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Collage.js
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Collage.js
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var _evancz$elm_graphics$Native_Collage = function()
{
function setStrokeStyle(ctx, style)
{
ctx.lineWidth = style.width;
var cap = style.cap.ctor;
ctx.lineCap = cap === 'Flat'
? 'butt'
: cap === 'Round'
? 'round'
: 'square';
var join = style.join.ctor;
ctx.lineJoin = join === 'Smooth'
? 'round'
: join === 'Sharp'
? 'miter'
: 'bevel';
ctx.miterLimit = style.join._0 || 10;
ctx.strokeStyle = _evancz$elm_graphics$Text$colorToCss(style.color);
}
function setFillStyle(redo, ctx, style)
{
var sty = style.ctor;
ctx.fillStyle = sty === 'Solid'
? _evancz$elm_graphics$Text$colorToCss(style._0)
: sty === 'Texture'
? texture(redo, ctx, style._0)
: gradient(ctx, style._0);
}
function trace(ctx, path)
{
var points = _elm_lang$core$Native_List.toArray(path);
var i = points.length - 1;
if (i <= 0)
{
return;
}
ctx.moveTo(points[i]._0, points[i]._1);
while (i--)
{
ctx.lineTo(points[i]._0, points[i]._1);
}
if (path.closed)
{
i = points.length - 1;
ctx.lineTo(points[i]._0, points[i]._1);
}
}
function line(ctx, style, path)
{
if (style.dashing.ctor === '[]')
{
trace(ctx, path);
}
else
{
customLineHelp(ctx, style, path);
}
ctx.scale(1, -1);
ctx.stroke();
}
function customLineHelp(ctx, style, path)
{
var points = _elm_lang$core$Native_List.toArray(path);
if (path.closed)
{
points.push(points[0]);
}
var pattern = _elm_lang$core$Native_List.toArray(style.dashing);
var i = points.length - 1;
if (i <= 0)
{
return;
}
var x0 = points[i]._0, y0 = points[i]._1;
var x1 = 0, y1 = 0, dx = 0, dy = 0, remaining = 0;
var pindex = 0, plen = pattern.length;
var draw = true, segmentLength = pattern[0];
ctx.moveTo(x0, y0);
while (i--)
{
x1 = points[i]._0;
y1 = points[i]._1;
dx = x1 - x0;
dy = y1 - y0;
remaining = Math.sqrt(dx * dx + dy * dy);
while (segmentLength <= remaining)
{
x0 += dx * segmentLength / remaining;
y0 += dy * segmentLength / remaining;
ctx[draw ? 'lineTo' : 'moveTo'](x0, y0);
// update starting position
dx = x1 - x0;
dy = y1 - y0;
remaining = Math.sqrt(dx * dx + dy * dy);
// update pattern
draw = !draw;
pindex = (pindex + 1) % plen;
segmentLength = pattern[pindex];
}
if (remaining > 0)
{
ctx[draw ? 'lineTo' : 'moveTo'](x1, y1);
segmentLength -= remaining;
}
x0 = x1;
y0 = y1;
}
}
function drawLine(ctx, style, path)
{
setStrokeStyle(ctx, style);
return line(ctx, style, path);
}
function texture(redo, ctx, src)
{
var img = new Image();
img.src = src;
img.onload = redo;
return ctx.createPattern(img, 'repeat');
}
function gradient(ctx, grad)
{
var g;
var stops = [];
if (grad.ctor === 'Linear')
{
var p0 = grad._0, p1 = grad._1;
g = ctx.createLinearGradient(p0._0, -p0._1, p1._0, -p1._1);
stops = _elm_lang$core$Native_List.toArray(grad._2);
}
else
{
var p0 = grad._0, p2 = grad._2;
g = ctx.createRadialGradient(p0._0, -p0._1, grad._1, p2._0, -p2._1, grad._3);
stops = _elm_lang$core$Native_List.toArray(grad._4);
}
var len = stops.length;
for (var i = 0; i < len; ++i)
{
var stop = stops[i];
g.addColorStop(stop._0, _evancz$elm_graphics$Text$colorToCss(stop._1));
}
return g;
}
function drawShape(redo, ctx, style, path)
{
trace(ctx, path);
setFillStyle(redo, ctx, style);
ctx.scale(1, -1);
ctx.fill();
}
// TEXT RENDERING
function fillText(redo, ctx, text)
{
drawText(ctx, text, ctx.fillText);
}
function strokeText(redo, ctx, style, text)
{
setStrokeStyle(ctx, style);
// Use native canvas API for dashes only for text for now
// Degrades to non-dashed on IE 9 + 10
if (style.dashing.ctor !== '[]' && ctx.setLineDash)
{
var pattern = _elm_lang$core$Native_List.toArray(style.dashing);
ctx.setLineDash(pattern);
}
drawText(ctx, text, ctx.strokeText);
}
function drawText(ctx, text, canvasDrawFn)
{
var textChunks = chunkText(copy(defaultFacts), text);
var totalWidth = 0;
var maxHeight = 0;
var numChunks = textChunks.length;
ctx.scale(1,-1);
for (var i = numChunks; i--; )
{
var chunk = textChunks[i];
