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var CShape = function(context, usePathObject) {
this._context = context;
if (usePathObject)
this._path = new Path2D();
else
this._path = context;
};
CShape.prototype.usePathObject = function() {
return this._path instanceof Path2D;
};
CShape.prototype.createShape = function() {
// override
};
CShape.prototype.draw = function() {
var context = this._context;
var path = this._path;
context.beginPath();
this.createShape();
if (this.usePathObject())
context.stroke(path);
else
context.stroke();
};
CShape.prototype.scroll = function() {
var context = this._context;
var path = this._path;
if (this.usePathObject())
context.scrollPathIntoView(path);
else
context.scrollPathIntoView();
};
var overrideShape = function(overrideMethod) {
var shape = function() {
CShape.apply(this, arguments);
};
shape.prototype = new CShape;
shape.prototype.createShape = overrideMethod;
return shape;
};
var CRect = overrideShape(function() {
var path = this._path;
path.rect(-50, -50, 100, 100);
});
var CCapsule = overrideShape(function() {
var path = this._path;
path.arc(-35, 0, 50, Math.PI / 2, Math.PI * 1.5, false);
path.lineTo(35, -50);
path.arc(50, 0, 50, Math.PI * 1.5, Math.PI / 2, false);
path.lineTo(-35, 50);
});
var CStar = overrideShape(function() {
var path = this._path;
path.moveTo(0, -50);
path.lineTo(-15, -10);
path.lineTo(-50, -10);
path.lineTo(-15, 10);
path.lineTo(-35, 50);
path.lineTo(0, 20);
path.lineTo(35, 50);
path.lineTo(15, 10);
path.lineTo(50, -10);
path.lineTo(15, -10);
path.lineTo(0, -50);
});
var CCurve = overrideShape(function() {
var path = this._path;
path.moveTo(-50, -50);
path.bezierCurveTo(-50, 10, 50, 10, 50, 50);
});
var container = document.querySelector("div[class='container']");
var canvas = document.querySelector("canvas");
var context = canvas.getContext("2d");
function getRealValue(shape, degree, usePathObject) {
// reset scroll
container.scrollTop = 0;
container.scrollLeft = 0;
// draw shape stroke on canvas
usePathObject = usePathObject == undefined || usePathObject == null ? false : true;
var s = new shape(context, usePathObject);
context.clearRect(0, 0, 400, 400);
context.save();
context.translate(200, 200);
if (degree != 0 && degree != undefined && degree != null)
context.rotate(Math.PI / 180 * degree);
s.draw();
s.scroll();
context.stroke();
context.restore();
return container.scrollTop;
}
function scrollTest(shape, degree, usePathObject, expectedValue) {
var classes = [ "", "border", "padding", "padding border", "margin" ];
var offset = [ 0, 500, 500, 1000, 500 ];
for (var i = 0; i < classes.length; i++) {
canvas.className = classes[i];
window.testValue = getRealValue(shape, degree, usePathObject);
shouldBe("testValue", String(expectedValue + offset[i]));
}
}
description("Series of tests to ensure correct results of scrolling path into view on canvas");
debug("Test case 1: scrollPathIntoView() / CTM == identity");
scrollTest(CRect, 0, false, 150);
scrollTest(CCapsule, 0, false, 150);
scrollTest(CCurve, 0, false, 150);
scrollTest(CStar, 0, false, 150);
debug("");
debug("Test case 2: scrollPathIntoView() / CTM != identity");
scrollTest(CRect, 20, false, 136);
scrollTest(CCapsule, 42, false, 106);
scrollTest(CCurve, 63, false, 133);
scrollTest(CStar, 40, false, 160);
debug("");
debug("Test case 3: scrollPathIntoView(path2d) / CTM == identity");
scrollTest(CRect, 0, true, 150);
scrollTest(CCapsule, 0, true, 150);
scrollTest(CCurve, 0, true, 150);
scrollTest(CStar, 0, true, 150);
debug("");
debug("Test case 4: scrollPathIntoView(path2d) / CTM != identity");
scrollTest(CRect, 20, true, 136);
scrollTest(CCapsule, 42, true, 106);
scrollTest(CCurve, 63, true, 133);
scrollTest(CStar, 40, true, 160);
debug("");
debug("Test case 5: exceptions");
shouldThrow("context.scrollPathIntoView(null);");
shouldThrow("context.scrollPathIntoView([]);");
shouldThrow("context.scrollPathIntoView({});");
debug("");
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