Example code from CudaText:

procedure EditorMarkerGotoLast(Ed: TATSynEdit; AndDelete: boolean);
  Caret: TATCaretItem;
  Mark: TATMarkerItem;
  if Ed.Carets.Count<>1 then exit;
  if Ed.Markers.Count=0 then exit;
  Caret:= Ed.Carets[0];
  Mark:= Ed.Markers[Ed.Markers.Count-1];
  Caret.PosX:= Mark.PosX;
  Caret.PosY:= Mark.PosY;
  if AndDelete then

Attribs object

type TATMarkers (same as for Markers). Holds list of additional color/font attribute items, these items are added to syntax hiliting and selection hiliting. Each item has properties:

  • PosX, PosY: position of attr, like caret pos.
  • SelLen: length if attr (attr is single line).
  • Ptr: object of type TATLinePartClass, which has Data field. This Data is record, it contains all color/font/borders properties of this attr.

Attribs object is used in CudaText: app adds attr items to hilite brackets, to hilite misspelled words, etc.

If you add attrib item, create new object of type TATLinePartClass, fill its Data, and pass object to TATMarkers.Add. This object is freed automatically if attrib item deleted or all attribs cleared.

Colors object

Contains color properties of type TColor. For ex, Colors.TextFont is text font color, Colors.TextBG is text background color.

Gaps object

List of gap items. Gap items have properties: line index, size (maybe more later). Gap item paints as rectangle (it is owner-drawn), just between lines N and N+1, not overlapping text. Example usages:

  • App wants to show picture preview, when picture is linked in HTML. It creates small preview picture e.g. 100x50, and adds gap: gap size=52, picture height and 2 pixels of border.
  • App runs linter on JS code, for JS errors it places bookmarks, and adds gaps with size=15 for error lines: in gaps it writes errors, maybe icons.

To add/remove gaps:

 ed.Gaps.Add(LineNum, Size);
 //to delete this gap
 ed.Gaps.DeleteForLineRange(LineNum, LineNum);

Event OnDrawGap is used to paint gaps, it gets canvas, and rectangle on canvas. Note: if you add gap to the last line, you must turn on option OptLastLineOnTop, better don't turn it off later (to not scroll, when gap added/removed).

What are the basic methods/properties?


  • property Strings: Strings object
  • property Carets: Carets object
  • property Gutter: Gutter object
  • property Keymap: Keymap object
  • property Fold: Fold object
  • property Markers: Markers object
  • property Attribs: Attribs object
  • property Colors: Colors object
  • property Gaps: Gaps object


  • procedure LoadFromFile(const AFilename: string): load text from file (filename uses utf-8)
  • procedure SaveToFile(const AFilename: string): save text to file


  • property Modified: modified state (cleared on file loading)
  • property ModeOverwrite: mode insert/overwrite state (Ins key toggles it)
  • property ModeReadOnly: mode read-only state


  • procedure Update(AUpdateWrapInfo: boolean = false; AUpdateCaretsCoords: boolean = true): to repaint+invalidate; 1st param must be True to recalculate WrapInfo object (usually it's auto updated, but if text change detection don't work, e.g. Strings object changed directly, pass True here)
  • procedure DoCommand(ACmd: integer; const AText: UnicodeString = ""): command runner, pass command code to run it (see file atsynedit_commands)
  • property Text: unicodestring which gives entire editor text with LF separator


  • procedure DoCaretSingle(AX, AY: integer): make single caret
  • function CaretPosToClientPos(P: TPoint): TPoint: convert caret coords to screen coords
  • function ClientPosToCaretPos(P: TPoint; out AEndOfLinePos: boolean): TPoint: convert screen coords to caret coords
  • function IsLineWithCaret(ALine: integer): boolean: is line index contains any caret


(P.Y is line index, P.X is char offset in line, 0-based)

  • property SelRect: for column selection, rectangle of column block
  • function IsSelRectEmpty: is column selection exists
  • procedure DoSelect_All: select all text (makes single caret)
  • procedure DoSelect_Line(P: TPoint): select single line
  • procedure DoSelect_Word(P: TPoint): select single word
  • procedure DoSelect_LineRange(ALineFrom: integer; P: TPoint): select several lines from line index to given point


