[Indigo]<Cedar>TEdit>TEditScrollingImpl.mesa!10

-- TEditScrollingImpl.mesa; Edited by Paxton on December 29, 1982 8:45 am

-- Edited by McGregor on July 30, 1982 10:04 am

Last Edited by: Maxwell, January 4, 1983 3:53 pm

Last Edited by: Plass, April 15, 1983 1:48 pm

Last Edited by: Russ Atkinson, April 15, 1983 12:38 pm

DIRECTORY

NodeStyle USING [Ref, Alloc, Free, ApplyAll, GetTopLeadingI, GetTopIndentI, GetLeadingI, GetBottomLeadingI],

RopeReader USING [Ref, SetPosition, Backwards, GetRopeReader, FreeRopeReader],

TEditDisplay USING [EstablishLine],

TEditDocument USING [LineTable, maxClip, Selection, SelectionId, SelectionPoint, TEditDocumentData],

TEditFormat USING [GetLineInfo],

TEditInput USING [MaxLevelShown],

TEditLocks USING [LockDocAndTdd, UnlockDocAndTdd],

TEditOps USING [RememberCurrentPosition],

TEditProfile USING [scrollBottomOffset, scrollTopOffset],

TEditSelection USING [InsertionPoint, pSel, sSel, fSel],

TEditScrolling,

TEditTouchup USING [LockAfterRefresh, PreScrollDownRec, refresh, UnlockAfterRefresh],

TextEdit USING [FetchChar, Offset, RefTextNode, Size],

TextNode USING [Backward, BackwardClipped, BadArgs, FirstChild, Forward, ForwardClipped, LastLocWithin, Level, Location, LocNumber, LocOffset, LocWithin, NarrowToTextNode, Parent, pZone, Ref, RefTextNode, Root, StepForward],

ViewerOps USING [PaintViewer],

ViewerClasses USING [ScrollProc, Viewer];

TEditScrollingImpl: CEDAR PROGRAM

IMPORTS NodeStyle, RopeReader, TEditDisplay, TEditFormat, TEditLocks, TEditSelection, TextEdit, TEditInput, TEditOps, TEditProfile, TEditTouchup, TextNode, ViewerOps

EXPORTS TEditScrolling =

BEGIN OPEN TEditDocument, TextNode;

BackUp: PROC

[viewer: ViewerClasses.Viewer, tdd: TEditDocumentData, pos: Location, goal: INTEGER]

RETURNS [newPos: Location, lines, totalLeading, topIndent: INTEGER] = BEGIN

pos argument is the current top line in the viewer. goal argument is the distance to back up.

algorithm works by incrementally formatting lines prior to pos until reaches goal height.

The incremental backup procedure preserves the following invariants:

newPos is the current line start

totalLeading is the leading from the baseline of newPos to the baseline of pos

topIndent is the distance from the viewer top to baseline of newPos if newPos goes at top

topLeading is the style value for topLeading corresponding to newPos

maxLevel: INTEGER ← tdd.clipLevel;

parent: TextNode.Ref;

level: INTEGER ← 0; -- in case we are doing level clipping

levelClipping: BOOLEAN ← maxLevel < maxClip;

IncrBackUp: PROC [pos: Location, goal, prevTopLeading: INTEGER]

RETURNS [prev: Location, totalLeading, lines, topIndent, topLeading: INTEGER] =

BEGIN

tPos: Location;

leading, bottomLeading: INTEGER;

lastBreak: TextEdit.Offset;

breakList: LIST OF TextEdit.Offset; -- breaks between first and last

textNode: RefTextNode;

where, endOffset, size: TextEdit.Offset;

IF pos.where=0 THEN DO -- back up to previous text node

tempNode: TextNode.Ref;

IF levelClipping THEN

[tempNode, parent, level] ← BackwardClipped[pos.node, maxLevel, parent, level]

ELSE [tempNode, parent, ----] ← Backward[pos.node, parent];

