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function ASSERT(pred) {
console.assert(pred, 'assert failed');
}
function LOG(...args) {
// comment out for non-debugging
// console.log(args);
}
function MakeCursor(CanvasKit) {
const linePaint = new CanvasKit.Paint();
linePaint.setColor([0,0,1,1]);
linePaint.setStyle(CanvasKit.PaintStyle.Stroke);
linePaint.setStrokeWidth(2);
linePaint.setAntiAlias(true);
const pathPaint = new CanvasKit.Paint();
pathPaint.setColor([0,0,1,0.25]);
linePaint.setAntiAlias(true);
return {
_line_paint: linePaint, // wrap in weak-ref so we can delete it?
_path_paint: pathPaint,
_x: 0,
_top: 0,
_bottom: 0,
_path: null, // only use x,top,bottom if path is null
_draws_per_sec: 2,
// pass 0 for no-draw, pass inf. for always on
setBlinkRate: function(blinks_per_sec) {
this._draws_per_sec = blinks_per_sec;
},
place: function(x, top, bottom) {
this._x = x;
this._top = top;
this._bottom = bottom;
this._path = null;
},
setPath: function(path) {
this._path = path;
},
draw_before: function(canvas) {
if (this._path) {
canvas.drawPath(this._path, this._path_paint);
}
},
draw_after: function(canvas) {
if (this._path) {
return;
}
if (Math.floor(Date.now() * this._draws_per_sec / 1000) & 1) {
canvas.drawLine(this._x, this._top, this._x, this._bottom, this._line_paint);
}
},
};
}
function MakeMouse() {
return {
_start_x: 0, _start_y: 0,
_curr_x: 0, _curr_y: 0,
_active: false,
isActive: function() {
return this._active;
},
setDown: function(x, y) {
this._start_x = this._curr_x = x;
this._start_y = this._curr_y = y;
this._active = true;
},
setMove: function(x, y) {
this._curr_x = x;
this._curr_y = y;
},
setUp: function(x, y) {
this._curr_x = x;
this._curr_y = y;
this._active = false;
},
getPos: function(dx, dy) {
return [ this._start_x + dx, this._start_y + dy, this._curr_x + dx, this._curr_y + dy ];
},
};
}
function runs_x_to_index(runs, x) {
for (const r of runs) {
for (let i = 1; i < r.offsets.length; i += 1) {
if (x < r.positions[i*2]) {
const mid = (r.positions[i*2-2] + r.positions[i*2]) * 0.5;
if (x <= mid) {
return r.offsets[i-1];
} else {
return r.offsets[i];
}
}
}
}
const r = runs[runs.length-1];
return r.offsets[r.offsets.length-1];
}
function lines_pos_to_index(lines, x, y) {
if (y < lines[0].top) {
return 0;
}
for (const l of lines) {
if (y <= l.bottom) {
return runs_x_to_index(l.runs, x);
}
}
return lines[lines.length - 1].textRange.last;
}
function runs_index_to_run(runs, index) {
for (const r of runs) {
if (index <= r.offsets[r.offsets.length-1]) {
return r;
}
}
return runs[runs.length-1]; // last run
}
function runs_index_to_x(runs, index) {
const r = runs_index_to_run(runs, index);
for (const i in r.offsets) {
if (index == r.offsets[i]) {
return r.positions[i*2];
}
}
return r.positions[r.positions.length-2]; // last x
}
function lines_index_to_line_index(lines, index) {
let i = 0;
for (const l of lines) {
if (index <= l.textRange.last) {
return i;
}
i += 1;
}
return lines.length-1;
}
function lines_index_to_line(lines, index) {
return lines[lines_index_to_line_index(lines, index)];
}
function lines_index_to_x(lines, index) {
for (const l of lines) {
if (index <= l.textRange.last) {
return runs_index_to_x(l.runs, index);
}
}
}
function lines_indices_to_path(lines, a, b, width) {
if (a == b) {
return null;
}
if (a > b) { [a, b] = [b, a]; }
const path = new CanvasKit.Path();
const la = lines_index_to_line(lines, a);