  • property LineTop: index of line visible at the top of control (almost vertical scroll, though exact scroll pos is different, it considers WrapInfo object)
  • property LineBottom: index of line visible at the bottom of control (because of folding you cannot simply calculate it)
  • property ColumnLeft: index of left visible column (ie, horizontal scroll)
  • procedure DoRangeFold(ARange: TATSynRange): fold range, which exists in the Fold object
  • procedure DoRangeUnfold(ARange: TATSynRange): unfold range
  • procedure DoScrollByDelta(Dx, Dy: integer): scroll editor area by Dx chars right and Dy lines down
  • procedure DoGotoPos(APnt: TPoint; AIndentHorz, AIndentVert: integer): scroll editor to given caret pos


I cannot post here options. See ATSynEdit properties beginning with "Opt", these are props which can change in design time in IDE. You can place on form ATSynEdit and see in IDE its "Opt" properties and see their values.


  • Strings.EncodingDetect: boolean
  • Strings.Encoding: enum (cEncAnsi, cEncUTF8, cEncWideLE, cEncWideBE)
  • Strings.EncodingCodepage: string (used for Encoding=cEncAnsi)
  • Strings.SaveSignUtf8: boolean

Basic example how to use?

  • Add "uses ATSynEdit".
  • Add variable "ed".
  • Add OnCreate event to new form.
  • How to load file "unit1.pas":
   procedure TForm1.FormCreate(Sender: TObject);
     ed:= TATSynEdit.Create(Self);
     ed.Parent:= Self;
     ed.Align:= alClient;
     ed.Font.Name:= 'Courier New';
     ed.OptUnprintedVisible:= false;
     ed.OptRulerVisible:= false;
  • How to save file: call "ed.SaveToFile()".

How does it manage the coordinates?

Carets object contains list of caret items. Each caret item has props PosY (line index in Strings object), PosX (char offset from line start). Strings object holds UnicodeString's, where each WideChar gives offset=1, and even Tab char gives offset=1. Before painting, PosX/PosY converted to properties CoordX/CoordY, screen coordinates. CoordY is pixels from top control edge (you don't need to change by ruler height), CoordX is pixels from left edge (you don't need to change by gutter width). Don't touch CoordX/CoordY. Change PosX/PosY (caret item position) and EndX/EndY (selection end for caret item, both -1 if no selection present for this item).

Caret pos to/from screen coords

Use these funcs if needed to convert caret pos to screen coordinates in pixels:

  • function CaretPosToClientPos(P: TPoint): TPoint.
  • function ClientPosToCaretPos(P: TPoint; out AEndOfLinePos: boolean): TPoint. Last param: returned true if caret pos is after real end-of-line, false if caret pos is inside line.

Functions give result.Y<0 if cannot calculate pos. For example, if line index is too big or line with this index is fully folded.

Property OptCaretVirtual exists. If true, caret is allowed after end-of-line. Functions (above) consider it.

Caret pos to/from column index

Use these funcs (unit ATStringProc) to convert tab-char-indenendent caret pos x, to/from tab-char-dependant column index:

  • function SCharPosToColumnPos
  • function SColumnPosToCharPos

How to manage the caret, the selection?

See topic above about "Carets object". To change position of carets, get Carets property of editor, and change caret items' properties PosX/PosY, then call editor's Update (repaint). To change selection for any caret (each caret has own selection), do the same: get any caret item, and change its propeties EndX/EndY (-1 to delete selection), then call editor's Update.

Better don't do overlapping selections (e.g. selection of caret-2 overlaps selection of caret-3), but even here you can call "Carets.Sort" which should sort carets by PosX/PosY and fix them.

You can delete caret items. Or add caret items.


   Caret: TATCaretItem;
   i: integer;
   for i:= 0 to edit.Carets.Count-1 do
     Caret:= edit.Carets[i];
     change here Caret.PosX and Caret.PosY

How to modify text?

See topic above about "Strings object". To change text, get Strings property of editor. "Strings.Count" is number of lines in object. Then access methods of Strings: LineAdd, LineInsert, LineDelete. To get/set lines by index, use properties of Strings: Strings.Lines[i], etc, listed above.