IF tempNode=NIL OR parent=NIL THEN RETURN[pos, 0, 0, 0, 0];

IF (textNode ← NarrowToTextNode[tempNode])=NIL THEN LOOP;

size ← endOffset ← where ← TextEdit.Size[textNode];

EXIT;

ENDLOOP

ELSE { -- back up past last char before pos

textNode ← NarrowToTextNode[pos.node];

size ← TextEdit.Size[textNode];

endOffset ← where ← pos.where-1 };

IF where < 4*MAX[12,goal] THEN where ← 0 -- don't bother to search backwards for CR

ELSE {

stop: TextEdit.Offset ← MAX[0, where-5000]; -- limit reading to 5000 characters

RopeReader.SetPosition[rdr, textNode.rope, where];

UNTIL (where ← where-1)<=stop DO

IF RopeReader.Backwards[rdr]=15C THEN {where ← where+1; EXIT};

ENDLOOP };

IF styleNode # textNode THEN NodeStyle.ApplyAll[style, styleNode ← textNode];

leading ← NodeStyle.GetLeadingI[style];

topLeading ← IF where=0 THEN NodeStyle.GetTopLeadingI[style] ELSE leading;

bottomLeading ← totalLeading ← IF pos.node = textNode THEN leading

ELSE MAX[prevTopLeading, NodeStyle.GetBottomLeadingI[style]];

topIndent ← NodeStyle.GetTopIndentI[style]; -- in case this line appears at top of viewer

IF where=size THEN { -- no more characters in the node. shows as blank line

lines ← 1; prev ← [textNode, where]; RETURN };

tPos ← [textNode, where];

lines ← 0;

DO -- format lines from tPos to starting pos

lastBreak ← tPos.where;

tPos ← TEditFormat.GetLineInfo[viewer, tdd, tPos, style].nextPos;

IF lines > 0 THEN totalLeading ← totalLeading+leading;

lines ← lines+1;

IF tPos.node#textNode OR tPos.where>=endOffset THEN EXIT;

IF lastBreak # where THEN breakList ← TextNode.pZone.CONS[lastBreak, breakList];

ENDLOOP;

When reach here, have found all the line breaks from [textNode, where] to initial pos.

where holds the offset for the first one

lastBreak holds the offset for the last one

breakList holds the offsets for the previous ones

IF totalLeading+topIndent >= goal THEN { -- have enough. find correct line

discardLines: INTEGER ← (totalLeading+topIndent-goal)/leading; -- too many lines

SELECT discardLines FROM

<= 0 => NULL; -- don't discard any

>= lines-1 => { -- discard all but one

where ← lastBreak; lines ← 1; totalLeading ← bottomLeading };

ENDCASE => { -- use breakList to find correct break

count: INTEGER; -- how far to go on list to find the break

lines ← lines-discardLines;

count ← lines-1; -- subtract 1 because lastBreak is not on list

totalLeading ← totalLeading-discardLines*leading;

FOR list: LIST OF TextEdit.Offset ← breakList, list.rest DO

IF (count ← count-1) = 0 THEN { where ← list.first; EXIT };

ENDLOOP;

};

prev ← [textNode, where];

END;

rdr: RopeReader.Ref ← RopeReader.GetRopeReader[];

style: NodeStyle.Ref ← NodeStyle.Alloc[];

styleNode: TextNode.Ref;

remainder: INTEGER ← goal;

dy: INTEGER ← LAST[INTEGER];

topLeading: INTEGER ← 0;

IF pos.where=0 THEN { -- need to get topLeading for pos.node

NodeStyle.ApplyAll[style, pos.node];

topLeading ← NodeStyle.GetTopLeadingI[style];

Once implement minGaps between lines, will also need topAscent for this line. Should be able to get that from the line table. (Except if continue to use this for top offset in ScrollToPosition... perhaps can just change that to back up a fixed number of lines.)