const lb = lines_index_to_line(lines, b);
const ax = runs_index_to_x(la.runs, a);
const bx = runs_index_to_x(lb.runs, b);
if (la == lb) {
path.addRect([ax, la.top, bx, la.bottom]);
} else {
path.addRect([ax, la.top, width, la.bottom]);
path.addRect([0, lb.top, bx, lb.bottom]);
if (la.bottom < lb.top) {
path.addRect([0, la.bottom, width, lb.top]); // extra lines inbetween
}
}
return path;
}
function string_del(str, start, end) {
return str.slice(0, start) + str.slice(end, str.length);
}
function make_default_paint() {
const p = new CanvasKit.Paint();
p.setAntiAlias(true);
return p;
}
function make_default_font(tf) {
const font = new CanvasKit.Font(tf);
font.setSubpixel(true);
return font;
}
function MakeStyle(length) {
return {
_length: length,
typeface: null,
size: null,
color: null,
bold: null,
italic: null,
_check_toggle: function(src, dst) {
if (src == 'toggle') {
return !dst;
} else {
return src;
}
},
// returns true if we changed something affecting layout
mergeFrom: function(src) {
let layoutChanged = false;
if (src.typeface && this.typeface !== src.typeface) {
this.typeface = src.typeface;
layoutChanged = true;
}
if (src.size && this.size !== src.size) {
this.size = src.size;
layoutChanged = true;
}
if (src.color) { this.color = src.color; }
if (src.bold) {
this.bold = this._check_toggle(src.bold, this.bold);
}
if (src.italic) {
this.italic = this._check_toggle(src.italic, this.italic);
}
if (src.size_add) {
this.size += src.size_add;
layoutChanged = true;
}
return layoutChanged;
}
};
}
function MakeEditor(text, style, cursor, width) {
const ed = {
_text: text,
_lines: null,
_cursor: cursor,
_width: width,
_index: { start: 0, end: 0 },
_styles: null,
// drawing
_X: 0,
_Y: 0,
_paint: make_default_paint(),
_font: make_default_font(style.typeface),
getLines: function() { return this._lines; },
width: function() {
return this._width;
},
height: function() {
return this._lines[this._lines.length-1].bottom;
},
bounds: function() {
return [this._X, this._Y, this._X + this.width(), this._Y + this.height()];
},
setXY: function(x, y) {
this._X = x;
this._Y = y;
},
_rebuild_selection: function() {
const a = this._index.start;
const b = this._index.end;
ASSERT(a >= 0 && a <= b && b <= this._text.length);
if (a === b) {
const l = lines_index_to_line(this._lines, a);
const x = runs_index_to_x(l.runs, a);
this._cursor.place(x, l.top, l.bottom);
} else {
this._cursor.setPath(lines_indices_to_path(this._lines, a, b, this._width));
}
},
setIndex: function(i) {
this._index.start = this._index.end = i;
this._rebuild_selection();
},
setIndices: function(a, b) {
if (a > b) { [a, b] = [b, a]; }
this._index.start = a;
this._index.end = b;
this._rebuild_selection();
},
moveDX: function(dx) {
let index;
if (this._index.start == this._index.end) {
// just adjust and pin
index = Math.max(Math.min(this._index.start + dx, this._text.length), 0);
} else {
// 'deselect' the region, and turn it into just a single index
index = dx < 0 ? this._index.start : this._index.end;
}
this.setIndex(index);
},
moveDY: function(dy) {
let index = (dy < 0) ? this._index.start : this._index.end;
const i = lines_index_to_line_index(this._lines, index);
if (dy < 0 && i == 0) {
index = 0;
} else if (dy > 0 && i == this._lines.length - 1) {
index = this._text.length;
} else {
const x = runs_index_to_x(this._lines[i].runs, index);
// todo: statefully track "original" x when an up/down sequence started,
// so we can avoid drift.