Strings.Lines[i] do not contain end-of-line chars. Usually not needed to change end-of-line chars. You can change them using Strings.LinesEnds[i].

  • You can read Strings from one editor1 and set it to Strings of editor2. This will make editor2 having same strings object (needed for split-tab).
  • Do call editor's Update method to repaint. Call Update(true) to force invalidate WrapInfo object and repaint.

How to highlight syntax?

There're 2 ways:

  • OnCalcHilite event (better, if your code is small, e.g. colorize few tokens)
  • Adapter (better, if your code is big, e.g. support for EControl lexers)

You can set handler of OnCalcHilite event. Adapter is different way to do the same. Instead of using event, you write code in the new class which is child of TATAdapterHilite. Then you link adapter to editor:

 Adapter.AddEditor(editor2); //if 2 editors share the same text buffer

To unlink adapter from all editors, call:


If adapter assigned, editor will call adapter's methods (first called adapter, next OnCalcHilite).

See file "atsynedit_adapters.pas". It has base class for such adapters. Main method in adapter, which is called by ATSynEdit is:

 procedure OnEditorCalcHilite(Sender: TObject;
     var AParts: TATLineParts;
     ALineIndex, ACharIndex, ALineLen: integer;
     var AColorAfterEol: TColor);

Parameters here:

  • Sender: editor object.
  • AParts: array of "parts": each part has Offset, Len, colors, font style. Adapter must create parts for entire string (1st part takes 1st chars of string, last part takes last chars of string). See code about TATLineParts.
  • ALineIndex: index of passed line (0-based).
  • ACharIndex: index of 1st char in line (it's not 0 if wrapped part of line is shown, 0-based).
  • ALineLen: length of substring to hilite.
  • AColorAfterEol: return here color for background of line after end-of-line. Return clNone if no color needed.

Real string which you must hilite: see example project how to get it.

How to set same text-source to several editors?

Several editors can have same text source, text source is ATStrings object which holds

  • same text for all editors
  • separate folding states for each editor

Each editor holds its own WrapInfo object so wrapped states are separate. Each editor holds its own Carets object, so carets/selections are separate.

Tech details: items in ATStrings object have fields:

   ItemHidden: packed array[0..cMaxStringsClients-1] of ByteBool;
     //this line is fully hidden
   ItemFoldFrom: packed array[0..cMaxStringsClients-1] of byte;
     //0: line not folded
     //>0: line folded from this char-pos

(constant can be changed in source). These fields allow to hold separate fold-info for each "editor client" of ATStrings. Each client must have it's own EditorIndex (0 to cMaxStringsClients-1). Example, make 4 editors ed0..ed3.

  • change cMaxStringsClients to 4
  • set ed0.EditorIndex:=0
  • set ed1.EditorIndex:=1
  • set ed2.EditorIndex:=2
  • set ed3.EditorIndex:=3
  • set ed1.Strings:=ed0.Strings
  • set ed2.Strings:=ed0.Strings
  • set ed3.Strings:=ed0.Strings

If user changes text in ed3, ed3 will update but others will not: you need to force it:

  • ed0.Update(true)
  • ed1.Update(true)
  • ed2.Update(true)

How to add/change commands?

To change action of internal commands (file atsynedit_commands.pas) you need to use event OnCommand which can do any action for any command (and return AHandled=True to disable default code). Better use OnCommand handler for all commands, even new ones. So you can call DoCommand() and have one handler to do anything.

Example func which adds new commands to Keymap object:

  cmd_FileNew = 2500;
procedure InitKeymapApp(M: TATKeymap);
  M.Add(cmd_FileNew, 'file: new file', ['Ctrl+N'], []);
  M.Add(cmd_FileOpen, 'file: open file', ['Ctrl+O'], []);
  M.Add(cmd_FileSave, 'file: save file', ['Ctrl+S'], []);

Example handler for new commands: some close editor tabs (special case: cannot close tabs just inside OnCommand) and some commands copy something to clipboard:

procedure TfmMain.EditorOnCommand(Sender: TObject; Cmd: integer; var Handled: boolean);
  Handled:= true; //by default command marked as handled
  case Cmd of
        //these commands close tabs so cannot handle here.
        //we start timer which will handle them.
	TimerCmd.Tag:= Cmd;
	TimerCmd.Enabled:= true;
    cmd_CopyLine:         DoCopyLine;
    cmd_CopyFilenameFull: DoCopyFilenameFull;
    cmd_CopyFilenameDir:  DoCopyFilenameDir;
    cmd_CopyFilenameName: DoCopyFilenameName;
      Handled:= false; //unknown command: don't mark handled

How to emulate Edit, Combobox?