};

newPos ← pos;

lines ← totalLeading ← topIndent ← 0;

UNTIL remainder<=0 DO

leading, newLines, newTopIndent: INTEGER;

[newPos, leading, newLines, newTopIndent, topLeading] ←

IncrBackUp[newPos, remainder, topLeading];

IF newLines <= 0 THEN EXIT; -- didn't get anything that time. at start of document.

totalLeading ← totalLeading+leading;

lines ← lines+newLines;

topIndent ← newTopIndent;

IF totalLeading+topIndent >= goal THEN EXIT; -- don't need to back up any farther

remainder ← remainder - leading;

ENDLOOP;

NodeStyle.Free[style];

RopeReader.FreeRopeReader[rdr];

END;

ScrollTEditDocument: PUBLIC ViewerClasses.ScrollProc = BEGIN

tdd: TEditDocumentData = NARROW[self.data];

lines: LineTable;

topLine: Location;

paintOp: REF ANY ← TEditTouchup.refresh;

iconic: BOOL = self.iconic;

levelChange: BOOL ← FALSE;

IF tdd = NIL THEN RETURN;

IF iconic THEN {

[] ← TEditLocks.LockDocAndTdd[tdd, "ScrollTEditDocument", read];

SELECT op FROM

up => TEditDisplay.EstablishLine[tdd, TextNode.LastLocWithin[tdd.text], 0];

down => TEditDisplay.EstablishLine[tdd, [TextNode.FirstChild[tdd.text],0], 0];

thumb => NULL;

query => NULL;

ENDCASE => ERROR;

TEditLocks.UnlockDocAndTdd[tdd];

RETURN };

IF ~TEditTouchup.LockAfterRefresh[tdd, "ScrollTEditDocument"] THEN RETURN;

lines ← tdd.lineTable;

topLine ← lines[0].pos;

SELECT op FROM

up => BEGIN

line: INTEGER ← 0;

newLevel: INTEGER;

IF amount > 0 AND lines.lastLine = 0 THEN { -- calculate next line start pos

IF lines[0].end = eon THEN { -- go to the next node, unless already at end of document

next: TextNode.Ref;

maxLevel: INTEGER = tdd.clipLevel;

next ← IF maxLevel < maxClip THEN

TextNode.ForwardClipped[topLine.node,maxLevel].nx

ELSE TextNode.StepForward[topLine.node];

IF next # NIL THEN topLine ← [next, 0] }

ELSE topLine.where ← topLine.where+lines[0].nChars }

ELSE { -- find new topLine on screen

UNTIL lines[line].yOffset+lines[line].descent >= amount OR

lines[line+1].pos.node=NIL DO

line ← line+1;

IF line >= lines.lastLine THEN EXIT; -- off end

ENDLOOP;

topLine ← lines[line].pos };

newLevel ← SELECT TRUE FROM

control AND shift => 1, -- first level only

control => maxClip, -- all levels

shift => MIN[maxClip, TEditInput.MaxLevelShown[tdd]+1], -- move levels

ENDCASE => tdd.clipLevel; -- no change

IF newLevel # tdd.clipLevel THEN { tdd.clipLevel ← newLevel; levelChange ← TRUE }

END;

down => {

numLines, totalLeading, topIndent: INTEGER;

[topLine, numLines, totalLeading, topIndent] ←

BackUp[self, tdd, topLine, MAX[amount, lines[0].yOffset]];

IF topLine # lines[0].pos THEN { -- make room for the new stuff

op: REF TEditTouchup.PreScrollDownRec ←

TextNode.pZone.NEW[TEditTouchup.PreScrollDownRec];

op.lines ← numLines;

op.distance ← topIndent+totalLeading-lines[0].yOffset;

paintOp ← op };

};

thumb => BEGIN

TEditOps.RememberCurrentPosition[self];

IF amount < 5 THEN ScrollToPosition[self, [FirstChild[tdd.text],0], FALSE]

ELSE BEGIN

totalChars: TextEdit.Offset = LocNumber[LastLocWithin[tdd.text]]-1;

pos: TextNode.Location ← LocWithin[tdd.text, (totalChars*amount)/100];