index = runs_x_to_index(this._lines[i+dy].runs, x);
}
this.setIndex(index);
},
_validateStyles: function() {
let len = 0;
for (const s of this._styles) {
len += s._length;
}
ASSERT(len === this._text.length);
},
_validateBlocks: function(blocks) {
let len = 0;
for (const b of blocks) {
len += b.length;
}
ASSERT(len === this._text.length);
},
_buildLines: function() {
this._validateStyles();
const build_sparse = true;
const blocks = [];
let block = null;
for (const s of this._styles) {
if (build_sparse) {
if (!block || (block.typeface === s.typeface && block.size === s.size)) {
if (!block) {
block = { length: 0, typeface: s.typeface, size: s.size };
}
block.length += s._length;
} else {
blocks.push(block);
block = { length: s._length, typeface: s.typeface, size: s.size };
}
} else {
// force a block on every style boundary for now
blocks.push({ length: s._length, typeface: s.typeface, size: s.size });
}
}
if (build_sparse) {
blocks.push(block);
}
this._validateBlocks(blocks);
this._lines = CanvasKit.ParagraphBuilder.ShapeText(this._text, blocks, this._width);
this._rebuild_selection();
// add textRange to each run, to aid in drawing
this._runs = [];
for (const l of this._lines) {
for (const r of l.runs) {
r.textRange = { start: r.offsets[0], end: r.offsets[r.offsets.length-1] };
this._runs.push(r);
}
}
},
// note: this does not rebuild lines/runs, or update the cursor,
// but it does edit the text and styles
// returns true if it deleted anything
_deleteRange: function(start, end) {
ASSERT(start >= 0 && end <= this._text.length);
ASSERT(start <= end);
if (start === end) {
return false;
}
this._delete_style_range(start, end);
// Do this after shrink styles (we use text.length in an assert)
this._text = string_del(this._text, start, end);
},
deleteSelection: function() {
let start = this._index.start;
if (start == this._index.end) {
if (start == 0) {
return; // nothing to do
}
this._deleteRange(start - 1, start);
start -= 1;
} else {
this._deleteRange(start, this._index.end);
}
this._index.start = this._index.end = start;
this._buildLines();
},
insert: function(charcode) {
if (this._index.start != this._index.end) {
this.deleteSelection();
}
const index = this._index.start;
// do this before edit the text (we use text.length in an assert)
const [i, prev_len] = this.find_style_index_and_prev_length(index);
this._styles[i]._length += 1;
// now grow the text
this._text = this._text.slice(0, index) + charcode + this._text.slice(index);
this._index.start = this._index.end = index + 1;
this._buildLines();
},
draw: function(canvas) {
canvas.save();
canvas.translate(this._X, this._Y);
this._cursor.draw_before(canvas);
const runs = this._runs;
const styles = this._styles;
const f = this._font;
const p = this._paint;
let s = styles[0];
let sindex = 0;
let s_start = 0;
let s_end = s._length;
let r = runs[0];
let rindex = 0;
let start = 0;
let end = 0;
while (start < this._text.length) {
while (r.textRange.end <= start) {
r = runs[++rindex];
if (!r) {
// ran out of runs, so the remaining text must just be WS
break;
}
}
if (!r) break;
while (s_end <= start) {
s = styles[++sindex];
s_start = s_end;
s_end += s._length;
}
end = Math.min(r.textRange.end, s_end);
LOG('New range: ', start, end,
'from run', r.textRange.start, r.textRange.end,
'style', s_start, s_end);
// check that we have anything to draw
if (r.textRange.start >= end) {
start = end;
continue; // could be a span of WS with no glyphs
}
// f.setTypeface(r.typeface); // r.typeface is always null (for now)
f.setSize(r.size);
f.setEmbolden(s.bold);
