-- TEditScrollingImpl.mesa; Edited by McGregor on January 13, 1983 2:47 pm
-- Edited by Paxton on December 29, 1982 8:45 am
Last Edited by: Maxwell, January 4, 1983 3:53 pm
Last Edited by: Plass, March 8, 1983 12:43 pm
DIRECTORY
NodeStyle USING [Ref, Alloc, Free, ApplyAll, GetTopLeadingI, GetTopIndentI, GetLeadingI, GetBottomLeadingI],
RopeReader USING [Ref, SetPosition, Backwards, GetRopeReader, FreeRopeReader],
Scaled USING [FromInt],
TEditDisplay USING [EstablishLine],
TEditDocument USING [LineTable, maxClip, Selection, SelectionId, SelectionPoint, TEditDocumentData],
TEditFormat USING [Allocate, FormatLine, LineInfo, Release],
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, 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, Scaled, 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;
lineInfo: TEditFormat.LineInfo;
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;
lineInfo ← TEditFormat.Allocate[];
DO
-- format lines from tPos to starting pos
lastBreak ← tPos.where;
TEditFormat.FormatLine[lineInfo, tdd, TextNode.NarrowToTextNode[tPos.node], tPos.where, style, Scaled.FromInt[viewer.cw], FALSE];
tPos ← lineInfo.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;
lineInfo.Release[]; lineInfo ← NIL;
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 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;
topLine: TextNode.Location;
style: NodeStyle.Ref ← NodeStyle.Alloc[];
lineInfo: TEditFormat.LineInfo;
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 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];
lineInfo ← TEditFormat.Allocate[];
DO
-- find the line containing [node, where]
lineInfo.FormatLine[tdd, TextNode.NarrowToTextNode[topLine.node], topLine.where, style, Scaled.FromInt[viewer.cw]];
IF lineInfo.nextPos.node#node OR lineInfo.nextPos.where>where OR lineInfo.nextPos=topLine THEN EXIT;
topLine ← lineInfo.nextPos;
IF topLine.where+lineInfo.nChars>where THEN EXIT;
ENDLOOP;
IF offset
THEN
BEGIN
-- move goal line a bit down from the top
goal: INTEGER = style.GetLeadingI[] * TEditProfile.scrollTopOffset;
IF goal*2 < viewer.ch THEN topLine ← BackUp[viewer, tdd, topLine, goal].newPos;
END;
lineInfo.Release[]; lineInfo ← NIL;
NodeStyle.Free[style];
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
END;
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;
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;
lineInfo: TEditFormat.LineInfo;
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];
lineInfo ← TEditFormat.Allocate[];
THROUGH [0..tryLines)
DO
IF pos.node=NIL THEN { NodeStyle.Free[style]; lineInfo.Release[]; RETURN [FALSE] };
lineInfo.FormatLine[tdd, TextNode.NarrowToTextNode[pos.node], pos.where, style, Scaled.FromInt[viewer.cw]];
newPos ← lineInfo.nextPos;
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];
lineInfo.Release[]; lineInfo ← NIL;
IF success
THEN
BEGIN
TEditDisplay.EstablishLine[tdd, lines[lineCount+glitchLines].pos, 0];
TEditTouchup.UnlockAfterRefresh[tdd];
ViewerOps.PaintViewer[viewer, client, FALSE, TEditTouchup.refresh];
END;
END;
IF viewer=NIL OR viewer.iconic OR viewer.destroyed THEN RETURN;
tdd ←
IF viewer=sel.viewer
THEN sel.data
ELSE
NARROW[viewer.data];
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 selPoint.line
IN [0..lines.lastLine]
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.