Special child of ATSynEdit exists: ATEdit. It's single line control in which all multiline text editing is disabled. And paste can give only single line. And scrollbars are disabled. And many commands (like "Move lines up/down") are removed from Keymap object.

Special child of ATEdit exists: ATComboEdit. It has micromap area which paints dropdown arrow to look like combobox. Click on this arrow gives popup-menu with entered variants.

atsynedit combo.png

Variants must be added to history by user code, using OnCommand handler: react to command "cCommand_KeyEnter". Example of handler:

procedure TfmCombo.ComboCommand(Sender: TObject; ACmd: integer;
  var AHandled: boolean);
  s: string;
  n: integer;
  if ACmd=cCommand_KeyEnter then
    with ed do
      s:= UTF8Encode(Trim(Text));
      Text:= '';
      DoCaretSingle(0, 0);
      n:= Items.IndexOf(s);
      if n>=0 then Items.Delete(n);
      Items.Insert(0, s);
    AHandled:= true;

What props are useful for statusbar?

  • number of carets: Carets.Count
  • positions of carets: Carets.Items[i].PosX (column), PosY (line)
  • text encoding: Strings.Encoding
    • cEncAnsi: then codepage is given by Strings.EncodingCodepage
    • cEncUTF8: then presence of utf8 bom is given by Strings.SaveSignUtf8
    • cEncWideLE, cEncWideBE: then presense of Unicode bom is given by Strings.SaveSignWide
  • text line endings (win/unix/mac): Strings.Endings
  • tab-char width: OptTabSize
  • tab-char entered by spaces: OptTabSpaces
  • index of top visible line: LineTop
  • index of left visible column: ColumnLeft
  • modified state: Modified
  • read-only mode: ModeReadOnly
  • insert/overwrite mode: ModeOverwrite
  • word-wrap mode: OptWrapMode
  • unprinted chars shown: OptUnprintedVisible
  • selection: get Carets.Items[i].PosX/PosY/EndX/EndY, for state of column selection get IsSelRectEmpty, SelRect

How to customize popup menu?

These properties allow to change all menus in control (you cannot modify default menu):

  • PopupText: for text area
  • PopupRuler
  • PopupMinimap
  • PopupMicromap
  • PopupGutterBm: for bookmarks column
  • PopupGutterFold: for folding column
  • PopupGutterNum: for line numbers column

Prop OptMouse* exists, which allows to show menus on mouse-down or on mouse-up.

How to know indexes of changed lines in OnChange?

You have event Strings.OnLog. It gives parameters:

  • ALine: index of line at which change occurs
  • ALen: len of text which is added (ALen>0) or deleted (ALen<0) at line start

Get the log, save it, and then parse it during OnChange.

How to export text to HTML?

Unit atsynedit_export_html has the function which does HTML report. It has several parameters to customize output. See example of usual parameters in the demo_editor.

ATSynEdit has API which allows to make report to any format. It's function DoCalcLineHiliteEx. It returns syntax highlight info for any line. Info is stored in TATLineParts struct, see HTML exporter code how to use it.

Short description of events?

