Text/Docu/Views.odc

TextViews

DEFINITION TextViews;

	IMPORT Models, Views, Containers, TextModels, TextRulers, TextSetters;

	CONST
		show = FALSE; hide = TRUE;
		any = FALSE; focusOnly = TRUE;

	TYPE
		View = POINTER TO ABSTRACT RECORD (Containers.View)
			(v: View) ThisModel (): TextModels.Model, EXTENSIBLE;
			(v: View) DisplayMarks (hide: BOOLEAN), NEW, ABSTRACT;
			(v: View) HidesMarks (): BOOLEAN, NEW, ABSTRACT;
			(v: View) SetSetter (setter: TextSetters.Setter), NEW, ABSTRACT;
			(v: View) ThisSetter (): TextSetters.Setter, NEW, ABSTRACT;
			(v: View) SetOrigin (org, dy: INTEGER), NEW, ABSTRACT;
			(v: View) PollOrigin (OUT org, dy: INTEGER), NEW, ABSTRACT;
			(v: View) SetDefaults (r: TextRulers.Ruler; a: TextModels.Attributes),
								NEW, ABSTRACT;
			(v: View) PollDefaults (OUT r: TextRulers.Ruler; OUT a: TextModels.Attributes),
								NEW, ABSTRACT;
			(v: View) GetThisLocation (f: Views.Frame; pos: INTEGER; OUT loc: Location),
								NEW, ABSTRACT;
			(v: View) GetRange (f: Views.Frame; OUT beg, end: INTEGER), NEW, ABSTRACT;
			(v: View) GetRect (f: Views.Frame; view: Views.View; OUT l, t, r, b: INTEGER);
			(v: View) ThisPos (f: Views.Frame; x, y: INTEGER): INTEGER, NEW, ABSTRACT;
			(v: View) ShowRangeIn (f: Views.Frame; beg, end: INTEGER), NEW, ABSTRACT;
			(v: View) ShowRange (beg, end: INTEGER; focusOnly: BOOLEAN), NEW, ABSTRACT
		END;

		Directory = POINTER TO RECORD
			defAttr-: TextModels.Attributes;
			(d: Directory) Set (defAttr: TextModels.Attributes), NEW, ABSTRACT;
			(d: Directory) New (text: TextModels.Model): View, NEW, ABSTRACT
		END;

		Location = RECORD
			start, pos: INTEGER;
			x, y: INTEGER;
			asc, dsc: INTEGER;
			view: Views.View;
			l, t, r, b: INTEGER
		END;

		PageMsg = RECORD (Views.PropMessage)
			current: INTEGER
		END;

		PositionMsg = RECORD (Models.Message)
			focusOnly: BOOLEAN;
			beg, end: INTEGER
		END;

	VAR
		ctrlDir-: Containers.Directory;
		dir-, stdDir-: Directory;

	PROCEDURE SetCtrlDir (d: Containers.Directory);
	PROCEDURE SetDir (d: Directory);
	PROCEDURE Focus (): View;
	PROCEDURE FocusText (): TextModels.Model;
	PROCEDURE Deposit;
	PROCEDURE ShowRange (text: TextModels.Model; beg, end: INTEGER; focusOnly: BOOLEAN);
	PROCEDURE ThisRuler (v: View; pos: INTEGER): TextRulers.Ruler;

END TextViews.


TextViews are the standard views for text models (TextModels).


CONST show, hide
Possible arguments to the hide parameter of view.DisplayMarks.

CONST any, focusOnly
Possible arguments to the focusOnly parameter of ShowRange and view.ShowRange.


TYPE View (Containers.View)
ABSTRACT
Standard view for text models.

PROCEDURE (v: View) ThisModel (): TextModels.Model
EXTENSBIBLE
Result type is narrowed.

PROCEDURE (v: View) DisplayMarks (hide: BOOLEAN)
NEW, ABSTRACT, [Operation]
Control hiding of hideable views embedded in the displayed text. If hiding is requested, all views that have a preference hideable will be suppressed, i.e. reduced to zero width and zero height. For example, this is used to selectively hide or show rulers in a text.
If v.context # NIL and ~v.context.Normalize(), this is an operation.

Post
v.HidesMarks() = hide

PROCEDURE (v: View) HidesMarks (): BOOLEAN
NEW, ABSTRACT
Current status: whether view hides hideable views, or not.