ctx.font = chunk.font;
var metrics = ctx.measureText(chunk.text);
chunk.width = metrics.width;
totalWidth += chunk.width;
if (chunk.height > maxHeight)
{
maxHeight = chunk.height;
}
}
var x = -totalWidth / 2.0;
for (var i = 0; i < numChunks; ++i)
{
var chunk = textChunks[i];
ctx.font = chunk.font;
ctx.fillStyle = chunk.color;
canvasDrawFn.call(ctx, chunk.text, x, maxHeight / 2);
x += chunk.width;
}
}
function toFont(facts)
{
return facts['font-style']
+ ' ' + facts['font-variant']
+ ' ' + facts['font-weight']
+ ' ' + facts['font-size']
+ ' ' + facts['font-family'];
}
// Convert the object returned by the text module
// into something we can use for styling canvas text
function chunkText(facts, text)
{
switch (text.ctor)
{
case 'Append':
var leftChunks = chunkText(copy(facts), text._0);
var rightChunks = chunkText(copy(facts), text._1);
return leftChunks.concat(rightChunks);
case 'Str':
return [{
text: text._0,
color: facts['color'],
height: facts['font-size'].slice(0, -2) | 0,
font: toFont(facts)
}];
case 'Link':
return chunkText(facts, text._1);
case 'Meta':
facts[text._0] = text._1;
return chunkText(facts, text._2);
}
}
function copy(facts)
{
return {
'font-style': facts['font-style'],
'font-variant': facts['font-variant'],
'font-weight': facts['font-weight'],
'font-size': facts['font-size'],
'font-family': facts['font-family'],
'color': facts['color']
};
}
var defaultFacts = {
'font-style': 'normal',
'font-variant': 'normal',
'font-weight': 'normal',
'font-size': '12px',
'font-family': 'sans-serif',
'color': 'black'
};
// IMAGES
function drawImage(redo, ctx, form)
{
var img = new Image();
img.onload = redo;
img.src = form._3;
var w = form._0,
h = form._1,
pos = form._2,
srcX = pos._0,
srcY = pos._1,
srcW = w,
srcH = h,
destX = -w / 2,
destY = -h / 2,
destW = w,
destH = h;
ctx.scale(1, -1);
ctx.drawImage(img, srcX, srcY, srcW, srcH, destX, destY, destW, destH);
}
function renderForm(redo, ctx, form)
{
ctx.save();
var x = form.x,
y = form.y,
theta = form.theta,
scale = form.scale;
if (x !== 0 || y !== 0)
{
ctx.translate(x, y);
}
if (theta !== 0)
{
ctx.rotate(theta % (Math.PI * 2));
}
if (scale !== 1)
{
ctx.scale(scale, scale);
}
if (form.alpha !== 1)
{
ctx.globalAlpha = ctx.globalAlpha * form.alpha;
}
ctx.beginPath();
var f = form.form;
switch (f.ctor)
{
case 'FPath':
drawLine(ctx, f._0, f._1);
break;
case 'FImage':
drawImage(redo, ctx, f);
break;
case 'FShape':
if (f._0.ctor === 'Line')
{
f._1.closed = true;
drawLine(ctx, f._0._0, f._1);
}
else
{
drawShape(redo, ctx, f._0._0, f._1);
}
break;
case 'FText':
fillText(redo, ctx, f._0);
break;
case 'FOutlinedText':
strokeText(redo, ctx, f._0, f._1);
break;
}
ctx.restore();
}
function formToMatrix(form)
{
var scale = form.scale;
var matrix = A6( _evancz$elm_graphics$Transform$matrix, scale, 0, 0, scale, form.x, form.y );
var theta = form.theta;
if (theta !== 0)
{
matrix = A2(
_evancz$elm_graphics$Transform$multiply,
matrix,
_evancz$elm_graphics$Transform$rotation(theta)
);
}
return matrix;
}
function str(n)
{
if (n < 0.00001 && n > -0.00001)
{
return 0;
}
return n;
}
function makeTransform(w, h, form, matrices)
{
var props = form.form._0._0.props;
var m = A6(
_evancz$elm_graphics$Transform$matrix,
1,
0,
0,
-1,
(w - props.width ) / 2,
(h - props.height) / 2
);
var len = matrices.length;
for (var i = 0; i < len; ++i)
{
m = A2( _evancz$elm_graphics$Transform$multiply, m, matrices[i] );
}
m = A2( _evancz$elm_graphics$Transform$multiply, m, formToMatrix(form) );
return 'matrix(' +
str( m[0]) + ', ' + str( m[3]) + ', ' +
str(-m[1]) + ', ' + str(-m[4]) + ', ' +
str( m[2]) + ', ' + str( m[5]) + ')';
}
function stepperHelp(list)
{
var arr = _elm_lang$core$Native_List.toArray(list);
var i = 0;
function peekNext()
{
return i < arr.length ? arr[i]._0.form.ctor : '';
}
// assumes that there is a next element
function next()
{
var out = arr[i]._0;
++i;
return out;
}
return {
peekNext: peekNext,
next: next
};
}
function formStepper(forms)
{
var ps = [stepperHelp(forms)];
var matrices = [];
var alphas = [];