  • OnBeforeCalcHilite: Called before OnCalcHilite for first visible line.
  • OnCalcBookmarkColor: Called to determine color of bookmark (background color of line with bookmark).
  • OnCalcHilite: Called to calculate syntax highlight for a line (or wrapped part of line). You need to fill TATLineParts struct for this line.
  • OnCalcStaple: Called to determine color of block staple (vertical line which is painted near fold-ranges).
  • OnChange: Called after any command which changes text.
  • OnChangeCaretPos: Called after any command which changes caret(s) position(s).
  • OnChangeState: Called after any command which changes editor state, such as read-only, insert/overwrite, word-wrap etc.
  • OnClickDouble: Called on double-click on text area.
  • OnClickGutter: Called on click on gutter area.
  • OnClickMicromap: Called on click on micromap area.
  • OnClickMiddle: Called on middle button click on text area.
  • OnClickTriple: Called on triple-click on text area.
  • OnClickMoveCaret: Called just before changing caret pos via mouse click (you get prev caret pos, new caret pos).
  • OnClickEndSelect: Called just after mouse-up, if single selection made (you get selection start pos, end pos).
  • OnCommand: Called before running any command. You can disable any command processing, or perform custom processing before/instead of command.
  • OnCommandAfter: Called after running command.
  • OnDrawBookmarkIcon: Called on painting gutter mark for line with bookmark.
  • OnDrawEditor: Called after painting entire text area.
  • OnDrawLine: Called after painting line (or wrapped part of line) on canvas. You can paint some "image" over this line.
  • OnDrawMicromap: Called on painting micromap area.
  • OnDrawRuler: Called after painting ruler area.
  • OnScroll: Called after any command which scrolls text.

What is logic of grouped-undo?

There're kinds of group-marks in undo-items: hard-marks, soft-marks.

  • Hard-marks are placed on undo-items if you call Strings.BeginUndoGroup, editing, Strings.EndUndoGroup. All items marked with hard-marks are undone as group, even of OptUndoGrouped=false.
  • Soft-marks used only if OptUndoGrouped=true. Soft-marks are placed on one next undo-item, when user does mouse click (or some similar action); or in code by call Strings.SetGroupMark. All items beginning with last soft-marked item are undone as group.

Example 1. OptUndoGrouped=true, such undo-items exist:

  • item1
  • item2
  • item3, soft-mark
  • item4
  • item5, hard-mark
  • item6, hard-mark
  • item7
  • item8, soft-mark
  • item9
  • item10


  • undone: item10..8; until soft-mark.
  • undone: item7..3; until soft-mark.
  • undone: item2..1.

Example 2. OptUndoGrouped=false, undo-items:

  • item1
  • item2
  • item3, hard-mark
  • item4, hard-mark
  • item5, hard-mark
  • item6
  • item7


  • Undone: item7
  • Undone: item6
  • Undone: item5..3
  • Undone: item2
  • Undone: item1

Soft-marks also used together with hard-marks. Soft-mark is placed with first hard-mark after call Strings.BeginUndoGroup. This allows to undo N groups of edits, if many items hard-marked (w/out gaps).

Example 3. Undo-items:

  • item1, hard-mark
  • item2, hard-mark, soft-mark
  • item3, hard-mark
  • item4, hard-mark, soft-mark
  • item5, hard-mark
  • item6, hard-mark


  • undone: item6..4
  • undone: item3..2
  • undone: item1

How to record/playback macros?

Macro support must be done on app level, component does support by event OnCommand. Handle OnCommand and you get all command codes which run. Real app adds more commands in Keymap object and it must decide which of them it wants to record (e.g. don't record commands to show dialogs, and record commands which comment/uncomment lines).

To playback macro, call DoCommand for all codes in macro.

Hint. CudaText also adds 3 commands to help with macros:

  • "mouse click" (command recorded in OnClick event of editor)
  • "goto pos" (command recorded by GoTo dialog)
  • "finder action" (command recorded when doing find/replace actions)


Auto-completion lists

General API

Unit atsynedit_form_complete has function to show completion-listbox for editor. Unit uses ATListbox. Listbox is not modal. It keeps editor caret blinking. While listbox shown, editor don't get keyboard input, but listbox passes typed chars/Backspace/Left/Right to editor. Listbox replaces text on Enter/Tab keys, hides on Esc or clicking outside.

  TATCompletionPropEvent = procedure (Sender: TObject;
    out AText: string; out ACharsLeft, ACharsRight: integer) of object;
procedure DoEditorCompletionListbox(AEd: TATSynEdit; AOnGetProp: TATCompletionPropEvent);

Callback params:

  • AText: Chr(13)-separated strings, each string is S_id+'|'+S_text+'|'+S_desc. S_id is a prefix before actual text (good to pass here short texts: "var", "func"). S_text (it is usually second item) is text which is inserted into editor on closing listbox. After id/text several items may exist, all '|'-separated, they will show in additional listbox columns. After items you may add Chr(9)+S_hint: item shows outside of listbox, in a hint window.