IF tdd.clipLevel < maxClip THEN { -- check level of target

delta: INTEGER ← TextNode.Level[pos.node]-tdd.clipLevel;

FOR i:INTEGER IN [0..delta) DO -- only do this if pos is too deep

pos ← [TextNode.Parent[pos.node],0];

ENDLOOP;

};

ScrollToPosition[self, pos, FALSE];

END;

TEditTouchup.UnlockAfterRefresh[tdd];

RETURN;

END;

query => BEGIN

toTop, toBottom, toEnd, totalChars, t, b: INT;

ll: INTEGER = lines.lastLine;

toTop ← LocOffset[[TextNode.FirstChild[tdd.text], 0], topLine ! BadArgs => GOTO Bad];

toBottom ← LocOffset[topLine, [lines[ll].pos.node, lines[ll].pos.where+lines[ll].nChars] !

BadArgs => GOTO Bad];

toEnd ← LocOffset[[lines[ll].pos.node, lines[ll].pos.where+lines[ll].nChars-1],

LastLocWithin[tdd.text] ! BadArgs => GOTO Bad];

totalChars ← toTop+toBottom+toEnd;

TEditTouchup.UnlockAfterRefresh[tdd];

IF totalChars<=0 THEN RETURN[0, 100];

-- make sure there's always something shown for big documents

t ← MIN[98, 100*toTop/totalChars];

b ← MAX[t+2, 100*(toTop+toBottom)/totalChars];

RETURN[t, b]; -- so compiler will coerce to short integers

EXITS Bad => { TEditTouchup.UnlockAfterRefresh[tdd]; RETURN };

This ugly hack is to protect again messed up line table.

END;

ENDCASE;

IF topLine # lines[0].pos OR levelChange THEN BEGIN

TEditDisplay.EstablishLine[tdd, topLine, 0];

IF levelChange THEN ViewerOps.PaintViewer[self, client] -- complete repaint

ELSE ViewerOps.PaintViewer[self, client, FALSE, paintOp];

END;

TEditTouchup.UnlockAfterRefresh[tdd];

END;

ScrollToPosition: PUBLIC PROC [viewer: ViewerClasses.Viewer, pos: TextNode.Location, offset: BOOLEAN] = BEGIN

tdd: TEditDocumentData = NARROW[viewer.data];

lines: LineTable;

node: TextNode.RefTextNode ← TextNode.NarrowToTextNode[pos.node];

where: INT ← MAX[0, MIN[pos.where, TextEdit.Size[node]-1]];

start: INT ← where;

icon: BOOL = viewer.iconic;

repaint: BOOL ← FALSE;

nChars: CARDINAL;

newPos, topLine: TextNode.Location;

style: NodeStyle.Ref ← NodeStyle.Alloc[];

leading: INTEGER;

backStop: INT ← MAX[0, where-300]; -- limit looking back too far when searching for CR's

Unlock: PROC = {

IF icon THEN TEditLocks.UnlockDocAndTdd[tdd]

ELSE TEditTouchup.UnlockAfterRefresh[tdd] };

IF tdd = NIL THEN RETURN;

IF icon THEN [] ← TEditLocks.LockDocAndTdd[tdd, "ScrollToPosition", read]

ELSE IF ~TEditTouchup.LockAfterRefresh[tdd, "ScrollToPosition"] THEN RETURN;

IF tdd.clipLevel < maxClip AND tdd.clipLevel < TextNode.Level[node] THEN {

repaint ← TRUE; tdd.clipLevel ← maxClip; -- turn off level clipping -- };

lines ← tdd.lineTable;

UNTIL start<=backStop OR TextEdit.FetchChar[node, start-1]=15C DO

start ← start - 1;

ENDLOOP;

topLine ← [node, start];

NodeStyle.ApplyAll[style, topLine.node];

DO -- find the line containing [node, where]

[----, ----, ----, newPos, nChars, leading] ← TEditFormat.GetLineInfo[

viewer, tdd, topLine, style];