function peekNext()
{
var len = ps.length;
var formType = '';
for (var i = 0; i < len; ++i )
{
if (formType = ps[i].peekNext()) return formType;
}
return '';
}
// assumes that there is a next element
function next(ctx)
{
while (!ps[0].peekNext())
{
ps.shift();
matrices.pop();
alphas.shift();
if (ctx)
{
ctx.restore();
}
}
var out = ps[0].next();
var f = out.form;
if (f.ctor === 'FGroup')
{
ps.unshift(stepperHelp(f._1));
var m = A2(_evancz$elm_graphics$Transform$multiply, f._0, formToMatrix(out));
ctx.save();
ctx.transform(m[0], m[3], m[1], m[4], m[2], m[5]);
matrices.push(m);
var alpha = (alphas[0] || 1) * out.alpha;
alphas.unshift(alpha);
ctx.globalAlpha = alpha;
}
return out;
}
function transforms()
{
return matrices;
}
function alpha()
{
return alphas[0] || 1;
}
return {
peekNext: peekNext,
next: next,
transforms: transforms,
alpha: alpha
};
}
function makeCanvas(w, h)
{
var canvas = _evancz$elm_graphics$Native_Element.createNode('canvas');
canvas.style.width = w + 'px';
canvas.style.height = h + 'px';
canvas.style.display = 'block';
canvas.style.position = 'absolute';
var ratio = window.devicePixelRatio || 1;
canvas.width = w * ratio;
canvas.height = h * ratio;
return canvas;
}
function render(model)
{
var div = _evancz$elm_graphics$Native_Element.createNode('div');
div.style.overflow = 'hidden';
div.style.position = 'relative';
update(div, model, model);
return div;
}
function nodeStepper(w, h, div)
{
var kids = div.childNodes;
var i = 0;
var ratio = window.devicePixelRatio || 1;
function transform(transforms, ctx)
{
ctx.translate( w / 2 * ratio, h / 2 * ratio );
ctx.scale( ratio, -ratio );
var len = transforms.length;
for (var i = 0; i < len; ++i)
{
var m = transforms[i];
ctx.save();
ctx.transform(m[0], m[3], m[1], m[4], m[2], m[5]);
}
return ctx;
}
function nextContext(transforms)
{
while (i < kids.length)
{
var node = kids[i];
if (node.getContext)
{
node.width = w * ratio;
node.height = h * ratio;
node.style.width = w + 'px';
node.style.height = h + 'px';
++i;
return transform(transforms, node.getContext('2d'));
}
div.removeChild(node);
}
var canvas = makeCanvas(w, h);
div.appendChild(canvas);
// we have added a new node, so we must step our position
++i;
return transform(transforms, canvas.getContext('2d'));
}
function addElement(matrices, alpha, form)
{
var kid = kids[i];
var elem = form.form._0;
var node = (!kid || kid.getContext)
? _evancz$elm_graphics$Native_Element.render(elem)
: _evancz$elm_graphics$Native_Element.update(kid, kid.oldElement, elem);
node.style.position = 'absolute';
node.style.opacity = alpha * form.alpha * elem._0.props.opacity;
_evancz$elm_graphics$Native_Element.addTransform(node.style, makeTransform(w, h, form, matrices));
node.oldElement = elem;
++i;
if (!kid)
{
div.appendChild(node);
}
else
{
div.insertBefore(node, kid);
}
}
function clearRest()
{
while (i < kids.length)
{
div.removeChild(kids[i]);
}
}
return {
nextContext: nextContext,
addElement: addElement,
clearRest: clearRest
};
}
function update(div, _, model)
{
var w = model.w;
var h = model.h;
var forms = formStepper(model.forms);
var nodes = nodeStepper(w, h, div);
var ctx = null;
var formType = '';
while (formType = forms.peekNext())
{
// make sure we have context if we need it
if (ctx === null && formType !== 'FElement')
{
ctx = nodes.nextContext(forms.transforms());
ctx.globalAlpha = forms.alpha();
}
var form = forms.next(ctx);
// if it is FGroup, all updates are made within formStepper when next is called.
if (formType === 'FElement')
{
// update or insert an element, get a new context
nodes.addElement(forms.transforms(), forms.alpha(), form);
ctx = null;
}
else if (formType !== 'FGroup')
{
renderForm(function() { update(div, model, model); }, ctx, form);
}
}
nodes.clearRest();
return div;
}
function collage(w, h, forms)
{
return A3(_evancz$elm_graphics$Native_Element.newElement, w, h, {
ctor: 'Custom',
type: 'Collage',
render: render,
update: update,
model: {w: w, h: h, forms: forms}
});
}
return {
collage: F3(collage)
};
}();