For ex, this gives listbox with 3 items:

AText:= 'func|Func1|(param1, param2)'#9'Func desc' + #13 + 'var|Var1' + #13 + 'var|Var2';

If you need to insert not only S_text but also additional substr, use such S_text: S_text+#1+S_before_caret+#1+S_after_caret (also substrings will be added before and after caret). This is used by HTML autocompletion: here S_before_caret is ">" and S_after_caret is "</tag>".

  • ACharsLeft, ACharsRight: count of chars, to the left and right of the caret, which will be replaced by selected listbox item. These counts must be detected by app. Some app may need to count only word chars, some may need spaces/brackets.


  • Func don't work for a) read-only editor, b) multi-carets.
  • You can change colors/sizes/font of listbox: see unit source.

SynWrite acp files

Unit atsynedit_form_complete_synwrite has function to show auto-completion listbox, from SynWrite .acp files. Acp file must be in the format described in SynWrite help file. You may copy acp files from SynWrite distro, or from additional lexers (zip files at "Control line" in acp file is suppoted.

Function reads text under caret and leaves only items which match the text. Like SynWrite.


CSS files

Unit atsynedit_form_complete_css has function to show auto-completion listbox, for CSS syntax. You must pass path of file "css_list.ini" from SynWrite distro (it is list of css tags/values). Completion works in 2 modes:

  • caret is on css attrib before ":" char - then list of css attribs is shown (which match the substring under caret),
  • caret is after css attrib and ":" char (before closing ";") - then list of values for this attrib is shown.


HTML files

Unit atsynedit_form_complete_html has function to show auto-completion listbox, for HTML syntax. You must pass path of file "html_list.ini" from SynWrite distro. Completion works in modes:

  • caret on opening/closing tag name: list of tags shown
  • caret after tag, on attribute place before "=": list of attribs for found tag shown
  • caret after tag, after attribute, after "=": list of values of found tag+attrib shown




Finder class TATEditorFinder exists in unit atsynedit_finder. To use it, create Finder object and set its props:

  • Editor: editor object (text will be read automatically)
  • StrFind: search-string (simple string or regex)
  • StrReplace: replace-string (simple string or some regex, eg with "$0", "$1")
  • boolean search flags:
    • OptRegex: treat StrFind/StrReplace as regex
    • OptCase: case-sensitive (for normal and regex modes)
    • OptWords: whole-words search (for non-regex mode, for regex you must use "\b" specifier in search-string)
    • OptBack: backward search (for non-regex mode)
    • OptWrapped: continue search from top, if bottom reached (for back-search: continue from bottom, if top reached)
    • OptFromCaret: search goes from position of first caret (else: from start/end of text)
    • OptConfirmReplace: each replace will occur after event OnConfirmReplace

Dialog of demo:

atsynedit finder.png

Call methods which will find/replace text (they will place selection over found match, and scroll editor to caret). You must also call UpdateBuffer before search: it reads editor text into internal buffer.

    procedure UpdateBuffer;
    function DoFindOrReplace(ANext, AReplace, AForMany: boolean; out AChanged: boolean): boolean;
    function DoReplaceSelectedMatch: boolean;
    function DoCountAll(AWithEvent: boolean): integer;
    function DoReplaceAll: integer;

Found position and len are props MatchPos, MatchLen. Internally Finder object uses ATStringBuffer to read editor lines into buffer and search inside buffer. Then ATStringBuffer methods used to calculate caret position (from buffer offset) and place caret/selection. Note for regex search: buffer contains only "\n" line ends, other ends don't happen (original file may have any ends).

Finder has events:

  • OnProgress: allows to show progressbar during search
  • OnBadRegex: called if incorrect regex passed
  • OnFound: called when result found
  • OnConfirmReplace: called before replacing text (to show confirmation) if OptConfirmReplace set

Adapter for EControl lexers

See ATSynEdit EControl adapter