PROCEDURE (v: View) SetSetter (setter: TextSetters.Setter)
NEW, ABSTRACT, Operation
Attach a setter to the view.

Pre
setter # NIL	20

Post
v.ThisSetter() = setter

PROCEDURE (v: View) ThisSetter (): TextSetters.Setter
NEW, ABSTRACT
Returns setter currently attached to view.

PROCEDURE (v: View) SetOrigin (org, dy: INTEGER)
NEW, ABSTRACT, [Operation]
Set the origin and vertical displacement of the view.
If v.context # NIL and ~v.context.Normalize(), this is an operation.

Pre
v.ThisModel() # NIL	20
0 <= org	21
org <= v.ThisModel().Length()	22
dy <= 0	23

Post
org = v.ThisSetter().ThisLine(org)
	v.PollOrigin(o, d): o = org, d = dy
org # v.ThisSetter().ThisLine(org)
	v.PollOrigin(o, d): o = v.ThisSetter().ThisLine(org), d = 0

PROCEDURE (v: View) PollOrigin (OUT org, dy: INTEGER)
NEW, ABSTRACT
Return origin and vertical displacement of view. The vertical displacement determines the offset (in units) of the top of the first displayed line, relative to the top of the view area. This is used to support partial display of the first line during scrolling.

Post
0 <= org <= v.ThisModel().Length()
dy <= 0

PROCEDURE (v: View) SetDefaults (r: TextRulers.Ruler; a: TextModels.Attributes)
NEW, ABSTRACT, Operation
Set the default ruler and attributes.

Pre
r # NIL	20
a # NIL	22

PROCEDURE (v: View) PollDefaults (OUT r: TextRulers.Ruler; OUT a: TextModels.Attributes)
NEW, ABSTRACT
Return default ruler and attributes.

PROCEDURE (v: View) GetThisLocation (f: Views.Frame; pos: INTEGER; OUT loc: Location)
NEW, ABSTRACT
Get the location characteristics of the position pos displayed in frame f. (The frame is required to take deciveђdependent character positioning inside words into account.) If pos lies outside view, the next best position inside will be taken.

Pre
f # NIL	20
Displayed(f)	21
0 <= pos	22
pos <= v.ThisModel().Length()	23

Post
loc.view # NIL
	loc.l <= loc.r, loc.t <= loc.b	bounding box of view

PROCEDURE (v: View) GetRect (f: Views.Frame; view: Views.View; OUT l, t, r, b: INTEGER)
Pre
f # NIL	20
Displayed(f)	21
view.context # NIL	22
view.context.ThisModel() = v.ThisModel()	23

Except for performace, equivalent to:
	VAR loc: Location;
	v.GetThisLocation(f, view.context(TextModels.Context).Pos(), loc);
	IF loc.view = view THEN
		l := loc.l; t := loc.t; r := loc.r; b := loc.b
	ELSE
		l := MAX(INTEGER(; t := MAX(INTEGER); r := l; b := t
	END

PROCEDURE (v: View) GetRange (f: Views.Frame; OUT beg, end: INTEGER)
NEW, ABSTRACT
Get the stretch [beg, end) visible in v.

Pre
f # NIL	20
Displayed(f)	21

Post
beg = BeginOf(FirstLineVisible(v))
end = EndOf(LastLineVisible(v))

PROCEDURE (v: View) ThisPos (f: Views.Frame; x, y: INTEGER): INTEGER;
NEW, ABSTRACT
Text position corresponding to the point (x, y) relative to frame f.

Pre
f # NIL	20
Displayed(f)	21

Post
v.GetOrigin(o, d): o <= result <= v.ThisModel().Length()

PROCEDURE (v: View) ShowRangeIn (f: Views.Frame; beg, end: INTEGER);
NEW, ABSTRACT
If possible, make specified stretch [beg, end) visible in f.

Pre
f # NIL	20
Displayed(f)	21

Post
If possible, BeginOf(FirstLineVisible(v)) <= k <= EndOf(LastLineVisible(v)):
	beg = end
		k = beg
	beg < end
		beg <= k < end

PROCEDURE (v: View) ShowRange (beg, end: INTEGER; focusOnly: BOOLEAN);
NEW, ABSTRACT
Locates a reference frame displaying v and performs v.ShowRangeIn on it. If ~focusOnly, an arbitrary frame will be taken, where a target frame takes precedence over all but a front frame, which takes precedence over all other frames. If focusOnly, only a front (or if none exists, a target) frame is taken as a reference, and no repositioning takes place if neither a target nor a front frame is found.


