{
node: Node ← lines[start].pos.node;
pos: INT ← lines[start].pos.where;
leading: INT ← 0;
topLeading: INT ← 0;
bottomLeading: INT ← 0;
nodeLeading: INT ← 0;
knowBottomLeading: BOOL ← (start = 0); -- otherwise need to get it
y: INT ← 0;
nodeSize: INT ← TextEdit.Size[node];
styleInit: BOOL ← TRUE;
yMatchRun: BOOL ← TRUE;
yMatch: BOOL ← FALSE;
eraseToEnd: BOOL ← FALSE;
lineInfo: TEditFormat.LineInfo ← TEditFormat.Allocate[];
nodeStyle: NodeStyle.Style ← NodeStyleOps.Alloc[];
Cleanup:
PROC = {
TEditFormat.Release[lineInfo]; lineInfo ← NIL;
NodeStyleOps.Free[nodeStyle]; nodeStyle ← NIL;
};
styleInfoNode: Node ← NIL; -- node for which we were last called to get style info
This is used to avoid redoing GetStyleInfo after have peeked at next node style as part of trying to move lines down.
GetStyleInfo:
PROC [node: Node] = {
IF node = styleInfoNode THEN RETURN; -- already have the style info
styleInfoNode ← node;
IF
NOT knowBottomLeading
AND pos=0
THEN {
-- get it from previous node
NodeStyleOps.ApplyAll[nodeStyle, lines[line-1].pos.node, kindOfStyle];
bottomLeading ← NodeStyle.GetBottomLeadingI[nodeStyle];
};
NodeStyleOps.ApplyAll[nodeStyle, node, kindOfStyle];
leading ← NodeStyle.GetLeadingI[nodeStyle];
topLeading ←
MAX[bottomLeading, NodeStyle.GetTopLeadingI[nodeStyle]];
use value of bottomLeading left from previous node
nodeLeading ←
MAX[bottomLeading, topLeading];
use previous value of bottomLeading
bottomLeading ← NodeStyle.GetBottomLeadingI[nodeStyle];
knowBottomLeading ← TRUE;
};
checkedVisible, fullyVisible: BOOL ← FALSE;
FullyVisible:
PROC
RETURNS [
BOOL] = {
IF
NOT checkedVisible
THEN {
fullyVisible ← ImagerBackdoor.TestViewRectangle[dc, 0, 0, viewer.cw, viewer.ch]=all;
checkedVisible ← TRUE;
};
RETURN [fullyVisible];
};
found: INT ← 0; -- set by FindBelow
TryMoveUp:
PROC
RETURNS [ok:
BOOL] = {
Returns true if found the desired line at a lower location on the screen. Blts the line and all following lines, clears out screen below them, then updates line table.
to, from, num, dist, bottom: INT;
diff: INTEGER;
dirtyScanlinesInFirstTextline: NAT ← 0;
FindBelow:
PROC
RETURNS [ok:
BOOL] = {
returns true if finds the desired line
Looks for valid line at or below current line with desired start location. Assumes oldBottomY has been set to bottom of previous line, so if found line starts below that it will be ok on the screen still. If finds such a line, stores its index in "found" and returns true.