IF newPos.node#node OR newPos.where>where OR newPos=topLine THEN EXIT;

topLine ← newPos;

IF topLine.where+nChars>where THEN EXIT;

ENDLOOP;

NodeStyle.Free[style];

IF offset THEN BEGIN -- move goal line a bit down from the top

goal: INTEGER = leading * TEditProfile.scrollTopOffset;

IF goal*2 < viewer.ch THEN topLine ← BackUp[viewer, tdd, topLine, goal].newPos;

END;

IF repaint OR topLine # lines[0].pos THEN BEGIN

TEditDisplay.EstablishLine[tdd, topLine, 0];

Unlock[];

IF repaint THEN ViewerOps.PaintViewer[viewer, client]

ELSE ViewerOps.PaintViewer[viewer, client, FALSE, TEditTouchup.refresh];

END

ELSE Unlock[];

END;

OnScreen: PROC [viewer: ViewerClasses.Viewer, point: TextNode.Location] RETURNS [BOOL] = {

OnScreen determines whether or not the given location is visible for the given viewer.

IF viewer = NIL OR point.node = NIL THEN RETURN [FALSE];

IF viewer.destroyed OR viewer.iconic THEN RETURN [FALSE];

WITH viewer.data SELECT FROM

tdd: TEditDocument.TEditDocumentData => {

Now we know that we have a Tioga document

IF TEditTouchup.LockAfterRefresh[tdd, "OnScreen"] THEN {

At this point tdd is really and truly locked up. We must release it at the end of the block or bad things will happen.

ENABLE {UNWIND => TEditTouchup.UnlockAfterRefresh[tdd]};

lines: TEditDocument.LineTable ← tdd.lineTable;

found: BOOL ← FALSE;

IF lines # NIL AND lines.lastLine >= 0 THEN {

first: TextNode.Location ← lines[0].pos;

last: TextNode.Location ← lines[lines.lastLine].pos;

each: TextNode.Ref ← first.node;

last.where ← last.where + lines[lines.lastLine].nChars;

IF point.node = first.node AND point.where < first.where THEN GO TO quickOut;

IF point.node = last.node AND point.where > last.where THEN GO TO quickOut;

WHILE each # NIL DO

IF each = point.node THEN {found ← TRUE; EXIT};

IF each = last.node THEN EXIT;

each ← TextNode.Forward[each].nx;

ENDLOOP;

EXITS quickOut => {};

};

TEditTouchup.UnlockAfterRefresh[tdd];

RETURN [found];

};

ENDCASE;

RETURN [FALSE];

};

AutoScroll: PUBLIC PROC [

viewer: ViewerClasses.Viewer ← TEditSelection.pSel.viewer,

tryToGlitch: BOOLEAN ← TRUE,

toEndOfDoc: BOOLEAN ← FALSE,

id: TEditDocument.SelectionId ← primary] = BEGIN

tdd: TEditDocumentData;

goal: TextNode.Location;

lines: LineTable;

onScreen: BOOL;

sel: Selection = SELECT id FROM

primary => TEditSelection.pSel,

secondary => TEditSelection.sSel,

feedback => TEditSelection.fSel,

ENDCASE => ERROR;

TryToGlitch: PROC RETURNS [success: BOOLEAN] = BEGIN

glitchLines: INTEGER = MIN[MAX[lines.lastLine/2, 1], TEditProfile.scrollBottomOffset];

Need to have the MAX or will fail to scroll in 1 or 2 line viewers.

tryLines: INTEGER = MAX[lines.lastLine/2-glitchLines, 2]; -- how far to search for caret

Needs to be bigger than glitchLines since burst input may move the caret several lines.

newPos: TextNode.Location;

style: NodeStyle.Ref;

lineCount: INTEGER ← 0;

pos: TextNode.Location ← lines[lines.lastLine].pos;

foundNode: BOOLEAN;