TYPE Directory
ABSTRACT
Directory for views.

defAttr-: TextModels.Attributes
Default attributes, used for initial formatting when typing to an empty text.

PROCEDURE (d: Directory) Set (defAttr: TextModels.Attributes)
NEW, EXTENSIBLE
Set the default attributes.

Pre
defAttr # NIL	not explicitly checked
defAttr.init	20

Post
d.defAttr = defAttr

PROCEDURE (d: Directory) New (text: TextModels.Model): View
NEW, ABSTRACT
Return a new view displaying text. If text = NIL, a new text is created using TextModels.dir.New.

Post
text = NIL
	result.ThisModel() = new-text
text # NIL
	result.ThisModel() = text


TYPE Location
Characteristics of an element's (i.e., a character's or embedded view's) location in a text view.

start, pos: INTEGER
Start of line and position of location.

x, y: INTEGER
Coordinates of location.

asc, dsc: INTEGER
Line's ascender and descender at location.

view: Views.View
l, t, r, b: INTEGER
If embedded view at location: The view and its bounding box.


TYPE  PageMsg (Views.PropMessage)
Message send by a text view to all embedded views on a page before rendering that page (for printing). This message can be used by views to display page number dependent behavior during printing.

current: INTEGER
Page number of the page to be rendered.


TYPE PositionMsg (Models.Message)
Message broadcast by ShowRange to request repositioning.

focusOnly: BOOLEAN
Reposition front (or, if none, target) view only.

beg, end: INTEGER
The range requested to become visible.


VAR ctrlDir-: Containers.Directory	stable ctrlDir # NIL
Controller directory object. If installed, this directory object is used by the view directory object to install a controller in a newly created view. Upon initialization, module TextViews tries to load module TextControllers which, if available, in turn installs the standard controller directory object in ctrlDir.


VAR dir-, stdDir-: Directory	dir # NIL, stdDir # NIL, stable stdDir = d
Directory and standard directory objects for views.


PROCEDURE SetCtrlDir (d: Containers.Directory)
Set controller directory object.

Pre
d # NIL	20

Post
ctrlDir = d

PROCEDURE SetDir (d: Directory)
Set directory object.

Pre
d # NIL	20

Post
stdDir' = NIL
	stdDir = d
dir = d

PROCEDURE Focus (): View
Return focus text view, if one exists.

Except for performace, equivalent to:
	VAR v: Views.View;
	v := Controllers.FocusView();
	IF (v # NIL) & (v IS View) THEN RETURN v(View) ELSE RETURN NIL END

PROCEDURE FocusText (): TextModels.Model
Return focus text, if one exists.

Except for performace, equivalent to:
	VAR v: View;
	v := Focus();
	IF v # NIL THEN RETURN v.ThisModel() ELSE RETURN NIL END

PROCEDURE Deposit
Deposit a default text view in the Views queue.

Except for performace, equivalent to:
	Views.Deposit(dir.New(NIL))

PROCEDURE ShowRange (text: TextModels.Model; beg, end: INTEGER;
												focusOnly: BOOLEAN)
For all views v displaying text, issue v.ShowRange(beg, end, focusOnly).

Pre
text # NIL	20

Except for performace, equivalent to:
	VAR pm: PositionMsg;
	pm.beg := beg; pm.end := end; pm.focusOnly := focusOnly;
	Models.Broadcast(text, pm)

PROCEDURE ThisRuler (v: View; pos: INTEGER): TextRulers.Ruler
Locate the ruler dominating position pos in the text displayed by v.

Pre
v # NIL	20
v.ThisModel() # NIL	21
0 <= pos	22
pos <= v.ThisModel().Length()	23

Except for performace, equivalent to:
	VAR r: TextRulers.Ruler; a: TextModels.Attributes; rpos: INTEGER;
	v.PollDefaults(r, a); rpos := -1; TextRulers.GetValidRuler(v.ThisModel(), pos, -1, r, rpos);
	RETURN r