FOR n:
INTEGER
IN [line..lines.lastLine]
DO
IF lines[n].valid
AND lines[n].pos=[node,pos]
THEN {
found ← n;
RETURN [lines[n].yOffset-lines[n].ascent > oldBottomY];
};
ENDLOOP;
RETURN [FALSE];
};
IF NOT FullyVisible[] OR NOT FindBelow[] THEN RETURN [FALSE];
IF found=lines.lastLine AND lines[found].yOffset+lines[found].descent >= viewer.ch
THEN RETURN [FALSE]; -- bottom is clipped
IF found>0
AND (
dirtyScanlinesInFirstTextline ←
MAX[0,
lines[found-1].yOffset+lines[found-1].descent - lines[found].yOffset-lines[found].ascent
]
) > 0 THEN lines[found].valid ← FALSE;
to ← y-lines[found].ascent + dirtyScanlinesInFirstTextline;
top of clean part of new line is destination for blt
from ← lines[found].yOffset-lines[found].ascent + dirtyScanlinesInFirstTextline;
uppermost source scan line
IF to < 0
THEN {
-- top of line is clipped
from ← from-to; -- move source down by amount to be clipped
to ← 0;
};
dist ← from-to; -- the distance to move
IF dist < 0 THEN RETURN [FALSE]; -- skip this bizarre case
bottom ← MIN[viewer.ch, lines.lastY];
num ← bottom-from; -- number of scan lines to move
IF num <= 0 THEN RETURN [FALSE];
ClearLine[oldBottomY, to]; -- clear gap above destination
MoveScanLines[to, from, num]; -- move the good scan lines up
ClearLine[bottom-dist, bottom]; -- clear the space at the bottom
lines.lastY ← lines.lastY-dist; -- lastY tells last used scan line in viewer
diff ← found-line; -- number of lines skipped
IF diff # 0
THEN {
-- update the line table info
FOR n:
INTEGER
IN [line..lines.lastLine-diff]
DO
lines[n] ← lines[n+diff]; -- move all the info up to new location
ENDLOOP;
ClearEntries[lines.lastLine-diff+1, lines.lastLine]; -- these lines no longer in use
lines.lastLine ← lines.lastLine-diff;
end ← end-diff;
};
FOR n:
INTEGER
IN [line..lines.lastLine]
DO
-- adjust the baselines
lines[n].yOffset ← lines[n].yOffset-dist;
ENDLOOP;
lines[lines.lastLine].valid ←
FALSE;
Set the last line invalid to force repaint to fill in gap at bottom of viewer.
RETURN [TRUE]
};
ClearEntries:
PROC [from, to:
INTEGER] = {
FOR n:
INTEGER
IN [from..to]
DO
lines[n] ← [pos: [NIL, 0], valid: FALSE, yOffset: 0, xOffset: 0, width: 0, ascent: 0, descent: 0];
ENDLOOP
};
MoveScanLines:
PROC [to, from, height:
INT] = {
IF height>0
THEN ImagerBackdoor.MoveViewRectangle[context: dc,
width: viewer.cw, -- full width of viewer
height: height, -- height of source
fromX: 0, fromY: viewer.ch-from-height,
toX: 0, toY: viewer.ch-to-height
];
};
TryMoveDown:
PROC [nchars:
INTEGER, end: TEditDocument.LineBreak] = {
We are about to put [node, pos] in line. It will contain nchars with break specified by end. This procedure looks to see if we will overwrite what we will next want to put in line+1. If so, move it down now. This happens whenever insert a single line.
This proc may need to call GetStyleInfo, so use all the style info you're interested in before you call it.
next: TextNode.Location;
from, lead, dist: INT;
IF NOT FullyVisible[] OR NOT lines[line].valid THEN RETURN;
from ← lines[line].yOffset-lines[line].ascent;
IF oldBottomY > from THEN RETURN; -- overwritten it already
next ← IF end=eon THEN [NextNode[], 0] ELSE [node, pos+nchars];
IF lines[line].pos # next THEN RETURN;
IF end=eon
THEN {
-- need to get leading info for the next node
GetStyleInfo[next.node]; lead ← nodeLeading;
}
ELSE lead ← leading;
dist ← y+lead-lines[line].yOffset; -- how far down to move it
MoveLinesDown[line, 1, from, dist, TRUE]
};
MoveLinesDown:
PROC [startLine, numLines:
INTEGER, from, dist:
INT, clear:
BOOL] = {
to: INT;
num: INT;
bottom: INT;
visible: BOOL ← FALSE;
dirtyScanlinesInFirstTextline: INT;
IF dist <= 0 THEN RETURN; -- skip this weird case
to ← from+dist;
bottom ← MIN[lines.lastY+dist, viewer.ch]; -- new bottom after blt
num ← bottom-to; -- the number of scan lines to blt
IF num <= 0 THEN RETURN; -- stuff to move down won't be visible
MoveScanLines[from+dist, from, num];
IF startLine > 0
AND (dirtyScanlinesInFirstTextline ←
lines[startLine-1].yOffset+lines[startLine-1].descent -
lines[startLine].yOffset-lines[startLine].ascent) > 0
THEN {
Repaint the top line if it got dirtied by descenders.