f.setSkewX(s.italic ? -0.2 : 0);
p.setColor(s.color ? s.color : [0,0,0,1]);
let gly = r.glyphs;
let pos = r.positions;
if (start > r.textRange.start || end < r.textRange.end) {
// search for the subset of glyphs to draw
let glyph_start, glyph_end;
for (let i = 0; i < r.offsets.length; ++i) {
if (r.offsets[i] >= start) {
glyph_start = i;
break;
}
}
for (let i = glyph_start+1; i < r.offsets.length; ++i) {
if (r.offsets[i] >= end) {
glyph_end = i;
break;
}
}
LOG(' glyph subrange', glyph_start, glyph_end);
gly = gly.slice(glyph_start, glyph_end);
pos = pos.slice(glyph_start*2, glyph_end*2);
} else {
LOG(' use entire glyph run');
}
canvas.drawGlyphs(gly, pos, 0, 0, f, p);
start = end;
}
this._cursor.draw_after(canvas);
canvas.restore();
},
// Styling
// returns [index, prev total length before this style]
find_style_index_and_prev_length: function(index) {
let len = 0;
for (let i = 0; i < this._styles.length; ++i) {
const l = this._styles[i]._length;
len += l;
// < favors the latter style if index is between two styles
if (index < len) {
return [i, len - l];
}
}
ASSERT(len === this._text.length);
return [this._styles.length-1, len];
},
_delete_style_range: function(start, end) {
// shrink/remove styles
//
// [.....][....][....][.....] styles
// [..................] start...end
//
// - trim the first style
// - remove the middle styles
// - trim the last style
let N = end - start;
let [i, prev_len] = this.find_style_index_and_prev_length(start);
let s = this._styles[i];
if (start > prev_len) {
// we overlap the first style (but not entirely
const skip = start - prev_len;
ASSERT(skip < s._length);
const shrink = Math.min(N, s._length - skip);
ASSERT(shrink > 0);
s._length -= shrink;
N -= shrink;
if (N === 0) {
return;
}
i += 1;
ASSERT(i < this._styles.length);
}
while (N > 0) {
s = this._styles[i];
if (N >= s._length) {
N -= s._length;
this._styles.splice(i, 1);
} else {
s._length -= N;
break;
}
}
},
applyStyleToRange: function(style, start, end) {
if (start > end) { [start, end] = [end, start]; }
ASSERT(start >= 0 && end <= this._text.length);
if (start === end) {
return;
}
LOG('trying to apply', style, start, end);
let i;
for (i = 0; i < this._styles.length; ++i) {
if (start <= this._styles[i]._length) {
break;
}
start -= this._styles[i]._length;
end -= this._styles[i]._length;
}
let s = this._styles[i];
// do we need to fission off a clean subset for the head of s?
if (start > 0) {
const ns = Object.assign({}, s);
s._length = start;
ns._length -= start;
LOG('initial splice', i, start, s._length, ns._length);
i += 1;
this._styles.splice(i, 0, ns);
end -= start;
// we don't use start any more
}
// merge into any/all whole styles we overlap
let layoutChanged = false;
while (end >= this._styles[i]._length) {
LOG('whole run merging for style index', i)
layoutChanged |= this._styles[i].mergeFrom(style);
end -= this._styles[i]._length;
i += 1;
if (end == 0) {
break;
}
}
// do we partially cover the last run
if (end > 0) {
s = this._styles[i];
const ns = Object.assign({}, s); // the new first half
ns._length = end;
s._length -= end; // trim the (unchanged) tail
LOG('merging tail', i, ns._length, s._length);
layoutChanged |= ns.mergeFrom(style);
this._styles.splice(i, 0, ns);
}
this._validateStyles();
LOG('after applying styles', this._styles);
if (layoutChanged) {
this._buildLines();
}
},
applyStyleToSelection: function(style) {
this.applyStyleToRange(style, this._index.start, this._index.end);
},
};
const s = MakeStyle(ed._text.length);
s.mergeFrom(style);
ed._styles = [ s ];
ed._buildLines();
return ed;
}