NextNode: PROC [node: TextNode.Ref] RETURNS [next: TextNode.Ref] = {

next ← IF tdd.clipLevel < maxClip THEN

TextNode.ForwardClipped[node,tdd.clipLevel].nx

ELSE TextNode.StepForward[node] };

IF TEditProfile.scrollBottomOffset<=0 THEN {

TEditTouchup.UnlockAfterRefresh[tdd];

RETURN [TRUE] }; -- never glitch in this case

success ← FALSE;

style ← NodeStyle.Alloc[];

IF lines[lines.lastLine].end = eon THEN {

pos ← [NextNode[lines[lines.lastLine].pos.node],0];

IF pos.node=NIL THEN { NodeStyle.Free[style]; RETURN [FALSE] }}

ELSE pos.where ← pos.where+lines[lines.lastLine].nChars;

foundNode ← pos.node=goal.node;

NodeStyle.ApplyAll[style, pos.node];

THROUGH [0..MIN[tryLines, lines.lastLine-glitchLines]) DO

IF pos.node=NIL THEN { NodeStyle.Free[style]; RETURN [FALSE] };

[----, ----, ----, newPos, ----, ----] ← TEditFormat.GetLineInfo[

viewer, tdd, pos, style];

IF newPos.node=goal.node THEN foundNode ← TRUE;

IF foundNode AND (newPos.node#goal.node OR newPos.where>goal.where)

THEN {success ← TRUE; EXIT};

lineCount ← lineCount+1;

IF newPos.node#pos.node THEN NodeStyle.ApplyAll[style, newPos.node];

pos ← newPos;

ENDLOOP;

NodeStyle.Free[style];

IF success THEN BEGIN

TEditDisplay.EstablishLine[tdd, lines[lineCount+glitchLines].pos, 0];

TEditTouchup.UnlockAfterRefresh[tdd];

ViewerOps.PaintViewer[viewer, client, FALSE, TEditTouchup.refresh];

END;

IF viewer=NIL OR viewer.iconic OR viewer.destroyed THEN RETURN;

onScreen ← OnScreen[viewer, sel.start.pos]; -- determines if selection is on the screen

tdd ← IF viewer=sel.viewer THEN sel.data ELSE NARROW[viewer.data];

IF tdd = NIL THEN RETURN;

IF ~TEditTouchup.LockAfterRefresh[tdd, "AutoScroll"] THEN RETURN;

lines ← tdd.lineTable;

IF toEndOfDoc THEN BEGIN -- scroll to end of document; used in typescripts

lines: LineTable = tdd.lineTable;

goal ← TextNode.LastLocWithin[TextNode.FirstChild[tdd.text]];

IF lines[lines.lastLine].pos.where+lines[lines.lastLine].nChars >= goal.where

THEN {TEditTouchup.UnlockAfterRefresh[tdd]; RETURN};

goal.where ← goal.where-1; -- last char correction

IF tryToGlitch AND TryToGlitch[] THEN RETURN;

END

ELSE IF sel.viewer # viewer THEN {TEditTouchup.UnlockAfterRefresh[tdd]; RETURN}

ELSE BEGIN -- scroll to end of selection

selPoint: TEditDocument.SelectionPoint = IF sel.insertion=before THEN sel.start ELSE sel.end;

clipped: BOOL = selPoint.clipped;

IF ~clipped AND onScreen THEN

{TEditTouchup.UnlockAfterRefresh[tdd]; RETURN}; -- visible on screen

goal ← TEditSelection.InsertionPoint[sel];

IF TextNode.Root[goal.node] # tdd.text THEN -- make sure that selection didn't leave

{TEditTouchup.UnlockAfterRefresh[tdd]; RETURN};

IF sel.insertion=before AND goal.where>0 THEN goal.where ← goal.where-1;

IF ~clipped AND tryToGlitch AND selPoint.line>0 AND TryToGlitch[] THEN RETURN;

END;

TEditTouchup.UnlockAfterRefresh[tdd];

-- glitch failed; use general scroll

ScrollToPosition[viewer, goal, TRUE];

END;

END.