lines[startLine].valid ← FALSE;
ClearLine[from, to + dirtyScanlinesInFirstTextline];
}
ELSE ClearLine[from, to]; -- clear the gap
FOR n:
INTEGER
DECREASING
IN [startLine..lines.lastLine]
DO
newOffset: INT;
IF n+numLines >= lines.maxLines THEN LOOP; -- avoid bounds fault
newOffset ← lines[n].yOffset+dist; -- the new baseline
IF newOffset-lines[n].ascent > viewer.ch THEN LOOP; -- off the bottom of viewer
IF
NOT visible
AND newOffset+lines[n].descent <= viewer.ch
THEN {
first fully visible line
visible ← TRUE;
lines.lastLine ← n+numLines;
lines[n].valid ← FALSE; -- force repaint at bottom of viewer
lines.lastY ← newOffset+lines[n].descent;
ClearLine[lines.lastY, viewer.ch]
};
lines[n+numLines] ← lines[n]; -- move all the info down by numLines
lines[n+numLines].yOffset ← newOffset; -- adjust the baseline
IF
NOT visible
THEN {
line must be partly visible at bottom of screen
lines.lastLine ← n+numLines;
lines.lastY ← newOffset+lines[n].descent;
lines[n+numLines].valid ← FALSE;
};
ENDLOOP;
};
level: INTEGER ← 0; -- in case we are doing level clipping
maxLevel: INTEGER = tdd.clipLevel;
levelClipping: BOOL = maxLevel < TEditDocument.maxClip;
last, next: Node;
NextNode:
PROC
RETURNS [Node] = {
returns next node to display
For future reference, TEditScrollingImpl.ScrollTEditDocument also has code to calculate next node for display to handle scrolling up in 1 line viewers.
IF node=last THEN RETURN [next]; -- 1 entry cache
last ← node;
IF levelClipping
THEN [next, level] ← TextNode.ForwardClipped[node,maxLevel,level]
ELSE next ← TextNode.StepForward[node];
RETURN [next]
};
ClearLine:
PROC [oldBottomY, newBottomY:
INT] = {
IF oldBottomY >= newBottomY THEN RETURN;
Imager.SetColor[dc, Imager.white];
Imager.MaskRectangleI[dc, 0, viewer.ch-newBottomY, viewer.cw, newBottomY-oldBottomY];
Imager.SetColor[dc, Imager.black];
};
ContinueReason: TYPE ~ {dont, inRange, invalidLine, whitewashed};
continueReason: ContinueReason ← dont;
WhyGoOn:
PROC [lineNumber:
INTEGER]
RETURNS [cr: ContinueReason] ~ {
SELECT
TRUE
FROM
(line >= lines.maxLines) => cr ← dont;
(line <= end) => cr ← inRange;
NOT (line <= lines.lastLine AND lines[line].valid AND lines[line].pos=[node, pos] AND yMatch) => cr ← invalidLine;
((NOT displayClear) AND line > 0 AND (lines[line].yOffset-lines[line].ascent < lines[line-1].yOffset+lines[line-1].descent)) => cr ← whitewashed;
ENDCASE => cr ← dont;
continueReason ← cr;
};
IF node =
NIL
OR (line ← start) > lines.lastLine
OR end < 0
THEN {
update not on screen
Cleanup[];
RETURN};
checkedVisible ← FALSE;
IF moveDownLines > 0
AND FullyVisible[]
THEN {
move things down before start repainting. This accelerates scrolling down.
MoveLinesDown[0, moveDownLines, 0, moveDownDistance, FALSE];
};
Paint lines until the line we would paint is:
(1) valid,
(2) past the range we were told to paint,
(3) matches the line table offsets (i.e. no ripple going forward), and
(4) matches in the Y coord.
(5) not partially whitened by paint of earlier lines.
An exit for end of text and off end of viewer are included below.
UNTIL WhyGoOn[line] = dont
DO
IF (refresh
AND TEditLocks.WaitingForWrite[lock])
OR tdd.interrupt > 0
THEN {
Either an edit is pending or a complete repaint is pending. In either case, we quit.
lines.lastLine ← MAX[line, lines.lastLine];
lines[line].pos ← [node, pos];
lines[line].valid ← FALSE;
Cleanup[];
RETURN;
};
GetStyleInfo[node];
y
--baseline-- ← (
IF line=0 THEN NodeStyle.GetTopIndentI[nodeStyle]
ELSE (IF line#start THEN y ELSE lines[line-1].yOffset) -- baseline --
+ (IF pos=0 THEN nodeLeading ELSE leading) -- leading --
);
yMatch ← y=lines[line].yOffset;
true if the new line is baseline aligned with the previous bits on the screen
IF y>=viewer.ch
AND line>0
THEN {eraseToEnd ←
TRUE;
EXIT};
if baseline would be off bottom of viewer and not the first line, don't show it.
oldBottomY ←
IF line=0
THEN 0
ELSE lines[line-1].yOffset+lines[line-1].descent;
bottom of the previous line
IF displayClear
OR
NOT TryMoveUp[]
THEN {
backgroundColor: Imager.Color ← NIL;
painter:
PROC ~ {
Imager.SetXY[dc, [lineInfo.xOffset.Float[], viewer.ch-y]];
SELECT
TRUE
FROM
displayClear, backgroundColor#NIL => {};
ENDCASE => ClearLine[oldBottomY, y-lineInfo.ymin];
oldBottomY ← y-lineInfo.ymin;
TEditFormat.Paint[lineInfo, dc];
};
TEditFormat.FormatLine[lineInfo: lineInfo, node: node, startOffset: pos, nodeStyle: nodeStyle, lineWidth: Scaled.FromInt[viewer.cw], kind: kindOfStyle];
IF NOT displayClear THEN TryMoveDown[lineInfo.nChars, lineInfo.break];
Need to finish with style info before call this. May call GetStyleInfo for next node.
IF oldBottomY <= y-lineInfo.ymax
THEN {
backgroundColor ← Imager.white;
IF NOT displayClear THEN ClearLine[oldBottomY, y-lineInfo.ymax];
oldBottomY ← y-lineInfo.ymax;
};
IF displayClear THEN painter[]
ELSE {
ymin: INT ← viewer.ch-y+lineInfo.ymin;
ymax: INT ← viewer.ch-y+lineInfo.ymax;
IF continueReason = whitewashed
THEN {
ymin ← MAX[viewer.ch-oldBottomY, ymin];
backgroundColor ← NIL;
};
IF ymin < ymax
THEN {
ImagerOps.DoWithBuffer[
context: dc,
action: painter,
x: 0, y: ymin,
w: viewer.cw, h: ymax-ymin,
backgroundColor: backgroundColor
];
};
};
lines[line] ← [valid: TRUE, pos: [node, pos], nChars: lineInfo.nChars, end: lineInfo.break, yOffset: y, xOffset: lineInfo.xOffset.Round[], width: lineInfo.xmax-lineInfo.xmin, ascent: MAX[0, lineInfo.ymax], descent: MAX[0, -lineInfo.ymin]];
};
pos ← pos + lines[line].nChars;
line ← line + 1;
IF continueReason = whitewashed THEN EXIT;
IF pos >= nodeSize
AND lines[line-1].end#cr
THEN {
nothing more to display in this node.
node ← NextNode[];
IF node = NIL THEN {eraseToEnd ← TRUE; EXIT};
nodeSize ← TextEdit.Size[node];
pos ← 0;
};
ENDLOOP;
clear former bottom lines if we run off end of text or viewer (partial line must be clipped)
IF eraseToEnd
OR line>=lines.maxLines
THEN {
eraseToEnd starts false. set true if reach end of document or stop with line that would have baseline below bottom of viewer.
bottomOfNewLines: INT ← 0;
IF line#0 THEN bottomOfNewLines ← lines[line-1].yOffset + lines[line-1].descent;
lines.lastLine ← MAX[line,1]-1; -- set end mark
ClearEntries[lines.lastLine+1, lines.maxLines-1];
IF
NOT displayClear
AND bottomOfNewLines < lines.lastY
THEN
white out old lines
ClearLine[bottomOfNewLines, lines.lastY];
lines.lastY ← bottomOfNewLines;
}
ELSE {
take this branch if got back in synch during repaint
IF y>viewer.ch OR displayClear THEN ERROR;
lines.lastLine ← MAX[lines.lastLine, MAX[line,1]-1];
lines.lastY ← MAX[y+lines[lines.lastLine].descent, lines.lastY];
};
Cleanup[];
};